From tvb at LeapSecond.com  Sat Nov  1 00:30:31 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 31 Oct 2008 17:30:31 -0700
Subject: [time-nuts] beautiful jump
References: <cd8.3ca64b57.363ca16a@aol.com>
Message-ID: <005c01c93bb9$0d4739d0$80490a0a@pc52>

> So I wonder if we have one of the most sensitive gravitational sensors out  
> there :)

Before you go there it would be good to isolate a few other
factors. First, let the unit free-run and see if there are still
jumps in the OCXO as compared to a local standard (Rb
or Cs or even another GPSDO).

Also, Said, can you tell from this unit's gpsstat if there is an
interaction between the coarse and the fine DAC?

I see in the colima.htm file the EFC went from 2.80299 to
2.80034. What the Hz/V for this unit? I.e., how many ppb
was this jump?

/tvb



From SAIDJACK at aol.com  Sat Nov  1 00:56:11 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Fri, 31 Oct 2008 20:56:11 EDT
Subject: [time-nuts] beautiful jump
Message-ID: <ce7.3d7643c9.363d032b@aol.com>

Hi Tom,
 
the fine dac on that unit has a 40mV range with hysteresis, the  coarsedac 
will not have been affected. I believe the 2.7mV change on the  large jump had 
an effect of approx. 2ppb frequency change.
 
The second jump of approx. 80 microvolts had only about 6E-011 change in  
frequency, that's enough to make the graph show a nice jump thanks to the GPS  
reference.
 
We need to keep in perspective just how small some of these jumps are, but  
even the small one still shows up as a 29ns deviation on the 1PPS lock..
 
bye,
Said
 
 
In a message dated 10/31/2008 17:31:15 Pacific Daylight Time,  
tvb at LeapSecond.com writes:

Also,  Said, can you tell from this unit's gpsstat if there is an
interaction  between the coarse and the fine DAC?

I see in the colima.htm file the  EFC went from 2.80299 to
2.80034. What the Hz/V for this unit? I.e., how  many ppb
was this  jump?

/tvb



From SAIDJACK at aol.com  Sat Nov  1 01:21:59 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Fri, 31 Oct 2008 21:21:59 EDT
Subject: [time-nuts] beautiful jump
Message-ID: <cb7.40a0c30d.363d0937@aol.com>

Hi Tom,
 
I did the math, and I think the closest voltage that a coarsedac  change may 
occur on the big jump would be 2.80855.
 
For sure the small jump is not a coarsedac change because the unit had  
already exceeded that voltage by several millivolts without any disturbance  (when 
the first jump happened the voltage was higher).
 
According to Murphy anything could happen of course :)
 
bye,
Said
 
 
In a message dated 10/31/2008 17:31:15 Pacific Daylight Time,  
tvb at LeapSecond.com writes:

Also,  Said, can you tell from this unit's gpsstat if there is an
interaction  between the coarse and the fine  DAC?



From richiem at hughes.net  Sat Nov  1 02:26:10 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 31 Oct 2008 19:26:10 -0700
Subject: [time-nuts] LP filter on EFC line
In-Reply-To: <mailman.70.1225500990.13535.time-nuts@febo.com>
References: <mailman.70.1225500990.13535.time-nuts@febo.com>
Message-ID: <03B0725A-34A0-4C88-A145-E122E03DC9F3@hughes.net>

Bruce, thanks for the tip on the anti-charge injection LP filter.  
Actually, early on, I put a 0.1uF cap across the EFC line on the osc,  
support board, so there is some LP filtering working there. But my  
old Tektronix "prayer wheel" Circuit Computer says that's only a 5ms  
TC -- prolly need quite a bit more or else buffer the EFC line from  
the DPM.

Best,
Dick Moore


On Oct 31, 2008, at 5:56 PM, time-nuts-request at febo.com wrote:

> ------------------------------
>
> Message: 6
> Date: Sat, 01 Nov 2008 11:00:59 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] OFC OCXO
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <490B801B.2060900 at xtra.co.nz>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Richard Moore wrote:
>> Hi Ernie -- thx for the feedback. I have had all of those effects and
>> more with an HP10811A and an EG&G Cinox version of the 10811A, so I
>> won't be surprised to see such things with this one either. I'm going
>> to try it with Bert Zauhar's FLL controller to see how it runs. You
>> can visit my experience to date at:
>>   www.moorepage.net/gps2.html
>>
>> I'll update the site again after I run the OFC for a while.
>>
>> Best,
>> Dick Moore
>>
> Dick
>
> The usual way of reducing charge injection transients from a DVM into
> the circuit being measured is to use an RC low pass filter between the
> circuit and THE DVM.
> Charge injection can be somewhat larger for those autozeroing DVMs  
> that
> do not use a precharge amplifier to reduce the effect.
> panel mount DVMs do not usually have a precharge amplifier.
>
> With a low pass filter it may be possible to reduce the value of  
> the 50K
> isolation resistor that you used.
> The value is relatively high because it relies on the DVM and wiring
> capacitance as the capacitive part of the RC low pass filter.
>
> Bruce
>


From bruce.griffiths at xtra.co.nz  Sat Nov  1 02:52:02 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sat, 01 Nov 2008 15:52:02 +1300
Subject: [time-nuts] LP filter on EFC line
In-Reply-To: <03B0725A-34A0-4C88-A145-E122E03DC9F3@hughes.net>
References: <mailman.70.1225500990.13535.time-nuts@febo.com>
	<03B0725A-34A0-4C88-A145-E122E03DC9F3@hughes.net>
Message-ID: <490BC452.4040503@xtra.co.nz>

Richard Moore wrote:
> Bruce, thanks for the tip on the anti-charge injection LP filter.  
> Actually, early on, I put a 0.1uF cap across the EFC line on the osc,  
> support board, so there is some LP filtering working there. But my  
> old Tektronix "prayer wheel" Circuit Computer says that's only a 5ms  
> TC -- prolly need quite a bit more or else buffer the EFC line from  
> the DPM.
>
> Best,
> Dick Moore
>
>
> On Oct 31, 2008, at 5:56 PM, time-nuts-request at febo.com wrote:
>
>   
Dick

Something like 1K, 10k, 100K in series with the Hi lead and 1nF, 10nF or
100nF to ground at the DPM end of the resistor.
With a floating DPM also need 1k, 10K, 100K series resistor with 10nF,
100nF or even 1uF to ground at the DPM end of the resistor.

Exact values and time constants required depend on the DPM and circuit
characteristics.
You will need to do the experiments to find out which combinations work
best.

Even with a buffer an output low pass RC filter will help.

Bruce


From grant at ghengineering.co.uk  Sat Nov  1 11:10:07 2008
From: grant at ghengineering.co.uk (Grant Hodgson)
Date: Sat, 01 Nov 2008 11:10:07 +0000
Subject: [time-nuts] 53310A
In-Reply-To: <mailman.44.1225409687.13535.time-nuts@febo.com>
References: <mailman.44.1225409687.13535.time-nuts@febo.com>
Message-ID: <490C390F.8070906@ghengineering.co.uk>

Henk

Yes, that worked - it was the reference bit that I didn't get - I 
thought the signal source - er - had a signal source in it.  Many thanks.

The 53310A seems to be a fairly competent Time Interval Counter; I 
wonder if anybody is using it for ADEV measurements or other 
applications apart from measuring VCOs and synthesisers (which are the 
markets it was aimed at)?  The big display and markers certainly make 
for a very nice instrument.

regards

Grant

Hi,
1. connect as shown on the Quick Start Signal Source.
2. Signal source ON,
3. select Frequency Modulation,
4. press Autoscale.

This should give a sine on the display.
Does this work? If yes I will make a scan of the manual.
My Quick Start Signal Source is still alive.
How about your eprom?

regards,

Henk


From True-Cal at swbell.net  Sat Nov  1 18:18:29 2008
From: True-Cal at swbell.net (Don @ True-Cal)
Date: Sat, 1 Nov 2008 13:18:29 -0500
Subject: [time-nuts] Test
References: <mailman.44.1225409687.13535.time-nuts@febo.com>
	<490C390F.8070906@ghengineering.co.uk>
Message-ID: <C7A8EE840B2144D9B361F861C5BD8437@proxy>

Test Message

Parden the clutter but having problems posting

Don

From stanley_reynolds at yahoo.com  Sat Nov  1 19:52:06 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Sat, 1 Nov 2008 12:52:06 -0700 (PDT)
Subject: [time-nuts] firmware bug ??? ( Trak Systems 8820 GPS Station )
References: <d60.38513f29.36390729@aol.com>
Message-ID: <108634.6659.qm@web30307.mail.mud.yahoo.com>

Trak Systems 8820 GPS Station 

Made some progress, LCD was repaired by several cleanings with a lint free cloth and alcohol of the PCB to display contact and careful realignment on assembly. Also removed flat washers which were causing a short between board and case.

The Laser jet III display was very similar but the connector was wrong so it is not the same.

My next issue is the RS232 ports which do not appear to work. The closest socket to the RS232 remote I/O connector is empty, it is a 16pin DIP labeled U42. Also in the area is three sockets for the GPIB option which are also missing. My best guess is that U42 is used to customize the interface Hardware handshake and DTE or DCE so maybe I need a jumper block ?

I can enter the correct date as MM/DD/YY but it is displayed as 1908 not 2008. As soon as the unit has tracking and locked the date is updated back to March 1989 and the number of days in the display is wrong again. If I don't find an updated firmware to fix the date then may have to hack the main processor eprom to fix the date. A simple fix would be to inhibit the date update and allow hour, minute, second GPS update. Would have to insure the date would roll at 24:00. If so?the patch could correct the number of days except for leap years and I can keep the Magnovox GPS.

The GPS DO section is working fine as the PPS signal is unaffected by date issues.

Would like to have some info on the Magnovox engine like pin out so if it does need replacement I can make the mods to the interface board.

Stanley

From hmurray at megapathdsl.net  Sat Nov  1 20:45:58 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sat, 01 Nov 2008 13:45:58 -0700
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: Message from "Steve Rooke" <sar10538@gmail.com> of "Fri,
	31 Oct 2008 08:01:45 +1300."
	<1231b6a80810301201x70634b43j4b7dd52a890648d4@mail.gmail.com> 
Message-ID: <20081101204559.ACB92BCD5@ip-64-139-1-69.sjc.megapath.net>


> When I communicate with the US, I have to work out which time-zone the
> place I'm talking to is in and correct for that. It's probably not so
> much of a problem for someone in America  as you get used to the
> time-zone differences but this adds complexity for an outsider. I just
> wondered if it would add global communications and buisiness to have a
> single World standard.

A single World standard won't change the problem, just push it around.  
Suppose you live in London and I ran my watch (and life) on UTC.  When should 
you call me?  You have to figure out when I'm at work.  With time zones, you 
can assume that normal working hours are 9-5, local time.  If I'm running on 
UTC, I'll shift my working hours to be local daytime.  If you want to call 
me, you have to figure out when I'm at work, how far I shifted my life 
relative to your time.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From hmurray at megapathdsl.net  Sat Nov  1 20:49:01 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sat, 01 Nov 2008 13:49:01 -0700
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: Message from "Lux, James P" <james.p.lux@jpl.nasa.gov> of "Thu,
	30 Oct 2008 12:17:07 PDT."
	<ECE7A93BD093E1439C20020FBE87C47FEB55C2FFA7@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>


> One can, of course, observe meridian passage for a variety of stars at
> night, and from that determine the time (given a calendar and the
> appropriate almanac data), so you could directly observe midnight. 

What does "directly observe" mean?

Stars aren't conveniently located where I want them.  I think I'd have to do 
something like time when a star that's close to midnight crosses a 
north-south line in the sky that's above my location.  So in addition to the 
almanac, I also need a (good?) compass.

Maybe I don't understand how navigation by sextant works.  They get latitude 
from the elevation of the sun above the horizon.  Do they also get time 
(local noon) by noting when the sun is highest?  I think that would be hard 
to do since you are looking for the peak of a sine curve.  That has a broad 
flat top.  There isn't any conspicuous peak.  Do the numbers work out?  Can I 
get the peak close enough to be useful for navigation?


> Don't forget too, that solar noon varies quite a bit (minutes) from
> "mean solar time" over the year.  If you're navigating your ship with
> noon sun sights, this is pretty important. 

What do I google for if I want that correction?

There are quite a few time scales.  Which one do navigators use?



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From brooke at pacific.net  Sat Nov  1 21:06:11 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 01 Nov 2008 14:06:11 -0700
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <490CC4C3.9090707@pacific.net>

Hi Hal:

A sextant is just an angle measuring instrument so can be used in a number of 
ways.  The classical way is to measure the elevation angle of any heavenly 
that's in your almanac.  Note you can determine your latitude from any of these 
elevation measurements.

The method called "lunar distance" is a more accurate way to get a position fix 
than the classical elevation method.  It requires the sextant be used at odd 
angles relative to the horizon, even horizontal to measure the separation of a 
star and the moon.

Have Fun,

Brooke Clarke
http://www.prc68.com/P/Prod.html  Products I make and sell
http://www.prc68.com/Alpha.shtml  All my web pages listed based on html name
http://www.PRC68.com
http://www.precisionclock.com
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam

Hal Murray wrote:
>> One can, of course, observe meridian passage for a variety of stars at
>> night, and from that determine the time (given a calendar and the
>> appropriate almanac data), so you could directly observe midnight. 
> 
> What does "directly observe" mean?
> 
> Stars aren't conveniently located where I want them.  I think I'd have to do 
> something like time when a star that's close to midnight crosses a 
> north-south line in the sky that's above my location.  So in addition to the 
> almanac, I also need a (good?) compass.
> 
> Maybe I don't understand how navigation by sextant works.  They get latitude 
> from the elevation of the sun above the horizon.  Do they also get time 
> (local noon) by noting when the sun is highest?  I think that would be hard 
> to do since you are looking for the peak of a sine curve.  That has a broad 
> flat top.  There isn't any conspicuous peak.  Do the numbers work out?  Can I 
> get the peak close enough to be useful for navigation?
> 
> 
>> Don't forget too, that solar noon varies quite a bit (minutes) from
>> "mean solar time" over the year.  If you're navigating your ship with
>> noon sun sights, this is pretty important. 
> 
> What do I google for if I want that correction?
> 
> There are quite a few time scales.  Which one do navigators use?
> 
> 
> 


From bruce.griffiths at xtra.co.nz  Sat Nov  1 21:28:02 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 02 Nov 2008 10:28:02 +1300
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <490CC9E2.50100@xtra.co.nz>

Hal Murray wrote:
>> One can, of course, observe meridian passage for a variety of stars at
>> night, and from that determine the time (given a calendar and the
>> appropriate almanac data), so you could directly observe midnight. 
>>     
>
> What does "directly observe" mean?
>
> Stars aren't conveniently located where I want them.  I think I'd have to do 
> something like time when a star that's close to midnight crosses a 
> north-south line in the sky that's above my location.  So in addition to the 
> almanac, I also need a (good?) compass.
>
>   
A compass isn't actually required for determining the meridian.
If you have located the Meridian and have identified the star, then its
not necessary to use one that has a meridan transit at local midnight.
In any event if you dont know exactly where you are identifying local
midnight may be problematic.
A PZT or equivalent may be easier to setup.

> Maybe I don't understand how navigation by sextant works.  They get latitude 
> from the elevation of the sun above the horizon.  Do they also get time 
> (local noon) by noting when the sun is highest?  I think that would be hard 
> to do since you are looking for the peak of a sine curve.  That has a broad 
> flat top.  There isn't any conspicuous peak.  Do the numbers work out?  Can I 
> get the peak close enough to be useful for navigation?
>
>
>   
An accurate watch or equivalent source of UTC is required.
Various techniques for determining the time from Astronomical
observations are somewhat impractical at sea.
>> Don't forget too, that solar noon varies quite a bit (minutes) from
>> "mean solar time" over the year.  If you're navigating your ship with
>> noon sun sights, this is pretty important. 
>>     
>
> What do I google for if I want that correction?
>
>   
Googling isnt a reliable technique for marine navigation, at least
during the journey.
> There are quite a few time scales.  Which one do navigators use?
>   

UTC is usually required in the calculations, as it is (currently)
closely tied to the Earth's orientation angle.

Bruce


From True-Cal at swbell.net  Sat Nov  1 21:29:26 2008
From: True-Cal at swbell.net (Don @ True-Cal)
Date: Sat, 1 Nov 2008 16:29:26 -0500
Subject: [time-nuts] ADEV and Tau-0 guestion
References: <mailman.44.1225409687.13535.time-nuts@febo.com><490C390F.8070906@ghengineering.co.uk>
	<C7A8EE840B2144D9B361F861C5BD8437@proxy>
Message-ID: <9CFE8786F6CD467BA1E84172D3C2EFA0@proxy>

Fellow Time-Nuts,

I am having great fun with Ulrich's EZGPIB and Plotter programs to automate my ADEV and TI measurements. Wow, what a nice set of programs, thanks Ulrich!

I use the SR620 TIC with a Fury board as an external reference. The Fury disciplines an 10811-60168 external oscillator. I can go unlocked to improve the range around Tau 100s if and when necessary. For a series of tests, I used an LPRO-101 10Mhz signal to drive B-Ch (Stop) of the SR620; the A-Ch (Start) was set to Ref. for a Zero-Crossing TIME measurement on the TIC. I streamlined the EZGPIB SR620 query program and experimented with counter settings to minimize the inevitable and inherent latencies of the computer layers, network, GPIB-Enet/100 bridge and the counter (counter being the worst). With the counter set to 100 samples and the 1KHz "Ref" being used as the START, I was expecting a new, 100 sample TI average, every 0.1 seconds. My first evidence of something not being ideal was embedded in the details of the EZGPIB output console and accompanying file. Sometimes there were 7, 8 or 9 samples per second of time and never 10. Also, the total time span of a large collection of samples was always slightly longer than the product of the sample rate and count. I used Excel to scan 18000, 0.1s TI samples to determine what the actual statistics might be:

Average = 0.122302796 sec
Min = 0.188015099 sec
Max = 0.108984648 sec

Since the ADEV function as well as Ulrich's Plotter program requires a constant Tau-0, I experimented with the nominal 0.1s and the real "average" of 0.1223s Tau-0 setting and attached a graph that illustrates the variance across Tau. My question is; what is "acceptable" practice for defining Tau-0 when the likelihood of having a stable sampling interval is difficult. It was rather simple to specify a more accurate time sample interval once determined by the extra step of spreadsheet analysis and the effect on the results is obvious. But that is still, only an average. What about the effect of the deviation about the average value? It would seem that would be a much more complex issue to deal with.

See attached export or Plotter graphic.

Regards...
Don
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From brooke at pacific.net  Sat Nov  1 21:48:54 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 01 Nov 2008 14:48:54 -0700
Subject: [time-nuts] ADEV and Tau-0 guestion
In-Reply-To: <9CFE8786F6CD467BA1E84172D3C2EFA0@proxy>
References: <mailman.44.1225409687.13535.time-nuts@febo.com><490C390F.8070906@ghengineering.co.uk>	<C7A8EE840B2144D9B361F861C5BD8437@proxy>
	<9CFE8786F6CD467BA1E84172D3C2EFA0@proxy>
Message-ID: <490CCEC6.9070908@pacific.net>

Hi Don:

If you want to average many (100, 1000) reads in one second you need to use the 
ARM function as described in appendix B of the PRS10 manual.
http://www.prc68.com/I/PRS10.shtml

Have Fun,

Brooke Clarke
http://www.prc68.com/P/Prod.html  Products I make and sell
http://www.prc68.com/Alpha.shtml  All my web pages listed based on html name
http://www.PRC68.com
http://www.precisionclock.com
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam

Don @ True-Cal wrote:
> Fellow Time-Nuts,
> 
> I am having great fun with Ulrich's EZGPIB and Plotter programs to automate my ADEV and TI measurements. Wow, what a nice set of programs, thanks Ulrich!
> 
> I use the SR620 TIC with a Fury board as an external reference. The Fury disciplines an 10811-60168 external oscillator. I can go unlocked to improve the range around Tau 100s if and when necessary. For a series of tests, I used an LPRO-101 10Mhz signal to drive B-Ch (Stop) of the SR620; the A-Ch (Start) was set to Ref. for a Zero-Crossing TIME measurement on the TIC. I streamlined the EZGPIB SR620 query program and experimented with counter settings to minimize the inevitable and inherent latencies of the computer layers, network, GPIB-Enet/100 bridge and the counter (counter being the worst). With the counter set to 100 samples and the 1KHz "Ref" being used as the START, I was expecting a new, 100 sample TI average, every 0.1 seconds. My first evidence of something not being ideal was embedded in the details of the EZGPIB output console and accompanying file. Sometimes there were 7, 8 or 9 samples per second of time and never 10. Also, the total time span of a large coll
ection of samples was always slightly longer than the product of the sample rate and count. I used Excel to scan 18000, 0.1s TI samples to determine what the actual statistics might be:
> 
> Average = 0.122302796 sec
> Min = 0.188015099 sec
> Max = 0.108984648 sec
> 
> Since the ADEV function as well as Ulrich's Plotter program requires a constant Tau-0, I experimented with the nominal 0.1s and the real "average" of 0.1223s Tau-0 setting and attached a graph that illustrates the variance across Tau. My question is; what is "acceptable" practice for defining Tau-0 when the likelihood of having a stable sampling interval is difficult. It was rather simple to specify a more accurate time sample interval once determined by the extra step of spreadsheet analysis and the effect on the results is obvious. But that is still, only an average. What about the effect of the deviation about the average value? It would seem that would be a much more complex issue to deal with.
> 
> See attached export or Plotter graphic.
> 
> Regards...
> Don
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


From james.p.lux at jpl.nasa.gov  Sat Nov  1 21:55:24 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Sat, 1 Nov 2008 14:55:24 -0700
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <490CC9E2.50100@xtra.co.nz>
Message-ID: <C5321E5C.23E4%James.P.Lux@jpl.nasa.gov>




On 11/1/08 2:28 PM, "Bruce Griffiths" <bruce.griffiths at xtra.co.nz> wrote:

> Hal Murray wrote:
>>> One can, of course, observe meridian passage for a variety of stars at
>>> night, and from that determine the time (given a calendar and the
>>> appropriate almanac data), so you could directly observe midnight.
>>>
>>
>> What does "directly observe" mean?
>>
>> Stars aren't conveniently located where I want them.  I think I'd have to do
>> something like time when a star that's close to midnight crosses a
>> north-south line in the sky that's above my location.  So in addition to the
>> almanac, I also need a (good?) compass.

If you're in the northern hemisphere (sorry Bruce..) one can easily know
where north is, to within a fraction of a degree (because Polaris doesn't
move much).

One could conceivably measure several stars and figure it out, too.



>>
>>
> A compass isn't actually required for determining the meridian.

True.. Presuming one has plenty of time, you could use the sun to determine
meridian (but that makes the whole thing sort of circular..)


> If you have located the Meridian and have identified the star, then its
> not necessary to use one that has a meridan transit at local midnight.
> In any event if you dont know exactly where you are identifying local
> midnight may be problematic.
> A PZT or equivalent may be easier to setup.
>
>> Maybe I don't understand how navigation by sextant works.  They get latitude
>> from the elevation of the sun above the horizon.  Do they also get time
>> (local noon) by noting when the sun is highest?  I think that would be hard
>> to do since you are looking for the peak of a sine curve.  That has a broad
>> flat top.

That's exactly what you do. Actually, you can make several measurements with
a local clock of unknown offset, and fit the elevation angles to the
approximately sinusoidal curve and solve for the peak.  That would solve for
your clock's offset from local solar noon.

You can measure elevation angles to several stars and solve a system of
equations. Still won't give you absolute time, though.  You need to measure
the stars AND something that moves against them (sun or moon) to solve for
everything.  There's a whole literature on doing celestial nav with star
trackers. Check out the papers by Kaplan.

  There isn't any conspicuous peak.  Do the numbers work out?  Can I
>> get the peak close enough to be useful for navigation?

What's useful?  If you're doing shadow and stick style navigation on foot,
and you can wait several hours, you can do bisection of angle sorts of
schemes using only geometry and no clock to determine north to better than a
degree.  The limiting factor for solar measurements without optical assist
is that the sun is 1/2 degree wide, so the shadow is indistinct.  A sextant
has a dark filter so you can pick one edge(limb) of the sun to use as a
reference point.


>>
>>
>>
> An accurate watch or equivalent source of UTC is required.
> Various techniques for determining the time from Astronomical
> observations are somewhat impractical at sea.

Not that impractical, because they were used for centuries.  Granted
Harrison's clock helped a lot, but lots of navigators used other techniques
well into the beginning of the 20th century.

The method of lunar distances is probably the most common "non-clock" means
for determining time. You measure the angular distance from the moon to
various stars (or look for occultations).  Since the moon moves about 15
degrees per day against the sky, one degree is a bit more (24/15ths) than an
hour.  If you can measure to a minute of arc, you're in the minutes of time
area, which corresponds to roughly 1 mile of nav precision (1 minute of
latitude = 1 nautical mile).  Not enough to do a narrow ship channel, but
good enough to not miss the island you're looking for.

You can also measure time by looking at Jupiter's moons.

>>> Don't forget too, that solar noon varies quite a bit (minutes) from
>>> "mean solar time" over the year.  If you're navigating your ship with
>>> noon sun sights, this is pretty important.
>>>
>>
>> What do I google for if I want that correction?

You carry a copy of the Nautical Almanac which sets you back about $20 in
paperback. This is a "motion of the heavens" thing, so it can be calculated
too.  Check out the paper about navigation using the analemma (google for
it).. The author demonstrates navigation using only the analemma and a slide
rule for calculation.
>>
>>
> Googling isnt a reliable technique for marine navigation, at least
> during the journey.
>> There are quite a few time scales.  Which one do navigators use?
>>
>
> UTC is usually required in the calculations, as it is (currently)
> closely tied to the Earth's orientation angle.

Folks use what ever their almanac/emphemeris tables are based on.
Historically GMT (Rule Britannia!) now UTC (because the Cassinis measured
the meter).

---

If you want to spend an interesting $20 or so, get the CD from the Institute
of Navigation (ION) with all the celestial nav papers on it.  All sorts of
stuff about how they go about printing the nautical almanac (an early use of
computer driven phototypesetting), to speculations about Columbus's
navigation, etc.

Another thing is to buy a cheap plastic sextant, an almanac (or use the
online ones) and sight reduction tables, and do some celestial nav in your
backyard. (I got within about 10km the first time I tried it).

A lot of the complexity in celestial nav is in trying to make the conversion
of sight to position doable without anything more than adding and
subtracting, so that's what the tables are. Essentially precomputed
solutions.



From brice at weaponeer.com  Sat Nov  1 22:23:35 2008
From: brice at weaponeer.com (brice at weaponeer.com)
Date: Sat, 01 Nov 2008 22:23:35 +0000
Subject: [time-nuts] Firmware bug /TRAK
Message-ID: <W7768110348235131225578215@webmail45>

I found the Magnavox board I have. Magnavox GPS Engine,meauures about 6.5 x 2.5 inches. 900578-801-6 / 40613463 (looks like) E320R
basicly, 900578. Came out of some oilfield electro-junk I bought from Exxon Houston a few years ago. Same thing????? Cheers, Bill


From tomknox at nist.gov  Sat Nov  1 22:29:22 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Sat, 01 Nov 2008 18:29:22 -0400
Subject: [time-nuts] Efratom MRT schematic
In-Reply-To: <20081031.140717.3856.2.cdelect@juno.com>
References: <20081031.140717.3856.2.cdelect@juno.com>
Message-ID: <20081101182922.23662tfmwckg8dvm@webmail.nist.gov>

Hi Time-Nuts
I am new to this group, but have been aware of Time-Nuts for years.
Someone may already have done this, but if not we should host a data  
base of manuals and notes for time and freq products and perhaps data  
on different products members have characterized. I would be willing  
to share any manuals I have and pitch in a little towards a hosting  
site to build on what is already an invaluable resource.
Best Wishes;
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting "Corby Dawson" <cdelect at juno.com>:

> Hi,
>
> I'm working on an Efratom MRT rubidium standard and I need the power
> supply schematic.
>
> Everything is working OK except the battery charge circuit is not
> working.
>
> With good batteries you can pull the AC cord and it runs on the batteries
> OK, but then when you plug the AC back in the charge current (with very
> discharged batteries) is very low. The batteries charge fine if a bench
> supply is used instead of the MRT supply.
>
> Anyone have a copy of the manual or can supply the schematic of the power
> supply and charger?
>
> Thanks,
>
> Corby Dawson
> ____________________________________________________________
> Criminal Lawyers - Click here.
> http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3oGdgUSMCXb8nALpcWDYwVWGvlod18EcSO0mdpEPQlyYZoHX/
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



From wsplawn at worldnet.att.net  Sat Nov  1 22:34:17 2008
From: wsplawn at worldnet.att.net (Wayne Splawn)
Date: Sat, 1 Nov 2008 15:34:17 -0700
Subject: [time-nuts] Looking for CINOX or EG&G Frequency Products 10 mHz
	OCXO pinout
Message-ID: <9C972C4711E948CDB7163B7EAC254390@OMAHA>

I recently acquired a CINOX OCXO.  Listed on the label is P/N 0950-0411,
Model H-128.  Measures 3.25"x2"x2".  SMC connector and four pins on one end
of the can.  
 
Any information on the pinout & voltage would be most appreciated.
 
Thank you & 73
Wayne - wa7ne

From ghane0 at gmail.com  Sat Nov  1 22:50:12 2008
From: ghane0 at gmail.com (Sanjeev Gupta)
Date: Sun, 2 Nov 2008 06:50:12 +0800
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <james.p.lux@jpl.nasa.gov>
	<ECE7A93BD093E1439C20020FBE87C47FEB55C2FFA7@ALTPHYEMBEVSP20.RES.AD.JPL>
	<20081101204902.798D7BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <158106a0811011550o28995c64wde500a00463704e6@mail.gmail.com>

On Sun, Nov 2, 2008 at 4:49 AM, Hal Murray <hmurray at megapathdsl.net> wrote:

> > Don't forget too, that solar noon varies quite a bit (minutes) from
> > "mean solar time" over the year.  If you're navigating your ship with
> > noon sun sights, this is pretty important.
>
> What do I google for if I want that correction?
>

Equation of Time.  http://en.wikipedia.org/wiki/Equation_of_time


> There are quite a few time scales.  Which one do navigators use?
>

Whichever were used in the almanac they are using.  That is the point of the
almanacs and compilations of tables, to have "reference frames" in which
(nearly) pre-computed solutions are listed.


-- 
Sanjeev Gupta
+65 98551208

From bruce.griffiths at xtra.co.nz  Sat Nov  1 23:02:45 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 02 Nov 2008 12:02:45 +1300
Subject: [time-nuts] Efratom MRT schematic
In-Reply-To: <20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
References: <20081031.140717.3856.2.cdelect@juno.com>
	<20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
Message-ID: <490CE015.5000200@xtra.co.nz>

tomknox at nist.gov wrote:
> Hi Time-Nuts
> I am new to this group, but have been aware of Time-Nuts for years.
> Someone may already have done this, but if not we should host a data  
> base of manuals and notes for time and freq products and perhaps data  
> on different products members have characterized. I would be willing  
> to share any manuals I have and pitch in a little towards a hosting  
> site to build on what is already an invaluable resource.
> Best Wishes;
> Thomas Knox
> NIST
> 4475 Whitney Place
> Boulder Colorado 80305
> 1-303-554-0307
> tomknox at nist.gov
>
>
>   
Thomas

Didier already hosts a collection of manuals on his site:

www.ko4bb.com <http://www.k04bb.com>

Bruce


From True-Cal at swbell.net  Sat Nov  1 23:17:40 2008
From: True-Cal at swbell.net (Don @ True-Cal)
Date: Sat, 1 Nov 2008 18:17:40 -0500
Subject: [time-nuts] ADEV and Tau-0 guestion
References: <mailman.44.1225409687.13535.time-nuts@febo.com><490C390F.8070906@ghengineering.co.uk>	<C7A8EE840B2144D9B361F861C5BD8437@proxy><9CFE8786F6CD467BA1E84172D3C2EFA0@proxy>
	<490CCEC6.9070908@pacific.net>
Message-ID: <7D699481C19B4D0CAFD6844ED858A31E@proxy>

Hi Brooke,

Yes, I am aware of appendix B procedure. I am using that exact setup with the exception of how I feed A-Ch. Not sure why, but I get less jitter of 5-7ps when I use the "Source" Ref feature to feed the external reference derived 1KHz to the A-Ch. When I use the BNC "T" method, I see about 10-12ps jitter. For all practical purposes, I am setup like appendix B and I use the ARMing mode as described.

All that said. The problem is when I try to do back to back GPIB MEAS? reads of the counter, the request and reply datum and subsequent time stamp is not real predictable. The end goal here is not to adjust the UUT to an accurate frequency as covered in appendix B but rather to build a list of time deviations with a consistent sampling rate to feed to the Plotter program. If I use an ARM sample of 1000 (1.0 sec), I see pretty good stability, less at 100 samples (0.1 sec) and really bad at 10 or 1 sample. This limits my Tau-0 to 0.1 sec for a reasonable ADEV analysis.

Regards...
Don 
  ----- Original Message ----- 
  From: Brooke Clarke 
  To: Discussion of precise time and frequency measurement 
  Sent: Saturday, November 01, 2008 4:48 PM
  Subject: Re: [time-nuts] ADEV and Tau-0 guestion


  Hi Don:

  If you want to average many (100, 1000) reads in one second you need to use the 
  ARM function as described in appendix B of the PRS10 manual.
  http://www.prc68.com/I/PRS10.shtml

  Have Fun,

  Brooke Clarke
  http://www.prc68.com/P/Prod.html  Products I make and sell
  http://www.prc68.com/Alpha.shtml  All my web pages listed based on html name
  http://www.PRC68.com
  http://www.precisionclock.com
  http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam

  Don @ True-Cal wrote:
  > Fellow Time-Nuts,
  > 
  > I am having great fun with Ulrich's EZGPIB and Plotter programs to automate my ADEV and TI measurements. Wow, what a nice set of programs, thanks Ulrich!
  > 
  > I use the SR620 TIC with a Fury board as an external reference. The Fury disciplines an 10811-60168 external oscillator. I can go unlocked to improve the range around Tau 100s if and when necessary. For a series of tests, I used an LPRO-101 10Mhz signal to drive B-Ch (Stop) of the SR620; the A-Ch (Start) was set to Ref. for a Zero-Crossing TIME measurement on the TIC. I streamlined the EZGPIB SR620 query program and experimented with counter settings to minimize the inevitable and inherent latencies of the computer layers, network, GPIB-Enet/100 bridge and the counter (counter being the worst). With the counter set to 100 samples and the 1KHz "Ref" being used as the START, I was expecting a new, 100 sample TI average, every 0.1 seconds. My first evidence of something not being ideal was embedded in the details of the EZGPIB output console and accompanying file. Sometimes there were 7, 8 or 9 samples per second of time and never 10. Also, the total time span of a large coll
  ection of samples was always slightly longer than the product of the sample rate and count. I used Excel to scan 18000, 0.1s TI samples to determine what the actual statistics might be:
  > 
  > Average = 0.122302796 sec
  > Min = 0.188015099 sec
  > Max = 0.108984648 sec
  > 
  > Since the ADEV function as well as Ulrich's Plotter program requires a constant Tau-0, I experimented with the nominal 0.1s and the real "average" of 0.1223s Tau-0 setting and attached a graph that illustrates the variance across Tau. My question is; what is "acceptable" practice for defining Tau-0 when the likelihood of having a stable sampling interval is difficult. It was rather simple to specify a more accurate time sample interval once determined by the extra step of spreadsheet analysis and the effect on the results is obvious. But that is still, only an average. What about the effect of the deviation about the average value? It would seem that would be a much more complex issue to deal with.
  > 
  > See attached export or Plotter graphic.
  > 
  > Regards...
  > Don
  > 
  > 
  > ------------------------------------------------------------------------
  > 
  > _______________________________________________
  > time-nuts mailing list -- time-nuts at febo.com
  > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  > and follow the instructions there.

  _______________________________________________
  time-nuts mailing list -- time-nuts at febo.com
  To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  and follow the instructions there.

From didier at cox.net  Sat Nov  1 23:23:18 2008
From: didier at cox.net (Didier)
Date: Sat, 1 Nov 2008 18:23:18 -0500
Subject: [time-nuts] Efratom MRT schematic
In-Reply-To: <20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
References: <20081031.140717.3856.2.cdelect@juno.com>
	<20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
Message-ID: <EE3F3C12E29D433486CDCF7E52F3DEA3@didierhp>

http://www.ko4bb.com/cgi-bin/manuals.pl 

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of tomknox at nist.gov
> Sent: Saturday, November 01, 2008 5:29 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Efratom MRT schematic
> 
> Hi Time-Nuts
> I am new to this group, but have been aware of Time-Nuts for years.
> Someone may already have done this, but if not we should host 
> a data base of manuals and notes for time and freq products 
> and perhaps data on different products members have 
> characterized. I would be willing to share any manuals I have 
> and pitch in a little towards a hosting site to build on what 
> is already an invaluable resource.
> Best Wishes;
> Thomas Knox
> NIST
> 4475 Whitney Place
> Boulder Colorado 80305
> 1-303-554-0307
> tomknox at nist.gov
> 
> 
> 
> Quoting "Corby Dawson" <cdelect at juno.com>:
> 
> > Hi,
> >
> > I'm working on an Efratom MRT rubidium standard and I need 
> the power 
> > supply schematic.
> >
> > Everything is working OK except the battery charge circuit is not 
> > working.
> >
> > With good batteries you can pull the AC cord and it runs on the 
> > batteries OK, but then when you plug the AC back in the 
> charge current 
> > (with very discharged batteries) is very low. The batteries charge 
> > fine if a bench supply is used instead of the MRT supply.
> >
> > Anyone have a copy of the manual or can supply the schematic of the 
> > power supply and charger?
> >
> > Thanks,
> >
> > Corby Dawson
> > ____________________________________________________________
> > Criminal Lawyers - Click here.
> > 
> http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3oGdgUSMCXb8nALpcWDY
> > wVWGvlod18EcSO0mdpEPQlyYZoHX/
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From stanley_reynolds at yahoo.com  Sat Nov  1 23:31:08 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Sat, 1 Nov 2008 16:31:08 -0700 (PDT)
Subject: [time-nuts] Firmware bug /TRAK
References: <W7768110348235131225578215@webmail45>
Message-ID: <754155.53464.qm@web30305.mail.mud.yahoo.com>

Bill

Close to my measurements 2 5/8 by 6 3/8 USA with a metal shield box on antenna connector end 2 1/2 by 2 1/2. 20 Pin connector on the diagonal edge from the antenna connector. Unable to read numbers as the interface board with backup battery is mounted on top. Think it does match Bj?rn's post script files which explains the need for an extra voltage regulator for?7 volts. Has a green led about center of the board. Magnovox GPS engine Trade Mark across the short antenna connector end of board. Thanks Bj?rn for the files.

Stanley






________________________________
From: "brice at weaponeer.com" <brice at weaponeer.com>
To: time-nuts at febo.com
Sent: Saturday, November 1, 2008 5:23:35 PM
Subject: Re: [time-nuts] Firmware bug /TRAK

I found the Magnavox board I have. Magnavox GPS Engine,meauures about 6.5 x 2.5 inches. 900578-801-6 / 40613463 (looks like) E320R
basicly, 900578. Came out of some oilfield electro-junk I bought from Exxon Houston a few years ago. Same thing????? Cheers, Bill

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From SAIDJACK at aol.com  Sat Nov  1 23:56:21 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Sat, 1 Nov 2008 19:56:21 EDT
Subject: [time-nuts] beautiful jump
Message-ID: <c33.4030af53.363e46a5@aol.com>

Hi Antonio,
 
good stuff. Please keep us updated on your results. This seems to be a  
multi-decade investigation :)
 
bye,
Said
 
 
In a message dated 10/31/2008 16:41:07 Pacific Daylight Time,  
iovane at inwind.it writes:

Along  with my friend Thomas Goodey ( http://www.allais.info ),
we are planning to  do, besides his paraconical pendulum 
tests, specific crystal and tuning  fork tests as well, at the 
occurrence of eclipses in the next years. In  some cases we 
will reach the eclipse  areas.



From ka2cdk at cox.net  Sat Nov  1 23:58:21 2008
From: ka2cdk at cox.net (Thomas A. Frank)
Date: Sat, 1 Nov 2008 19:58:21 -0400
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <1231b6a80810300551q21b49efenf04a22fef1bf6145@mail.gmail.com>
References: <1231b6a80810300453h117e2ef6o929e23f40c3ed236@mail.gmail.com>
	<4909A498.6020005@tiscali.co.uk>
	<1231b6a80810300551q21b49efenf04a22fef1bf6145@mail.gmail.com>
Message-ID: <56FA2B32-90FE-48B2-BB4A-7A92A28EA9B0@cox.net>

>> I would say it's very unlikely to happen.  People tend to prefer the
>> time in their area to match up with the day.  So, having the sun  
>> come up
>> at 7pm wouldn't suit a lot of people.
>
> But people would get used to it after a while, maybe a generation, and
> whose to say that the sun should come up at 7am, it's really just an
> arbitrary concept.


In his book "100 Days" (about the 1982 war in the Falklands), Admiral  
Woodward points out that the British forces kept their clocks set to  
Greenwich Time, and shifted their days to match.

Which is to say that they still had breakfast right before dawn, but  
the clock might have said 1000 hours, and dinner might have been  
right after sunset (the Argentine Air Force being limited to daylight  
operations), when the clock might have indicted 2200 hours.

So the numbers on the clock were indeed considered arbitrary; they  
still sync'd life to the sun (for obvious reasons).

It was also helpful, in as much as the higher-ups back in the UK were  
on Greenwich time, so Woodward could stay in sync with their comings  
and goings.

Interesting book, by the way.

Tom Frank




From had at to-way.com  Sun Nov  2 00:26:23 2008
From: had at to-way.com (Had)
Date: Sat, 01 Nov 2008 17:26:23 -0700
Subject: [time-nuts] Efratom MRT schematic
In-Reply-To: <20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
References: <20081031.140717.3856.2.cdelect@juno.com>
	<20081101182922.23662tfmwckg8dvm@webmail.nist.gov>
Message-ID: <20081102002627.018A01B5030@mail-in07.adhost.com>


There is also,  www.to-way.com for time-nut related stuff.

Hadley, K7MLR


At 03:29 PM 11/1/2008, you wrote:
>Hi Time-Nuts
>I am new to this group, but have been aware of Time-Nuts for years.
>Someone may already have done this, but if not we should host a data
>base of manuals and notes for time and freq products and perhaps data
>on different products members have characterized. I would be willing
>to share any manuals I have and pitch in a little towards a hosting
>site to build on what is already an invaluable resource.
>Best Wishes;
>Thomas Knox
>NIST
>4475 Whitney Place
>Boulder Colorado 80305
>1-303-554-0307
>tomknox at nist.gov
>
>
>
>Quoting "Corby Dawson" <cdelect at juno.com>:
>
> > Hi,
> >
> > I'm working on an Efratom MRT rubidium standard and I need the power
> > supply schematic.
> >
> > Everything is working OK except the battery charge circuit is not
> > working.
> >
> > With good batteries you can pull the AC cord and it runs on the batteries
> > OK, but then when you plug the AC back in the charge current (with very
> > discharged batteries) is very low. The batteries charge fine if a bench
> > supply is used instead of the MRT supply.
> >
> > Anyone have a copy of the manual or can supply the schematic of the power
> > supply and charger?
> >
> > Thanks,
> >
> > Corby Dawson
> > ____________________________________________________________
> > Criminal Lawyers - Click here.
> > 
> http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3oGdgUSMCXb8nALpcWDYwVWGvlod18EcSO0mdpEPQlyYZoHX/
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.

From tractorb at ihug.co.nz  Sun Nov  2 00:46:54 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Sun, 2 Nov 2008 13:46:54 +1300
Subject: [time-nuts] HP1600A manual
References: <490ACB7D.5090700@tudelft.nl>
Message-ID: <09f401c93c84$815cebf0$7900a8c0@athlon1200>

I have a mint 1600A plus manual (s?) here somewhere, Jeroen- will  try 
to find it/them!  Sorry, no digital copy though but I should be able 
to scan some of it for you.
DaveB, NZ

----- Original Message ----- 
From: "Jeroen Bastemeijer" <j.bastemeijer at tudelft.nl>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Friday, October 31, 2008 10:10 PM
Subject: [time-nuts] HP1600A manual


> Dear All,
>
> Is there anyone out there who has a digital copy of the HP 1600A 
> logic
> analyzer manual? I found such an old machine, and I'm wondering if 
> it is
> still working...
>
> There are manuals for sale for approx $50 (excl. shipping). However, 
> the
> HP1600A seems not to be very responsive. So, investing $50 for a 
> machine
> which is defective and probably cannot be repaired seems like a 
> waste.
>
> Or is there anyone who can give a hint on how to test a HP 1600A, to 
> get
> a good indication if it is still functioning (reasonably) okay. At 
> this
> moment the machine seems to be locked up. Allthough there is a nice
> pattern of 1's and 0's on the screen....
>
> Thanks, best regards Jeroen
>


--------------------------------------------------------------------------------


> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


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From yuri at ostry.ru  Sun Nov  2 02:21:55 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Sun, 2 Nov 2008 05:21:55 +0300
Subject: [time-nuts] Rb lamp lifetime...
Message-ID: <1393325470.20081102052155@ostry.ru>

Hello,

Readed list archives and googled a lot, and seen two opposing points of
view - one is that there is nothing to age in Rb lamp, another is that
Rb lamp is degrading when in operation (without details, how and why).

I'm planning to get some Efratom Rb oscillator to use it in a
constantly running home lab frequency reference. Trying to understand
for myself, is it worth to get spare unit (or even two) of the same
model just to have replacement lamp on hand.

One more question - does someone seen Rb standard that is
malfunctioned due to degraded lamp, that, at same time, does have
good vacuum. If so, which model, and how the failed lamp looks like?
Was there any attempts to "rejuvenate" the lamp? (for example, heating
to remove glass darkening, if any, or similar experiments).

By the way, I'm very curious about physical process that may cause
lamp degradation.

Rubidium-87 that is included in the lamp (according to
manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
billion years half life) to stable Strontium-87, emitting 282.62keV
electrons and (anti?)neutrino. I don't think that 87Rb decay may
interfere with unit operation after tens of years, unless 87Sr is
"poisonous" so much so it can interfere with lamp operation even in
tiniest amounts. 

The only reference I located to date, is following article, that is
not available to general public. It is hard to understand for me just
from this abstract, does it specifically related to space environment
factors, or it is something that may cause degradation of Rb clocks
that is operated in average lab on Earth. ;)

> A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
> Red-Mode Transition in rf-Discharge Lamps 
> Camparo, J.   Mackay, R.   
> Aerosp. Corp., El Segundo;
> 
> 
> This paper appears in: Frequency Control Symposium, 2007 Joint with
> the 21st European Frequency and Time Forum. IEEE International 
> Publication Date: May 29 2007-June 1 2007
> On page(s): 45-48
> Location: Geneva, 
> ISSN: 1075-6787
> ISBN: 978-1-4244-0647-0
> INSPEC Accession Number: 9805223
> Digital Object Identifier: 10.1109/FREQ.2007.4319027
> Current Version Published: 2007-10-01 
> 
>  
>  
>  
>  
> Abstract
> In the vapor-cell atomic clock, long-term stability can be
> influenced by slow variations in the discharge lamp's output via the
> light-shift effect. Additionally, over a multi-year mission lifetime
> the lamp's aging can degrade its optical pumping efficiency.
> Understanding the mechanism(s) that drives these changes is
> particularly important for spacecraft devices, where the atomic
> clocks are called upon to function continuously and reliably for
> many years. Here, we consider the two well-known, but little
> studied, modes associated with alkali rf-discharge lamp operation:
> the ring mode and the red mode. Consistent with previous research,
> we find that the ring mode is best for optical pumping, and that the
> clock-signal amplitude degrades significantly when the lamp operates
> in the red mode. Examining the emission spectrum as the lamp
> transitions between these two modes, we show that the ring-mode to
> red-mode transition is driven by radiation trapping within the lamp.


-- 
Sincerely,
 Yuri UA3ATQ/KI7XJ                     mailto:yuri at ostry.ru




From wb6bnq at cox.net  Sun Nov  2 03:31:32 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Sat, 01 Nov 2008 20:31:32 -0700
Subject: [time-nuts] Rb lamp lifetime...
References: <1393325470.20081102052155@ostry.ru>
Message-ID: <490D1F14.DD39B9F2@cox.net>

Hi Yuri,

Unless you need the longer term stability of an undisciplined Rb source, I think
you would be better served to get one of the ?Timenuts group? Trimble Thunderbolt
GPS units to use as a home standard.  It is available via this page:

http://www.tapr.org/kits_thunder.html

and info about the unit is available at this URL:

http://www.leapsecond.com/tbolt-faq.htm

Add an external very high quality crystal oscillator locked to the Trimble and
you will have the same stability of a good Rb source.  Most would use a high
quality Rb source, undisciplined, as a tool for comparing or generating
specifications of crystal oscillators.

It seems that the Rb standards last longer turned off.  My understanding (subject
to disagreement) is the Rubidium in the lamp ends up coating the walls of the
lamp and reducing the transmission through the glass, i.e., the signal gets more
and more noisy as time goes on.  Also, it seems that the Rubidium may permeate
through the walls of the glass housing and thus reduce the amount of Rb over
time.  I have not heard of anyone reversing the condition.  Of course, other
things can go wrong with the Rb source besides the lamp.

A very high quality crystal oscillator would most likely last longer with fewer
problems.  I have several +40 year old hp counters with decent oscillators still
operating.

Bill....WB6BNQ



Yuri Ostry wrote:

> Hello,
>
> Readed list archives and googled a lot, and seen two opposing points of
> view - one is that there is nothing to age in Rb lamp, another is that
> Rb lamp is degrading when in operation (without details, how and why).
>
> I'm planning to get some Efratom Rb oscillator to use it in a
> constantly running home lab frequency reference. Trying to understand
> for myself, is it worth to get spare unit (or even two) of the same
> model just to have replacement lamp on hand.
>
> One more question - does someone seen Rb standard that is
> malfunctioned due to degraded lamp, that, at same time, does have
> good vacuum. If so, which model, and how the failed lamp looks like?
> Was there any attempts to "rejuvenate" the lamp? (for example, heating
> to remove glass darkening, if any, or similar experiments).
>
> By the way, I'm very curious about physical process that may cause
> lamp degradation.
>
> Rubidium-87 that is included in the lamp (according to
> manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
> billion years half life) to stable Strontium-87, emitting 282.62keV
> electrons and (anti?)neutrino. I don't think that 87Rb decay may
> interfere with unit operation after tens of years, unless 87Sr is
> "poisonous" so much so it can interfere with lamp operation even in
> tiniest amounts.
>
> The only reference I located to date, is following article, that is
> not available to general public. It is hard to understand for me just
> from this abstract, does it specifically related to space environment
> factors, or it is something that may cause degradation of Rb clocks
> that is operated in average lab on Earth. ;)
>
> > A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
> > Red-Mode Transition in rf-Discharge Lamps
> > Camparo, J.   Mackay, R.
> > Aerosp. Corp., El Segundo;
> >
> >
> > This paper appears in: Frequency Control Symposium, 2007 Joint with
> > the 21st European Frequency and Time Forum. IEEE International
> > Publication Date: May 29 2007-June 1 2007
> > On page(s): 45-48
> > Location: Geneva,
> > ISSN: 1075-6787
> > ISBN: 978-1-4244-0647-0
> > INSPEC Accession Number: 9805223
> > Digital Object Identifier: 10.1109/FREQ.2007.4319027
> > Current Version Published: 2007-10-01
> >
> >
> >
> >
> >
> > Abstract
> > In the vapor-cell atomic clock, long-term stability can be
> > influenced by slow variations in the discharge lamp's output via the
> > light-shift effect. Additionally, over a multi-year mission lifetime
> > the lamp's aging can degrade its optical pumping efficiency.
> > Understanding the mechanism(s) that drives these changes is
> > particularly important for spacecraft devices, where the atomic
> > clocks are called upon to function continuously and reliably for
> > many years. Here, we consider the two well-known, but little
> > studied, modes associated with alkali rf-discharge lamp operation:
> > the ring mode and the red mode. Consistent with previous research,
> > we find that the ring mode is best for optical pumping, and that the
> > clock-signal amplitude degrades significantly when the lamp operates
> > in the red mode. Examining the emission spectrum as the lamp
> > transitions between these two modes, we show that the ring-mode to
> > red-mode transition is driven by radiation trapping within the lamp.
>
> --
> Sincerely,
>  Yuri UA3ATQ/KI7XJ                     mailto:yuri at ostry.ru
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From wb6bnq at cox.net  Sun Nov  2 05:28:26 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Sat, 01 Nov 2008 22:28:26 -0700
Subject: [time-nuts] Rb lamp lifetime...
References: <1393325470.20081102052155@ostry.ru> <490D1F14.DD39B9F2@cox.net>
Message-ID: <490D3A7A.8F8EBF23@cox.net>

Yuri,

Sorry about that, but I guess the Trimble Thunderbolts are out of stock all ready.

Bill....WB6BNQ


WB6BNQ wrote:

> Hi Yuri,
>
> Unless you need the longer term stability of an undisciplined Rb source, I think
> you would be better served to get one of the ?Timenuts group? Trimble Thunderbolt
> GPS units to use as a home standard.  It is available via this page:
>
> http://www.tapr.org/kits_thunder.html
>
> and info about the unit is available at this URL:
>
> http://www.leapsecond.com/tbolt-faq.htm
>
> Add an external very high quality crystal oscillator locked to the Trimble and
> you will have the same stability of a good Rb source.  Most would use a high
> quality Rb source, undisciplined, as a tool for comparing or generating
> specifications of crystal oscillators.
>
> It seems that the Rb standards last longer turned off.  My understanding (subject
> to disagreement) is the Rubidium in the lamp ends up coating the walls of the
> lamp and reducing the transmission through the glass, i.e., the signal gets more
> and more noisy as time goes on.  Also, it seems that the Rubidium may permeate
> through the walls of the glass housing and thus reduce the amount of Rb over
> time.  I have not heard of anyone reversing the condition.  Of course, other
> things can go wrong with the Rb source besides the lamp.
>
> A very high quality crystal oscillator would most likely last longer with fewer
> problems.  I have several +40 year old hp counters with decent oscillators still
> operating.
>
> Bill....WB6BNQ
>
> Yuri Ostry wrote:
>
> > Hello,
> >
> > Readed list archives and googled a lot, and seen two opposing points of
> > view - one is that there is nothing to age in Rb lamp, another is that
> > Rb lamp is degrading when in operation (without details, how and why).
> >
> > I'm planning to get some Efratom Rb oscillator to use it in a
> > constantly running home lab frequency reference. Trying to understand
> > for myself, is it worth to get spare unit (or even two) of the same
> > model just to have replacement lamp on hand.
> >
> > One more question - does someone seen Rb standard that is
> > malfunctioned due to degraded lamp, that, at same time, does have
> > good vacuum. If so, which model, and how the failed lamp looks like?
> > Was there any attempts to "rejuvenate" the lamp? (for example, heating
> > to remove glass darkening, if any, or similar experiments).
> >
> > By the way, I'm very curious about physical process that may cause
> > lamp degradation.
> >
> > Rubidium-87 that is included in the lamp (according to
> > manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
> > billion years half life) to stable Strontium-87, emitting 282.62keV
> > electrons and (anti?)neutrino. I don't think that 87Rb decay may
> > interfere with unit operation after tens of years, unless 87Sr is
> > "poisonous" so much so it can interfere with lamp operation even in
> > tiniest amounts.
> >
> > The only reference I located to date, is following article, that is
> > not available to general public. It is hard to understand for me just
> > from this abstract, does it specifically related to space environment
> > factors, or it is something that may cause degradation of Rb clocks
> > that is operated in average lab on Earth. ;)
> >
> > > A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
> > > Red-Mode Transition in rf-Discharge Lamps
> > > Camparo, J.   Mackay, R.
> > > Aerosp. Corp., El Segundo;
> > >
> > >
> > > This paper appears in: Frequency Control Symposium, 2007 Joint with
> > > the 21st European Frequency and Time Forum. IEEE International
> > > Publication Date: May 29 2007-June 1 2007
> > > On page(s): 45-48
> > > Location: Geneva,
> > > ISSN: 1075-6787
> > > ISBN: 978-1-4244-0647-0
> > > INSPEC Accession Number: 9805223
> > > Digital Object Identifier: 10.1109/FREQ.2007.4319027
> > > Current Version Published: 2007-10-01
> > >
> > >
> > >
> > >
> > >
> > > Abstract
> > > In the vapor-cell atomic clock, long-term stability can be
> > > influenced by slow variations in the discharge lamp's output via the
> > > light-shift effect. Additionally, over a multi-year mission lifetime
> > > the lamp's aging can degrade its optical pumping efficiency.
> > > Understanding the mechanism(s) that drives these changes is
> > > particularly important for spacecraft devices, where the atomic
> > > clocks are called upon to function continuously and reliably for
> > > many years. Here, we consider the two well-known, but little
> > > studied, modes associated with alkali rf-discharge lamp operation:
> > > the ring mode and the red mode. Consistent with previous research,
> > > we find that the ring mode is best for optical pumping, and that the
> > > clock-signal amplitude degrades significantly when the lamp operates
> > > in the red mode. Examining the emission spectrum as the lamp
> > > transitions between these two modes, we show that the ring-mode to
> > > red-mode transition is driven by radiation trapping within the lamp.
> >
> > --
> > Sincerely,
> >  Yuri UA3ATQ/KI7XJ                     mailto:yuri at ostry.ru
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From sar10538 at gmail.com  Sun Nov  2 05:49:53 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 2 Nov 2008 18:49:53 +1300
Subject: [time-nuts] Time-zones and World time..
In-Reply-To: <56FA2B32-90FE-48B2-BB4A-7A92A28EA9B0@cox.net>
References: <1231b6a80810300453h117e2ef6o929e23f40c3ed236@mail.gmail.com>
	<4909A498.6020005@tiscali.co.uk>
	<1231b6a80810300551q21b49efenf04a22fef1bf6145@mail.gmail.com>
	<56FA2B32-90FE-48B2-BB4A-7A92A28EA9B0@cox.net>
Message-ID: <1231b6a80811012249k651b0917m58625ac7b82df10e@mail.gmail.com>

2008/11/2 Thomas A. Frank <ka2cdk at cox.net>:
>> But people would get used to it after a while, maybe a generation, and
>> whose to say that the sun should come up at 7am, it's really just an
>> arbitrary concept.
>
>
> In his book "100 Days" (about the 1982 war in the Falklands), Admiral
> Woodward points out that the British forces kept their clocks set to
> Greenwich Time, and shifted their days to match.
>
> Which is to say that they still had breakfast right before dawn, but
> the clock might have said 1000 hours, and dinner might have been
> right after sunset (the Argentine Air Force being limited to daylight
> operations), when the clock might have indicted 2200 hours.
>
> So the numbers on the clock were indeed considered arbitrary; they
> still sync'd life to the sun (for obvious reasons).
>
> It was also helpful, in as much as the higher-ups back in the UK were
> on Greenwich time, so Woodward could stay in sync with their comings
> and goings.
>
> Interesting book, by the way.

My point exactly.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From kc0ukk at msosborn.com  Sun Nov  2 06:28:34 2008
From: kc0ukk at msosborn.com (Matt Osborn)
Date: Sun, 02 Nov 2008 01:28:34 -0500
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
Message-ID: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>

I think that I've managed to keep a low profile here, trusting that I
would learn more if I refrained from random interjections of
ill-informed thoughts.  However, there comes a point in every man's
life...

A year or two ago, I took advantage of Said's offer and purchased one
of the Jackson Labs OEM external OCXO Fury units and am attempting to
put it to work. I've decided to use an Isotemp OCXO134-10 oscillator
and have several decisions which I would like to vet with those of you
that have been down this road before.

The Isotemp unit has an EFC range of 0 to 8 Volts; the Fury has an EFC
range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
Isotemp to 10 MHz +- 5 mHz with an EFC voltage of 4.64 volts. That is
within the adjustment range of the Fury, but I'm not sure of the
accuracy of the HP53131A.  Should I construct a resistive network ala
Brooks Shera to 'boost' the EFC range just in case or would I be
better off just using the Fury 'as is'?

Secondly, the Jackson Labs advises that since the Fury uses the
external oscillator as its clock, that the oscillator should be
powered up before the Fury itself.  I was hoping that I would be able
to use a single power switch to power both the oscillator and the Fury
simultaneously, but now I'm not so sure.

Finally, are there any of you that have used the Isotemp OXCO134-10
with the Fury?  Have any of you worked out the various SERVO settings
that the Fury makes available?  I'm interested in the  DAC gain, EFC
scale, EFC dampening and Phase compensation.

Any and all advice will be gratefully accepted.

-- kc0ukk at msosborn dot com


From bruce.griffiths at xtra.co.nz  Sun Nov  2 07:58:49 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 02 Nov 2008 20:58:49 +1300
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
In-Reply-To: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
References: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
Message-ID: <490D5DB9.4070709@xtra.co.nz>

Matt Osborn wrote:
> I think that I've managed to keep a low profile here, trusting that I
> would learn more if I refrained from random interjections of
> ill-informed thoughts.  However, there comes a point in every man's
> life...
>
> A year or two ago, I took advantage of Said's offer and purchased one
> of the Jackson Labs OEM external OCXO Fury units and am attempting to
> put it to work. I've decided to use an Isotemp OCXO134-10 oscillator
> and have several decisions which I would like to vet with those of you
> that have been down this road before.
>
> The Isotemp unit has an EFC range of 0 to 8 Volts; the Fury has an EFC
> range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
> Isotemp to 10 MHz +- 5 mHz with an EFC voltage of 4.64 volts. That is
> within the adjustment range of the Fury, but I'm not sure of the
> accuracy of the HP53131A.  Should I construct a resistive network ala
> Brooks Shera to 'boost' the EFC range just in case or would I be
> better off just using the Fury 'as is'?
>
>   
If you use a non inverting buffer amplifier with a gain of 1.6 you will
increase the allowance for OCXO aging, otherwise you are a little close
to the Fury EFC output limit of 5V.
Have you tried connecting the OCXO to the Fury and seen how close to the
limit the OCXO EFC is when lock is achieved?
> Secondly, the Jackson Labs advises that since the Fury uses the
> external oscillator as its clock, that the oscillator should be
> powered up before the Fury itself.  I was hoping that I would be able
> to use a single power switch to power both the oscillator and the Fury
> simultaneously, but now I'm not so sure.
>
>   
You still can if you use a suitable delay circuit.
> Finally, are there any of you that have used the Isotemp OXCO134-10
> with the Fury?  Have any of you worked out the various SERVO settings
> that the Fury makes available?  I'm interested in the  DAC gain, EFC
> scale, EFC dampening and Phase compensation.
>
> Any and all advice will be gratefully accepted.
>
> -- kc0ukk at msosborn dot com
>
>   
Bruce



From wb6bnq at cox.net  Sun Nov  2 08:14:29 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Sun, 02 Nov 2008 01:14:29 -0700
Subject: [time-nuts] Rb lamp lifetime...
References: <22227456.1225602911305.JavaMail.root@elwamui-rustique.atl.sa.earthlink.net>
Message-ID: <490D6165.142C6911@cox.net>

Hi Dick,

I guess I should have been more clear.  By ?locking? I meant using the
1pps output of the Trimble and a
separate house standard connected to a separate controller board such as
Brooks Shera?s circuit.

The oscillator in the Trimble is ok, but it is not the same as a high
quality crystal oscillator with a larger
thermal mass and a double oven.  The Trimble specs for a 1 second
measurement period (i.e., using it as an
external reference for your counter) is only good to 1xE-9.  To get the
1.16xE-12 takes a 24 hour period as
noted in the spec sheet.

An hp 10544B is spec?d for short term stability at 1E-11 for 1 second
averaging.  It would be a better
flywheel (when GPS is screwing up) for a house reference source using
the GPS to keep the long term average in
check.

For the extreme, if you want to spend the money, use a Rubidium
oscillator.  The difference being what happens
during any period when the GPS is not in control.  Of course a Rubidium
would make a good short term portable
source without the GPS control.

If possible it is better to keep a reference standard unperturbed and
just keep track of the actual value.
>From that data you know the deviation and slope of any drift.  It is all a matter of keeping records.  In
primary labs that is what is done with primary standards as most are not
?adjustable,? they are not messed
with and only the measurement values are reported.  It is up to the
owner to know what to do with the
information.  Of course there are some items that are adjustable and may
very well be adjusted, would depend
upon the item and the customer needs.

In the case of a high quality Rubidium, it is stable enough to be
treated as a short term reference.  In such
a case it would only be compared to, not controlled by the GPS.  Careful
measurement, extremely careful
adjustment and good records would allow it being used as high quality
portable standard if it is kept hot the
whole time during its use.

Bill....WB6BNQ


"Richard W. Solomon" wrote:

> I am confused (a normal state).
> Why would locking an external oscillator to the Trimble
> be better than using the 10 MHz output of the Trimble ?
> Wouldn't the external oscillator follow the Trimble signal ?
> Since I have one and just use the 10 MHz output you got my
> attention.
> I do have a 970 MHz "brick" locked to one of my HB GPSDO's
> that I use for Service Monitor Calibration. Perhaps you were
> thinking of locking a Sig Gen using the Trimble ??
>
> 73, Dick, W1KSZ
>
> -----Original Message-----
> >From: WB6BNQ <wb6bnq at cox.net>
> >Sent: Nov 1, 2008 8:31 PM
> >To: Yuri Ostry <yuri at ostry.ru>, Discussion of precise time and frequency measurement <time-nuts at febo.com>
> >Subject: Re: [time-nuts] Rb lamp lifetime...
> >
> >Hi Yuri,
> >
> >Unless you need the longer term stability of an undisciplined Rb source, I think
> >you would be better served to get one of the ??Timenuts group?? Trimble Thunderbolt
> >GPS units to use as a home standard.  It is available via this page:
> >
> >http://www.tapr.org/kits_thunder.html
> >
> >and info about the unit is available at this URL:
> >
> >http://www.leapsecond.com/tbolt-faq.htm
> >
> >Add an external very high quality crystal oscillator locked to the Trimble and
> >you will have the same stability of a good Rb source.  Most would use a high
> >quality Rb source, undisciplined, as a tool for comparing or generating
> >specifications of crystal oscillators.
> >
> >It seems that the Rb standards last longer turned off.  My understanding (subject
> >to disagreement) is the Rubidium in the lamp ends up coating the walls of the
> >lamp and reducing the transmission through the glass, i.e., the signal gets more
> >and more noisy as time goes on.  Also, it seems that the Rubidium may permeate
> >through the walls of the glass housing and thus reduce the amount of Rb over
> >time.  I have not heard of anyone reversing the condition.  Of course, other
> >things can go wrong with the Rb source besides the lamp.
> >
> >A very high quality crystal oscillator would most likely last longer with fewer
> >problems.  I have several +40 year old hp counters with decent oscillators still
> >operating.
> >
> >Bill....WB6BNQ
> >
> >
> >
> >Yuri Ostry wrote:
> >
> >> Hello,
> >>
> >> Readed list archives and googled a lot, and seen two opposing points of
> >> view - one is that there is nothing to age in Rb lamp, another is that
> >> Rb lamp is degrading when in operation (without details, how and why).
> >>
> >> I'm planning to get some Efratom Rb oscillator to use it in a
> >> constantly running home lab frequency reference. Trying to understand
> >> for myself, is it worth to get spare unit (or even two) of the same
> >> model just to have replacement lamp on hand.
> >>
> >> One more question - does someone seen Rb standard that is
> >> malfunctioned due to degraded lamp, that, at same time, does have
> >> good vacuum. If so, which model, and how the failed lamp looks like?
> >> Was there any attempts to "rejuvenate" the lamp? (for example, heating
> >> to remove glass darkening, if any, or similar experiments).
> >>
> >> By the way, I'm very curious about physical process that may cause
> >> lamp degradation.
> >>
> >> Rubidium-87 that is included in the lamp (according to
> >> manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
> >> billion years half life) to stable Strontium-87, emitting 282.62keV
> >> electrons and (anti?)neutrino. I don't think that 87Rb decay may
> >> interfere with unit operation after tens of years, unless 87Sr is
> >> "poisonous" so much so it can interfere with lamp operation even in
> >> tiniest amounts.
> >>
> >> The only reference I located to date, is following article, that is
> >> not available to general public. It is hard to understand for me just
> >> from this abstract, does it specifically related to space environment
> >> factors, or it is something that may cause degradation of Rb clocks
> >> that is operated in average lab on Earth. ;)
> >>
> >> > A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
> >> > Red-Mode Transition in rf-Discharge Lamps
> >> > Camparo, J.   Mackay, R.
> >> > Aerosp. Corp., El Segundo;
> >> >
> >> >
> >> > This paper appears in: Frequency Control Symposium, 2007 Joint with
> >> > the 21st European Frequency and Time Forum. IEEE International
> >> > Publication Date: May 29 2007-June 1 2007
> >> > On page(s): 45-48
> >> > Location: Geneva,
> >> > ISSN: 1075-6787
> >> > ISBN: 978-1-4244-0647-0
> >> > INSPEC Accession Number: 9805223
> >> > Digital Object Identifier: 10.1109/FREQ.2007.4319027
> >> > Current Version Published: 2007-10-01
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > Abstract
> >> > In the vapor-cell atomic clock, long-term stability can be
> >> > influenced by slow variations in the discharge lamp's output via the
> >> > light-shift effect. Additionally, over a multi-year mission lifetime
> >> > the lamp's aging can degrade its optical pumping efficiency.
> >> > Understanding the mechanism(s) that drives these changes is
> >> > particularly important for spacecraft devices, where the atomic
> >> > clocks are called upon to function continuously and reliably for
> >> > many years. Here, we consider the two well-known, but little
> >> > studied, modes associated with alkali rf-discharge lamp operation:
> >> > the ring mode and the red mode. Consistent with previous research,
> >> > we find that the ring mode is best for optical pumping, and that the
> >> > clock-signal amplitude degrades significantly when the lamp operates
> >> > in the red mode. Examining the emission spectrum as the lamp
> >> > transitions between these two modes, we show that the ring-mode to
> >> > red-mode transition is driven by radiation trapping within the lamp.
> >>
> >> --
> >> Sincerely,
> >>  Yuri UA3ATQ/KI7XJ                     mailto:yuri at ostry.ru
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at febo.com
> >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >
> >
> >_______________________________________________
> >time-nuts mailing list -- time-nuts at febo.com
> >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >and follow the instructions there.


From hmurray at megapathdsl.net  Sun Nov  2 09:26:54 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 02 Nov 2008 01:26:54 -0800
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
In-Reply-To: Message from Matt Osborn <kc0ukk@msosborn.com> of "Sun,
	02 Nov 2008 01:28:34 CDT." <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
Message-ID: <20081102092655.29C70BCD5@ip-64-139-1-69.sjc.megapath.net>


> Secondly, the Jackson Labs advises that since the Fury uses the
> external oscillator as its clock, that the oscillator should be
> powered up before the Fury itself.  I was hoping that I would be able
> to use a single power switch to power both the oscillator and the Fury
> simultaneously, but now I'm not so sure. 

Give it a try and see what happens.  Or wait and see what Said says.

Getting started is one of the messy areas of "digital" design.

The general idea is that you have to hold the CPU reset until power is stable 
and the oscillator is generating a clean signal.

To see if a design will work cleanly, you have to find that part of the CPU 
data sheet, the startup specs for your oscillator, and the specs for the 
power-up reset logic.  If you are lucky, the power-up reset logic is a tiny 
magic chip that has clean specs.

The reset logic is built-in to many of the smaller micros (cost savings), but 
they sometimes requires some power ramp-up specs.  (aka they don't work 
cleanly in brownouts.)

I can't find any startup specs on my copy of the data sheet for the Isotemp 
OCXO134-10.  (Maybe I missed it.)  I'm not looking for the stability type 
warmup time of several minutes.  I'm looking for something like a few ms, the 
time it takes the crystal to get past the startup transient and put out a 
clean signal even if the frequency isn't right yet.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From iovane at inwind.it  Sun Nov  2 10:06:48 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Sun,  2 Nov 2008 11:06:48 +0100
Subject: [time-nuts] Rb lamp lifetime...
Message-ID: <K9PARC$80501DDF1307E4CC0449577D1CC5004E@libero.it>

Yuri,

as a rule of thumb, read my message posted here last month:

http://www.febo.com/pipermail/time-nuts/2008-October/033926.html

I have 10 EFRATOM LPRO, and only one came with a faulty lamp.
I think it lost vacuum, and the glass looks clear but with
small white pigments. I inspected some of the other lamps,
and the glass looks more or less brownish.
No other tests made on the lamps.

73,
Antonio I8IOV

> Hello,
> 
> Readed list archives and googled a lot, and seen two opposing points of
> view - one is that there is nothing to age in Rb lamp, another is that
> Rb lamp is degrading when in operation (without details, how and why).




From namichie at gmail.com  Sun Nov  2 11:10:40 2008
From: namichie at gmail.com (Neville Michie)
Date: Sun, 2 Nov 2008 22:10:40 +1100
Subject: [time-nuts] Rb lamp lifetime...
In-Reply-To: <K9PARC$80501DDF1307E4CC0449577D1CC5004E@libero.it>
References: <K9PARC$80501DDF1307E4CC0449577D1CC5004E@libero.it>
Message-ID: <737A55B5-209B-4F22-A1F6-305877DE43FA@gmail.com>

Hi Antonio,
I have taken the cover off my LPRO but I could not see the lamp.
I guess it is in the smaller housing.
What does the lamp look like and how do you remove it?
I do not want to damage my unit.

cheers, Neville Michie


On 02/11/2008, at 9:06 PM, iovane@@inwind..it wrote:

> Yuri,
>
> as a rule of thumb, read my message posted here last month:
>
> http://www.febo.com/pipermail/time-nuts/2008-October/033926.html
>
> I have 10 EFRATOM LPRO, and only one came with a faulty lamp.
> I think it lost vacuum, and the glass looks clear but with
> small white pigments. I inspected some of the other lamps,
> and the glass looks more or less brownish.
> No other tests made on the lamps.
>
> 73,
> Antonio I8IOV
>
>> Hello,
>>
>> Readed list archives and googled a lot, and seen two opposing  
>> points of
>> view - one is that there is nothing to age in Rb lamp, another is  
>> that
>> Rb lamp is degrading when in operation (without details, how and  
>> why).
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.



From iovane at inwind.it  Sun Nov  2 14:20:46 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Sun,  2 Nov 2008 15:20:46 +0100
Subject: [time-nuts] Rb lamp lifetime...
Message-ID: <K9PMIM$FE7FC4F5EC2E5FC11F74F0FA9F1A72E6@libero.it>

Hi Neville,

inspecting the lamp is a quite easy job.
Yes, it is in the smaller housing.
Unlock the check nut just enough, and unscrew the lamp (along 
with the check nut) using a point shaped tool (a toothpick). 
It is easy. 
Don't touch it with fingers.
Before doing this, take note of how much the lamp protrudes 
from the housing.
If you have problems, feel free to ask.

Antonio I8IOV

> Hi Antonio,
> I have taken the cover off my LPRO but I could not see the lamp.
> I guess it is in the smaller housing.
> What does the lamp look like and how do you remove it?
> I do not want to damage my unit.
> 
> cheers, Neville Michie




From perseidjh at hotmail.com  Sun Nov  2 19:43:29 2008
From: perseidjh at hotmail.com (Jim Hall)
Date: Sun, 2 Nov 2008 12:43:29 -0700
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
In-Reply-To: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
References: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
Message-ID: <BAY105-DS1FFC33F5D0A9826DE82B2B1220@phx.gbl>

Regarding your second question concerning power supply sequencing.  How 
about using one of the "Power Supply Sequencer" chips (e.g. MAX6819)).  The 
output of your power supply would go directly to the external OCXO, the 
Power Supply Sequencer chip and the input to a MOSFET switch.  Output of the 
MOSFET switch goes to the Fury.

When the power supply is switched on the following sequence occurs (assuming 
a MAX6819):
1) Power is applied to the OCXO,  MAX6819 and MOSFET switch input
2) The MAX6819 starts a 200 millisecond delay
3) After 200 milliseconds the MAX6819 turns the MOSFET switch On, powering 
the Fury On

MOSFET switches can be used that have only a few tenths (or less) of an ohm 
of "ON" resistance.  This minimizes degradation in voltage regulation of the 
power applied to the Fury.

The MAX6819 data sheet gives useful examples applicable to the above 
application.

73,

Jim Hall W4TVI



--------------------------------------------------
From: "Matt Osborn" <kc0ukk at msosborn.com>
Sent: Saturday, November 01, 2008 11:28 PM
To: "time-nuts" <time-nuts at febo.com>
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10

> I think that I've managed to keep a low profile here, trusting that I
> would learn more if I refrained from random interjections of
> ill-informed thoughts.  However, there comes a point in every man's
> life...
>
> A year or two ago, I took advantage of Said's offer and purchased one
> of the Jackson Labs OEM external OCXO Fury units and am attempting to
> put it to work. I've decided to use an Isotemp OCXO134-10 oscillator
> and have several decisions which I would like to vet with those of you
> that have been down this road before.
>
> The Isotemp unit has an EFC range of 0 to 8 Volts; the Fury has an EFC
> range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
> Isotemp to 10 MHz +- 5 mHz with an EFC voltage of 4.64 volts. That is
> within the adjustment range of the Fury, but I'm not sure of the
> accuracy of the HP53131A.  Should I construct a resistive network ala
> Brooks Shera to 'boost' the EFC range just in case or would I be
> better off just using the Fury 'as is'?
>
> Secondly, the Jackson Labs advises that since the Fury uses the
> external oscillator as its clock, that the oscillator should be
> powered up before the Fury itself.  I was hoping that I would be able
> to use a single power switch to power both the oscillator and the Fury
> simultaneously, but now I'm not so sure.
>
> Finally, are there any of you that have used the Isotemp OXCO134-10
> with the Fury?  Have any of you worked out the various SERVO settings
> that the Fury makes available?  I'm interested in the  DAC gain, EFC
> scale, EFC dampening and Phase compensation.
>
> Any and all advice will be gratefully accepted.
>
> -- kc0ukk at msosborn dot com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From phk at phk.freebsd.dk  Sun Nov  2 20:10:53 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Sun, 02 Nov 2008 20:10:53 +0000
Subject: [time-nuts] DIY Loran-C frequency receiver: release 0.0
In-Reply-To: Your message of "Mon, 27 Oct 2008 22:54:06 GMT."
	<51888.1225148046@critter.freebsd.dk> 
Message-ID: <36601.1225656653@critter.freebsd.dk>


A number of time-nuts have indicated that they want in on this crazy
little project of mine, so I have slapped together a release 0.0
of my software, and a paper that goes with it:

The paper:
	http://phk.freebsd.dk/AducLoran/AducLoran-0.0.pdf

The software:
	http://phk.freebsd.dk/AducLoran/AducLoran-0.0.tgz

Loran-C does not get any simpler than this...

Have fun!

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From sam.mosel at baesystems.com  Sun Nov  2 22:21:00 2008
From: sam.mosel at baesystems.com (MOSEL Sam)
Date: Mon, 3 Nov 2008 09:21:00 +1100
Subject: [time-nuts] What's the time Mr Wolf...
Message-ID: <200811022221.mA2ML03n025457@sprint3.tenix.com>

 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Steve Rooke
Sent: Thursday, 30 October 2008 11:16 PM
> 10) If they are geostationary, or move in relation to the ground,
> how are the affects of the Einstein time dilation handled as they
> may be travelling at a different speed than a point on the surface
> of the Earth?

Internally, the GPS satellites have an approximately 10.23 MHz
oscillator which is:

1. multiplied by 120 to generate the L2 carrier (1227.6 MHz),
2. multiplied by 154 to generate the L1 carrier (1575.42 MHz),
2a. Multiplied by 115 to generate the L5 carrier (1176.45 MHz, Block III
sats only)
3. passed directly to the P(Y) code generator (10.23 MHz symbol rate)
4. divided by 10 to generate the C/A code (1.023 MHz symbol rate), and
5. divided by 20460 to generate the data (50 Hz bit rate).

So everything is derived from this oscillator, which is actually
10.22999999543 MHz. This -4.57 mHz corrects for relativistic effects.

Sam. 

Disclaimer :
The contents of this e-mail including any attachments are intended only
for the person or entity to which this e-mail is addressed.  If you are not,
or believe you may not be, the intended recipient, please advise the sender
immediately by return e-mail, delete this e-mail and destroy any copies.
The Company does not warrant nor guarantee that this email communication is free
from errors, virus, interception or interference.



From rfnuts at arcor.de  Mon Nov  3 00:46:37 2008
From: rfnuts at arcor.de (Adrian)
Date: Mon, 03 Nov 2008 01:46:37 +0100
Subject: [time-nuts] Rb lamp lifetime...
In-Reply-To: <1393325470.20081102052155@ostry.ru>
References: <1393325470.20081102052155@ostry.ru>
Message-ID: <490E49ED.80906@arcor.de>

Hello,

there are some interesting hints (including lamp rejuvenation) in the 
attached papaer that was posted here a few months ago by Gerald 
Molenkamp VK3FGJM.

Regards,
Adrian


Yuri Ostry schrieb:
> Hello,
>
> Readed list archives and googled a lot, and seen two opposing points of
> view - one is that there is nothing to age in Rb lamp, another is that
> Rb lamp is degrading when in operation (without details, how and why).
>
> I'm planning to get some Efratom Rb oscillator to use it in a
> constantly running home lab frequency reference. Trying to understand
> for myself, is it worth to get spare unit (or even two) of the same
> model just to have replacement lamp on hand.
>
> One more question - does someone seen Rb standard that is
> malfunctioned due to degraded lamp, that, at same time, does have
> good vacuum. If so, which model, and how the failed lamp looks like?
> Was there any attempts to "rejuvenate" the lamp? (for example, heating
> to remove glass darkening, if any, or similar experiments).
>
> By the way, I'm very curious about physical process that may cause
> lamp degradation.
>
> Rubidium-87 that is included in the lamp (according to
> manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
> billion years half life) to stable Strontium-87, emitting 282.62keV
> electrons and (anti?)neutrino. I don't think that 87Rb decay may
> interfere with unit operation after tens of years, unless 87Sr is
> "poisonous" so much so it can interfere with lamp operation even in
> tiniest amounts. 
>
> The only reference I located to date, is following article, that is
> not available to general public. It is hard to understand for me just
> from this abstract, does it specifically related to space environment
> factors, or it is something that may cause degradation of Rb clocks
> that is operated in average lab on Earth. ;)
>
>   
>> A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
>> Red-Mode Transition in rf-Discharge Lamps 
>> Camparo, J.   Mackay, R.   
>> Aerosp. Corp., El Segundo;
>>
>>
>> This paper appears in: Frequency Control Symposium, 2007 Joint with
>> the 21st European Frequency and Time Forum. IEEE International 
>> Publication Date: May 29 2007-June 1 2007
>> On page(s): 45-48
>> Location: Geneva, 
>> ISSN: 1075-6787
>> ISBN: 978-1-4244-0647-0
>> INSPEC Accession Number: 9805223
>> Digital Object Identifier: 10.1109/FREQ.2007.4319027
>> Current Version Published: 2007-10-01 
>>
>>  
>>  
>>  
>>  
>> Abstract
>> In the vapor-cell atomic clock, long-term stability can be
>> influenced by slow variations in the discharge lamp's output via the
>> light-shift effect. Additionally, over a multi-year mission lifetime
>> the lamp's aging can degrade its optical pumping efficiency.
>> Understanding the mechanism(s) that drives these changes is
>> particularly important for spacecraft devices, where the atomic
>> clocks are called upon to function continuously and reliably for
>> many years. Here, we consider the two well-known, but little
>> studied, modes associated with alkali rf-discharge lamp operation:
>> the ring mode and the red mode. Consistent with previous research,
>> we find that the ring mode is best for optical pumping, and that the
>> clock-signal amplitude degrades significantly when the lamp operates
>> in the red mode. Examining the emission spectrum as the lamp
>> transitions between these two modes, we show that the ring-mode to
>> red-mode transition is driven by radiation trapping within the lamp.
>>     
>
>
>   

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From wittend at wwrinc.com  Mon Nov  3 01:09:00 2008
From: wittend at wwrinc.com (David M. Witten II)
Date: Sun, 02 Nov 2008 19:09:00 -0600
Subject: [time-nuts]  Testing frequency using NTP
References: 000301c924c7$26073c30$0300a8c0@pc52
Message-ID: <490E4F2C.30201@wwrinc.com>


Poul-Henning Kamp wrote:

#--

Actually, the best hardware for the job is the Soekris NET4501
which can timestamp a signal to a quarter microsecond.

That's why we use it for NTP servers in the first place.

All the software you need is in the FreeBSD kernel, and there
is a handy userland program to get the measurments into ascii
format (the earlier mentioned ppsapitest program).

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

#--

I am familiar with your articles relating to the use of the Soekris 
NET4501 and its characterization when used with FreeBSD for timing 
purposes.  I am fortunate to have one on hand, but have some questions.

Can I still expect to see similar performance using more recent versions 
of FreeBSD than you originally used?

Will a usable build of FreeBSD 7.x run in the memory available on the 
older Soekris boards? (64 MB RAM)

I understand that there are features that made boards incorporating the 
133 MHz AMD ElanSC520 processors suitable for this purpose.  Are these 
features still present in the newer AMD Geode LX based boards?

Though I know that you have worked with Soekris products a lot, is there 
any reason that the same techniques cannot be applied to the WRAP and 
ALIX boards from PCEngines?  or perhaps an One Laptop Per Child (OLPC) XO?

I would appreciate any information that you can provide me.


Dave Witten


From wittend at wwrinc.com  Mon Nov  3 01:28:27 2008
From: wittend at wwrinc.com (David M. Witten II)
Date: Sun, 02 Nov 2008 19:28:27 -0600
Subject: [time-nuts]  Rb lamp lifetime...
Message-ID: <490E53BB.9010705@wwrinc.com>


How much would be reasonable to pay for one of these on EBay?  I see 
someone asking $259 for one.  I'm sure that TAPR's price was much 
better, but I wasn't paying attention.

Dave Witten



WB6BNQ wrote:


Yuri,

Sorry about that, but I guess the Trimble Thunderbolts are out of stock 
all ready.

Bill....WB6BNQ


WB6BNQ wrote:

 > Hi Yuri,
 >
 > Unless you need the longer term stability of an undisciplined Rb 
source, I think
 > you would be better served to get one of the ?Timenuts group? Trimble 
Thunderbolt
 > GPS units to use as a home standard.  It is available via this page:
 >


From SAIDJACK at aol.com  Mon Nov  3 01:35:36 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Sun, 2 Nov 2008 20:35:36 EST
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
Message-ID: <cc1.47d5d343.363faf68@aol.com>

Hello Matt,
 
let me try to answer some of your questions about the Fury with an  
Isotemp-134.
 
First I tried finding a datasheet for it, but Isotemp removed it from their  
website. All I could find was that it has about 5ppb -30 to +60C stability. So 
 it's performance is between our JLT standard single oven and double oven  
OCXO's. Not knowing the EFC sensitivity of the unit, I will give you some servo  
settings to try out and play with.
 
On the power up issues, you can try to run both the OCXO and the Fury from  
the same power supply. If the OCXO does not provide a stable 10MHz before the  
Fury comes out of reset then it won't boot up. So if you try power  cycling 
say 5 to 10 times and it always comes up (LED's turn on for several  seconds) 
then you are good to go. If it is marginal, then you may have to delay  the Fury 
power as some have suggested here. Or simply press the reset   button after 
power on (I presume you won't power cycle the unit very often when  in 
operation, so pressing reset after power on may work for you if the unit does  not 
boot).
 
On the EFC range, this depends on the aging and thermal sensitivity of the  
OCXO. 4.64V is still quite a ways below 5V, but it's getting to the edge of the 
 Fury range. There is no reason that it should not work, even if you go up to 
 4.8V or so due to aging etc.
 
If the unit ages downward (EFC voltage decreasing over time) then I would  
not worry. I would only add external circuitry to increase the EFC range if  
absolutely necessary, since any circuitry you will add will probably add  noise.
 
Now on the servo settings, try the following:
 
* Slope polarity: depends on the OCXO. If frequency goes up with increased  
EFC voltage, then set it to "positive". You can try changing the coarsedac up  
and down to see the slope of your OCXO (use the command serv:coarsedac  x   
where x is 0 to 255. Higher values result in higher efc  voltage.
 
* For this type of thermal stability, I would try a servo:efcs setting of  
about 2 to 4
 
* Try damping of 30. This value is not really that critical, any value will  
work that does not cause oscillation. Higher values result in "slower" 
sawtooth  filters and thus less noise
 
* Phaseco: try values of 15 to 25 and see how fast the unit pushes the  phase 
offset to 0ns. If its too slow for you, increase this value, but not to  the 
point where it oscillates.
 
* DAC gain: this depends on the OCXO EFC sensitivity. If it is a standard  
-20Hz to +20Hz over 0V to 5V then a value of 15 seems to work well.
 
If your unit locks up without overshoot/oscillation within 30 minutes with  
these settings then you are doing well, and can fine-tune the parameters from  
there.
 
Hope this helps,
bye,
Said
 
 
 
 
 




From: Matt Osborn <_kc0ukk at msosborn.com_ (mailto:kc0ukk at msosborn.com) >
Date:  November 1, 2008 23:28:34 PDT
To: time-nuts <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
Subject:  [time-nuts] Jackson Labs Fury & Isotemp  OCXO134-10
Reply-To: Discussion of precise time and frequency  measurement 
<_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >





I think that I've managed to keep a low profile here, trusting  that I
would learn more if I refrained from random  interjections of
ill-informed thoughts.  However, there  comes a point in every  man's
life...

A year or two  ago, I took advantage of Said's offer and purchased one
of  the Jackson Labs OEM external OCXO Fury units and am attempting  to
put it to work. I've decided to use an Isotemp OCXO134-10  oscillator
and have several decisions which I would like to  vet with those of you
that have been down this road  before.

The Isotemp unit has an EFC range  of 0 to 8 Volts; the Fury has an EFC
range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
Isotemp to  10 MHz +- 5 mHz with an EFC voltage of 4.64 volts. That  is
within the adjustment range of the Fury, but I'm not sure  of the
accuracy of the HP53131A.  Should I construct a  resistive network ala
Brooks Shera to 'boost' the EFC range  just in case or would I be
better off just using the Fury  'as is'?

Secondly, the Jackson Labs advises  that since the Fury uses the
external oscillator as its  clock, that the oscillator should be
powered up before the  Fury itself.  I was hoping that I would be able
to use  a single power switch to power both the oscillator and the  Fury
simultaneously, but now I'm not so  sure.

Finally, are there any of you that  have used the Isotemp OXCO134-10
with the Fury?  Have  any of you worked out the various SERVO settings
that the  Fury makes available?  I'm interested in the  DAC gain,  EFC
scale, EFC dampening and Phase  compensation.

Any and all advice will be  gratefully accepted.

-- kc0ukk at msosborn  dot  com

_______________________________________________
time-nuts  mailing list -- _time-nuts at febo.com_ (mailto:time-nuts at febo.com) 
To  unsubscribe, go to 
_https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) 
and  follow the instructions  there.


=


From wb6bnq at cox.net  Mon Nov  3 02:04:47 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Sun, 02 Nov 2008 18:04:47 -0800
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
References: <cc1.47d5d343.363faf68@aol.com>
Message-ID: <490E5C3F.C571D22C@cox.net>

Said,

Find attached two PDF files of the specs, drawing and pinout for the Isotemp 134-10.

Bill....WB6BNQ

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From imp at bsdimp.com  Mon Nov  3 02:32:46 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sun, 02 Nov 2008 19:32:46 -0700 (MST)
Subject: [time-nuts] Testing frequency using NTP
In-Reply-To: <490E4F2C.30201@wwrinc.com>
References: <490E4F2C.30201@wwrinc.com>
Message-ID: <20081102.193246.-625041382.imp@bsdimp.com>

In message: <490E4F2C.30201 at wwrinc.com>
            "David M. Witten II" <wittend at wwrinc.com> writes:
: Will a usable build of FreeBSD 7.x run in the memory available on the 
: older Soekris boards? (64 MB RAM)

No.  My router/dhcp server, mail forwarding anti-spam agent, external
DNS server are all on my soekris 4521.  I'm running 7.0 on it.  It
only has 64MB of memory and I've never had memory problems.

Warner


From imp at bsdimp.com  Mon Nov  3 02:38:15 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sun, 02 Nov 2008 19:38:15 -0700 (MST)
Subject: [time-nuts] Testing frequency using NTP
In-Reply-To: <20081102.193246.-625041382.imp@bsdimp.com>
References: <490E4F2C.30201@wwrinc.com>
	<20081102.193246.-625041382.imp@bsdimp.com>
Message-ID: <20081102.193815.1887074052.imp@bsdimp.com>

In message: <20081102.193246.-625041382.imp at bsdimp.com>
            "M. Warner Losh" <imp at bsdimp.com> writes:
: In message: <490E4F2C.30201 at wwrinc.com>
:             "David M. Witten II" <wittend at wwrinc.com> writes:
: : Will a usable build of FreeBSD 7.x run in the memory available on the 
: : older Soekris boards? (64 MB RAM)
: 
: No.  My router/dhcp server, mail forwarding anti-spam agent, external
: DNS server are all on my soekris 4521.  I'm running 7.0 on it.  It
: only has 64MB of memory and I've never had memory problems.

Errr, I should have said 'Yes.' My no was answering the question 'Will
it run out of memory?'

%vmstat
 procs      memory      page                   disk   faults      cpu
 r b w     avm    fre  flt  re  pi  po  fr  sr ad0   in   sy  cs us sy id
 0 0 0   38492  22576    2   0   0   0   1   0   0 1354   25 488  1  3 96

Warner


From SAIDJACK at aol.com  Mon Nov  3 03:56:29 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Sun, 2 Nov 2008 22:56:29 EST
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
Message-ID: <bc2.362c22e6.363fd06d@aol.com>

Hi Bill,
 
thanks for sending the datasheets.
 
Looks like the unit has nominally +/-6Hz EFC range, slightly less than the  
OCXO's we typically use.
 
I would thus try increasing the DAC Gain to about 30 to 40 and see how that  
works.
 
bye,
Said
 
 
In a message dated 11/2/2008 18:06:18 Pacific Standard Time, wb6bnq at cox.net  
writes:

Said,

Find attached two PDF files of the specs, drawing and  pinout for the Isotemp 
 134-10.

Bill....WB6BNQ



_______________________________________________
time-nuts  mailing list -- time-nuts at febo.com
To unsubscribe, go to  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.


From hmurray at megapathdsl.net  Mon Nov  3 08:21:38 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Mon, 03 Nov 2008 00:21:38 -0800
Subject: [time-nuts] What's the time Mr Wolf...
In-Reply-To: Message from "MOSEL Sam" <sam.mosel@baesystems.com> of "Mon,
	03 Nov 2008 09:21:00 +1100."
	<200811022221.mA2ML03n025457@sprint3.tenix.com> 
Message-ID: <20081103082139.4E8B1BCD5@ip-64-139-1-69.sjc.megapath.net>


> So everything is derived from this oscillator, which is actually
> 10.22999999543 MHz. This -4.57 mHz corrects for relativistic effects. 

Neat.  Thanks.

I got curious.  How does that compare to the Doppler shifts?

google found this nice description of GPS :
  http://www.go.ednet.ns.ca/~larry/gps/gps_talk.html

It says the Doppler shift is up to 2400 HZ.

That's a half-million times the relativistic correction.




-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From phk at phk.freebsd.dk  Mon Nov  3 08:51:27 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Mon, 03 Nov 2008 08:51:27 +0000
Subject: [time-nuts] Testing frequency using NTP
In-Reply-To: Your message of "Sun, 02 Nov 2008 19:09:00 CST."
	<490E4F2C.30201@wwrinc.com> 
Message-ID: <40399.1225702287@critter.freebsd.dk>

In message <490E4F2C.30201 at wwrinc.com>, "David M. Witten II" writes:

>Can I still expect to see similar performance using more recent versions 
>of FreeBSD than you originally used?

Yes, the timestamping is done in hardware, so it does not depend on
the OS version.

>Will a usable build of FreeBSD 7.x run in the memory available on the 
>older Soekris boards? (64 MB RAM)

Absolutely.

>I understand that there are features that made boards incorporating the 
>133 MHz AMD ElanSC520 processors suitable for this purpose.  Are these 
>features still present in the newer AMD Geode LX based boards?

No.

>Though I know that you have worked with Soekris products a lot, is there 
>any reason that the same techniques cannot be applied to the WRAP and 
>ALIX boards from PCEngines?  or perhaps an One Laptop Per Child (OLPC) XO?

It all comes down to the special counter hardware in the Elan520 CPU,
any board with an Elan520 where you can get at the timer1 pin is fine.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From richiem at hughes.net  Mon Nov  3 09:05:04 2008
From: richiem at hughes.net (Richard Moore)
Date: Mon, 3 Nov 2008 01:05:04 -0800
Subject: [time-nuts] Isotemp 134-10 & Fury
In-Reply-To: <mailman.4.1225677892.2542.time-nuts@febo.com>
References: <mailman.4.1225677892.2542.time-nuts@febo.com>
Message-ID: <FC568505-8BA8-4762-B644-49EFE3736986@hughes.net>

The Isotemp 134-10 *may* have a screw in the side of the case that  
gives access to a trimmer for the frequency. You can set your Fury to  
an EFC output of 2.5V and try adjusting the trimmer for 10MHz or as  
close as you can get it. This will optimize your control range from  
the Fury, with the proviso that the Isotemp's control slope is not  
linear. My OFC version does not have the access port, but it it a  
much earlier model than the Isotemp 134. The Isotemp has a positive  
control slope -- increasing EFC increases frequency. Mine has an EFC  
sensitivity of about 2E-7 per Volt.

Dick Moore


> From: Matt Osborn <_kc0ukk at msosborn.com_  
> (mailto:kc0ukk at msosborn.com) >
> Date:  November 1, 2008 23:28:34 PDT
> To: time-nuts <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
> Subject:  [time-nuts] Jackson Labs Fury & Isotemp  OCXO134-10
> Reply-To: Discussion of precise time and frequency  measurement
> <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
>
> I think that I've managed to keep a low profile here, trusting  that I
> would learn more if I refrained from random  interjections of
> ill-informed thoughts.  However, there  comes a point in every  man's
> life...
>
> A year or two  ago, I took advantage of Said's offer and purchased one
> of  the Jackson Labs OEM external OCXO Fury units and am  
> attempting  to
> put it to work. I've decided to use an Isotemp OCXO134-10  oscillator
> and have several decisions which I would like to  vet with those of  
> you
> that have been down this road  before.
>
> The Isotemp unit has an EFC range  of 0 to 8 Volts; the Fury has an  
> EFC
> range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
> Isotemp to  10 MHz +- 5 mHz with an EFC voltage of 4.64 volts.  
> That  is
> within the adjustment range of the Fury, but I'm not sure  of the
> accuracy of the HP53131A.  Should I construct a  resistive network ala
> Brooks Shera to 'boost' the EFC range  just in case or would I be
> better off just using the Fury  'as is'?
>
> Secondly, the Jackson Labs advises  that since the Fury uses the
> external oscillator as its  clock, that the oscillator should be
> powered up before the  Fury itself.  I was hoping that I would be able
> to use  a single power switch to power both the oscillator and the   
> Fury
> simultaneously, but now I'm not so  sure.
>
> Finally, are there any of you that  have used the Isotemp OXCO134-10
> with the Fury?  Have  any of you worked out the various SERVO settings
> that the  Fury makes available?  I'm interested in the  DAC gain,  EFC
> scale, EFC dampening and Phase  compensation.
>
> Any and all advice will be  gratefully accepted.
>
> -- kc0ukk at msosborn  dot  com
>


From bg at lysator.liu.se  Mon Nov  3 11:07:07 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Mon, 03 Nov 2008 12:07:07 +0100
Subject: [time-nuts] What's the time Mr Wolf...
In-Reply-To: <20081103082139.4E8B1BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081103082139.4E8B1BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <1225710427.6068.13.camel@bg-desktop>

On Mon, 2008-11-03 at 00:21 -0800, Hal Murray wrote:
> > So everything is derived from this oscillator, which is actually
> > 10.22999999543 MHz. This -4.57 mHz corrects for relativistic
> effects. 
> 
> Neat.  Thanks.
> 
> I got curious.  How does that compare to the Doppler shifts?
> 
> google found this nice description of GPS :
>   http://www.go.ednet.ns.ca/~larry/gps/gps_talk.html
> 
> It says the Doppler shift is up to 2400 HZ.
> 
> That's a half-million times the relativistic correction.

There is also about 1 kHz frequency uncertainty from the crystal driving
the GPS receiver. As most receivers use oscillators specified at about
0.5ppm.

btw... I once heard a story that early GPS SVs could turn off the
relativistic compensation. There was also a switch to reverse the
sign... ;-)

--

    Bj?rn



From phill.r1 at btinternet.com  Mon Nov  3 11:43:43 2008
From: phill.r1 at btinternet.com (Roy Phillips)
Date: Mon, 3 Nov 2008 11:43:43 -0000
Subject: [time-nuts] Rb lamp lifetime...
In-Reply-To: <490E53BB.9010705@wwrinc.com>
References: <490E53BB.9010705@wwrinc.com>
Message-ID: <E2CC0DFDEE7442B58F24331DE0D634AC@LapTop>

David

I would suggest that you email Bob Mokia ,(China) ,directly at 
mokia1985 at gmail.com  requesting his "best" price. I obtained my TBolt from 
this source. It was a 2004 issue, and in excellent condition. It has been 
performing superbly for the past three weeks, and in my case it had replaced 
my Odetics 325.
I trust I am not breaking the rules by making this suggestion, but I was 
also disappointed when I failed to obtain a TBolt through TAPR when the 
offers were made.

Roy Phillips

----- Original Message ----- 
From: "David M. Witten II" <wittend at wwrinc.com>
To: <time-nuts at febo.com>; <wb6bnq at cox.net>
Sent: Monday, November 03, 2008 1:28 AM
Subject: [time-nuts] Rb lamp lifetime...



How much would be reasonable to pay for one of these on EBay?  I see
someone asking $259 for one.  I'm sure that TAPR's price was much
better, but I wasn't paying attention.

Dave Witten



WB6BNQ wrote:


Yuri,

Sorry about that, but I guess the Trimble Thunderbolts are out of stock
all ready.

Bill....WB6BNQ


WB6BNQ wrote:

 > Hi Yuri,
 >
 > Unless you need the longer term stability of an undisciplined Rb
source, I think
 > you would be better served to get one of the ?Timenuts group? Trimble
Thunderbolt
 > GPS units to use as a home standard.  It is available via this page:
 >

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.




From tvb at LeapSecond.com  Mon Nov  3 13:35:48 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Mon, 3 Nov 2008 05:35:48 -0800
Subject: [time-nuts] What's the time Mr Wolf...
References: <20081103082139.4E8B1BCD5@ip-64-139-1-69.sjc.megapath.net>
	<1225710427.6068.13.camel@bg-desktop>
Message-ID: <004401c93db9$153bbb50$76490a0a@pc52>

> btw... I once heard a story that early GPS SVs could turn off the
> relativistic compensation. There was also a switch to reverse the
> sign... ;-)

I don't remember hearing there was a sign reversal switch,
but all the other details on the first pre-GPS SV are here:

http://www.leapsecond.com/history/Ashby-Relativity.htm

/tvb



From j.bastemeijer at tudelft.nl  Mon Nov  3 14:37:45 2008
From: j.bastemeijer at tudelft.nl (Jeroen Bastemeijer)
Date: Mon, 03 Nov 2008 15:37:45 +0100
Subject: [time-nuts] HP1600A manual
In-Reply-To: <09f401c93c84$815cebf0$7900a8c0@athlon1200>
References: <490ACB7D.5090700@tudelft.nl>
	<09f401c93c84$815cebf0$7900a8c0@athlon1200>
Message-ID: <490F0CB9.5060001@tudelft.nl>

Hi Dave,

Thank you! Usually there is a section in the manual to do a quick 
performance test. If it would be possible to scan this part, that would 
help a lot!

Thank you, looking forward to your next message.

Best regards, Jeroen

Dave Brown wrote:
> I have a mint 1600A plus manual (s?) here somewhere, Jeroen- will  try 
> to find it/them!  Sorry, no digital copy though but I should be able 
> to scan some of it for you.
> DaveB, NZ
>
> ----- Original Message ----- 
> From: "Jeroen Bastemeijer" <j.bastemeijer at tudelft.nl>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> Sent: Friday, October 31, 2008 10:10 PM
> Subject: [time-nuts] HP1600A manual
>
>
>   
>> Dear All,
>>
>> Is there anyone out there who has a digital copy of the HP 1600A 
>> logic
>> analyzer manual? I found such an old machine, and I'm wondering if 
>> it is
>> still working...
>>
>> There are manuals for sale for approx $50 (excl. shipping). However, 
>> the
>> HP1600A seems not to be very responsive. So, investing $50 for a 
>> machine
>> which is defective and probably cannot be repaired seems like a 
>> waste.
>>
>> Or is there anyone who can give a hint on how to test a HP 1600A, to 
>> get
>> a good indication if it is still functioning (reasonably) okay. At 
>> this
>> moment the machine seems to be locked up. Allthough there is a nice
>> pattern of 1's and 0's on the screen....
>>
>> Thanks, best regards Jeroen
>>
>>     
>
>
> --------------------------------------------------------------------------------
>
>
>   
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>     
>
>
> --------------------------------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.175 / Virus Database: 270.8.5/1757 - Release Date: 
> 30/10/2008 14:35
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>   
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From gretchendenisebaxter at gmail.com  Mon Nov  3 17:03:01 2008
From: gretchendenisebaxter at gmail.com (Gretchen Baxter)
Date: Mon, 3 Nov 2008 12:03:01 -0500
Subject: [time-nuts] =?windows-1252?q?Do_any_regulations_or_laws_require_t?=
	=?windows-1252?q?ime_to_be_accurate_within_=91x=92_seconds=3F?=
Message-ID: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>

Greetings,

There are a lot of regulations that mandate synchronized time.

But do any of these regulations or laws require time to be accurate within
'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
time.

Thanx,

Gretchen

From alan.melia at btinternet.com  Mon Nov  3 19:21:55 2008
From: alan.melia at btinternet.com (Alan Melia)
Date: Mon, 3 Nov 2008 19:21:55 -0000
Subject: [time-nuts]
	=?iso-8859-1?q?Do_any_regulations_or_laws_require_tim?=
	=?iso-8859-1?q?e_to_be_accurate_within_=27x=27_seconds=3F?=
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
Message-ID: <000f01c93de9$8cbf6e80$0900a8c0@AM>


----- Original Message -----
From: "Gretchen Baxter" <gretchendenisebaxter at gmail.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Monday, November 03, 2008 5:03 PM
Subject: [time-nuts] Do any regulations or laws require time to be accurate
within 'x' seconds?


> Greetings,
>
> There are a lot of regulations that mandate synchronized time.
>
> But do any of these regulations or laws require time to be accurate within
> 'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
> time.
>
> Thanx,
>
> Gretchen
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From nhbbobb at gmail.com  Mon Nov  3 19:23:51 2008
From: nhbbobb at gmail.com (bbobb mokai)
Date: Tue, 4 Nov 2008 03:23:51 +0800
Subject: [time-nuts] Rb lamp lifetime...
Message-ID: <3eb99ee60811031123y31391f33u44f6de214be6f4f8@mail.gmail.com>

Hello Roy
Thanks,I am Bob also the fluke.l on ebay.Most of the gentlemans at here seem
have known me.

As the Time-nuts member .if any  member buy any stuff on my ebay store.
if you Directly use the  Paypal not from ebay,i will  offer 5 % discount .

and if my goods have any problem and No Function when you get.just tell me.
let me solve it.

Most of time,just pay me the shipping fee will ok.i send the replacement.

About some one say how i can get so many Rubidium oscillator for selling .

This Q

Most of the Rb , from USA ,the every lucent's or Nortel's BTS have one Rb as
standard.


Thanks and best regards
Bob

2008/11/3 <time-nuts-request at febo.com>

> Send time-nuts mailing list submissions to
>        time-nuts at febo.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
>        https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> or, via email, send a message with subject or body 'help' to
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>
> You can reach the person managing the list at
>        time-nuts-owner at febo.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of time-nuts digest..."
>
>
> Today's Topics:
>
>   1. Re: Testing frequency using NTP (M. Warner Losh)
>   2. Re: Testing frequency using NTP (M. Warner Losh)
>   3. Re: Jackson Labs Fury & Isotemp OCXO134-10 (SAIDJACK at aol.com)
>   4. Re: What's the time Mr Wolf... (Hal Murray)
>   5. Re: Testing frequency using NTP (Poul-Henning Kamp)
>   6. Re: Isotemp 134-10 & Fury (Richard Moore)
>   7. Re: What's the time Mr Wolf... (Bj?rn Gabrielsson)
>   8. Re: Rb lamp lifetime... (Roy Phillips)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 02 Nov 2008 19:32:46 -0700 (MST)
> From: "M. Warner Losh" <imp at bsdimp.com>
> Subject: Re: [time-nuts] Testing frequency using NTP
> To: time-nuts at febo.com, wittend at wwrinc.com
> Message-ID: <20081102.193246.-625041382.imp at bsdimp.com>
> Content-Type: Text/Plain; charset=us-ascii
>
> In message: <490E4F2C.30201 at wwrinc.com>
>            "David M. Witten II" <wittend at wwrinc.com> writes:
> : Will a usable build of FreeBSD 7.x run in the memory available on the
> : older Soekris boards? (64 MB RAM)
>
> No.  My router/dhcp server, mail forwarding anti-spam agent, external
> DNS server are all on my soekris 4521.  I'm running 7.0 on it.  It
> only has 64MB of memory and I've never had memory problems.
>
> Warner
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 02 Nov 2008 19:38:15 -0700 (MST)
> From: "M. Warner Losh" <imp at bsdimp.com>
> Subject: Re: [time-nuts] Testing frequency using NTP
> To: time-nuts at febo.com, wittend at wwrinc.com
> Message-ID: <20081102.193815.1887074052.imp at bsdimp.com>
> Content-Type: Text/Plain; charset=us-ascii
>
> In message: <20081102.193246.-625041382.imp at bsdimp.com>
>            "M. Warner Losh" <imp at bsdimp.com> writes:
> : In message: <490E4F2C.30201 at wwrinc.com>
> :             "David M. Witten II" <wittend at wwrinc.com> writes:
> : : Will a usable build of FreeBSD 7.x run in the memory available on the
> : : older Soekris boards? (64 MB RAM)
> :
> : No.  My router/dhcp server, mail forwarding anti-spam agent, external
> : DNS server are all on my soekris 4521.  I'm running 7.0 on it.  It
> : only has 64MB of memory and I've never had memory problems.
>
> Errr, I should have said 'Yes.' My no was answering the question 'Will
> it run out of memory?'
>
> %vmstat
>  procs      memory      page                   disk   faults      cpu
>  r b w     avm    fre  flt  re  pi  po  fr  sr ad0   in   sy  cs us sy id
>  0 0 0   38492  22576    2   0   0   0   1   0   0 1354   25 488  1  3 96
>
> Warner
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 2 Nov 2008 22:56:29 EST
> From: SAIDJACK at aol.com
> Subject: Re: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
> To: time-nuts at febo.com
> Message-ID: <bc2.362c22e6.363fd06d at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Hi Bill,
>
> thanks for sending the datasheets.
>
> Looks like the unit has nominally +/-6Hz EFC range, slightly less than the
> OCXO's we typically use.
>
> I would thus try increasing the DAC Gain to about 30 to 40 and see how that
> works.
>
> bye,
> Said
>
>
> In a message dated 11/2/2008 18:06:18 Pacific Standard Time,
> wb6bnq at cox.net
> writes:
>
> Said,
>
> Find attached two PDF files of the specs, drawing and  pinout for the
> Isotemp
>  134-10.
>
> Bill....WB6BNQ
>
>
>
> _______________________________________________
> time-nuts  mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the  instructions there.
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 03 Nov 2008 00:21:38 -0800
> From: Hal Murray <hmurray at megapathdsl.net>
> Subject: Re: [time-nuts] What's the time Mr Wolf...
> To: Discussion of precise time and frequency measurement
>        <time-nuts at febo.com>
> Message-ID: <20081103082139.4E8B1BCD5 at ip-64-139-1-69.sjc.megapath.net>
> Content-Type: text/plain; charset=us-ascii
>
>
> > So everything is derived from this oscillator, which is actually
> > 10.22999999543 MHz. This -4.57 mHz corrects for relativistic effects.
>
> Neat.  Thanks.
>
> I got curious.  How does that compare to the Doppler shifts?
>
> google found this nice description of GPS :
>  http://www.go.ednet.ns.ca/~larry/gps/gps_talk.html<http://www.go.ednet.ns.ca/%7Elarry/gps/gps_talk.html>
>
> It says the Doppler shift is up to 2400 HZ.
>
> That's a half-million times the relativistic correction.
>
>
>
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 03 Nov 2008 08:51:27 +0000
> From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
> Subject: Re: [time-nuts] Testing frequency using NTP
> To: Discussion of precise time and frequency measurement
>        <time-nuts at febo.com>
> Message-ID: <40399.1225702287 at critter.freebsd.dk>
>
> In message <490E4F2C.30201 at wwrinc.com>, "David M. Witten II" writes:
>
> >Can I still expect to see similar performance using more recent versions
> >of FreeBSD than you originally used?
>
> Yes, the timestamping is done in hardware, so it does not depend on
> the OS version.
>
> >Will a usable build of FreeBSD 7.x run in the memory available on the
> >older Soekris boards? (64 MB RAM)
>
> Absolutely.
>
> >I understand that there are features that made boards incorporating the
> >133 MHz AMD ElanSC520 processors suitable for this purpose.  Are these
> >features still present in the newer AMD Geode LX based boards?
>
> No.
>
> >Though I know that you have worked with Soekris products a lot, is there
> >any reason that the same techniques cannot be applied to the WRAP and
> >ALIX boards from PCEngines?  or perhaps an One Laptop Per Child (OLPC) XO?
>
> It all comes down to the special counter hardware in the Elan520 CPU,
> any board with an Elan520 where you can get at the timer1 pin is fine.
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 3 Nov 2008 01:05:04 -0800
> From: Richard Moore <richiem at hughes.net>
> Subject: Re: [time-nuts] Isotemp 134-10 & Fury
> To: time-nuts at febo.com
> Message-ID: <FC568505-8BA8-4762-B644-49EFE3736986 at hughes.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> The Isotemp 134-10 *may* have a screw in the side of the case that
> gives access to a trimmer for the frequency. You can set your Fury to
> an EFC output of 2.5V and try adjusting the trimmer for 10MHz or as
> close as you can get it. This will optimize your control range from
> the Fury, with the proviso that the Isotemp's control slope is not
> linear. My OFC version does not have the access port, but it it a
> much earlier model than the Isotemp 134. The Isotemp has a positive
> control slope -- increasing EFC increases frequency. Mine has an EFC
> sensitivity of about 2E-7 per Volt.
>
> Dick Moore
>
>
> > From: Matt Osborn <_kc0ukk at msosborn.com_
> > (mailto:kc0ukk at msosborn.com) >
> > Date:  November 1, 2008 23:28:34 PDT
> > To: time-nuts <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
> > Subject:  [time-nuts] Jackson Labs Fury & Isotemp  OCXO134-10
> > Reply-To: Discussion of precise time and frequency  measurement
> > <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
> >
> > I think that I've managed to keep a low profile here, trusting  that I
> > would learn more if I refrained from random  interjections of
> > ill-informed thoughts.  However, there  comes a point in every  man's
> > life...
> >
> > A year or two  ago, I took advantage of Said's offer and purchased one
> > of  the Jackson Labs OEM external OCXO Fury units and am
> > attempting  to
> > put it to work. I've decided to use an Isotemp OCXO134-10  oscillator
> > and have several decisions which I would like to  vet with those of
> > you
> > that have been down this road  before.
> >
> > The Isotemp unit has an EFC range  of 0 to 8 Volts; the Fury has an
> > EFC
> > range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
> > Isotemp to  10 MHz +- 5 mHz with an EFC voltage of 4.64 volts.
> > That  is
> > within the adjustment range of the Fury, but I'm not sure  of the
> > accuracy of the HP53131A.  Should I construct a  resistive network ala
> > Brooks Shera to 'boost' the EFC range  just in case or would I be
> > better off just using the Fury  'as is'?
> >
> > Secondly, the Jackson Labs advises  that since the Fury uses the
> > external oscillator as its  clock, that the oscillator should be
> > powered up before the  Fury itself.  I was hoping that I would be able
> > to use  a single power switch to power both the oscillator and the
> > Fury
> > simultaneously, but now I'm not so  sure.
> >
> > Finally, are there any of you that  have used the Isotemp OXCO134-10
> > with the Fury?  Have  any of you worked out the various SERVO settings
> > that the  Fury makes available?  I'm interested in the  DAC gain,  EFC
> > scale, EFC dampening and Phase  compensation.
> >
> > Any and all advice will be  gratefully accepted.
> >
> > -- kc0ukk at msosborn  dot  com
> >
>
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 03 Nov 2008 12:07:07 +0100
> From: Bj?rn Gabrielsson <bg at lysator.liu.se>
> Subject: Re: [time-nuts] What's the time Mr Wolf...
> To: Discussion of precise time and frequency measurement
>        <time-nuts at febo.com>
> Message-ID: <1225710427.6068.13.camel at bg-desktop>
> Content-Type: text/plain; charset=utf-8
>
> On Mon, 2008-11-03 at 00:21 -0800, Hal Murray wrote:
> > > So everything is derived from this oscillator, which is actually
> > > 10.22999999543 MHz. This -4.57 mHz corrects for relativistic
> > effects.
> >
> > Neat.  Thanks.
> >
> > I got curious.  How does that compare to the Doppler shifts?
> >
> > google found this nice description of GPS :
> >   http://www.go.ednet.ns.ca/~larry/gps/gps_talk.html<http://www.go.ednet.ns.ca/%7Elarry/gps/gps_talk.html>
> >
> > It says the Doppler shift is up to 2400 HZ.
> >
> > That's a half-million times the relativistic correction.
>
> There is also about 1 kHz frequency uncertainty from the crystal driving
> the GPS receiver. As most receivers use oscillators specified at about
> 0.5ppm.
>
> btw... I once heard a story that early GPS SVs could turn off the
> relativistic compensation. There was also a switch to reverse the
> sign... ;-)
>
> --
>
>    Bj?rn
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 3 Nov 2008 11:43:43 -0000
> From: "Roy Phillips" <phill.r1 at btinternet.com>
> Subject: Re: [time-nuts] Rb lamp lifetime...
> To: "Discussion of precise time and frequency measurement"
>        <time-nuts at febo.com>
> Message-ID: <E2CC0DFDEE7442B58F24331DE0D634AC at LapTop>
> Content-Type: text/plain; format=flowed; charset="Windows-1252";
>        reply-type=original
>
> David
>
> I would suggest that you email Bob Mokia ,(China) ,directly at
> mokia1985 at gmail.com  requesting his "best" price. I obtained my TBolt from
> this source. It was a 2004 issue, and in excellent condition. It has been
> performing superbly for the past three weeks, and in my case it had
> replaced
> my Odetics 325.
> I trust I am not breaking the rules by making this suggestion, but I was
> also disappointed when I failed to obtain a TBolt through TAPR when the
> offers were made.
>
> Roy Phillips
>
> ----- Original Message -----
> From: "David M. Witten II" <wittend at wwrinc.com>
> To: <time-nuts at febo.com>; <wb6bnq at cox.net>
> Sent: Monday, November 03, 2008 1:28 AM
> Subject: [time-nuts] Rb lamp lifetime...
>
>
>
> How much would be reasonable to pay for one of these on EBay?  I see
> someone asking $259 for one.  I'm sure that TAPR's price was much
> better, but I wasn't paying attention.
>
> Dave Witten
>
>
>
> WB6BNQ wrote:
>
>
> Yuri,
>
> Sorry about that, but I guess the Trimble Thunderbolts are out of stock
> all ready.
>
> Bill....WB6BNQ
>
>
> WB6BNQ wrote:
>
>  > Hi Yuri,
>  >
>  > Unless you need the longer term stability of an undisciplined Rb
> source, I think
>  > you would be better served to get one of the ?Timenuts group? Trimble
> Thunderbolt
>  > GPS units to use as a home standard.  It is available via this page:
>  >
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
>
>
> ------------------------------
>
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
> End of time-nuts Digest, Vol 52, Issue 10
> *****************************************
>

From nhbbobb at gmail.com  Mon Nov  3 19:26:23 2008
From: nhbbobb at gmail.com (bbobb mokai)
Date: Tue, 4 Nov 2008 03:26:23 +0800
Subject: [time-nuts] Rb lamp lifetime...
Message-ID: <3eb99ee60811031126p58bd872ax337d1111efc60ce2@mail.gmail.com>

Hello
Thanks for your PDF

Bob



> Message: 5
> Date: Mon, 03 Nov 2008 01:46:37 +0100
> From: Adrian <rfnuts at arcor.de>
> Subject: Re: [time-nuts] Rb lamp lifetime...
> To: Yuri Ostry <yuri at ostry.ru>,         Discussion of precise time and
>        frequency measurement <time-nuts at febo.com>
> Message-ID: <490E49ED.80906 at arcor.de>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello,
>
> there are some interesting hints (including lamp rejuvenation) in the
> attached papaer that was posted here a few months ago by Gerald
> Molenkamp VK3FGJM.
>
> Regards,
> Adrian
>
>
> Yuri Ostry schrieb:
> > Hello,
> >
> > Readed list archives and googled a lot, and seen two opposing points of
> > view - one is that there is nothing to age in Rb lamp, another is that
> > Rb lamp is degrading when in operation (without details, how and why).
> >
> > I'm planning to get some Efratom Rb oscillator to use it in a
> > constantly running home lab frequency reference. Trying to understand
> > for myself, is it worth to get spare unit (or even two) of the same
> > model just to have replacement lamp on hand.
> >
> > One more question - does someone seen Rb standard that is
> > malfunctioned due to degraded lamp, that, at same time, does have
> > good vacuum. If so, which model, and how the failed lamp looks like?
> > Was there any attempts to "rejuvenate" the lamp? (for example, heating
> > to remove glass darkening, if any, or similar experiments).
> >
> > By the way, I'm very curious about physical process that may cause
> > lamp degradation.
> >
> > Rubidium-87 that is included in the lamp (according to
> > manuals) is a radionuclide, beta emitter. It decays very slowly (4.7
> > billion years half life) to stable Strontium-87, emitting 282.62keV
> > electrons and (anti?)neutrino. I don't think that 87Rb decay may
> > interfere with unit operation after tens of years, unless 87Sr is
> > "poisonous" so much so it can interfere with lamp operation even in
> > tiniest amounts.
> >
> > The only reference I located to date, is following article, that is
> > not available to general public. It is hard to understand for me just
> > from this abstract, does it specifically related to space environment
> > factors, or it is something that may cause degradation of Rb clocks
> > that is operated in average lab on Earth. ;)
> >
> >
> >> A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to
> >> Red-Mode Transition in rf-Discharge Lamps
> >> Camparo, J.   Mackay, R.
> >> Aerosp. Corp., El Segundo;
> >>
> >>
> >> This paper appears in: Frequency Control Symposium, 2007 Joint with
> >> the 21st European Frequency and Time Forum. IEEE International
> >> Publication Date: May 29 2007-June 1 2007
> >> On page(s): 45-48
> >> Location: Geneva,
> >> ISSN: 1075-6787
> >> ISBN: 978-1-4244-0647-0
> >> INSPEC Accession Number: 9805223
> >> Digital Object Identifier: 10.1109/FREQ.2007.4319027
> >> Current Version Published: 2007-10-01
> >>
> >>
> >>
> >>
> >>
> >> Abstract
> >> In the vapor-cell atomic clock, long-term stability can be
> >> influenced by slow variations in the discharge lamp's output via the
> >> light-shift effect. Additionally, over a multi-year mission lifetime
> >> the lamp's aging can degrade its optical pumping efficiency.
> >> Understanding the mechanism(s) that drives these changes is
> >> particularly important for spacecraft devices, where the atomic
> >> clocks are called upon to function continuously and reliably for
> >> many years. Here, we consider the two well-known, but little
> >> studied, modes associated with alkali rf-discharge lamp operation:
> >> the ring mode and the red mode. Consistent with previous research,
> >> we find that the ring mode is best for optical pumping, and that the
> >> clock-signal amplitude degrades significantly when the lamp operates
> >> in the red mode. Examining the emission spectrum as the lamp
> >> transitions between these two modes, we show that the ring-mode to
> >> red-mode transition is driven by radiation trapping within the lamp.
> >>
> >
> >
> >
>
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: EFRATOM Model FRS Lamp assembly repair.pdf
> Type: application/pdf
> Size: 59765 bytes
> Desc: not available
> Url :
> http://www.febo.com/pipermail/time-nuts/attachments/20081103/c205b683/attachment.pdf
>
> ------------------------------
>
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
> End of time-nuts Digest, Vol 52, Issue 8
> ****************************************
>

From kc0ukk at msosborn.com  Tue Nov  4 00:59:42 2008
From: kc0ukk at msosborn.com (Matt Osborn)
Date: Mon, 03 Nov 2008 18:59:42 -0600
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
In-Reply-To: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
References: <nkfqg4p4rn09u764uo56t48e85irc2ptmm@4ax.com>
Message-ID: <nr5vg4dm8hkeol99g93gk8ic5puqrvpcub@4ax.com>

On Sun, 02 Nov 2008 01:28:34 -0500, Matt Osborn <kc0ukk at msosborn.com>
wrote:

Hi all,

Thanks for all the help and ideas with the IsoTemp/Fury combination. I
followed Hal Murray's advice fired up the combination yesterday (its
been running for about 24 hours now) and everything is working as
advertised.  The IsoTemp locked in with an EFC of 4.523xxxx and today
is down to 4.498xxxx volts and falling slowly, so it would appear that
boosting the Fury EFC range won't be necessary.

Bruce Griffiths suggested a 1.6 gain buffer amplifier and Jim Miller
had designed that exact amplifier to boost an EFC range of 0 - 5v to 0
- 8v specifically for the IsoTemp OCXO134.  Jim had a PCB available,
so I ordered it and will build that up if the IsoTemp starts aging in
the wrong direction. I believe that problem has been addressed.

I've not yet solved the power sequence problem (if it exists); I'll
follow Said's advice and just try powering both from the same supply
and see if the Fury reset hold time is sufficient.  If not, I'll
pursue Jim Hall's MAX6819 approach. That would seem to be a simple and
inexpensive  solution.

Now I'm trying to understand Bill Jones' GPSCon program and what it is
telling me about the Fury GPSDO.  With some history provided by GPSCon
and a better understanding of just what, exactly, I should expect to
see and to strive for, I will apply Said's suggestions and see what
develops.

BTW, it would appear as though my HP 53131A counter reads 220 mHz low
with a 2 second gate time.  There appears to be no appreciable drift;
it always reads 220 mHz low.  I'm sure there is a name for that
measurement, I hope to learn it soon.

Thanks to all for your help. I'm amazed at the high signal to noise
ratio on this list.

-- kc0ukk at msosborn dot com


From hmurray at megapathdsl.net  Tue Nov  4 01:14:26 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Mon, 03 Nov 2008 17:14:26 -0800
Subject: [time-nuts] Jackson Labs Fury & Isotemp OCXO134-10
In-Reply-To: Message from Matt Osborn <kc0ukk@msosborn.com> of "Mon,
	03 Nov 2008 18:59:42 CST." <nr5vg4dm8hkeol99g93gk8ic5puqrvpcub@4ax.com>
Message-ID: <20081104011427.790EABCD5@ip-64-139-1-69.sjc.megapath.net>


> BTW, it would appear as though my HP 53131A counter reads 220 mHz low
> with a 2 second gate time.  There appears to be no appreciable drift;
> it always reads 220 mHz low.  I'm sure there is a name for that
> measurement, I hope to learn it soon. 

Congratulations.  You just measured the frequency of the crystal inside your 
53131A.

Stand on your head and it will make sense.  If you feed an unknown signal in, 
you can measure its frequency.  But that's only as accurate as the internal 
clock.  If you know the frequency of the external signal more accurately than 
the internal clock you end up measuring the internal clock.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From w1ksz at earthlink.net  Tue Nov  4 02:55:24 2008
From: w1ksz at earthlink.net (Richard W. Solomon)
Date: Mon, 3 Nov 2008 19:55:24 -0700 (GMT-07:00)
Subject: [time-nuts] Trimble T-Bolt Order
Message-ID: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>

Have folks received their T-Bolts from the last batch via TAPR ?

A friend ordered one the first day, got his confirmation and is still
waiting.

Thanks, Dick, W1KSZ


From aa8k at comcast.net  Tue Nov  4 03:32:58 2008
From: aa8k at comcast.net (Mike Naruta AA8K)
Date: Mon, 03 Nov 2008 22:32:58 -0500
Subject: [time-nuts] Trimble T-Bolt Order
In-Reply-To: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>
References: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>
Message-ID: <490FC26A.5020907@comcast.net>

Got mine a couple of days ago.

Thanks TAPR!  I finally have a standard besides WWV.


Mike - AA8K



Richard W. Solomon wrote:
> Have folks received their T-Bolts from the last batch via TAPR ?
> 
> A friend ordered one the first day, got his confirmation and is still
> waiting.
> 
> Thanks, Dick, W1KSZ
> 


From ernieperes at aol.com  Tue Nov  4 06:11:00 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Tue, 04 Nov 2008 01:11:00 -0500
Subject: [time-nuts] Trimble T-Bolt Order
In-Reply-To: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>
References: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>
Message-ID: <8CB0C5B3E03AC97-EC8-A74@MBLK-M30.sysops.aol.com>

Hi Dick,

So far not yet received but the unit usually goes thru the custom 
office long process...

Rgds Ernie.


-----Original Message-----
From: Richard W. Solomon <w1ksz at earthlink.net>
To: time-nuts at febo.com
Sent: Tue, 4 Nov 2008 3:55 am
Subject: [time-nuts] Trimble T-Bolt Order



Have folks received their T-Bolts from the last batch via TAPR ?

A friend ordered one the first day, got his confirmation and is still
waiting.

Thanks, Dick, W1KSZ

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From stanley_reynolds at yahoo.com  Tue Nov  4 13:31:05 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Tue, 4 Nov 2008 05:31:05 -0800 (PST)
Subject: [time-nuts] Trimble T-Bolt Order
References: <31946930.1225767325206.JavaMail.root@elwamui-milano.atl.sa.earthlink.net>
Message-ID: <790706.22830.qm@web30301.mail.mud.yahoo.com>

Dick

Yes, Received an email the day they shipped to let me know that they charged my credit card. Thanks to all that made this possible. 

Stanley




________________________________
From: Richard W. Solomon <w1ksz at earthlink.net>
To: time-nuts at febo.com
Sent: Monday, November 3, 2008 8:55:24 PM
Subject: [time-nuts] Trimble T-Bolt Order

Have folks received their T-Bolts from the last batch via TAPR ?

A friend ordered one the first day, got his confirmation and is still
waiting.

Thanks, Dick, W1KSZ

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From pvince at theiet.org  Tue Nov  4 13:38:30 2008
From: pvince at theiet.org (Peter Vince)
Date: Tue, 04 Nov 2008 13:38:30 +0000
Subject: [time-nuts] Time-zones and World time..
Message-ID: <1575.1225805910@uk2.net>



On Sat Nov  1 20:49 , Hal Murray <hmurray at megapathdsl.net> sent:

>> Don't forget too, that solar noon varies quite a bit (minutes) from
>> "mean solar time" over the year.  If you're navigating your ship with
>> noon sun sights, this is pretty important. 
>
>What do I google for if I want that correction?

This is known as the Equation of Time.  If the position of the sun was plotted (or
<a href="http://www.analemma.de/english/analem.html">photographed!</a>) at the
same time every day, a figure-of-eight shaped path would be drawn, which is known
as the analemma.  Two websites which have excellent descriptions of the effect,
and hence why a sundial can often apparently be "wrong", are
http://www.analemma.com/ and http://www.sundials.co.uk/equation.htm

Peter



From jsa at science.uva.nl  Tue Nov  4 15:18:37 2008
From: jsa at science.uva.nl (Hans Agema)
Date: Tue, 04 Nov 2008 16:18:37 +0100
Subject: [time-nuts] HP1600A manual
Message-ID: <200811041518.mA4FIaOl011393@postduif.ic.uva.nl>


Hi Jeroen,

I recalled having seen that 1600A typenumber somewhere at work, so I 
delved into the cellar and dug out the beast.
In the pouch is a mint O&S manual and it has a 12 page section 
"Performance check and adjustments".
I can lend you the manual to make a copy or scan, or I can just scan 
the 12 pages and email them.
Let me know off list, cheers,

Hans Agema


At 15:37 3-11-2008, you wrote:
>Hi Dave,
>
>Thank you! Usually there is a section in the manual to do a quick 
>performance test. If it would be possible to scan this part, that 
>would help a lot!
>
>Thank you, looking forward to your next message.
>
>Best regards, Jeroen
>
>Dave Brown wrote:
>>I have a mint 1600A plus manual (s?) here somewhere, Jeroen- 
>>will  try to find it/them!  Sorry, no digital copy though but I 
>>should be able to scan some of it for you.
>>DaveB, NZ
>>
>>----- Original Message ----- From: "Jeroen Bastemeijer" 
>><j.bastemeijer at tudelft.nl>
>>To: "Discussion of precise time and frequency measurement" 
>><time-nuts at febo.com>
>>Sent: Friday, October 31, 2008 10:10 PM
>>Subject: [time-nuts] HP1600A manual
>>
>>
>>
>>>Dear All,
>>>
>>>Is there anyone out there who has a digital copy of the HP 1600A logic
>>>analyzer manual? I found such an old machine, and I'm wondering if it is
>>>still working...
>>>
>>>There are manuals for sale for approx $50 (excl. shipping). However, the
>>>HP1600A seems not to be very responsive. So, investing $50 for a machine
>>>which is defective and probably cannot be repaired seems like a waste.
>>>
>>>Or is there anyone who can give a hint on how to test a HP 1600A, to get
>>>a good indication if it is still functioning (reasonably) okay. At this
>>>moment the machine seems to be locked up. Allthough there is a nice
>>>pattern of 1's and 0's on the screen....
>>>
>>>Thanks, best regards Jeroen



From brett at librum.org  Tue Nov  4 17:08:00 2008
From: brett at librum.org (Brett Eisenberg)
Date: Tue, 4 Nov 2008 09:08:00 -0800
Subject: [time-nuts] Trimble T-Bolt Order
In-Reply-To: <mailman.5.1225800002.6589.time-nuts@febo.com>
References: <mailman.5.1225800002.6589.time-nuts@febo.com>
Message-ID: <BA30B6B9-981C-4B17-BB95-BA3F4ED719AD@librum.org>

While this topic is open: is there going to be another batch available?

best,
Brett


From tractorb at ihug.co.nz  Tue Nov  4 18:30:29 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Wed, 5 Nov 2008 07:30:29 +1300
Subject: [time-nuts] HP1600A manual
References: <200811041518.mA4FIaOl011393@postduif.ic.uva.nl>
Message-ID: <141901c93eab$6a966260$7900a8c0@athlon1200>

This is your best option, Jeroen-not found my 1600A-let alone the 
manual, as yet!
DaveB

----- Original Message ----- 
From: "Hans Agema" <jsa at science.uva.nl>
To: <time-nuts at febo.com>
Sent: Wednesday, November 05, 2008 4:18 AM
Subject: Re: [time-nuts] HP1600A manual


>
> Hi Jeroen,
>
> I recalled having seen that 1600A typenumber somewhere at work, so I
> delved into the cellar and dug out the beast.
> In the pouch is a mint O&S manual and it has a 12 page section
> "Performance check and adjustments".
> I can lend you the manual to make a copy or scan, or I can just scan
> the 12 pages and email them.
> Let me know off list, cheers,
>
> Hans Agema
>
>
> At 15:37 3-11-2008, you wrote:
>>Hi Dave,
>>
>>Thank you! Usually there is a section in the manual to do a quick
>>performance test. If it would be possible to scan this part, that
>>would help a lot!
>>
>>Thank you, looking forward to your next message.
>>
>>Best regards, Jeroen
>>
>>Dave Brown wrote:
>>>I have a mint 1600A plus manual (s?) here somewhere, Jeroen-
>>>will  try to find it/them!  Sorry, no digital copy though but I
>>>should be able to scan some of it for you.
>>>DaveB, NZ
>>>
>>>----- Original Message ----- From: "Jeroen Bastemeijer"
>>><j.bastemeijer at tudelft.nl>
>>>To: "Discussion of precise time and frequency measurement"
>>><time-nuts at febo.com>
>>>Sent: Friday, October 31, 2008 10:10 PM
>>>Subject: [time-nuts] HP1600A manual
>>>
>>>
>>>
>>>>Dear All,
>>>>
>>>>Is there anyone out there who has a digital copy of the HP 1600A 
>>>>logic
>>>>analyzer manual? I found such an old machine, and I'm wondering if 
>>>>it is
>>>>still working...
>>>>
>>>>There are manuals for sale for approx $50 (excl. shipping). 
>>>>However, the
>>>>HP1600A seems not to be very responsive. So, investing $50 for a 
>>>>machine
>>>>which is defective and probably cannot be repaired seems like a 
>>>>waste.
>>>>
>>>>Or is there anyone who can give a hint on how to test a HP 1600A, 
>>>>to get
>>>>a good indication if it is still functioning (reasonably) okay. At 
>>>>this
>>>>moment the machine seems to be locked up. Allthough there is a 
>>>>nice
>>>>pattern of 1's and 0's on the screen....
>>>>
>>>>Thanks, best regards Jeroen
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


--------------------------------------------------------------------------------



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3/11/2008 16:59



From w3kl at w3kl.com  Tue Nov  4 18:38:30 2008
From: w3kl at w3kl.com (w3kl at w3kl.com)
Date: Tue, 4 Nov 2008 10:38:30 -0800 (PST)
Subject: [time-nuts] FTS 4060
Message-ID: <44782.74495.qm@web35402.mail.mud.yahoo.com>

All:
?
By any chance, does the FTS 4060 Cesium standard use an HP5061B beam tube?
?
Thanks
Jeff

Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402

From tvb at LeapSecond.com  Tue Nov  4 19:26:37 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Tue, 4 Nov 2008 11:26:37 -0800
Subject: [time-nuts] FTS 4060
References: <44782.74495.qm@web35402.mail.mud.yahoo.com>
Message-ID: <000c01c93eb3$466b6040$0600a8c0@pc52>

> By any chance, does the FTS 4060 Cesium standard use an HP5061B beam tube?

No, wrong size (Corby, can you confirm?).

But it is not uncommon to see the reverse: FTS tubes retrofitted
into 5061 frames.

/tvb



From had at to-way.com  Tue Nov  4 19:55:03 2008
From: had at to-way.com (Had)
Date: Tue, 04 Nov 2008 11:55:03 -0800
Subject: [time-nuts] FTS 4060
In-Reply-To: <44782.74495.qm@web35402.mail.mud.yahoo.com>
References: <44782.74495.qm@web35402.mail.mud.yahoo.com>
Message-ID: <20081104195504.84A15164838@mail-in06.adhost.com>


Jeff,

No, it does not. A new tube can be had from Symmetricom but you don't 
want to know the price.

Had, K7MLR


At 10:38 AM 11/4/2008, you wrote:
>All:
>
>By any chance, does the FTS 4060 Cesium standard use an HP5061B beam tube?
>
>Thanks
>Jeff
>
>Jeffrey K. Okamitsu, PhD, MBA
>+1-609-638-5402
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.

From w3kl at w3kl.com  Tue Nov  4 20:11:20 2008
From: w3kl at w3kl.com (w3kl at w3kl.com)
Date: Tue, 4 Nov 2008 12:11:20 -0800 (PST)
Subject: [time-nuts] FTS 4060
In-Reply-To: <20081104195504.84A15164838@mail-in06.adhost.com>
Message-ID: <284932.40128.qm@web35408.mail.mud.yahoo.com>

Had.? A new 5061B tube???I thought Symmetricom was not making them anymore?
?
73, Jeff

Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402

--- On Tue, 11/4/08, Had <had at to-way.com> wrote:

From: Had <had at to-way.com>
Subject: Re: [time-nuts] FTS 4060
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Tuesday, November 4, 2008, 2:55 PM

Jeff,

No, it does not. A new tube can be had from Symmetricom but you don't 
want to know the price.

Had, K7MLR


At 10:38 AM 11/4/2008, you wrote:
>All:
>
>By any chance, does the FTS 4060 Cesium standard use an HP5061B beam tube?
>
>Thanks
>Jeff
>
>Jeffrey K. Okamitsu, PhD, MBA
>+1-609-638-5402
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From had at to-way.com  Tue Nov  4 21:06:13 2008
From: had at to-way.com (Had)
Date: Tue, 04 Nov 2008 13:06:13 -0800
Subject: [time-nuts] FTS 4060
In-Reply-To: <284932.40128.qm@web35408.mail.mud.yahoo.com>
References: <20081104195504.84A15164838@mail-in06.adhost.com>
	<284932.40128.qm@web35408.mail.mud.yahoo.com>
Message-ID: <20081104210614.90388192825@mail-in04.adhost.com>


Oops, got my C Beams mixed up. It uses a FTS manufactured tube.

Sorry.
Had, K7MLR


At 12:11 PM 11/4/2008, you wrote:
>Had.  A new 5061B tube?  I thought Symmetricom was not making them anymore?
>
>73, Jeff
>
>Jeffrey K. Okamitsu, PhD, MBA
>+1-609-638-5402
>
>--- On Tue, 11/4/08, Had <had at to-way.com> wrote:
>
>From: Had <had at to-way.com>
>Subject: Re: [time-nuts] FTS 4060
>To: "Discussion of precise time and frequency measurement" 
><time-nuts at febo.com>
>Date: Tuesday, November 4, 2008, 2:55 PM
>
>Jeff,
>
>No, it does not. A new tube can be had from Symmetricom but you don't
>want to know the price.
>
>Had, K7MLR
>
>
>At 10:38 AM 11/4/2008, you wrote:
> >All:
> >
> >By any chance, does the FTS 4060 Cesium standard use an HP5061B beam tube?
> >
> >Thanks
> >Jeff
> >
> >Jeffrey K. Okamitsu, PhD, MBA
> >+1-609-638-5402
> >_______________________________________________
> >time-nuts mailing list -- time-nuts at febo.com
> >To unsubscribe, go to
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >and follow the instructions there.
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.

From rk at timing-consultants.com  Tue Nov  4 21:25:34 2008
From: rk at timing-consultants.com (Rob Kimberley)
Date: Tue, 4 Nov 2008 21:25:34 -0000
Subject: [time-nuts] FTS 4060
In-Reply-To: <20081104210614.90388192825@mail-in04.adhost.com>
References: <20081104195504.84A15164838@mail-in06.adhost.com><284932.40128.qm@web35408.mail.mud.yahoo.com>
	<20081104210614.90388192825@mail-in04.adhost.com>
Message-ID: <A156DCD84B7E4C6084FDD9388FF52F96@Robin>

FTS is Datum/Symmetricom. Were you thinking FEI?

Rob K 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Had
Sent: 04 November 2008 21:06
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] FTS 4060


Oops, got my C Beams mixed up. It uses a FTS manufactured tube.

Sorry.
Had, K7MLR


At 12:11 PM 11/4/2008, you wrote:
>Had.  A new 5061B tube?  I thought Symmetricom was not making them anymore?
>
>73, Jeff
>
>Jeffrey K. Okamitsu, PhD, MBA
>+1-609-638-5402
>
>--- On Tue, 11/4/08, Had <had at to-way.com> wrote:
>
>From: Had <had at to-way.com>
>Subject: Re: [time-nuts] FTS 4060
>To: "Discussion of precise time and frequency measurement" 
><time-nuts at febo.com>
>Date: Tuesday, November 4, 2008, 2:55 PM
>
>Jeff,
>
>No, it does not. A new tube can be had from Symmetricom but you don't 
>want to know the price.
>
>Had, K7MLR
>
>
>At 10:38 AM 11/4/2008, you wrote:
> >All:
> >
> >By any chance, does the FTS 4060 Cesium standard use an HP5061B beam
tube?
> >
> >Thanks
> >Jeff
> >
> >Jeffrey K. Okamitsu, PhD, MBA
> >+1-609-638-5402
> >_______________________________________________
> >time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >and follow the instructions there.
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From n3izn at aol.com  Tue Nov  4 22:06:31 2008
From: n3izn at aol.com (n3izn at aol.com)
Date: Tue, 04 Nov 2008 17:06:31 -0500
Subject: [time-nuts] For you hams in the UK
Message-ID: <8CB0CE0BA46F651-C60-E93@Webmail-mg11.sim.aol.com>

Hello to the hams in the UK. I'm in the early stages of planning a trip to?Cornwall next summer. To take the rug rats to see grandma who refuses to fly any more. Any how it's been maybe 10 years since my last visit. When I lived on the east coast and active on HF I had many regulars I talked to daily and when I made my trips I made arrangements with some of them to bring radios. The prices in the US were half of what you guys had to pay. With Internet sales maybe it has come down, I don't know.

Summer is a long way off and I'm not sure how this email will be accepted. I'm offering to buy a rig of your choice .I'll use it for a week and a half or so and make arrangements to give it to you on my way back to London. I'll have the box and original accessories. You will be able to hear it and inspect before buying it.

Obviously I have to pack it in luggage, so no large base radios. One of those CB sized all in one boxes is what I was thinking. If no serious takers I'll bring my FT100D. You will have to figure out how to convert it to UK version if necessary. I'll be using HF and maybe 144 on the highways between London and Bodmin. Maybe a HT would fit in the YL bag?

Not looking to double my money, just have use of a radio while I'm over there and maybe make a few bucks?or quid to pay the rental car.

Contact me off list.
73
Chris




From John.Reid at team.telstra.com  Wed Nov  5 04:41:02 2008
From: John.Reid at team.telstra.com (Reid, John H)
Date: Wed, 5 Nov 2008 15:41:02 +1100
Subject: [time-nuts] Trimble T-Bolt Order
Message-ID: <FA5A3E1F24026943B8C331C9767161FF2277DA30F4@WSMSG3154V.srv.dir.telstra.com>

Dick,

I ordered, and the order failed. When I wrote asking about delivery, the office replied that they had no record of it, even though the website indicated a successful transaction.

I left it too long before I asked, and they had all gone. Disappointing.

Regards,

John.




From gbusg at comcast.net  Wed Nov  5 06:10:29 2008
From: gbusg at comcast.net (Greg Burnett)
Date: Tue, 4 Nov 2008 23:10:29 -0700
Subject: [time-nuts] Trimble T-Bolt Order
References: <FA5A3E1F24026943B8C331C9767161FF2277DA30F4@WSMSG3154V.srv.dir.telstra.com>
Message-ID: <00d101c93f0d$345c03a0$6501a8c0@gb02>

Now that you mention it, I didn't receive an order confirmation email this 
time, like I did for my first order back in June. I'm in no hurry so I'd not 
given it any thought until your message. But, if lack of an initial email 
order confirmation message is an indication, I might be in the same boat as 
you.

Greg


----- Original Message ----- 
From: "Reid, John H" <John.Reid at team.telstra.com>
To: <time-nuts at febo.com>
Sent: Tuesday, November 04, 2008 9:41 PM
Subject: Re: [time-nuts] Trimble T-Bolt Order


Dick,

I ordered, and the order failed. When I wrote asking about delivery, the 
office replied that they had no record of it, even though the website 
indicated a successful transaction.

I left it too long before I asked, and they had all gone. Disappointing.

Regards,

John.



_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there. 



From magnus at rubidium.dyndns.org  Wed Nov  5 13:21:35 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Wed, 5 Nov 2008 14:21:35 +0100 (CET)
Subject: [time-nuts] Tektronix Type 602 manual
Message-ID: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>

Hi!

While it may seem slightly off topic, I'd like to get the schematics if
not full manual of the Tek Type 602 vector scope. I have a Z-mod display
with a problem, I no longer get a dot on the screen.

The intended use is time-nuts compatible. :)

It will be less heat and noise than the old Tek 547 scope, and I want to
use that for other purposes anyway.

Cheers,
Magnus


From cdelect at juno.com  Wed Nov  5 16:11:32 2008
From: cdelect at juno.com (Corby Dawson)
Date: Wed, 5 Nov 2008 08:11:32 -0800
Subject: [time-nuts] FTS 4060
Message-ID: <20081105.081133.2228.0.cdelect@juno.com>

Jeffery,

No the FTS 4060 does not use an HP 5061B tube (physically too big!)
However a 4060 tube can be used in a 5061A/B with a little work.

Corby Dawson
____________________________________________________________
Are you safe? Click for quotes on a home security system. 
http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3ni3c7rKgWw2fQOc1nMEPrKNalzitmM16geNMX8di6rLAYYh/


From w3kl at w3kl.com  Wed Nov  5 16:35:57 2008
From: w3kl at w3kl.com (w3kl at w3kl.com)
Date: Wed, 5 Nov 2008 08:35:57 -0800 (PST)
Subject: [time-nuts] FTS 4060
In-Reply-To: <20081105.081133.2228.0.cdelect@juno.com>
Message-ID: <184083.72678.qm@web35406.mail.mud.yahoo.com>

Corby.? Thanks for your feedback.? What has to be done to utilize a 4060 tube in a 5061B?? What is the relative performance of a 4060 tube versus a high perforamance 5061B tube?
?
jeff

Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402

--- On Wed, 11/5/08, Corby Dawson <cdelect at juno.com> wrote:

From: Corby Dawson <cdelect at juno.com>
Subject: [time-nuts] FTS 4060
To: time-nuts at febo.com
Date: Wednesday, November 5, 2008, 11:11 AM

Jeffery,

No the FTS 4060 does not use an HP 5061B tube (physically too big!)
However a 4060 tube can be used in a 5061A/B with a little work.

Corby Dawson
____________________________________________________________
Are you safe? Click for quotes on a home security system. 
http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3ni3c7rKgWw2fQOc1nMEPrKNalzitmM16geNMX8di6rLAYYh/

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From geraldo at decampos.net  Wed Nov  5 18:10:16 2008
From: geraldo at decampos.net (Geraldo Lino de Campos)
Date: Wed, 5 Nov 2008 16:10:16 -0200
Subject: [time-nuts] thunderbolt with +-15V?
Message-ID: <de9711fa0811051010w3e175aa3s4161d6b4ae6b3291@mail.gmail.com>

Do someone know if the thunderbolt supports operating with +-15V instead of
+-12V?

I looked at the voltage tolerance but could?t find any hints.

-- 
------------------------------------
Geraldo Lino de Campos
geraldo at decampos.net

From GandalfG8 at aol.com  Wed Nov  5 18:23:32 2008
From: GandalfG8 at aol.com (GandalfG8 at aol.com)
Date: Wed, 5 Nov 2008 13:23:32 EST
Subject: [time-nuts] thunderbolt with +-15V?
Message-ID: <cec.4699b3ed.36433ea4@aol.com>

In a message dated 05/11/2008 18:11:11 GMT Standard Time,  
geraldo at decampos.net writes:
Do someone know if the thunderbolt supports  operating with +-15V instead of
+-12V?

I looked at the voltage  tolerance but could?t find any hints.
----------------
Page 3-4 of version  5 of the Thunderbolt manual, available online as 
"ThunderBoltBook2002.pdf", has  the supply voltage specification......

+12v +/-10% max current 750  mA
+5v +/-5% max current 400 mA
-12v +/-10% max current 10  mA

Ripple
+5v 50 mV peak-to-peak, 15 mVrms
+/-12v 75 mV  peak-to-peak, 20 mVrms

Regards
Nigel
GM8PZR
 


From GandalfG8 at aol.com  Wed Nov  5 18:25:38 2008
From: GandalfG8 at aol.com (GandalfG8 at aol.com)
Date: Wed, 5 Nov 2008 13:25:38 EST
Subject: [time-nuts] thunderbolt with +-15V?
Message-ID: <c4c.3f310097.36433f22@aol.com>

 
In a message dated 05/11/2008 18:22:53 GMT Standard Time, GandalfG8 at aol.com  
writes:

Page 3-4  of version  5 of the Thunderbolt manual, available online as  
"ThunderBoltBook2002.pdf", has  the supply voltage  specification......


Whoops........
 
That should read..."ThunderBoltBook2003.pdf"
 
Sorry

From brooke at pacific.net  Wed Nov  5 23:07:57 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Wed, 05 Nov 2008 15:07:57 -0800
Subject: [time-nuts] Thunderbolt Monitor Manual?
Message-ID: <4912274D.7040809@pacific.net>

Hi:

Is there a manual for the Monitor program?
For example is there a way to change the "Stored Position" from a yellow to 
green dot?

-- 
Have Fun,

Brooke Clarke
http://www.prc68.com


From chris.kuethe at gmail.com  Wed Nov  5 23:43:58 2008
From: chris.kuethe at gmail.com (Chris Kuethe)
Date: Wed, 5 Nov 2008 15:43:58 -0800
Subject: [time-nuts] Thunderbolt Monitor Manual?
In-Reply-To: <4912274D.7040809@pacific.net>
References: <4912274D.7040809@pacific.net>
Message-ID: <91981b3e0811051543v4f16d508i319d7ddc32f536d1@mail.gmail.com>

I haven't see a nice user's guide for tboltmon. Lots of exciting
opportunities for discovery and enlightenment :)

Setup menu > Position, fill in your known location and hit "save
segment". that should change that dot.

On Wed, Nov 5, 2008 at 3:07 PM, Brooke Clarke <brooke at pacific.net> wrote:
> Hi:
>
> Is there a manual for the Monitor program?
> For example is there a way to change the "Stored Position" from a yellow to
> green dot?
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?


From didier at cox.net  Thu Nov  6 02:40:59 2008
From: didier at cox.net (Didier)
Date: Wed, 5 Nov 2008 20:40:59 -0600
Subject: [time-nuts] Thunderbolt Monitor Manual?
In-Reply-To: <4912274D.7040809@pacific.net>
References: <4912274D.7040809@pacific.net>
Message-ID: <F4316BA6B30347759D80F03289B710F0@didierhp>

Brooke,

That is covered in my wiki:

http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:store_position_on
_trimble_thunderbolt

Courtesy of John Miles :-)

Didier KO4BB 

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Brooke Clarke
> Sent: Wednesday, November 05, 2008 5:08 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Thunderbolt Monitor Manual?
> 
> Hi:
> 
> Is there a manual for the Monitor program?
> For example is there a way to change the "Stored Position" 
> from a yellow to green dot?
> 
> --
> Have Fun,
> 
> Brooke Clarke
> http://www.prc68.com
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From N3IZN at aol.com  Thu Nov  6 03:59:31 2008
From: N3IZN at aol.com (N3IZN at aol.com)
Date: Wed, 5 Nov 2008 22:59:31 EST
Subject: [time-nuts] GPSDO on that auction site.
Message-ID: <ccd.46a952f4.3643c5a3@aol.com>

I put another Trimble unit and another unknown unit with a Furuno GPS  engine 
on our favorite auction site. Search for "GPSDO" and you'll see my  2.
 
Chris
**************AOL Search: Your one stop for directions, recipes and all other 
Holiday needs. Search Now. 
(http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays-from
-aol-search/?ncid=emlcntussear00000001)

From bill at iaxs.net  Thu Nov  6 05:48:35 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Wed, 5 Nov 2008 23:48:35 -0600
Subject: [time-nuts] Lucent RFTG-XO performance...
In-Reply-To: <47A667CF.60804@febo.com>
References: <47A667CF.60804@febo.com>
Message-ID: <C9D2C7B789364C6CB4F1D8250959AAD7@cyrus>

John,

Back in February, you looked at the Lucent GPSDO and declared it the
worst you'd seen.

Did you ever update that opinion? Is the complete set for $400 not worth
buying if you
have a pair of Z3801s that perform some heroic jumps? This is just a
hobby, not long
baseline interferometry.

Bill Hawkins
 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Ackermann N8UR
Sent: Sunday, February 03, 2008 7:18 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Lucent RFTG-XO performance...

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit?  I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second
out to 40,000 seconds.  At 100,000 seconds, it drops to the high 11s.*
To this point I haven't seen anything that looks like the normal GPSDO
characteristic of a rapid ADEV improvement from around 1000 seconds or
so.  In fact, this is about the flattest ADEV plot I've ever seen from
an oscillator.

The frequency difference plot** shows a bang-bang effect of about
1.6x10e-9 over the course of a few minutes.  This seems to go on
continuously (at least over the 4 days of data so far).  That certainly
explains the mediocre ADEV performance.

The thing does appear to be locked to GPS, but if my unit is working
properly, it's about the worst performing GPSDO I've seen.

By the way -- to do this test, I started with both the -XO and -RB units
online and interconnected the way they were supposed to be.  After a
couple of days of operation, I pulled the interconnect cable and the -RB
went off line, while the -XO came on.  I then started data collection.
After I'm satisfied with the amount of XO data I have, I'll reconnect
the cable and do the same test on the -RB side.  The full set of plots
is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
I get more data.

John

* http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png
** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From david.partridge at dsl.pipex.com  Thu Nov  6 07:01:50 2008
From: david.partridge at dsl.pipex.com (David C. Partridge)
Date: Thu, 6 Nov 2008 07:01:50 -0000
Subject: [time-nuts] Thunderbolt Monitor Manual?
In-Reply-To: <4912274D.7040809@pacific.net>
References: <4912274D.7040809@pacific.net>
Message-ID: <11519638E60A4810A32280E3A0B112DC@APOLLO>

It will change when self-survey is complete 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brooke Clarke
Sent: 05 November 2008 23:08
To: time-nuts at febo.com
Subject: [time-nuts] Thunderbolt Monitor Manual?

Hi:

Is there a manual for the Monitor program?
For example is there a way to change the "Stored Position" from a yellow to
green dot?

--
Have Fun,

Brooke Clarke
http://www.prc68.com

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From don.key at ntlworld.com  Thu Nov  6 12:35:43 2008
From: don.key at ntlworld.com (Don Key)
Date: Thu, 6 Nov 2008 12:35:43 -0000
Subject: [time-nuts] Thunderbolt Monitor Manual?
In-Reply-To: <11519638E60A4810A32280E3A0B112DC@APOLLO>
References: <4912274D.7040809@pacific.net>
	<11519638E60A4810A32280E3A0B112DC@APOLLO>
Message-ID: <97FBC03D5C144324B7658A2B6FBB097A@JimPC>

Mine stays yellow, even after completion of self survey.
As mentioned earlier, you need to store it manually.

----- Original Message ----- 
From: "David C. Partridge" <david.partridge at dsl.pipex.com>
To: <brooke at pacific.net>; "'Discussion of precise time and frequency 
measurement'" <time-nuts at febo.com>
Sent: Thursday, November 06, 2008 7:01 AM
Subject: Re: [time-nuts] Thunderbolt Monitor Manual?


> It will change when self-survey is complete
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Brooke Clarke
> Sent: 05 November 2008 23:08
> To: time-nuts at febo.com
> Subject: [time-nuts] Thunderbolt Monitor Manual?
>
> Hi:
>
> Is there a manual for the Monitor program?
> For example is there a way to change the "Stored Position" from a yellow 
> to
> green dot?
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
> 



From don.key at ntlworld.com  Thu Nov  6 12:50:32 2008
From: don.key at ntlworld.com (Don Key)
Date: Thu, 6 Nov 2008 12:50:32 -0000
Subject: [time-nuts] Thunderbolt Monitor Manual?
In-Reply-To: <11519638E60A4810A32280E3A0B112DC@APOLLO>
References: <4912274D.7040809@pacific.net>
	<11519638E60A4810A32280E3A0B112DC@APOLLO>
Message-ID: <341BD27F3EBF4E13865D879ED31AEDFB@JimPC>

The monitor program is described in the ThunderBoltBook 2003 on the Trimble
website:-

http://trl.trimble.com/docushare/dsweb/Get/Document-10001/ThunderBoltBook2003.pdf


> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Brooke Clarke
> Sent: 05 November 2008 23:08
> To: time-nuts at febo.com
> Subject: [time-nuts] Thunderbolt Monitor Manual?
>
> Hi:
>
> Is there a manual for the Monitor program?
> For example is there a way to change the "Stored Position" from a yellow 
> to
> green dot?
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
> 



From jra at febo.com  Thu Nov  6 13:12:49 2008
From: jra at febo.com (John Ackermann N8UR)
Date: Thu, 06 Nov 2008 08:12:49 -0500
Subject: [time-nuts] Lucent RFTG-XO performance...
In-Reply-To: <C9D2C7B789364C6CB4F1D8250959AAD7@cyrus>
References: <47A667CF.60804@febo.com> <C9D2C7B789364C6CB4F1D8250959AAD7@cyrus>
Message-ID: <4912ED51.7080909@febo.com>

Hi Bill --

I haven't done any more testing, but I'm pretty convinced that there is 
something wrong with my hardware, though the monitoring software didn't 
indicate any obvious problems.  I need to go back and revisit, but due 
to a bunch of health problems earlier this year (now just about over 
with), I haven't gotten very much done in the basement for a while.

John
----

Bill Hawkins wrote:
> John,
> 
> Back in February, you looked at the Lucent GPSDO and declared it the
> worst you'd seen.
> 
> Did you ever update that opinion? Is the complete set for $400 not worth
> buying if you
> have a pair of Z3801s that perform some heroic jumps? This is just a
> hobby, not long
> baseline interferometry.
> 
> Bill Hawkins
>  
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of John Ackermann N8UR
> Sent: Sunday, February 03, 2008 7:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Lucent RFTG-XO performance...
> 
> Has anyone here done any performance measurements of the Lucent RFTG-XO
> unit?  I am testing one now and getting extremely unimpressive results,
> and wonder if anyone else has looked closely at these things.
> 
> What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second
> out to 40,000 seconds.  At 100,000 seconds, it drops to the high 11s.*
> To this point I haven't seen anything that looks like the normal GPSDO
> characteristic of a rapid ADEV improvement from around 1000 seconds or
> so.  In fact, this is about the flattest ADEV plot I've ever seen from
> an oscillator.
> 
> The frequency difference plot** shows a bang-bang effect of about
> 1.6x10e-9 over the course of a few minutes.  This seems to go on
> continuously (at least over the 4 days of data so far).  That certainly
> explains the mediocre ADEV performance.
> 
> The thing does appear to be locked to GPS, but if my unit is working
> properly, it's about the worst performing GPSDO I've seen.
> 
> By the way -- to do this test, I started with both the -XO and -RB units
> online and interconnected the way they were supposed to be.  After a
> couple of days of operation, I pulled the interconnect cable and the -RB
> went off line, while the -XO came on.  I then started data collection.
> After I'm satisfied with the amount of XO data I have, I'll reconnect
> the cable and do the same test on the -RB side.  The full set of plots
> is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
> I get more data.
> 
> John
> 
> * http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png
> ** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From scmcgrath at gmail.com  Thu Nov  6 16:17:11 2008
From: scmcgrath at gmail.com (Scott McGrath)
Date: Thu, 6 Nov 2008 11:17:11 -0500
Subject: [time-nuts]
	=?windows-1252?q?Do_any_regulations_or_laws_require_t?=
	=?windows-1252?q?ime_to_be_accurate_within_=91x=92_seconds=3F?=
In-Reply-To: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
Message-ID: <c9ffea950811060817p3a816bc3n4b18caa693c013c4@mail.gmail.com>

Yes -

PCI (Payment Card Industry) for one, Active Directory for another that
needs timing withing 30 seconds  - why do you ask?.

On Mon, Nov 3, 2008 at 12:03 PM, Gretchen Baxter
<gretchendenisebaxter at gmail.com> wrote:
> Greetings,
>
> There are a lot of regulations that mandate synchronized time.
>
> But do any of these regulations or laws require time to be accurate within
> 'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
> time.
>
> Thanx,
>
> Gretchen
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>


From masondg44 at comcast.net  Thu Nov  6 15:23:12 2008
From: masondg44 at comcast.net (Dave M)
Date: Thu, 6 Nov 2008 10:23:12 -0500
Subject: [time-nuts] Tektronix Type 602 manual
Message-ID: <2F2F0EBF464A4E4AB5C487A850007471@DELL2350>

I didn't find a free download on any of my manuals links, but here are a few online vendors who have the TEK 602 manual in stock:
https://www.ridgeequipment.com/store/manuals/detail.php?id=1148
https://www.ridgeequipment.com/store/manuals/detail.php?id=18240
http://www.manualsplus.com
http://www.vintagemanuals.com/search.php?find=602

Cheers!!!
-- 
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster it goes. 

Date: Wed, 5 Nov 2008 14:21:35 +0100 (CET)
From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
Subject: [time-nuts] Tektronix Type 602 manual
To: time-nuts at febo.com
Message-ID:
<1687b9e9fa3e0769bda8834016266c25.squirrel at rubidium.dyndns.org>
Content-Type: text/plain;charset=iso-8859-1

Hi!

While it may seem slightly off topic, I'd like to get the schematics if
not full manual of the Tek Type 602 vector scope. I have a Z-mod display
with a problem, I no longer get a dot on the screen.

The intended use is time-nuts compatible. :)

It will be less heat and noise than the old Tek 547 scope, and I want to
use that for other purposes anyway.

Cheers,
Magnus

From rdarlington at gmail.com  Thu Nov  6 16:58:24 2008
From: rdarlington at gmail.com (Robert Darlington)
Date: Thu, 6 Nov 2008 09:58:24 -0700
Subject: [time-nuts]
	=?windows-1252?q?Do_any_regulations_or_laws_require_t?=
	=?windows-1252?q?ime_to_be_accurate_within_=91x=92_seconds=3F?=
In-Reply-To: <c9ffea950811060817p3a816bc3n4b18caa693c013c4@mail.gmail.com>
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
	<c9ffea950811060817p3a816bc3n4b18caa693c013c4@mail.gmail.com>
Message-ID: <b3bd5fcb0811060858x287921eeq97a5e7b8f4951962@mail.gmail.com>

There is no law or regulation that requires this though, just a technical
requirement.  Apparently the Nortel VPN client requires it too, as I just
had to fix my timezone info to get connected to work!

-Bob

On Thu, Nov 6, 2008 at 9:17 AM, Scott McGrath <scmcgrath at gmail.com> wrote:

> Yes -
>
> PCI (Payment Card Industry) for one, Active Directory for another that
> needs timing withing 30 seconds  - why do you ask?.
>
> On Mon, Nov 3, 2008 at 12:03 PM, Gretchen Baxter
> <gretchendenisebaxter at gmail.com> wrote:
> > Greetings,
> >
> > There are a lot of regulations that mandate synchronized time.
> >
> > But do any of these regulations or laws require time to be accurate
> within
> > 'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
> > time.
> >
> > Thanx,
> >
> > Gretchen
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From gretchendenisebaxter at gmail.com  Thu Nov  6 17:07:43 2008
From: gretchendenisebaxter at gmail.com (Gretchen Baxter)
Date: Thu, 6 Nov 2008 12:07:43 -0500
Subject: [time-nuts]
	=?windows-1252?q?Do_any_regulations_or_laws_require_t?=
	=?windows-1252?q?ime_to_be_accurate_within_=91x=92_seconds=3F?=
In-Reply-To: <c9ffea950811060817p3a816bc3n4b18caa693c013c4@mail.gmail.com>
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
	<c9ffea950811060817p3a816bc3n4b18caa693c013c4@mail.gmail.com>
Message-ID: <4fdb424f0811060907w1767f7e9hf4a51f02efc77912@mail.gmail.com>

Thanx for the reply.



I was looking for a reference to s specific amount of time that clocks needs
to be in sync, i.e., within 10 seconds.  You mentioned PCI. Yes, it requires
synchronization, but in section 10.4, it does not mandate that it must be
synchronized to within a specific amount of time.



So my original question still remains unanswered   :(





On Thu, Nov 6, 2008 at 11:17 AM, Scott McGrath <scmcgrath at gmail.com> wrote:

> Yes -
>
> PCI (Payment Card Industry) for one, Active Directory for another that
> needs timing withing 30 seconds  - why do you ask?.
>
> On Mon, Nov 3, 2008 at 12:03 PM, Gretchen Baxter
> <gretchendenisebaxter at gmail.com> wrote:
> > Greetings,
> >
> > There are a lot of regulations that mandate synchronized time.
> >
> > But do any of these regulations or laws require time to be accurate
> within
> > 'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
> > time.
> >
> > Thanx,
> >
> > Gretchen
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From gwinn at raytheon.com  Thu Nov  6 17:28:37 2008
From: gwinn at raytheon.com (Joseph M Gwinn)
Date: Thu, 6 Nov 2008 12:28:37 -0500
Subject: [time-nuts]
 =?iso-8859-1?q?Do_any_regulations_or_laws_require_tim?=
 =?iso-8859-1?q?e_to_be_accurate_within_=3Fx=3F_seconds=3F?=
In-Reply-To: <4fdb424f0811060907w1767f7e9hf4a51f02efc77912@mail.gmail.com>
Message-ID: <OF36ED6841.223BD01D-ON852574F9.005E7C16-852574F9.00600180@mck.us.ray.com>

time-nuts-bounces at febo.com wrote on 11/06/2008 12:07:43 PM:

> Thanx for the reply.
> 
> 
> 
> I was looking for a reference to s specific amount of time that
> clocks needs
> to be in sync, i.e., within 10 seconds.  You mentioned PCI. 
> Yes, it requires
> synchronization, but in section 10.4, it does not mandate that it must 
be
> synchronized to within a specific amount of time.
> 
> 
> 
> So my original question still remains unanswered   :(

I have a vague recollection that the US Securities and Exchanges 
Commission (http://www.sec.gov/) requires timestamping of trades to within 
three seconds of UTC.  I would ask the SEC and perhaps the Commodities 
Futures Trading Commission (http://www.cftc.gov/). 

Joe Gwinn


> 
> On Thu, Nov 6, 2008 at 11:17 AM, Scott McGrath 
> <scmcgrath at gmail.com> wrote:
> 
> > Yes -
> >
> > PCI (Payment Card Industry) for one, Active Directory for another that
> > needs timing withing 30 seconds  - why do you ask?.
> >
> > On Mon, Nov 3, 2008 at 12:03 PM, Gretchen Baxter
> > <gretchendenisebaxter at gmail.com> wrote:
> > > Greetings,
> > >
> > > There are a lot of regulations that mandate synchronized time.
> > >
> > > But do any of these regulations or laws require time to be accurate
> > within
> > > 'x' seconds?  Such as, 'time much be synchronized within 5 
> seconds of GPS
> > > time.
> > >
> > > Thanx,
> > >
> > > Gretchen
> > > _______________________________________________
> > > time-nuts mailing list -- time-nuts at febo.com
> > > To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > > and follow the instructions there.
> > >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-
> bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From Murray.Greenman at rakon.com  Thu Nov  6 17:32:33 2008
From: Murray.Greenman at rakon.com (Murray Greenman)
Date: Fri, 7 Nov 2008 06:32:33 +1300
Subject: [time-nuts] Tek 602
In-Reply-To: <mailman.48.1225950518.2542.time-nuts@febo.com>
References: <mailman.48.1225950518.2542.time-nuts@febo.com>
Message-ID: <BE50C3A72EBA61449C804B2C8B4AE381D05A1B@NEPTUNE.rakon.net>

Magnus,

I can't help you with the manual, but I agree, it will be useful for T&F
applications. I have a newer model X-Y display (the one with storage,
forget the model) which I intend to use for T&F.

By the way, for anyone who is wondering, a conventional TV Vectorscope
works great as a phase comparator for T&F, provided your reference
frequency is suitable. I have the PAL model (4.433MHz colour
subcarrier), and it works fine at 5MHz. I feed 0dBm 5MHz reference into
the subcarrier input, and any other 5MHz signal for phase comparison in
one of the video inputs. You get a dot on the screen which rotates with
phase, and it's easy to see phase jitter and changes as small as a
couple of ns.

Regards,

Murray ZL1BPU



From bill at iaxs.net  Thu Nov  6 17:40:14 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Thu, 6 Nov 2008 11:40:14 -0600
Subject: [time-nuts] Tektronix Type 602 manual
In-Reply-To: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>
References: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>
Message-ID: <C054FD8806CF4F368DDDCDFBB28CC362@cyrus>

Magnus,

That sounds like a leaky coupling capacitor. Complexity depends on
whether the 602 has a Z amplifier, with a gain control somewhere.
Simple scopes just couple the CRT grid (or cathode) to a rear
panel connector with a single cap. Look for a "black beauty" with
a cracked, oily case.

That's something to do while waiting for a manual.

Bill Hawkins
 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, November 05, 2008 7:22 AM
To: time-nuts at febo.com
Subject: [time-nuts] Tektronix Type 602 manual

Hi!

While it may seem slightly off topic, I'd like to get the schematics if
not full manual of the Tek Type 602 vector scope. I have a Z-mod display
with a problem, I no longer get a dot on the screen.

The intended use is time-nuts compatible. :)

It will be less heat and noise than the old Tek 547 scope, and I want to
use that for other purposes anyway.

Cheers,
Magnus

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From ch at murgatroid.com  Thu Nov  6 17:49:36 2008
From: ch at murgatroid.com (christopher hoover)
Date: Thu, 6 Nov 2008 09:49:36 -0800
Subject: [time-nuts] Do any regulations or laws require time to be
	within ?x? seconds?
Message-ID: <000901c94038$094c4770$1be4d650$@com>

On Mon, Nov 3, 2008 at 12:03 PM, Gretchen Baxter
<gretchendenisebaxter at gmail.com> wrote:

> There are a lot of regulations that mandate synchronized time.

> 

> But do any of these regulations or laws require time to be accurate 

> within 'x' seconds?  Such as, 'time much be synchronized within 5 

> seconds of GPS time.

 

Financial services industries (FSI) operate under very strict rules on the
order that trades execute and on the currency (ha ha!) of price quotations.
See Rule 601 and 610.  (Cf. http://en.wikipedia.org/wiki/RegNMS )

 

I know of at least one company that has asked for better than what a typical
x86 server + ntp will do.

 

- ch

 


From smace at intt.net  Thu Nov  6 18:25:59 2008
From: smace at intt.net (Scott Mace)
Date: Thu, 06 Nov 2008 12:25:59 -0600
Subject: [time-nuts]
 =?windows-1252?q?Do_any_regulations_or_laws_require_t?=
 =?windows-1252?q?ime_to_be_accurate_within_=91x=92_seconds=3F?=
In-Reply-To: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
Message-ID: <491336B7.6060301@intt.net>

Google  "CALEA millisecond".

	Scott

Gretchen Baxter wrote:
> Greetings,
> 
> There are a lot of regulations that mandate synchronized time.
> 
> But do any of these regulations or laws require time to be accurate within
> 'x' seconds?  Such as, 'time much be synchronized within 5 seconds of GPS
> time.
> 
> Thanx,
> 
> Gretchen
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From tractorb at ihug.co.nz  Thu Nov  6 19:33:30 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Fri, 7 Nov 2008 08:33:30 +1300
Subject: [time-nuts] Tektronix Type 602 manual
References: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>
Message-ID: <1c9901c94046$8d187b10$7900a8c0@athlon1200>

I'm in the middle of scanning a 602 manual right now- might be next 
week till I get done though.
Been chasing one for a while now although not enthusiastically enough 
to pay anyone for it as my 602 is still operating OK.  Recently found 
a friend had one salted away complete with manual so have borrowed the 
manual to scan.

Lest there be some confusion, the 602 is just a basic X Y Z crt 
display. So there's only a few schematics, the power supply, the Z 
amp, the deflection amps and the CRT cct.

DaveB, NZ

----- Original Message ----- 
From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
To: <time-nuts at febo.com>
Sent: Thursday, November 06, 2008 2:21 AM
Subject: [time-nuts] Tektronix Type 602 manual


> Hi!
>
> While it may seem slightly off topic, I'd like to get the schematics 
> if
> not full manual of the Tek Type 602 vector scope. I have a Z-mod 
> display
> with a problem, I no longer get a dot on the screen.
>
> The intended use is time-nuts compatible. :)
>
> It will be less heat and noise than the old Tek 547 scope, and I 
> want to
> use that for other purposes anyway.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.175 / Virus Database: 270.8.6/1769 - Release Date: 
5/11/2008 07:17



From tvb at LeapSecond.com  Fri Nov  7 06:06:26 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Thu, 6 Nov 2008 22:06:26 -0800
Subject: [time-nuts] Time-zones and World time..
References: <1575.1225805910@uk2.net>
Message-ID: <ECF750FBE2C244F4AF7C258153AD2FE1@pc52>

>>> Don't forget too, that solar noon varies quite a bit (minutes) from
>>> "mean solar time" over the year.  If you're navigating your ship with
>>> noon sun sights, this is pretty important. 
>>
>>What do I google for if I want that correction?
> 
> This is known as the Equation of Time.

I noticed that Physics Today this month has an article:

<On ships, trains, and the equation of time>
http://link.aip.org/link/PHTOAD/v61/i11/p76/s1/pdf
http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_61/iss_11/76_1.shtml

For equation-of-time-nuts, the article references this wonderful 49-page paper:

<The Analemma for Latitudinally-Challenged People>
http://www.math.nus.edu.sg/aslaksen/projects/tsy.pdf

/tvb



From magnus at rubidium.dyndns.org  Fri Nov  7 11:14:47 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 7 Nov 2008 12:14:47 +0100 (CET)
Subject: [time-nuts] Tektronix Type 602 manual
In-Reply-To: <1c9901c94046$8d187b10$7900a8c0@athlon1200>
References: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>
	<1c9901c94046$8d187b10$7900a8c0@athlon1200>
Message-ID: <dddae869ef38792dc488c8202e34b924.squirrel@rubidium.dyndns.org>

> I'm in the middle of scanning a 602 manual right now- might be next
> week till I get done though.
> Been chasing one for a while now although not enthusiastically enough
> to pay anyone for it as my 602 is still operating OK.  Recently found
> a friend had one salted away complete with manual so have borrowed the
> manual to scan.
>
> Lest there be some confusion, the 602 is just a basic X Y Z crt
> display. So there's only a few schematics, the power supply, the Z
> amp, the deflection amps and the CRT cct.

This is exactly what I am looking for. :)

If you could manage to scan the schematics that would give me a head
start, but I am in interested in the full manual of course.

The 602 is very nice as you can hook it up to a SR620, which is what I need.
The only dowside is that the 602 expects wide range of signals. A pair of
simple audio frequency gain stages would solve that.

However, currently I am lacking the dot on the screen to begin with. Power
lines seems OKish but could be trimmed.

Cheers,
Magnus


From cfharris at erols.com  Fri Nov  7 14:23:17 2008
From: cfharris at erols.com (Chuck Harris)
Date: Fri, 07 Nov 2008 09:23:17 -0500
Subject: [time-nuts] Tektronix Type 602 manual
In-Reply-To: <dddae869ef38792dc488c8202e34b924.squirrel@rubidium.dyndns.org>
References: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>	<1c9901c94046$8d187b10$7900a8c0@athlon1200>
	<dddae869ef38792dc488c8202e34b924.squirrel@rubidium.dyndns.org>
Message-ID: <49144F55.1060601@erols.com>

Magnus Danielson wrote:
>> I'm in the middle of scanning a 602 manual right now- might be next
>> week till I get done though.
>> Been chasing one for a while now although not enthusiastically enough
>> to pay anyone for it as my 602 is still operating OK.  Recently found
>> a friend had one salted away complete with manual so have borrowed the
>> manual to scan.
>>
>> Lest there be some confusion, the 602 is just a basic X Y Z crt
>> display. So there's only a few schematics, the power supply, the Z
>> amp, the deflection amps and the CRT cct.
> 
> This is exactly what I am looking for. :)
> 
> If you could manage to scan the schematics that would give me a head
> start, but I am in interested in the full manual of course.
> 
> The 602 is very nice as you can hook it up to a SR620, which is what I need.
> The only dowside is that the 602 expects wide range of signals. A pair of
> simple audio frequency gain stages would solve that.
> 
> However, currently I am lacking the dot on the screen to begin with. Power
> lines seems OKish but could be trimmed.

Pull the deflection plate wires off of the neck of the CRT and see if your
dot comes back.

-Chuck Harris


From magnus at rubidium.dyndns.org  Fri Nov  7 14:35:11 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 7 Nov 2008 15:35:11 +0100 (CET)
Subject: [time-nuts] Tektronix Type 602 manual
In-Reply-To: <49144F55.1060601@erols.com>
References: <1687b9e9fa3e0769bda8834016266c25.squirrel@rubidium.dyndns.org>
	<1c9901c94046$8d187b10$7900a8c0@athlon1200>
	<dddae869ef38792dc488c8202e34b924.squirrel@rubidium.dyndns.org>
	<49144F55.1060601@erols.com>
Message-ID: <ae25a9ca6a3af5760ff9fae46cdcc1e7.squirrel@rubidium.dyndns.org>

> Magnus Danielson wrote:
>>> I'm in the middle of scanning a 602 manual right now- might be next
>>> week till I get done though.
>>> Been chasing one for a while now although not enthusiastically enough
>>> to pay anyone for it as my 602 is still operating OK.  Recently found
>>> a friend had one salted away complete with manual so have borrowed the
>>> manual to scan.
>>>
>>> Lest there be some confusion, the 602 is just a basic X Y Z crt
>>> display. So there's only a few schematics, the power supply, the Z
>>> amp, the deflection amps and the CRT cct.
>>
>> This is exactly what I am looking for. :)
>>
>> If you could manage to scan the schematics that would give me a head
>> start, but I am in interested in the full manual of course.
>>
>> The 602 is very nice as you can hook it up to a SR620, which is what I
>> need.
>> The only dowside is that the 602 expects wide range of signals. A pair
>> of
>> simple audio frequency gain stages would solve that.
>>
>> However, currently I am lacking the dot on the screen to begin with.
>> Power
>> lines seems OKish but could be trimmed.
>
> Pull the deflection plate wires off of the neck of the CRT and see if your
> dot comes back.

Could try that. However, from previous operation you could always see that
it was offscreen. I consider Z mod or something to be off. All the boards
are simple to reach on the sides and it would be quite possible to reverse
engineer it but schematics and component placements rules. Circuit
description and trimming indications help further naturally.

For things like this, digital scopes does not really cut it. They are good
for other things thought.

Cheers,
Magnus


From jason at extremeoverclocking.com  Fri Nov  7 15:33:15 2008
From: jason at extremeoverclocking.com (Jason Rabel)
Date: Fri, 7 Nov 2008 09:33:15 -0600
Subject: [time-nuts] Trimble T-Bolt Order
In-Reply-To: <mailman.3.1225886402.13670.time-nuts@febo.com>
References: <mailman.3.1225886402.13670.time-nuts@febo.com>
Message-ID: <6BB87E3289F6437CBB19D436BC379E3C@Inspiron>

Hey guys,

I hate to pollute the list with FS stuff, but I'm just trying to give back a
little.

I jumped in on the first group buy and got two tbolts on an impulse, but
really all I need is one. Since the thunderbolts seem to be out of stock
(again) and people have been asking about them, I figured I would offer up
my spare tbolt package to someone on the list. I'm not looking to make any
money, just want to recoup my initial cost. The date on it is 9/14/04 and
it's a Rev E (if that matters). This is for the thunderbolt AND power
supply.

First come, first serve.. $125 shipped (US only) - Please contact me OFF
LIST.

Oh, if you need a serial cable I have an extra (still in a bag unopened) 10'
9-pin M/F (straight through - what you need for the tbolt). I'll sell for an
extra $5.



From holrum at hotmail.com  Fri Nov  7 16:07:27 2008
From: holrum at hotmail.com (Mark Sims)
Date: Fri, 7 Nov 2008 16:07:27 +0000
Subject: [time-nuts] Tektronix Type 602 manual
In-Reply-To: <mailman.3.1226059201.7622.time-nuts@febo.com>
References: <mailman.3.1226059201.7622.time-nuts@febo.com>
Message-ID: <BLU125-W29CF7C3C0CE013228B0AE3CE190@phx.gbl>


Crank up the intensity control,  turn the unit on,  wait a minute or so and turn the unit off (preferably in a dark room).If you can see any flash or light on the screen,  your power supply is (mostly) OK.  If you see no sign of life,  you probably have a power supply problem (most likely the high voltage).
_________________________________________________________________
Color coding for safety: Windows Live Hotmail alerts you to suspicious email.
http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_safety_112008

From brice at weaponeer.com  Fri Nov  7 17:30:05 2008
From: brice at weaponeer.com (brice at weaponeer.com)
Date: Fri, 07 Nov 2008 17:30:05 +0000
Subject: [time-nuts] TRAK GPS issue
Message-ID: <W753301324819681226079005@webmail19>

 Sorry for the delay, I missed a few of my emails. It's very close, the measurements are right (I gave you the lazy, "not even close" expected response).
All part numbers are on the bottom, there are no connectors on the back of this. quite similar, no large battery. This may be a older version. There is a display in the middle of the board, it is white, and appears to be one of the earlier ones that could display red or green. Many ic's have 93/94 date code. 
I can send a .jpg to your email address, probably the easiest solution. (I can not upload photos right now, the old weaponeer site is now controlled by my freinds wife, after many break-ins and endless crashes. Plus it is 200 miles away now. Working on my own URL's content.) 
Cheers, Bill
---------------------
Bill

Close to my measurements 25/8 by 6 3/8 USA with a metal shield box on antenna connector end 2 1/2by 2 1/2. 20 Pin connector on the diagonal edge from the antennaconnector. Unable to read numbers as the interface board with backupbattery is mounted on top. Think it does match Bj?rn's post scriptfiles which explains the need for an extra voltage regulator for?7volts. Has a green led about center of the board. Magnovox GPS engineTrade Mark across the short antenna connector end of board. ThanksBj?rn for the files.

Stanley
----------------------



From jason at extremeoverclocking.com  Fri Nov  7 19:25:29 2008
From: jason at extremeoverclocking.com (Jason Rabel)
Date: Fri, 7 Nov 2008 13:25:29 -0600
Subject: [time-nuts] Trimble T-Bolt Order
Message-ID: <924853AF946B4F40A540C4D0EDFE3DDD@Inspiron>

Thanks to everyone that emailed me, the unit is sold! I think the first
reply I got was within 5 minutes of me posting the original message!

Jason



From richiem at hughes.net  Fri Nov  7 21:03:56 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 7 Nov 2008 13:03:56 -0800
Subject: [time-nuts] Tek 602, no trace
In-Reply-To: <mailman.3.1226059201.7622.time-nuts@febo.com>
References: <mailman.3.1226059201.7622.time-nuts@febo.com>
Message-ID: <AE0C170C-5DDD-40B5-9453-AFAC52CA3178@hughes.net>

>

Magnus, a few thoughts that have most likely already occurred to you --
1) HV supply failure -- I think it will be around 2 or 3kV if working.
2) X or Y deflection amp has failed, moving the trace offscreen.
3) CRT heater dead.

Either 1 or 2 should be easy to detect. Having the manual will  
certainly help with repair. 3, however, is really discouraging.

Dick Moore


> However, currently I am lacking the dot on the screen to begin  
> with. Power
> lines seems OKish but could be trimmed.
>
> Cheers,
> Magnus
>

> End of time-nuts Digest, Vol 52, Issue 18
> *****************************************



From magnus at rubidium.dyndns.org  Sat Nov  8 00:30:17 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sat, 08 Nov 2008 01:30:17 +0100
Subject: [time-nuts] Tek 602, no trace
In-Reply-To: <AE0C170C-5DDD-40B5-9453-AFAC52CA3178@hughes.net>
References: <mailman.3.1226059201.7622.time-nuts@febo.com>
	<AE0C170C-5DDD-40B5-9453-AFAC52CA3178@hughes.net>
Message-ID: <4914DD99.10103@rubidium.dyndns.org>

Richard Moore skrev:
> 
> Magnus, a few thoughts that have most likely already occurred to you --
> 1) HV supply failure -- I think it will be around 2 or 3kV if working.

It's 3,9 kV. There is a test point, but I need to dig up a very old HV 
probe lying around somewhere in the junk. Finally I get some use for 
it... maybe

> 2) X or Y deflection amp has failed, moving the trace offscreen.

The X deflection amp seems to work at least.

> 3) CRT heater dead.

No, I have a very faint ligthening up on the screen which the horizontal 
control can move on or off screen. I need to shield the screen from 
light to see it. It's so out of focus that it hits the full screen. 
Could be an HV issue, but I am not sure at this moment.

> Either 1 or 2 should be easy to detect. Having the manual will  
> certainly help with repair. 3, however, is really discouraging.

Certainly. I have enought of large scopes at a friends place to be able 
to salvage tubes before being tossed. I even think he still has the 
spare tube NOS. :)

Cheers,
Magnus


From sar10538 at gmail.com  Sat Nov  8 01:26:00 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sat, 8 Nov 2008 14:26:00 +1300
Subject: [time-nuts] Tek 602, no trace
In-Reply-To: <4914DD99.10103@rubidium.dyndns.org>
References: <mailman.3.1226059201.7622.time-nuts@febo.com>
	<AE0C170C-5DDD-40B5-9453-AFAC52CA3178@hughes.net>
	<4914DD99.10103@rubidium.dyndns.org>
Message-ID: <1231b6a80811071726r5ec5d7fetd089e0de9618c563@mail.gmail.com>

2008/11/8 Magnus Danielson <magnus at rubidium.dyndns.org>:
> Richard Moore skrev:
>>
>> Magnus, a few thoughts that have most likely already occurred to you --
>> 1) HV supply failure -- I think it will be around 2 or 3kV if working.
>
> It's 3,9 kV. There is a test point, but I need to dig up a very old HV
> probe lying around somewhere in the junk. Finally I get some use for
> it... maybe

So do you mean that it should read 3.9kV or that you have tested it to
be that value?

>> 2) X or Y deflection amp has failed, moving the trace offscreen.
>
> The X deflection amp seems to work at least.

If you place a meter between the X plates you should see 0 or very low
volts with the X position control in the middle position.
What voltage do you get between one of the X plates and ground? Is
there a beam-finder button on the scope as this should brighen up the
beam and bring it onto the display if it is too far off. Sorry, I
don't know this scope.

>> 3) CRT heater dead.
>
> No, I have a very faint ligthening up on the screen which the horizontal
> control can move on or off screen. I need to shield the screen from
> light to see it. It's so out of focus that it hits the full screen.
> Could be an HV issue, but I am not sure at this moment.

Quite often there is a little window in the screen around the CRT
shield which should give you a good view of the glowing heater. Make
sure there is a good bright orange glow. Cheaper/early scopes used ac
directly to the heater winding so there was never a problem with the
heater voltage but to reduce the ripple effect of the ac voltage,
better scopes used dc so you would be wise to check the heater voltage
in that case and look for something like 6-7V if the heater looks a
bit dim.

If the anode voltage looks good, check out the voltages at the cathode
and the grid. As the design of analog scopes try to keep the X and Y
plates near earth potential, you should see a large negative voltage
on the cathode and grid. If the grid is more negative than the cathode
by about 20V or more the beam is likely to be cutoff. You should see
the voltage difference between the cathode to grid drop (with the grid
being more negative than the cathode) as you increase the brightness
control. I don't know what the cathode voltage would be in your case
but with an anode voltage around 4kV I would be expecting to see
something in the region of -1.5kV give or minus 500V.

>> Either 1 or 2 should be easy to detect. Having the manual will
>> certainly help with repair. 3, however, is really discouraging.
>
> Certainly. I have enought of large scopes at a friends place to be able
> to salvage tubes before being tossed. I even think he still has the
> spare tube NOS. :)

Assuming any replacement tube has a similar spec you would be OK to
substitute but really need to check computability.

Hope any of this helps, I don't know too much about the Teks but have
some experience with old HP and Gould scopes. If you want to discuss
more feel free to PM me.

73, Steve
--
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From richiem at hughes.net  Sat Nov  8 06:08:43 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 7 Nov 2008 22:08:43 -0800
Subject: [time-nuts] Tek 602
In-Reply-To: <mailman.66.1226107563.2542.time-nuts@febo.com>
References: <mailman.66.1226107563.2542.time-nuts@febo.com>
Message-ID: <273B49BD-0A00-4D18-8D76-673FC9984D3E@hughes.net>

Magnus, what everyone else said, plus, I have seen a few older Tek  
scopes with bad focus and/or intensity controls as well as HV divider  
resistors for the screens. If the HVs at the anode cap and cathode  
are good, then I would look there. The heater is, of course, at high  
voltage to prevent arcing to the cathode and it is run off a winding  
of the HV transformer. HV could be as much as 10kV, so be careful.
>
> Message: 8
> Date: Sat, 08 Nov 2008 01:30:17 +0100
> From: Magnus Danielson <magnus at rubidium.dyndns.org>
> Subject: Re: [time-nuts] Tek 602, no trace
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <4914DD99.10103 at rubidium.dyndns.org>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Richard Moore skrev:
>>
>> Magnus, a few thoughts that have most likely already occurred to  
>> you --
>> 1) HV supply failure -- I think it will be around 2 or 3kV if  
>> working.
>
> It's 3,9 kV. There is a test point, but I need to dig up a very old HV
> probe lying around somewhere in the junk. Finally I get some use for
> it... maybe
>
>> 2) X or Y deflection amp has failed, moving the trace offscreen.
>
> The X deflection amp seems to work at least.
>
>> 3) CRT heater dead.
>
> No, I have a very faint ligthening up on the screen which the  
> horizontal
> control can move on or off screen. I need to shield the screen from
> light to see it. It's so out of focus that it hits the full screen.
> Could be an HV issue, but I am not sure at this moment.
>
>> Either 1 or 2 should be easy to detect. Having the manual will
>> certainly help with repair. 3, however, is really discouraging.
>
> Certainly. I have enought of large scopes at a friends place to be  
> able
> to salvage tubes before being tossed. I even think he still has the
> spare tube NOS. :)
>
> Cheers,
> Magnus
>
> End of time-nuts Digest, Vol 52, Issue 19
> *****************************************


From hamradio at oz.net  Sat Nov  8 18:16:45 2008
From: hamradio at oz.net (Randy)
Date: Sat, 8 Nov 2008 10:16:45 -0800
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <F4316BA6B30347759D80F03289B710F0@didierhp>
References: <4912274D.7040809@pacific.net>
	<F4316BA6B30347759D80F03289B710F0@didierhp>
Message-ID: <039401c941ce$28d7ceb0$6601a8c0@Laptop>

I was wondering if it is worthwhile or even feasible to compare an LPRO
Rubidium standard against a Z3801.  Since their frequencies are probably
going to be extremely close anyway it would seem some special
method/equipment would be required for high precision.  Suggestions?


Randy, W7HR
Port Orchard, WA





From jltran at worldnet.att.net  Sat Nov  8 18:26:09 2008
From: jltran at worldnet.att.net (J. L. Trantham)
Date: Sat, 8 Nov 2008 12:26:09 -0600
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <039401c941ce$28d7ceb0$6601a8c0@Laptop>
Message-ID: <224DDCB43C58466E8F1E45B9AFF304F7@S0028384766>

Randy,

I use a 'lissajous' figure.  I have a Tek 485 scope that permits 'X' input
on channel 1 and 'Y' input on channel 2 and it is a 350 MHz scope.  By
choosing the 'X-Y' display, as long as the frequencies are close or have a
common divisor, you can measure (with a stop watch) how long it takes the
lissajous figure to make one complete cycle.  From there, you can calculate
the frequency difference between the two.  If they are 'exactly' related,
the lissajous figure will be 'frozen' on the screen.

Hope this helps.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Randy
Sent: Saturday, November 08, 2008 12:17 PM
To: 'Discussion of precise time and frequency measurement'
Subject: [time-nuts] Checking accuracy of Rubidium standards

I was wondering if it is worthwhile or even feasible to compare an LPRO
Rubidium standard against a Z3801.  Since their frequencies are probably
going to be extremely close anyway it would seem some special
method/equipment would be required for high precision.  Suggestions?


Randy, W7HR
Port Orchard, WA




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time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From brooke at pacific.net  Sat Nov  8 18:39:26 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 08 Nov 2008 10:39:26 -0800
Subject: [time-nuts] ThunderBolt External Oscillator Option?
Message-ID: <4915DCDE.8080908@pacific.net>

Hi:

While learning about the ThunderBolt I found there may be a provision for an 
external oscillator.  See:
http://www.prc68.com/I/ThunderBolt.shtml#ExO
Note that there is a TSIP command that controls the tuning voltage and it's 
also part of the Tbolt Monitor program under SETUP DISCIPLINING.

Has anyone confirmed this?
-- 
Have Fun,

Brooke Clarke
http://www.prc68.com


From jpawlan at pawlan.com  Sat Nov  8 18:40:52 2008
From: jpawlan at pawlan.com (Jeffrey Pawlan)
Date: Sat, 8 Nov 2008 10:40:52 -0800 (PST)
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <039401c941ce$28d7ceb0$6601a8c0@Laptop>
References: <4912274D.7040809@pacific.net>
	<F4316BA6B30347759D80F03289B710F0@didierhp>
	<039401c941ce$28d7ceb0$6601a8c0@Laptop>
Message-ID: <Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>



On Sat, 8 Nov 2008, Randy wrote:

> I was wondering if it is worthwhile or even feasible to compare an LPRO
> Rubidium standard against a Z3801.  Since their frequencies are probably
> going to be extremely close anyway it would seem some special
> method/equipment would be required for high precision.  Suggestions?
>
>
> Randy, W7HR
> Port Orchard, WA

The best way would be to compare the highest possible frequencies you can 
generate with these two sources. I use two 10GHz sources that are each phase 
locked to an external 10MHz reference. Then the 10GHz outputs can be compared 
using either of these easy methods:
1) look at the DC/IF output of a microwave mixer where the LO and RF ports are 
driven by the two 10GHz sources. Don't overdrive the RF input to a level that 
can burn out your mixer.

2) use a good microwave frequency counter to read one of the 10GHz outputs while 
driving the counter's 10MHz ext ref input with the 10MHz from the other 10MHz 
source. This is very fast but will only give you accuracy readings that are a 
function of the resolution of the counter plus the bounce of the last digit 
owing to sampling and triggering.

3) if you have access to a lab with one or two microwave synthesized signal 
generators, then you can apply the 10MHz sources to the ext ref inputs of each 
of these signal generators and then proceed as in 1) or 2)
I have done comparison at 26GHz this way so I have a bit more resolution.

73,

Jeffrey Pawlan  WA6KBL



From robert8rpi at yahoo.co.uk  Sat Nov  8 19:04:00 2008
From: robert8rpi at yahoo.co.uk (Robert Atkinson)
Date: Sat, 8 Nov 2008 19:04:00 +0000 (GMT)
Subject: [time-nuts] ThunderBolt External Oscillator Option?
In-Reply-To: <4915DCDE.8080908@pacific.net>
Message-ID: <250112.75507.qm@web27101.mail.ukl.yahoo.com>

Hi Brooke,
I came across this recently, http://www.thegleam.com/ke5fx/tbolt.htm?which seems to confirm the exernal option.
?
Robert G8RPI

--- On Sat, 8/11/08, Brooke Clarke <brooke at pacific.net> wrote:

From: Brooke Clarke <brooke at pacific.net>
Subject: [time-nuts] ThunderBolt External Oscillator Option?
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Date: Saturday, 8 November, 2008, 6:39 PM

Hi:

While learning about the ThunderBolt I found there may be a provision for an 
external oscillator.  See:
http://www.prc68.com/I/ThunderBolt.shtml#ExO
Note that there is a TSIP command that controls the tuning voltage and it's

also part of the Tbolt Monitor program under SETUP DISCIPLINING.

Has anyone confirmed this?
-- 
Have Fun,

Brooke Clarke
http://www.prc68.com

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



      

From danrae at verizon.net  Sat Nov  8 19:18:13 2008
From: danrae at verizon.net (Dan Rae)
Date: Sat, 08 Nov 2008 11:18:13 -0800
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <039401c941ce$28d7ceb0$6601a8c0@Laptop>
References: <4912274D.7040809@pacific.net>
	<F4316BA6B30347759D80F03289B710F0@didierhp>
	<039401c941ce$28d7ceb0$6601a8c0@Laptop>
Message-ID: <4915E5F5.4090608@verizon.net>

Randy wrote:
> I was wondering if it is worthwhile or even feasible to compare an LPRO
> Rubidium standard against a Z3801.  Since their frequencies are probably
> going to be extremely close anyway it would seem some special
> method/equipment would be required for high precision.  Suggestions?
>
>   
Randy, As I have just been doing this, I'll offer my 2 cent's worth.  
The problem I found is that the Rb standard, in my case an hp 5065A, has 
better short term stability than the gps unit.  So for getting down to 
the best accuracy that the Rb unit is capable of requires integration of 
some kind over a longish period.    I find using a pen recorder on the 
IF output of a mixer, with crude LP filtering on it will permit setting 
an Rb standard with confidence down to the 10 e -11 level. 

For approximate setting, triggering a double beam scope from your 
reference with the time base at it's fastest setting and the x 10 
magnifier in,  and the gain on the channel with the unit under test 
wound right up to give near vertical zero crossings, will enable you to 
see small phase shifts of the unit under test. With the 465B I was using 
for example that's 2 nanoseconds per major division  But it gets tiring 
watching it for a long time :^)

Fun though!

Dan



From tractorb at ihug.co.nz  Sat Nov  8 21:03:25 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Sun, 9 Nov 2008 10:03:25 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>
	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>
Message-ID: <051701c941e5$71f6b680$7900a8c0@athlon1200>


----- Original Message ----- 
From: "Jeffrey Pawlan" <jpawlan at pawlan.com>
To: <hamradio at oz.net>; "Discussion of precise time and frequency 
measurement" <time-nuts at febo.com>
Sent: Sunday, November 09, 2008 7:40 AM
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards


>
>
> On Sat, 8 Nov 2008, Randy wrote:
>
>> I was wondering if it is worthwhile or even feasible to compare an 
>> LPRO
>> Rubidium standard against a Z3801.  Since their frequencies are 
>> probably
>> going to be extremely close anyway it would seem some special
>> method/equipment would be required for high precision. 
>> Suggestions?
>>
>>
>> Randy, W7HR
>> Port Orchard, WA
>
> The best way would be to compare the highest possible frequencies 
> you can
> generate with these two sources. I use two 10GHz sources that are 
> each phase
> locked to an external 10MHz reference. <snip>

Jeffrey-
 Details on the 10 GHz sources? Are these commercial or home built? 
I've been looking at this kind of scheme on and off for a while now 
but other than collecting up some possibly useful ex-commercial 
multipliers (10 GHz o/p w/g  assys) I have not progressed any.
DaveB, NZ




From jpawlan at pawlan.com  Sat Nov  8 21:24:02 2008
From: jpawlan at pawlan.com (Jeffrey Pawlan)
Date: Sat, 8 Nov 2008 13:24:02 -0800 (PST)
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <051701c941e5$71f6b680$7900a8c0@athlon1200>
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>
	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>
	<051701c941e5$71f6b680$7900a8c0@athlon1200>
Message-ID: <Pine.GSO.4.60.0811081315070.2322@jeffrey150.pawlan.com>

Dear Dave,

    I was fortunate to find two surplus "brick" PLOs that had 10MHz input.
But I also have synthesized microwave signal generators with ext ref inputs and 
an EIP 575 with ext ref input. Perhaps there is a commercial lab or engineering 
school where you can use equipment like this and do the experiments. Otherwise, 
beating two 10MHz sources together will require a strip chart recorder so you 
can see the long term trends over days as indicated by someone else who 
responded. The methods I use do not take into account long term drift but are 
simply meant to be measurements that can display 1E-9 or 1E-10 in just one 
second of your time. To get finer than that, you patiently wait.

73,

Jeffrey Pawlan  WA6KBL


From alan.melia at btinternet.com  Sat Nov  8 21:43:49 2008
From: alan.melia at btinternet.com (Alan Melia)
Date: Sat, 8 Nov 2008 21:43:49 -0000
Subject: [time-nuts] Checking accuracy of Rubidium standards
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>
	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>
Message-ID: <005501c941eb$1c3dc520$0900a8c0@AM>

This is an interesting thread again.....it may be similar to ones that have
been discussed, but one or two furthur questions occur to me. I have a
Montronics sytem that does comparisons by the multiply and mix process, and
I find (also common to more modern Kethly systems) that the limitation is
around a part in 10^10 where the noise on the phase output makes it not
really usable (without a lot of averaging) being around or in excess of 90
degreees even with a couple of very good OXCOs. How does the 10G comparision
avoid this problem with standard multipliers? I doubt you can go all that
way with low-noise multipliers and have any useful signal left, or have I
missed something. At present I use a phase meter (lock in amps can be quite
good) at the MHz range and datalog the phase drift for several hours. I have
determined that setting "on the nose" is not necessary (for my
applications). It is more useful to know how far a source is "off".
How does the mix down compare with the seemingly more popular "mix down and
timestamp" I understand from previous threads that this has more potential
but might it also be as good even using simpler circuits that the NIST
system.

Thanks for all your efforts inthe background John..... great reading
material !

Alan G3NYK

----- Original Message -----
From: "Jeffrey Pawlan" <jpawlan at pawlan.com>
To: <hamradio at oz.net>; "Discussion of precise time and frequency
measurement" <time-nuts at febo.com>
Sent: Saturday, November 08, 2008 6:40 PM
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards


>
>
> On Sat, 8 Nov 2008, Randy wrote:
>
> > I was wondering if it is worthwhile or even feasible to compare an LPRO
> > Rubidium standard against a Z3801.  Since their frequencies are probably
> > going to be extremely close anyway it would seem some special
> > method/equipment would be required for high precision.  Suggestions?
> >
> >
> > Randy, W7HR
> > Port Orchard, WA
>
> The best way would be to compare the highest possible frequencies you can
> generate with these two sources. I use two 10GHz sources that are each
phase
> locked to an external 10MHz reference. Then the 10GHz outputs can be
compared
> using either of these easy methods:
> 1) look at the DC/IF output of a microwave mixer where the LO and RF ports
are
> driven by the two 10GHz sources. Don't overdrive the RF input to a level
that
> can burn out your mixer.
>
> 2) use a good microwave frequency counter to read one of the 10GHz outputs
while
> driving the counter's 10MHz ext ref input with the 10MHz from the other
10MHz
> source. This is very fast but will only give you accuracy readings that
are a
> function of the resolution of the counter plus the bounce of the last
digit
> owing to sampling and triggering.
>
> 3) if you have access to a lab with one or two microwave synthesized
signal
> generators, then you can apply the 10MHz sources to the ext ref inputs of
each
> of these signal generators and then proceed as in 1) or 2)
> I have done comparison at 26GHz this way so I have a bit more resolution.
>
> 73,
>
> Jeffrey Pawlan  WA6KBL
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From bruce.griffiths at xtra.co.nz  Sat Nov  8 22:05:42 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 09 Nov 2008 11:05:42 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <005501c941eb$1c3dc520$0900a8c0@AM>
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>
	<005501c941eb$1c3dc520$0900a8c0@AM>
Message-ID: <49160D36.9050700@xtra.co.nz>

Alan Melia wrote:
> This is an interesting thread again.....it may be similar to ones that have
> been discussed, but one or two furthur questions occur to me. I have a
> Montronics sytem that does comparisons by the multiply and mix process, and
> I find (also common to more modern Kethly systems) that the limitation is
> around a part in 10^10 where the noise on the phase output makes it not
> really usable (without a lot of averaging) being around or in excess of 90
> degreees even with a couple of very good OXCOs. How does the 10G comparision
> avoid this problem with standard multipliers? I doubt you can go all that
> way with low-noise multipliers and have any useful signal left, or have I
> missed something. At present I use a phase meter (lock in amps can be quite
> good) at the MHz range and datalog the phase drift for several hours. I have
> determined that setting "on the nose" is not necessary (for my
> applications). It is more useful to know how far a source is "off".
> How does the mix down compare with the seemingly more popular "mix down and
> timestamp" I understand from previous threads that this has more potential
> but might it also be as good even using simpler circuits that the NIST
> system.
>
> Thanks for all your efforts inthe background John..... great reading
> material !
>
> Alan G3NYK
>
>   
Alan

The principal limitation with dual mixer systems is the relatively large
phase shift tempco of the mixers (~ 10ps/C for 10MHz inputs).
If one uses a high end sound card (or equivalent ADC) to timestamp the
beat frequency zero crossings a resolution of better than 1E-12/Tau is
possible when the thermal environment permits.
However a stable low noise offset source frequency is required.
It is also essential to ensure there is sufficient isolation between the
sources being compared to avoid injection locking.

A low end sound card can also be used together with a Collin's style
bandpass limiter/slope amplifier to achieve similar performance if the
slope gain is large enough.

Bruce


From namichie at gmail.com  Sat Nov  8 22:08:45 2008
From: namichie at gmail.com (Neville Michie)
Date: Sun, 9 Nov 2008 09:08:45 +1100
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <005501c941eb$1c3dc520$0900a8c0@AM>
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>
	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>
	<005501c941eb$1c3dc520$0900a8c0@AM>
Message-ID: <CEEBA8F2-A130-44B3-87E7-B8E8F00BB410@gmail.com>

Hi,
I have a plan which involves the dividing down of the 10MHz of a GPSDO
and a rubidium (LPRO) to about 1MHz or 100kHZ and applying them to a
XOR or D latch to get a PWM signal that can be averaged for a strip  
chart recorder or
12 bit analogue data logger. The DC output gives a range of 5 volts  
for one
microsecond or 10 microseconds phase difference and folds back if  
this difference is exceeded.
The data from the datalogger is in a format that a spreadsheet can use.
With time and phase measurements I wonder how hard it is to get Allen  
variance.
I realise the PWM method requires a low pass filter and this will  
prevent short period
variances from being calculated.
cheers, Neville Michie

On 09/11/2008, at 8:43 AM, Alan Melia wrote:

> This is an interesting thread again.....it may be similar to ones  
> that have
> been discussed, but one or two furthur questions occur to me. I have a
> Montronics sytem that does comparisons by the multiply and mix  
> process, and
> I find (also common to more modern Kethly systems) that the  
> limitation is
> around a part in 10^10 where the noise on the phase output makes it  
> not
> really usable (without a lot of averaging) being around or in  
> excess of 90
> degreees even with a couple of very good OXCOs. How does the 10G  
> comparision
> avoid this problem with standard multipliers? I doubt you can go  
> all that
> way with low-noise multipliers and have any useful signal left, or  
> have I
> missed something. At present I use a phase meter (lock in amps can  
> be quite
> good) at the MHz range and datalog the phase drift for several  
> hours. I have
> determined that setting "on the nose" is not necessary (for my
> applications). It is more useful to know how far a source is "off".
> How does the mix down compare with the seemingly more popular "mix  
> down and
> timestamp" I understand from previous threads that this has more  
> potential
> but might it also be as good even using simpler circuits that the NIST
> system.
>
> Thanks for all your efforts inthe background John..... great reading
> material !
>
> Alan G3NYK
>
> ----- Original Message -----
> From: "Jeffrey Pawlan" <jpawlan at pawlan.com>
> To: <hamradio at oz.net>; "Discussion of precise time and frequency
> measurement" <time-nuts at febo.com>
> Sent: Saturday, November 08, 2008 6:40 PM
> Subject: Re: [time-nuts] Checking accuracy of Rubidium standards
>
>
>>
>>
>> On Sat, 8 Nov 2008, Randy wrote:
>>
>>> I was wondering if it is worthwhile or even feasible to compare  
>>> an LPRO
>>> Rubidium standard against a Z3801.  Since their frequencies are  
>>> probably
>>> going to be extremely close anyway it would seem some special
>>> method/equipment would be required for high precision.  Suggestions?
>>>
>>>
>>> Randy, W7HR
>>> Port Orchard, WA
>>
>> The best way would be to compare the highest possible frequencies  
>> you can
>> generate with these two sources. I use two 10GHz sources that are  
>> each
> phase
>> locked to an external 10MHz reference. Then the 10GHz outputs can be
> compared
>> using either of these easy methods:
>> 1) look at the DC/IF output of a microwave mixer where the LO and  
>> RF ports
> are
>> driven by the two 10GHz sources. Don't overdrive the RF input to a  
>> level
> that
>> can burn out your mixer.
>>
>> 2) use a good microwave frequency counter to read one of the 10GHz  
>> outputs
> while
>> driving the counter's 10MHz ext ref input with the 10MHz from the  
>> other
> 10MHz
>> source. This is very fast but will only give you accuracy readings  
>> that
> are a
>> function of the resolution of the counter plus the bounce of the last
> digit
>> owing to sampling and triggering.
>>
>> 3) if you have access to a lab with one or two microwave synthesized
> signal
>> generators, then you can apply the 10MHz sources to the ext ref  
>> inputs of
> each
>> of these signal generators and then proceed as in 1) or 2)
>> I have done comparison at 26GHz this way so I have a bit more  
>> resolution.
>>
>> 73,
>>
>> Jeffrey Pawlan  WA6KBL
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.



From bruce.griffiths at xtra.co.nz  Sat Nov  8 22:18:51 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 09 Nov 2008 11:18:51 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <CEEBA8F2-A130-44B3-87E7-B8E8F00BB410@gmail.com>
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp><039401c941ce$28d7ceb0$6601a8c0@Laptop>	<Pine.GSO.4.60.0811081028560.1991@jeffrey150.pawlan.com>	<005501c941eb$1c3dc520$0900a8c0@AM>
	<CEEBA8F2-A130-44B3-87E7-B8E8F00BB410@gmail.com>
Message-ID: <4916104B.9000509@xtra.co.nz>

Neville Michie wrote:
> Hi,
> I have a plan which involves the dividing down of the 10MHz of a GPSDO
> and a rubidium (LPRO) to about 1MHz or 100kHZ and applying them to a
> XOR or D latch to get a PWM signal that can be averaged for a strip  
> chart recorder or
> 12 bit analogue data logger. The DC output gives a range of 5 volts  
> for one
> microsecond or 10 microseconds phase difference and folds back if  
> this difference is exceeded.
> The data from the datalogger is in a format that a spreadsheet can use.
> With time and phase measurements I wonder how hard it is to get Allen  
> variance.
> I realise the PWM method requires a low pass filter and this will  
> prevent short period
> variances from being calculated.
> cheers, Neville Michie
>
>   
Neville

A low pass filter or equivalent means of limiting/defining the
measurement bandwidth is required when measuring ADEV.

The limitation with all such digital phase detectors is the nonlinearity
as the ends of the range are approached.
It is possible to achieve a resolution of around 4E-11/Tau with such
phase detectors if a higher resolution ratiometric ADC is used.


Bruce



From bill at iaxs.net  Sat Nov  8 23:41:38 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Sat, 8 Nov 2008 17:41:38 -0600
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <039401c941ce$28d7ceb0$6601a8c0@Laptop>
References: <4912274D.7040809@pacific.net><F4316BA6B30347759D80F03289B710F0@didierhp>
	<039401c941ce$28d7ceb0$6601a8c0@Laptop>
Message-ID: <1E26CEC0A9DC4EEA933A8D69568B1319@cyrus>

You didn't say anything about the precision you need or the
time you were willing to wait to get it. Nor did you mention
the equipment you have available, so I'll assume no fancy
counters or deviation plotters.

Get two clocks, and do what you have to do to run them on
10 MHz. You could even derive 60 Hz from your sources and
run a pair of synchronous motor clocks. Ah, you'll need to
run everything from uninterruptable power. After a year,
you'll be able to see 3 parts in 10E-9 if you can read one
second of difference. It would take 100 years to get down
to one part in 10E-11, where the people on this list start
getting interested.

So you really need to get something that you can read with
100 nanosecond precision, computer connections for two of
them, and a program that will process and record the data. 

Ask yourself why you want to do this. Is it a 'horsepower'
race to get the best number? If you want an accuracy of one
cycle in 10 MHz, you're already there, if the units are
within specs. A simple Lissajous display will show you one
part in 10E-8 in ten seconds, as has been mentioned.

Bill Hawkins


-----Original Message-----
From: Randy
Sent: Saturday, November 08, 2008 12:17 PM

I was wondering if it is worthwhile or even feasible to compare an LPRO
Rubidium standard against a Z3801.  Since their frequencies are probably
going to be extremely close anyway it would seem some special
method/equipment would be required for high precision.  Suggestions?

Randy, W7HR
Port Orchard, WA



From wa1zms at att.net  Sun Nov  9 00:58:35 2008
From: wa1zms at att.net (wa1zms at att.net)
Date: Sat, 8 Nov 2008 19:58:35 -0500
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <CEEBA8F2-A130-44B3-87E7-B8E8F00BB410@gmail.com>
Message-ID: <FBEDKEIEMDPKGDDCPGNCMEOKDPAA.wa1zms@att.net>

This sounds to be a very similar method that my Tracor 895A uses.
Does that sound correct?

-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Neville Michie
Sent: Saturday, November 08, 2008 5:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards


Hi,
I have a plan which involves the dividing down of the 10MHz of a GPSDO
and a rubidium (LPRO) to about 1MHz or 100kHZ and applying them to a
XOR or D latch to get a PWM signal that can be averaged for a strip  
chart recorder or
12 bit analogue data logger. The DC output gives a range of 5 volts  
for one
microsecond or 10 microseconds phase difference and folds back if  
this difference is exceeded.
The data from the datalogger is in a format that a spreadsheet can use.
With time and phase measurements I wonder how hard it is to get Allen  
variance.
I realise the PWM method requires a low pass filter and this will  
prevent short period
variances from being calculated.
cheers, Neville Michie
and follow the instructions there.


From jltran at worldnet.att.net  Sun Nov  9 02:26:57 2008
From: jltran at worldnet.att.net (J. L. Trantham)
Date: Sat, 8 Nov 2008 20:26:57 -0600
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <FBEDKEIEMDPKGDDCPGNCMEOKDPAA.wa1zms@att.net>
Message-ID: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>

I have been enjoying this discussion.  

Since the original question was the desire to 'compare' the frequency of an
LPRO to a Z3801, it seems that you could consider that from two (at least)
perspectives.

Before I begin, I confess that I am a novice in this arena and please
correct me in any area that needs it.

The first perspective is the issue of frequency.  That seems to me to be the
issue of the average frequency of the LPRO versus the average frequency of
the Z3801.  Assuming that there is no gross difference of the 10 MHz
signals, a lissajous figure (X-Y display) on a scope with the appropriate
bandwidth amplifiers would be a reasonable initial approach.

Assuming that they are both near 10 MHz and you do not know which is the
most accurate (although the Z3801 would seem to be the default standard), if
it takes 10 minutes for a single cycle of the lissajous figure to complete,
then it is 1 cycle per 600 seconds difference between the two and therefore
the two are within 1/600 Hz or 1.67 mHz of each other.  If we assume that
they are both close to 10 MHz, then that is 1.67 parts in 10E-10 difference
between the two.  Is my logic faulty?

The other perspective is the issue of 'purity'.  That is to say, what is the
'frequency modulation' of the source?  This, I think, is the issue of phase
noise.  Correct?

That is something that I have not yet had a chance to contemplate as far as
how to measure.  It would appear to require a particularly stable (pure)
source as a reference though.  Various multiplying or dividing protocols
would seem to introduce a host of other variables that would seem to be
difficult to account for though they might accentuate an impurity in the
signal in question.  I have read Bruce's comments and I still do not
understand the basics of time stamping or how a sound card might provide
this.

I would appreciate any direction for further reading regarding this and I
would appreciate any direction/correction/etc. in the thoughts above.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of wa1zms at att.net
Sent: Saturday, November 08, 2008 6:59 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards

This sounds to be a very similar method that my Tracor 895A uses.
Does that sound correct?

-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Neville Michie
Sent: Saturday, November 08, 2008 5:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards


Hi,
I have a plan which involves the dividing down of the 10MHz of a GPSDO
and a rubidium (LPRO) to about 1MHz or 100kHZ and applying them to a
XOR or D latch to get a PWM signal that can be averaged for a strip  
chart recorder or
12 bit analogue data logger. The DC output gives a range of 5 volts  
for one
microsecond or 10 microseconds phase difference and folds back if  
this difference is exceeded.
The data from the datalogger is in a format that a spreadsheet can use.
With time and phase measurements I wonder how hard it is to get Allen  
variance.
I realise the PWM method requires a low pass filter and this will  
prevent short period
variances from being calculated.
cheers, Neville Michie
and follow the instructions there.

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From bruce.griffiths at xtra.co.nz  Sun Nov  9 02:44:56 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 09 Nov 2008 15:44:56 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
Message-ID: <49164EA8.70601@xtra.co.nz>

J. L. Trantham wrote:
> I have been enjoying this discussion.  
>
> Since the original question was the desire to 'compare' the frequency of an
> LPRO to a Z3801, it seems that you could consider that from two (at least)
> perspectives.
>
> Before I begin, I confess that I am a novice in this arena and please
> correct me in any area that needs it.
>
> The first perspective is the issue of frequency.  That seems to me to be the
> issue of the average frequency of the LPRO versus the average frequency of
> the Z3801.  Assuming that there is no gross difference of the 10 MHz
> signals, a lissajous figure (X-Y display) on a scope with the appropriate
> bandwidth amplifiers would be a reasonable initial approach.
>
> Assuming that they are both near 10 MHz and you do not know which is the
> most accurate (although the Z3801 would seem to be the default standard), if
> it takes 10 minutes for a single cycle of the lissajous figure to complete,
> then it is 1 cycle per 600 seconds difference between the two and therefore
> the two are within 1/600 Hz or 1.67 mHz of each other.  If we assume that
> they are both close to 10 MHz, then that is 1.67 parts in 10E-10 difference
> between the two.  Is my logic faulty?
>
> The other perspective is the issue of 'purity'.  That is to say, what is the
> 'frequency modulation' of the source?  This, I think, is the issue of phase
> noise.  Correct?
>
> That is something that I have not yet had a chance to contemplate as far as
> how to measure.  It would appear to require a particularly stable (pure)
> source as a reference though.  Various multiplying or dividing protocols
> would seem to introduce a host of other variables that would seem to be
> difficult to account for though they might accentuate an impurity in the
> signal in question.  I have read Bruce's comments and I still do not
> understand the basics of time stamping or how a sound card might provide
> this.
>
> I would appreciate any direction for further reading regarding this and I
> would appreciate any direction/correction/etc. in the thoughts above.
>
> Joe
>
>   
Joe

There is sufficient information available from the sound card samples to
calculate the input signal at any time between 2 samples and in
particular derive the time at which the signal crosses zero.
This is the time stamp for that zero crossing.
The frequency and ADEV of a signal can then be calculated from such a
sequence of time stamps.
However it is necessary to either calibrate the sound card sampling
frequency or lock it to a known frequency.
The method used to interpolate between samples is called WSK (Whittaker
Shannon Kotelnikov) interpolation.

Bruce


From sar10538 at gmail.com  Sun Nov  9 06:45:34 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 9 Nov 2008 19:45:34 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <49164EA8.70601@xtra.co.nz>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
	<49164EA8.70601@xtra.co.nz>
Message-ID: <1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>

Bruce and Joe,

I have been enjoying this discussion too.

2008/11/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
> J. L. Trantham wrote:
...
>> That is something that I have not yet had a chance to contemplate as far as
>> how to measure.  It would appear to require a particularly stable (pure)
>> source as a reference though.  Various multiplying or dividing protocols
>> would seem to introduce a host of other variables that would seem to be
>> difficult to account for though they might accentuate an impurity in the
>> signal in question.  I have read Bruce's comments and I still do not
>> understand the basics of time stamping or how a sound card might provide
>> this.

> There is sufficient information available from the sound card samples to
> calculate the input signal at any time between 2 samples and in
> particular derive the time at which the signal crosses zero.
> This is the time stamp for that zero crossing.
> The frequency and ADEV of a signal can then be calculated from such a
> sequence of time stamps.
> However it is necessary to either calibrate the sound card sampling
> frequency or lock it to a known frequency.
> The method used to interpolate between samples is called WSK (Whittaker
> Shannon Kotelnikov) interpolation.

Given Joe's comments, doesn't making ADEV measurements rely on highly
accurately spaced sound card samples and the nature of system based
upon this hardware affect the accuracy of any such based system? Does
the accuracy of the measuring system not have to meet or exceed the
accuracy of the DUT?

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From bruce.griffiths at xtra.co.nz  Sun Nov  9 07:24:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 09 Nov 2008 20:24:16 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49164EA8.70601@xtra.co.nz>
	<1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>
Message-ID: <49169020.9020209@xtra.co.nz>

Steve Rooke wrote:
> Bruce and Joe,
>
> I have been enjoying this discussion too.
>
> 2008/11/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
>   
>> J. L. Trantham wrote:
>>     
> ...
>   
>>> That is something that I have not yet had a chance to contemplate as far as
>>> how to measure.  It would appear to require a particularly stable (pure)
>>> source as a reference though.  Various multiplying or dividing protocols
>>> would seem to introduce a host of other variables that would seem to be
>>> difficult to account for though they might accentuate an impurity in the
>>> signal in question.  I have read Bruce's comments and I still do not
>>> understand the basics of time stamping or how a sound card might provide
>>> this.
>>>       
>
>   
>> There is sufficient information available from the sound card samples to
>> calculate the input signal at any time between 2 samples and in
>> particular derive the time at which the signal crosses zero.
>> This is the time stamp for that zero crossing.
>> The frequency and ADEV of a signal can then be calculated from such a
>> sequence of time stamps.
>> However it is necessary to either calibrate the sound card sampling
>> frequency or lock it to a known frequency.
>> The method used to interpolate between samples is called WSK (Whittaker
>> Shannon Kotelnikov) interpolation.
>>     
>
> Given Joe's comments, doesn't making ADEV measurements rely on highly
> accurately spaced sound card samples and the nature of system based
> upon this hardware affect the accuracy of any such based system? Does
> the accuracy of the measuring system not have to meet or exceed the
> accuracy of the DUT?
>
> 73, Steve
>   

Steve

When one is measuring the beat frequency between an offset standard and
the DUT, the sound card timebase doesn't have to be more accurate than
the the DUT as it is only measuring the error in the small offset
between the DUT and the offset standard.
However the local standard against which the DUT is being compared does.

For example with a 10MHz DUT and a 10MHz local standard offset by 100Hz
from 10MHz, the sound card only has to measure the  100Hz offset
frequency ( between the DUT and the offset standard) to an accuracy of
1E-7 in order to determine the frequency of the DUT to an accuracy of
1E-12.

When one uses a dual mixer system to compare 2 non offset 10MHz signals,
most of the error contributions from the offset source and ADC sampling
clock are common to both channels and tend to cancel on subtraction.

Bruce


From sar10538 at gmail.com  Sun Nov  9 13:30:39 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Mon, 10 Nov 2008 02:30:39 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <49169020.9020209@xtra.co.nz>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
	<49164EA8.70601@xtra.co.nz>
	<1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>
	<49169020.9020209@xtra.co.nz>
Message-ID: <1231b6a80811090530v575ca7fl50d27b7217c923c4@mail.gmail.com>

2008/11/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
> When one is measuring the beat frequency between an offset standard and
> the DUT, the sound card timebase doesn't have to be more accurate than
> the the DUT as it is only measuring the error in the small offset
> between the DUT and the offset standard.
> However the local standard against which the DUT is being compared does.

So as this is just measuring a beat, there is no requirement for
absolute accuracy in the measuring system, it just needs the reference
frequency to be as accurate as the desired measure of absolute
accuracy. Yes, I can see that.

> For example with a 10MHz DUT and a 10MHz local standard offset by 100Hz
> from 10MHz, the sound card only has to measure the  100Hz offset
> frequency ( between the DUT and the offset standard) to an accuracy of
> 1E-7 in order to determine the frequency of the DUT to an accuracy of
> 1E-12.

So 100Hz offset from 10MHz is 1E-5 and if I can measure the 100Hz to
an accuracy of 1E-7 that would give an overall measurement of 1E-12.
So that would mean that the sound card device would somehow have to
sample with at least 1E-7 accuracy. That would mean taking enough
samples of sufficient accuracy to determine this 1E-7 accuracy. A
sound card has a sample frequency of approx 44KHz but to see an offset
of 1E-7 would that not take a fairly long sample time? How would this
affect the ability of such a system to determine ADEV for small tau?

> When one uses a dual mixer system to compare 2 non offset 10MHz signals,
> most of the error contributions from the offset source and ADC sampling
> clock are common to both channels and tend to cancel on subtraction.

I can see that, assuming both channels are sampled at the same time.

Thanks Bruce.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From bruce.griffiths at xtra.co.nz  Sun Nov  9 20:57:50 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 09:57:50 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <1231b6a80811090530v575ca7fl50d27b7217c923c4@mail.gmail.com>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49164EA8.70601@xtra.co.nz>	<1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>	<49169020.9020209@xtra.co.nz>
	<1231b6a80811090530v575ca7fl50d27b7217c923c4@mail.gmail.com>
Message-ID: <49174ECE.5030608@xtra.co.nz>

Steve Rooke wrote:
> 2008/11/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
>   
>> When one is measuring the beat frequency between an offset standard and
>> the DUT, the sound card timebase doesn't have to be more accurate than
>> the the DUT as it is only measuring the error in the small offset
>> between the DUT and the offset standard.
>> However the local standard against which the DUT is being compared does.
>>     
>
> So as this is just measuring a beat, there is no requirement for
> absolute accuracy in the measuring system, it just needs the reference
> frequency to be as accurate as the desired measure of absolute
> accuracy. Yes, I can see that.
>
>   
>> For example with a 10MHz DUT and a 10MHz local standard offset by 100Hz
>> from 10MHz, the sound card only has to measure the  100Hz offset
>> frequency ( between the DUT and the offset standard) to an accuracy of
>> 1E-7 in order to determine the frequency of the DUT to an accuracy of
>> 1E-12.
>>     
>
> So 100Hz offset from 10MHz is 1E-5 and if I can measure the 100Hz to
> an accuracy of 1E-7 that would give an overall measurement of 1E-12.
> So that would mean that the sound card device would somehow have to
> sample with at least 1E-7 accuracy. That would mean taking enough
> samples of sufficient accuracy to determine this 1E-7 accuracy. A
> sound card has a sample frequency of approx 44KHz but to see an offset
> of 1E-7 would that not take a fairly long sample time? How would this
> affect the ability of such a system to determine ADEV for small tau?
>
>   
>> When one uses a dual mixer system to compare 2 non offset 10MHz signals,
>> most of the error contributions from the offset source and ADC sampling
>> clock are common to both channels and tend to cancel on subtraction.
>>     
>
> I can see that, assuming both channels are sampled at the same time.
>
> Thanks Bruce.
>
> 73, Steve
>   
If the signal has sufficiently high SNR the measurement time need not be
very long.
For example if the noise is an additive random Gaussian signal then a 40
dB SNR is equivalent to a period jitter of 0.3%.
For a 100Hz signal the corresponding time jitter is 30us.
If the measurement time is 1 second then the corresponding rms error in
measuring the 100Hz signal is 4.2E-5 or 4.2E-10 of the 10MHz signal.
Thus a measurement time of 420 sec or more would reduce the noise to
1E-12 rms or less.
In practice the beat frequency signal will, with low noise sources, have
a somewhat higher SNR.
Some filtering of the beat signal to reduce the noise will be required.
With a 100Hz beat frequency the shortest value of Tau achievable using
this technique is 10ms.

As long as the requirements of the sampling theorem are satisfied the
choice of sampling rate isnt critical as one can accurately interpolate
between samples to produce as high an effective sampling rate as
required. An effective sampling rate of 10MHz or more is sufficient to
achieve a resolution of 1E-12 or better (at 10MHz) with a 100Hz beat
frequency.
However calculating all the interpolated samples for a 10MHz clock isnt
the most efficient technique since only the zero crossings are of interest.

An alternative technique is to implement a Costas receiver in software.
Such a receiver has both in phase and quadrature outputs allowing the
phase of the receiver output signal to be calculated for each sample.

Bruce


From bruce.griffiths at xtra.co.nz  Sun Nov  9 21:36:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 10:36:16 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <1231b6a80811090530v575ca7fl50d27b7217c923c4@mail.gmail.com>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49164EA8.70601@xtra.co.nz>	<1231b6a80811082245x7cf9c2c2j3d124464c7d8628c@mail.gmail.com>	<49169020.9020209@xtra.co.nz>
	<1231b6a80811090530v575ca7fl50d27b7217c923c4@mail.gmail.com>
Message-ID: <491757D0.4020005@xtra.co.nz>

Steve Rooke wrote:
> 2008/11/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
>   
>> When one is measuring the beat frequency between an offset standard and
>> the DUT, the sound card timebase doesn't have to be more accurate than
>> the the DUT as it is only measuring the error in the small offset
>> between the DUT and the offset standard.
>> However the local standard against which the DUT is being compared does.
>>     
>
> So as this is just measuring a beat, there is no requirement for
> absolute accuracy in the measuring system, it just needs the reference
> frequency to be as accurate as the desired measure of absolute
> accuracy. Yes, I can see that.
>
>   
>> For example with a 10MHz DUT and a 10MHz local standard offset by 100Hz
>> from 10MHz, the sound card only has to measure the  100Hz offset
>> frequency ( between the DUT and the offset standard) to an accuracy of
>> 1E-7 in order to determine the frequency of the DUT to an accuracy of
>> 1E-12.
>>     
>
> So 100Hz offset from 10MHz is 1E-5 and if I can measure the 100Hz to
> an accuracy of 1E-7 that would give an overall measurement of 1E-12.
> So that would mean that the sound card device would somehow have to
> sample with at least 1E-7 accuracy. That would mean taking enough
> samples of sufficient accuracy to determine this 1E-7 accuracy. A
> sound card has a sample frequency of approx 44KHz but to see an offset
> of 1E-7 would that not take a fairly long sample time? How would this
> affect the ability of such a system to determine ADEV for small tau?
>
>   
>> When one uses a dual mixer system to compare 2 non offset 10MHz signals,
>> most of the error contributions from the offset source and ADC sampling
>> clock are common to both channels and tend to cancel on subtraction.
>>     
>
> I can see that, assuming both channels are sampled at the same time.
>
> Thanks Bruce.
>
> 73, Steve
>   
Steve

The effect of the finite resolution of the sound card ADC can be
estimated as follows:
For a 16 bit ADC and a sinusoidal beat frequency signal with 10MHz mixer
inputs a 16 bit ADC has a quantisation noise of about 8.8 ppm of the
amplitude of a full scale sinewave.
This corresponds to a zero crossing measurement jitter of about 140fs
(at 10MHz).
This result is independent of the beat frequency.
The corresponding system noise level due to the finite ADC resolution is
about 1.4E-13/Tau.

This is a gross approximation and the corresponding system noise will be
somewhat larger.
Thus it is advisable to either use an ADC with greater resolution to
achieve such low noise, or to increase the beat frequency signal slew
rate at the zero crossing.
The finite signal bandwidth of the sound card will limit the maximum
slope amplification to around 100X or so.
If one uses a mixer where both the RF and LO ports are saturated then
the beat frequency waveform will be trapezoidal with a slew rate at the
zero crossing about 3X that if the signal were sinusoidal.

Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 10 02:38:32 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 15:38:32 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
Message-ID: <49179EA8.4040104@xtra.co.nz>

Joe
J. L. Trantham wrote:
> I have been enjoying this discussion.  
>
> Since the original question was the desire to 'compare' the frequency of an
> LPRO to a Z3801, it seems that you could consider that from two (at least)
> perspectives.
>
> Before I begin, I confess that I am a novice in this arena and please
> correct me in any area that needs it.
>
> The first perspective is the issue of frequency.  That seems to me to be the
> issue of the average frequency of the LPRO versus the average frequency of
> the Z3801.  Assuming that there is no gross difference of the 10 MHz
> signals, a lissajous figure (X-Y display) on a scope with the appropriate
> bandwidth amplifiers would be a reasonable initial approach.
>
>   
The limitation with using Lissajous figures is that eventually the noise
in the relatively wide oscilloscope bandwidth (due to amplifier noise
and signal phase noise) limits the figure rotation rate that can
reliably discerned. Also the lack of a record of changes limits the
ability to see long term trends/drifts.

However it can be a useful/instructive starting point particularly when
the frequency difference is relatively large but still small enough that
the figure rotation can be seen.
> Assuming that they are both near 10 MHz and you do not know which is the
> most accurate (although the Z3801 would seem to be the default standard), if
> it takes 10 minutes for a single cycle of the lissajous figure to complete,
> then it is 1 cycle per 600 seconds difference between the two and therefore
> the two are within 1/600 Hz or 1.67 mHz of each other.  If we assume that
> they are both close to 10 MHz, then that is 1.67 parts in 10E-10 difference
> between the two.  Is my logic faulty?
>
> The other perspective is the issue of 'purity'.  That is to say, what is the
> 'frequency modulation' of the source?  This, I think, is the issue of phase
> noise.  Correct?
>
> That is something that I have not yet had a chance to contemplate as far as
> how to measure.  It would appear to require a particularly stable (pure)
> source as a reference though.  Various multiplying or dividing protocols
> would seem to introduce a host of other variables that would seem to be
> difficult to account for though they might accentuate an impurity in the
> signal in question.  I have read Bruce's comments and I still do not
> understand the basics of time stamping or how a sound card might provide
> this.
>
>   
One technique is to use a three cornered hat technique.
If the phase fluctuations of 3 oscillators are statistically
independent, then it is possible to determine the statistical
fluctuations in each of them.
> I would appreciate any direction for further reading regarding this and I
> would appreciate any direction/correction/etc. in the thoughts above.
>
> Joe
>
>   
Bruce


From N3IZN at aol.com  Mon Nov 10 02:49:31 2008
From: N3IZN at aol.com (N3IZN at aol.com)
Date: Sun, 9 Nov 2008 21:49:31 EST
Subject: [time-nuts] Link for T Mon
Message-ID: <c9d.37940424.3648fb3b@aol.com>

I had an old laptop with T-Bolt mon and another program that synced the time 
with the T-Bolt but the hard drive died. I dug out a 486-300 to replace it.

The link I had to down load the Thunderbolt software is no longer valid. Does 
any one have a valid link?

TIA
Chris


**************
AOL Search: Your one stop for directions, recipes and all 
other Holiday needs. Search Now. 
(http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays
-from-aol-search/?ncid=emlcntussear00000001)

From namichie at gmail.com  Mon Nov 10 02:55:36 2008
From: namichie at gmail.com (Neville Michie)
Date: Mon, 10 Nov 2008 13:55:36 +1100
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <49179EA8.4040104@xtra.co.nz>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>
	<49179EA8.4040104@xtra.co.nz>
Message-ID: <5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>

Bruce, how does the three cornered hat scheme work?

If I had two LPRO Rubidium oscillators and a TBOLT GPSDO, and I  
divided each of them down to
100KHz, then I could compare pairs of them with D latches and record  
3 different analogue
signals of phase difference.
One of the LPRO oscillators is in an oven to remove ambient  
temperature influence.
If I ran them for several weeks and logged the signals every 10 minutes,
what could I expect to recover from the data and how would I apply  
the 3 cornered hat scheme?
I ask this question because this is about where my building program  
is taking me.
cheers, Neville Michie


On 10/11/2008, at 1:38 PM, Bruce Griffiths wrote:

> Joe
> J. L. Trantham wrote:
>> I have been enjoying this discussion.
>>
>> Since the original question was the desire to 'compare' the  
>> frequency of an
>> LPRO to a Z3801, it seems that you could consider that from two  
>> (at least)
>> perspectives.
>>
>> Before I begin, I confess that I am a novice in this arena and please
>> correct me in any area that needs it.
>>
>> The first perspective is the issue of frequency.  That seems to me  
>> to be the
>> issue of the average frequency of the LPRO versus the average  
>> frequency of
>> the Z3801.  Assuming that there is no gross difference of the 10 MHz
>> signals, a lissajous figure (X-Y display) on a scope with the  
>> appropriate
>> bandwidth amplifiers would be a reasonable initial approach.
>>
>>
> The limitation with using Lissajous figures is that eventually the  
> noise
> in the relatively wide oscilloscope bandwidth (due to amplifier noise
> and signal phase noise) limits the figure rotation rate that can
> reliably discerned. Also the lack of a record of changes limits the
> ability to see long term trends/drifts.
>
> However it can be a useful/instructive starting point particularly  
> when
> the frequency difference is relatively large but still small enough  
> that
> the figure rotation can be seen.
>> Assuming that they are both near 10 MHz and you do not know which  
>> is the
>> most accurate (although the Z3801 would seem to be the default  
>> standard), if
>> it takes 10 minutes for a single cycle of the lissajous figure to  
>> complete,
>> then it is 1 cycle per 600 seconds difference between the two and  
>> therefore
>> the two are within 1/600 Hz or 1.67 mHz of each other.  If we  
>> assume that
>> they are both close to 10 MHz, then that is 1.67 parts in 10E-10  
>> difference
>> between the two.  Is my logic faulty?
>>
>> The other perspective is the issue of 'purity'.  That is to say,  
>> what is the
>> 'frequency modulation' of the source?  This, I think, is the issue  
>> of phase
>> noise.  Correct?
>>
>> That is something that I have not yet had a chance to contemplate  
>> as far as
>> how to measure.  It would appear to require a particularly stable  
>> (pure)
>> source as a reference though.  Various multiplying or dividing  
>> protocols
>> would seem to introduce a host of other variables that would seem  
>> to be
>> difficult to account for though they might accentuate an impurity  
>> in the
>> signal in question.  I have read Bruce's comments and I still do not
>> understand the basics of time stamping or how a sound card might  
>> provide
>> this.
>>
>>
> One technique is to use a three cornered hat technique.
> If the phase fluctuations of 3 oscillators are statistically
> independent, then it is possible to determine the statistical
> fluctuations in each of them.
>> I would appreciate any direction for further reading regarding  
>> this and I
>> would appreciate any direction/correction/etc. in the thoughts above.
>>
>> Joe
>>
>>
> Bruce
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.



From stanley_reynolds at yahoo.com  Mon Nov 10 03:47:36 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Sun, 9 Nov 2008 19:47:36 -0800 (PST)
Subject: [time-nuts] Link for T Mon
References: <c9d.37940424.3648fb3b@aol.com>
Message-ID: <282607.69876.qm@web30307.mail.mud.yahoo.com>

http://www.trimble.com/support_trl.asp?pt=Thunderbolt%C3%82%C2%AE%20GPS%20Disciplined%20Clock&Nav=Collection-2357

http://trl.trimble.com/dscgi/ds.py/Get/File-33741/Tboltmon.exe


?



________________________________
From: "N3IZN at aol.com" <N3IZN at aol.com>
To: time-nuts at febo.com
Sent: Sunday, November 9, 2008 8:49:31 PM
Subject: [time-nuts] Link for T Mon

I had an old laptop with T-Bolt mon and another program that synced the time 
with the T-Bolt but the hard drive died. I dug out a 486-300 to replace it.

The link I had to down load the Thunderbolt software is no longer valid. Does 
any one have a valid link?

TIA
Chris


**************
AOL Search: Your one stop for directions, recipes and all 
other Holiday needs. Search Now. 
(http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays
-from-aol-search/?ncid=emlcntussear00000001)
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From bruce.griffiths at xtra.co.nz  Mon Nov 10 03:59:32 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 16:59:32 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49179EA8.4040104@xtra.co.nz>
	<5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>
Message-ID: <4917B1A4.9020401@xtra.co.nz>

Neville Michie wrote:
> Bruce, how does the three cornered hat scheme work?
>
> If I had two LPRO Rubidium oscillators and a TBOLT GPSDO, and I  
> divided each of them down to
> 100KHz, then I could compare pairs of them with D latches and record  
> 3 different analogue
> signals of phase difference.
> One of the LPRO oscillators is in an oven to remove ambient  
> temperature influence.
> If I ran them for several weeks and logged the signals every 10 minutes,
> what could I expect to recover from the data and how would I apply  
> the 3 cornered hat scheme?
> I ask this question because this is about where my building program  
> is taking me.
> cheers, Neville Michie
>
>   
Neville

When the fluctuations of 3 quantities are independent then comparing 2
of them the individual variances of the add:

VAR(1,2) = VAR(1) + VAR(2)
VAR(1,3) = VAR(1) + VAR(3)
VAR(2,3) = VAR(2)+ VAR(3)

Where
VAR(1,2) denotes the variance of the fluctuations in the difference
between quantities 1 and 2.
VAR(1,3) denotes the variance of the fluctuations in the difference
between quantities 1 and 3.
VAR(2,3) denotes the variance of the fluctuations in the difference
between quantities 2 and 3.
VAR(1) denotes the variance of the quantity 1.
VAR(2) denotes the variance of the quantity 2.
VAR(3) denotes the variance of the quantity 3.

Thus
VAR(1) = (VAR(1,2) + VAR(1,3) - VAR(2,3))/2
VAR(2) = (VAR(1,2) + VAR(2,3) - VAR(1,3))/2
VAR(3) = (VAR(1,3) + VAR(1,3) - VAR(1,2))/2

The same results hold for ADEV (used for characterising the stability of
oscillators as  variance of the phase is divergent for oscillators).

ADEV(1,2) = ADEV(1) + ADEV(2)
ADEV(1,3) = ADEV(1) + ADEV(3)
ADEV(2,3) = ADEV(2) + ADEV(3)

Where
ADEV(1,2) denotes the Allen variance of the fluctuations in the phase
difference between oscillators 1 and 2.
ADEV(1,3) denotes the Allen variance of the fluctuations in the phase
difference between oscillators 1 and 3.
ADEV(2,3) denotes the Allen variance of the fluctuations in the phase
difference between oscillators 2 and 3.
ADEV(1) denotes the Allen variance of the phase fluctuations of
oscillator 1.
ADEV(2) denotes the Allen variance of the phase fluctuations of
oscillator 2.
ADEV(3) denotes the Allen variance of the phase fluctuations of
oscillator 3.

Thus
ADEV(1) = (ADEV(1,2) + ADEV(1,3) - ADEV(2,3))/2
ADEV(2) = (ADEV(1,2) + ADEV(2,3) - ADEV(1,3))/2
ADEV(3) = (ADEV(1,3) + ADEV(1,3) - ADEV(1,2))/2


Note it is essential to measure the relative phase fluctuations between
all 3 oscillator pairs simultaneously.

The limitation is that the oscillators should all have similar ADEV.
If the calculations assign negative values to one or more of the
individual variances then the phase fluctuations for the individual
oscillators may be correlated or at least one of the oscillators may be
much quieter than the others.

Eventually common environmental variations such as temperature pressure
and humidity fluctuations introduce correlations invalidating the above
simplified analysis.
However in this case the theory has been extended to include the effect
of correlations which are adjusted to ensure that the calculated
individual variances are positive definite.

Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 10 04:11:09 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 17:11:09 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49179EA8.4040104@xtra.co.nz>
	<5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>
Message-ID: <4917B45D.5070107@xtra.co.nz>

Neville Michie wrote:
> Bruce, how does the three cornered hat scheme work?
>
> If I had two LPRO Rubidium oscillators and a TBOLT GPSDO, and I  
> divided each of them down to
> 100KHz, then I could compare pairs of them with D latches and record  
> 3 different analogue
> signals of phase difference.
> One of the LPRO oscillators is in an oven to remove ambient  
> temperature influence.
> If I ran them for several weeks and logged the signals every 10 minutes,
> what could I expect to recover from the data and how would I apply  
> the 3 cornered hat scheme?
> I ask this question because this is about where my building program  
> is taking me.
> cheers, Neville Michie
>
>   
Neville

If the phase differences are recorded every 10 minutes then the smallest
value of tau for which you can determine AVAR is 10 minutes.

Bruce


From bill at iaxs.net  Mon Nov 10 04:38:37 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Sun, 9 Nov 2008 22:38:37 -0600
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <4917B1A4.9020401@xtra.co.nz>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49179EA8.4040104@xtra.co.nz><5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>
	<4917B1A4.9020401@xtra.co.nz>
Message-ID: <A6763DC1838549A9B179E923285855F3@cyrus>


-----Original Message-----
From: Bruce Griffiths
Sent: Sunday, November 09, 2008 10:00 PM

-------%<--------
Thus
VAR(1) = (VAR(1,2) + VAR(1,3) - VAR(2,3))/2
VAR(2) = (VAR(1,2) + VAR(2,3) - VAR(1,3))/2
VAR(3) = (VAR(1,3) + VAR(1,3) - VAR(1,2))/2

and
-------%<--------
Thus
ADEV(1) = (ADEV(1,2) + ADEV(1,3) - ADEV(2,3))/2
ADEV(2) = (ADEV(1,2) + ADEV(2,3) - ADEV(1,3))/2
ADEV(3) = (ADEV(1,3) + ADEV(1,3) - ADEV(1,2))/2


Bruce,

Does the third equation really use ADEV(1,3) twice?
It doesn't have the same symmetry as the first and second
where each index shows up twice.

Bill Hawkins



From bruce.griffiths at xtra.co.nz  Mon Nov 10 04:43:04 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 17:43:04 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <A6763DC1838549A9B179E923285855F3@cyrus>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49179EA8.4040104@xtra.co.nz><5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>	<4917B1A4.9020401@xtra.co.nz>
	<A6763DC1838549A9B179E923285855F3@cyrus>
Message-ID: <4917BBD8.3040706@xtra.co.nz>

Bill Hawkins wrote:
> -----Original Message-----
> From: Bruce Griffiths
> Sent: Sunday, November 09, 2008 10:00 PM
>
> -------%<--------
> Thus
> VAR(1) = (VAR(1,2) + VAR(1,3) - VAR(2,3))/2
> VAR(2) = (VAR(1,2) + VAR(2,3) - VAR(1,3))/2
> VAR(3) = (VAR(1,3) + VAR(1,3) - VAR(1,2))/2
>
> and
> -------%<--------
> Thus
> ADEV(1) = (ADEV(1,2) + ADEV(1,3) - ADEV(2,3))/2
> ADEV(2) = (ADEV(1,2) + ADEV(2,3) - ADEV(1,3))/2
> ADEV(3) = (ADEV(1,3) + ADEV(1,3) - ADEV(1,2))/2
>
>
> Bruce,
>
> Does the third equation really use ADEV(1,3) twice?
> It doesn't have the same symmetry as the first and second
> where each index shows up twice.
>
> Bill Hawkins
>
>
>   
Bill

No it shouldn't, I obviously missed this when editing.

they should be:

VAR(3) = (VAR(1,3) + VAR(2,3) - VAR(1,2))/2


ADEV(3) = (ADEV(1,3) + ADEV(2,3) - ADEV(1,2))/2


Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 10 09:29:01 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 10 Nov 2008 22:29:01 +1300
Subject: [time-nuts] Checking accuracy of Rubidium standards
In-Reply-To: <4917BBD8.3040706@xtra.co.nz>
References: <6BFF626D22B04A3BA34C2907B3004F7C@S0028384766>	<49179EA8.4040104@xtra.co.nz><5B504943-6779-46E6-A233-4E098CC3F037@gmail.com>	<4917B1A4.9020401@xtra.co.nz>	<A6763DC1838549A9B179E923285855F3@cyrus>
	<4917BBD8.3040706@xtra.co.nz>
Message-ID: <4917FEDD.6090907@xtra.co.nz>

Bruce Griffiths wrote:
> Bill Hawkins wrote:
>   
>> -----Original Message-----
>> From: Bruce Griffiths
>> Sent: Sunday, November 09, 2008 10:00 PM
>>
>> -------%<--------
>> Thus
>> VAR(1) = (VAR(1,2) + VAR(1,3) - VAR(2,3))/2
>> VAR(2) = (VAR(1,2) + VAR(2,3) - VAR(1,3))/2
>> VAR(3) = (VAR(1,3) + VAR(1,3) - VAR(1,2))/2
>>
>> and
>> -------%<--------
>> Thus
>> ADEV(1) = (ADEV(1,2) + ADEV(1,3) - ADEV(2,3))/2
>> ADEV(2) = (ADEV(1,2) + ADEV(2,3) - ADEV(1,3))/2
>> ADEV(3) = (ADEV(1,3) + ADEV(1,3) - ADEV(1,2))/2
>>
>>
>> Bruce,
>>
>> Does the third equation really use ADEV(1,3) twice?
>> It doesn't have the same symmetry as the first and second
>> where each index shows up twice.
>>
>> Bill Hawkins
>>
>>
>>   
>>     
> Bill
>
> No it shouldn't, I obviously missed this when editing.
>
> they should be:
>
> VAR(3) = (VAR(1,3) + VAR(2,3) - VAR(1,2))/2
>
>
> ADEV(3) = (ADEV(1,3) + ADEV(2,3) - ADEV(1,2))/2
>
>
> Bruce
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>   
Oops, the last 3 equations should actually have been:

AVAR(1) = (AVAR(1,2) + AVAR(1,3) - AVAR(2,3))/2
AVAR(2) = (AVAR(1,2) + AVAR(2,3) - AVAR(1,3))/2
AVAR(3) = (AVAR(1,3) + AVAR(2,3) - AVAR(1,2))/2

That is the Allan variances, not the Allan Deviations.

Bruce


From don.key at ntlworld.com  Mon Nov 10 12:15:39 2008
From: don.key at ntlworld.com (Don Key)
Date: Mon, 10 Nov 2008 12:15:39 -0000
Subject: [time-nuts] Link for T Mon
In-Reply-To: <c9d.37940424.3648fb3b@aol.com>
References: <c9d.37940424.3648fb3b@aol.com>
Message-ID: <7B6206BA9A9C49DC8F59BCDBA6C2C810@JimPC>

As well as Tboltmon, I found that DSPMon v1.53 also works (which is the 
current software for the Thunderbolt E). 
http://www.trimble.com/timing/thunderbolt-e.aspx?dtID=support

There is also a program called TrimbleMon_V1-05-0, which is the software 
mentioned in the Thunderbolt E manual, but which doesn't appear to be 
supported by Trimble anymore.
This software features a skyplot, so you can visually see the positions of 
the satellites. Unfortunately, the position fields in the main window don't 
appear to work.
The only place I found to download it was here:- 
http://bigredbee.com/docs/blgps


----- Original Message ----- 
From: <N3IZN at aol.com>
To: <time-nuts at febo.com>
Sent: Monday, November 10, 2008 2:49 AM
Subject: [time-nuts] Link for T Mon


>I had an old laptop with T-Bolt mon and another program that synced the 
>time
> with the T-Bolt but the hard drive died. I dug out a 486-300 to replace 
> it.
>
> The link I had to down load the Thunderbolt software is no longer valid. 
> Does
> any one have a valid link?
>
> TIA
> Chris
>
>
> **************
> AOL Search: Your one stop for directions, recipes and all
> other Holiday needs. Search Now.
> (http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays
> -from-aol-search/?ncid=emlcntussear00000001)
>
> 



From karl.f.strauss at jpl.nasa.gov  Mon Nov 10 22:27:57 2008
From: karl.f.strauss at jpl.nasa.gov (Strauss, Karl F)
Date: Mon, 10 Nov 2008 14:27:57 -0800
Subject: [time-nuts] Using GPS for space-based instrument
Message-ID: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>

I've been tasked (or was it I was volunteered?) to do some basic design & definition work on an ultra-stable master frequency system for a proposed instrument that is currently planned to be in an Earth-trailing orbit.   Given the first order accuracy requirement of 1 part in 1E-10, my first thought was to grab the GPS timing signal.

Sorry for the newbie questions here:    a) Do all satellites in the constellation broadcast a signal into space  (as opposed to, say,  bouncing off some ionospheric boundary layer); and b) is there some website/technical paper describing expected signal strength for these space-radiated signals?

Again, apologies to all for the Newbie Q's.  Hopefully this will be a fun topic of discussion

Thanks

Karl

From hmurray at megapathdsl.net  Mon Nov 10 22:42:39 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Mon, 10 Nov 2008 14:42:39 -0800
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: Message from "Strauss, Karl F" <karl.f.strauss@jpl.nasa.gov> 
	of "Mon, 10 Nov 2008 14:27:57 PST."
	<AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <20081110224241.16EF7BCD5@ip-64-139-1-69.sjc.megapath.net>


> I've been tasked (or was it I was volunteered?) to do some basic
> design & definition work on an ultra-stable master frequency system
> for a proposed instrument that is currently planned to be in an
> Earth-trailing orbit.

How far from Earth is "Earth-trailing"?

This might help:
  http://www.go.ednet.ns.ca/~larry/gps/gps_talk.html
It's far from official, but it seemed helpful when I was looking for 
something.  (I forget what.)


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From SAIDJACK at aol.com  Mon Nov 10 22:48:00 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Mon, 10 Nov 2008 17:48:00 EST
Subject: [time-nuts] Using GPS for space-based instrument
Message-ID: <d3d.2fec9915.364a1420@aol.com>

Hi Karl,
 
commercial receivers are limited to 1000 knots by regulation.
 
Considering that your space based vehicle will probably zomm about pretty  
quickly (not geo-stationary) it sounds like you need a special "unlocked"  
receiver, or a P-code military one.
 
bye,
Said
 
 
In a message dated 11/10/2008 14:29:16 Pacific Standard Time,  
karl.f.strauss at jpl.nasa.gov writes:

I've  been tasked (or was it I was volunteered?) to do some basic design &  
definition work on an ultra-stable master frequency system for a proposed  
instrument that is currently planned to be in an Earth-trailing  orbit.   Given 
the first order accuracy requirement of 1 part in  1E-10, my first thought was 
to grab the GPS timing  signal.


From brooke at pacific.net  Mon Nov 10 22:51:40 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Mon, 10 Nov 2008 14:51:40 -0800
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <4918BAFC.1070204@pacific.net>

Hi Karl:

Tom Clark may be the person who can answer that question.

I seem to remember that the very first GPS satellites had antennas only aimed 
at the Earth, but because many satellites now use GPS for a number of functions 
they also radiate some signal away from the Earth.

In addition there's the question of getting a license for a military grade GPS 
receiver.  Note that civilian grade GPS receivers have limits on elevation, 
speed, acceleration and jerk which prevents them working in military aircraft, 
missiles and space environments.  It may be that the your satellite already has 
a GPS receiver for some other purpose so that you only need access to the 1 PPS 
or 10 MHz output?

Have Fun,

Brooke Clarke
http://www.prc68.com

Strauss, Karl F wrote:
> I've been tasked (or was it I was volunteered?) to do some basic design & definition work on an ultra-stable master frequency system for a proposed instrument that is currently planned to be in an Earth-trailing orbit.   Given the first order accuracy requirement of 1 part in 1E-10, my first thought was to grab the GPS timing signal.
> 
> Sorry for the newbie questions here:    a) Do all satellites in the constellation broadcast a signal into space  (as opposed to, say,  bouncing off some ionospheric boundary layer); and b) is there some website/technical paper describing expected signal strength for these space-radiated signals?
> 
> Again, apologies to all for the Newbie Q's.  Hopefully this will be a fun topic of discussion
> 
> Thanks
> 
> Karl
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From bruce.griffiths at xtra.co.nz  Mon Nov 10 22:52:39 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 11 Nov 2008 11:52:39 +1300
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <4918BB37.4050203@xtra.co.nz>

Strauss, Karl F wrote:
> I've been tasked (or was it I was volunteered?) to do some basic design & definition work on an ultra-stable master frequency system for a proposed instrument that is currently planned to be in an Earth-trailing orbit.   Given the first order accuracy requirement of 1 part in 1E-10, my first thought was to grab the GPS timing signal.
>
> Sorry for the newbie questions here:    a) Do all satellites in the constellation broadcast a signal into space  (as opposed to, say,  bouncing off some ionospheric boundary layer); and b) is there some website/technical paper describing expected signal strength for these space-radiated signals?
>
> Again, apologies to all for the Newbie Q's.  Hopefully this will be a fun topic of discussion
>
> Thanks
>
> Karl
>   
Karl

The GPS SVs are well above the ionosphere.
However they use circularly polarised directional antennas that point at
the Earth.
Signal strength in orbits closer to the Earth than the GPS SVs will be
comparable with that on the surface of the Earth.

When the orbit id further out than those of the GPS SVs the signal
strength will be somewhat lower than expected from the inverse square
law, as the orbit will only be illuminated by weak sidelobes from
favourably positioned GPS SVs.

Bruce


From james.p.lux at jpl.nasa.gov  Mon Nov 10 23:04:45 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Mon, 10 Nov 2008 15:04:45 -0800
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <ECE7A93BD093E1439C20020FBE87C47FEB55C30320@ALTPHYEMBEVSP20.RES.AD.JPL>

I'd suggest giving the GPS folks at JPL a call.  They've probably looked into all the issues you're interested in, and can make suitable suggestions where to go for answers (subject to the usual export control restrictions).Jim Zumberge is the Section Manager of the Tracking Systems and Applications Section (which does the GPS stuff). Try James.F.Zumberge at jpl.nasa.gov

http://iono.jpl.nasa.gov/ might give you a start.
http://www.gdgps.net/


There have been proposals, for instance, to receive GPS signals at the moon, based, as another poster mentioned, on the GPS signal from a satellite that is not occulted by the Earth.  The GPS satellites are fairly high up and the overall beam is fairly broad, so if you're almost in line with the Earth and the satellite, you might get decent signal strengths.

James Lux, P.E.
Task Manager, SOMD Software Defined Radios
Flight Communications Systems Section
Jet Propulsion Laboratory
4800 Oak Grove Drive, Mail Stop 161-213
Pasadena, CA, 91109
+1(818)354-2075 phone
+1(818)393-6875 fax

> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Strauss, Karl F
> Sent: Monday, November 10, 2008 2:28 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Using GPS for space-based instrument
>
> I've been tasked (or was it I was volunteered?) to do some
> basic design & definition work on an ultra-stable master
> frequency system for a proposed instrument that is currently
> planned to be in an Earth-trailing orbit.   Given the first
> order accuracy requirement of 1 part in 1E-10, my first
> thought was to grab the GPS timing signal.
>
> Sorry for the newbie questions here:    a) Do all satellites
> in the constellation broadcast a signal into space  (as
> opposed to, say,  bouncing off some ionospheric boundary
> layer); and b) is there some website/technical paper
> describing expected signal strength for these space-radiated signals?
>
> Again, apologies to all for the Newbie Q's.  Hopefully this
> will be a fun topic of discussion
>
> Thanks
>
> Karl
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe,
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>


From mctylr at gmail.com  Tue Nov 11 00:01:00 2008
From: mctylr at gmail.com (michael taylor)
Date: Mon, 10 Nov 2008 19:01:00 -0500
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <25630a120811101601p60bc9f7ejbaee0db8a0a3683d@mail.gmail.com>

On Mon, Nov 10, 2008 at 5:27 PM, Strauss, Karl F
<karl.f.strauss at jpl.nasa.gov> wrote:
> I've been tasked (or was it I was volunteered?) to do some basic design & definition work on an ultra-stable master frequency system for a proposed instrument that is currently planned to be in an Earth-trailing orbit.   Given the first order accuracy requirement of 1 part in 1E-10, my first thought was to grab the GPS timing signal.

Depending on your application requirements, I wonder if an OCXO (Oven
Controlled Crystal Oscillators) in a ruggedised packaging might be
suitable for your needs. For example one well-known frequency source
vendor, Symmetricom offers a number of OCXO packagings that may be
suitable for satellites.

 <http://www.symmetricom.com/products/frequency-references/high-reliabilityruggedized-frequency-sources/>

Another option would be a Rubidium (Rb) frequency standard.

A lot depends on your "accuracy" definition and requirements. Does it
need to be accurate relative to UTC / UT / TAI? Depending on your
application, dealing with details like leap seconds may not be worth
staying in sync with UTC / GPS. Or do you need a stable local clock
(within the SV)? Are you concerned with accuracy / stability over a
short period of time (e.g. 1 second) or a longer period of time (e.g.
1 day / month / etc.)?


From magnus at rubidium.dyndns.org  Tue Nov 11 00:13:02 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Tue, 11 Nov 2008 01:13:02 +0100
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <d3d.2fec9915.364a1420@aol.com>
References: <d3d.2fec9915.364a1420@aol.com>
Message-ID: <4918CE0E.40003@rubidium.dyndns.org>

SAIDJACK at aol.com skrev:
> Hi Karl,
>  
> commercial receivers are limited to 1000 knots by regulation.
>  
> Considering that your space based vehicle will probably zomm about pretty  
> quickly (not geo-stationary) it sounds like you need a special "unlocked"  
> receiver, or a P-code military one.

This is why the GEC Plessey/Zarlink based receivers with adapted 
software have been popular for research shots and satellites. The 
original development kit contained the receiver software in source form, 
so it could be adapted for all kinds of purposes, including this. You 
will find several papers online showing such work.

US export conditions for commercial receivers includes speed and heigth 
limits which makes them unsuitable for sat work. However, the actual 
receiver chips is not that limited, but some can be dopper difference 
limited.

If the sat you are going to do GPS for is a low-flying bird (eg LEO) 
then a standard GPS solution is possible.

To answer the questions:

 > a) Do all satellites in the constellation broadcast a signal into
 > space  (as opposed to, say,  bouncing off some ionospheric boundary
 > layer)

Yes. They fly at 26600 km in fairly circular orbits with a orbit time of 
11 hours and 58 min, which makes their orbit pattern stable. They emit 
signal directed towards the earth, reaching about half the earth. The 
antenna rig makes the signal strengts straight down weaker than towards 
the edge of the earth, to compensate for the longer distance and thus 
increased free space propagation loss.

 > b) is there some website/technical paper describing expected signal
 > strength for these space-radiated signals?

The free space propagation loss is fairly simple. It's basically 20*log(d).

The good news is that there is no tropospheric error and less 
ionospheric error, but that can be handled.

I'd pick up "Understanding GPS Principles and Applications", Second 
Edition by Kaplan and Hegarty ISBN 1-58053-894-0 and "Global Positioning 
System; Signals, Measurements and Performance", Second Edition, by Misra 
and Enge. ISBN 0-9709544-1-7 to read up on GPS. There are further books 
to pick up, including a pair on GPS software receivers.

For a sat I think regular receiver chips or a frontend followed by a 
FPGA for digital correlator frontend and then use some suitable 
processor for loop processing. The benefit of a FPGA would be that the 
receiver can be upgraded in flight.

Cheers,
Magnus


From N3IZN at aol.com  Tue Nov 11 01:37:33 2008
From: N3IZN at aol.com (N3IZN at aol.com)
Date: Mon, 10 Nov 2008 20:37:33 EST
Subject: [time-nuts] Link for T Mon
Message-ID: <cb4.46815c60.364a3bdd@aol.com>

 
Thanks for all the replies off and on list. I did find Timekeeper for the  
Thunderbolt. It syncs up your PC time using the T-Bolt. No one seemed to know  
about that. I have it if any one is interested. Also found something called "TR 
 Configurator" in the same folder with all the T-Bolt stuff. Not sure what 
that  is for, been a while since I messed with it.
 
73
Chris

I had an  old laptop with T-Bolt mon and another program that synced the time 
with  the T-Bolt but the hard drive died. I dug out a 486-300 to replace  it.

The link I had to down load the Thunderbolt software is no longer  valid. 
Does 
any one have a valid  link?

TIA
Chris




**************AOL Search: Your one stop for directions, recipes and all other 
Holiday needs. Search Now. 
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-aol-search/?ncid=emlcntussear00000001)

From rk at timing-consultants.com  Tue Nov 11 08:37:10 2008
From: rk at timing-consultants.com (Rob Kimberley)
Date: Tue, 11 Nov 2008 08:37:10 -0000
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <25630a120811101601p60bc9f7ejbaee0db8a0a3683d@mail.gmail.com>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
	<25630a120811101601p60bc9f7ejbaee0db8a0a3683d@mail.gmail.com>
Message-ID: <AC6678991B4F4DEDA5EFDA723690E3D6@Robin>

Both Symmetricom and Frequency Electronics provide specialist space
qualified products. It's not just a case of ruggedisation, but radiation
hardening, g sensitivity which need to be designed in.

Rob Kimberley 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of michael taylor
Sent: 11 November 2008 00:01
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Using GPS for space-based instrument

On Mon, Nov 10, 2008 at 5:27 PM, Strauss, Karl F
<karl.f.strauss at jpl.nasa.gov> wrote:
> I've been tasked (or was it I was volunteered?) to do some basic design &
definition work on an ultra-stable master frequency system for a proposed
instrument that is currently planned to be in an Earth-trailing orbit.
Given the first order accuracy requirement of 1 part in 1E-10, my first
thought was to grab the GPS timing signal.

Depending on your application requirements, I wonder if an OCXO (Oven
Controlled Crystal Oscillators) in a ruggedised packaging might be suitable
for your needs. For example one well-known frequency source vendor,
Symmetricom offers a number of OCXO packagings that may be suitable for
satellites.

 
<http://www.symmetricom.com/products/frequency-references/high-reliabilityru
ggedized-frequency-sources/>

Another option would be a Rubidium (Rb) frequency standard.

A lot depends on your "accuracy" definition and requirements. Does it need
to be accurate relative to UTC / UT / TAI? Depending on your application,
dealing with details like leap seconds may not be worth staying in sync with
UTC / GPS. Or do you need a stable local clock (within the SV)? Are you
concerned with accuracy / stability over a short period of time (e.g. 1
second) or a longer period of time (e.g.
1 day / month / etc.)?

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From ik1odo at spin-it.com  Tue Nov 11 08:49:21 2008
From: ik1odo at spin-it.com (Marco IK1ODO -2)
Date: Tue, 11 Nov 2008 09:49:21 +0100
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <AC6678991B4F4DEDA5EFDA723690E3D6@Robin>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>
	<25630a120811101601p60bc9f7ejbaee0db8a0a3683d@mail.gmail.com>
	<AC6678991B4F4DEDA5EFDA723690E3D6@Robin>
Message-ID: <20081111084317.A8387E91444@mail.ebirds.it>

At 09.37 11/11/2008, you wrote:
>Both Symmetricom and Frequency Electronics provide specialist space
>qualified products. It's not just a case of ruggedisation, but radiation
>hardening, g sensitivity which need to be designed in.
>
>Rob Kimberley

Also, space qualified GPS must handle the larger doppler shifts due 
to the relative spacecraft velocity. A "standard" GPS will not work, 
it is necessary to modify the algorhytms.

Karl, if you know nothing about GPS, possibly it's best to start 
reading a tutorial, like http://www.trimble.com/gps/index.shtml - the 
amount of information to digest before putting a GPS receiver on a 
spacecraft is huge.

Marco



From kirbybq at bellsouth.net  Tue Nov 11 10:55:02 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Tue, 11 Nov 2008 04:55:02 -0600
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <20081111084317.A8387E91444@mail.ebirds.it>
References: <AABA350887228049AE592E06809BF27FD8E190FD5B@ALTPHYEMBEVSP20.RES.AD.JPL>	<25630a120811101601p60bc9f7ejbaee0db8a0a3683d@mail.gmail.com>	<AC6678991B4F4DEDA5EFDA723690E3D6@Robin>
	<20081111084317.A8387E91444@mail.ebirds.it>
Message-ID: <49196486.1020802@bellsouth.net>

Somewhere out there is the specs that GPS was designed to.  It list some 
of what they had to do, to make the rubidiums and cesiums work in the 
environment they put them in.  Believe they are called ICD-GPS-200 or 
something like that

Marco IK1ODO -2 wrote:
> At 09.37 11/11/2008, you wrote:
>> Both Symmetricom and Frequency Electronics provide specialist space
>> qualified products. It's not just a case of ruggedisation, but radiation
>> hardening, g sensitivity which need to be designed in.
>>
>> Rob Kimberley
> 
> Also, space qualified GPS must handle the larger doppler shifts due 
> to the relative spacecraft velocity. A "standard" GPS will not work, 
> it is necessary to modify the algorhytms.
> 
> Karl, if you know nothing about GPS, possibly it's best to start 
> reading a tutorial, like http://www.trimble.com/gps/index.shtml - the 
> amount of information to digest before putting a GPS receiver on a 
> spacecraft is huge.
> 
> Marco
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From phill.r1 at btinternet.com  Tue Nov 11 12:01:14 2008
From: phill.r1 at btinternet.com (Roy Phillips)
Date: Tue, 11 Nov 2008 12:01:14 -0000
Subject: [time-nuts] The other Trimble - NTPX26AB-06
Message-ID: <B88545AFAB0D4640B2339FCA40C68CC9@LapTop>

I have just received a Trimble NTPX26AB-06, to add to the TBolt which performs perfectly. I am aware that some exchanges have taken place in the past with reference to this unit which it would seem was a Trimble design to offer a less expensive alternative to the HP- Z3801A.
The obvious difference with the TBolt's facilities would seem to be the single BNC 10 MHz output, and the I/O (25 way "D" connector) which provides an RS-422 serial interface with TBoltMon and your  PC.
I do not have an RS-422 adaptor or PC card at present, and I am wondering if it is necessary to obtain one in light of the article investigating the HP-Z3801A. This makes it clear that the Z3801A had the facility to be simply modified by strapping, to change to RS-232 interface. I have examined my NTPX26AB-06, and find that on the narrow secondary PCB that carries the six status LED's on the front panel, there is a location (unpopulated), for a 9 pin PCB mount "D" connector, which if it was fitted, would protrude out of the front of the unit. More to the point, there are tracks to pins 2,3 and 5 which are carried back to the main PCB via the interconnection cable, which would appear to be carrying  data to this location. I have not had time to investigate this further, but it would seem that Trimble had made this facility available as part of the specification, but it was unused ?

Question, if it is a normal RS-232 (Trimble) interface, is it likely that it would be usable without modification ? -  - is it possible that both interfaces are accessible at the same time  - - or would one have to "switch" the other output off ?   Further, I find that the I/O ( 25 way "D" ), offers the same additional 10 MHz and 1 pps signals as the Z3801A, although at non-standard levels. If anybody has investigated this unit and has been successful in modifying this facility, I would be pleased to have the information. I would rather have this unit interfaced with my existing RS-232 interface, than seek additional RS-422 equipment.

I apologize if I am covering "old ground", but I would appreciate any information on this item.

Thank you

Roy Phillips
 

From james.p.lux at jpl.nasa.gov  Tue Nov 11 14:47:49 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Tue, 11 Nov 2008 06:47:49 -0800
Subject: [time-nuts] Using GPS for space-based instrument
In-Reply-To: <49196486.1020802@bellsouth.net>
Message-ID: <C53EDB15.270A%James.P.Lux@jpl.nasa.gov>




On 11/11/08 2:55 AM, "Brian Kirby" <kirbybq at bellsouth.net> wrote:

> Somewhere out there is the specs that GPS was designed to.  It list some
> of what they had to do, to make the rubidiums and cesiums work in the
> environment they put them in.  Believe they are called ICD-GPS-200 or
> something like that
>
ICD-GPS-200 is the spec that defines the interface among the various GPS
segments, specifically, the RF waveform and nav message is defined there.
I don't know that it gives the environmental requirements for the s/v
hardware.

In any event, space qualified GPS receivers are an "off-the-shelf" item (as
much as anything space qualified is) and will set you back a good chunk of a
million dollars, by the time you get it and the accompanying paperwork.

For that matter, flight qualified Xos and OCXOs are readily available, and
much cheaper, but 1E-10 is a pretty stringent tolerance.  Check into the
UltraStableOscillator (USO)s made by, e.g., Applied Physics Lab, which  are
used for deep space missions.

Such things are used for doing precise measurements, not only of of s/c
position, but also radio science (occultations, gravity measurements),
although two way coherent ranging is also done. For the latter, you
basically send a signal locked to a hydrogen maser signal to the spacecraft,
where it is recovered and used to synthesize a return signal. A typical spec
might be ADEV<4E-16 in 1000 seconds.  (and, why yes, verifying that the box
sitting on the bench can do that performance is a non-trivial matter)

Jim Lux



From didier at cox.net  Tue Nov 11 15:06:13 2008
From: didier at cox.net (Didier)
Date: Tue, 11 Nov 2008 09:06:13 -0600
Subject: [time-nuts] Link for T Mon
In-Reply-To: <c9d.37940424.3648fb3b@aol.com>
References: <c9d.37940424.3648fb3b@aol.com>
Message-ID: <0966B95C2C344C03B160A47C60E644F3@didierhp>

I have this and other Trimble software and documentation on my web site:
http://www.ko4bb.com/cgi-bin/manuals.pl

Search for Trimble

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of N3IZN at aol.com
> Sent: Sunday, November 09, 2008 8:50 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Link for T Mon
> 
> I had an old laptop with T-Bolt mon and another program that 
> synced the time with the T-Bolt but the hard drive died. I 
> dug out a 486-300 to replace it.
> 
> The link I had to down load the Thunderbolt software is no 
> longer valid. Does any one have a valid link?
> 
> TIA
> Chris
> 



From Brucekareen at aol.com  Tue Nov 11 17:27:58 2008
From: Brucekareen at aol.com (Brucekareen at aol.com)
Date: Tue, 11 Nov 2008 12:27:58 EST
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
Message-ID: <d31.41a80dfe.364b1a9e@aol.com>

 
I  have an EIP Model 548 counter with a YIG-tuned front end that can be 
programmed  to scan over narrow frequency ranges.  By feeding the rubidium 
oscillator under test into the 10 MHz clock input  of the counter, is there any 
reasonably simple way to directly measure the  frequency of a GPS satellite 
transmission so as to ascertain the accuracy of the  rubidium source?  The counter has 
an  input sensitivity in the order of about ?25 dBm -- not sufficient to 
measure  directly from an amplified antenna, but perhaps through an amplifier.  I 
am not sure whether the input YIG  tuner selectivity is sufficient to separate 
transmissions from the various  satellite?s (or are they TDMS?).  What do you 
think?   
Bruce,  KG6OJI
**************AOL Search: Your one stop for directions, recipes and all other 
Holiday needs. Search Now. 
(http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays-from
-aol-search/?ncid=emlcntussear00000001)

From james.p.lux at jpl.nasa.gov  Tue Nov 11 17:39:21 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Tue, 11 Nov 2008 09:39:21 -0800
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <d31.41a80dfe.364b1a9e@aol.com>
References: <d31.41a80dfe.364b1a9e@aol.com>
Message-ID: <ECE7A93BD093E1439C20020FBE87C47FEB55C3037A@ALTPHYEMBEVSP20.RES.AD.JPL>

> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Brucekareen at aol.com
> Sent: Tuesday, November 11, 2008 9:28 AM
> To: time-nuts at febo.com
> Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
>
>
> I  have an EIP Model 548 counter with a YIG-tuned front end
> that can be programmed  to scan over narrow frequency ranges.
>  By feeding the rubidium oscillator under test into the 10
> MHz clock input  of the counter, is there any reasonably
> simple way to directly measure the  frequency of a GPS
> satellite transmission so as to ascertain the accuracy of the
>  rubidium source?

Not a chance.. The signal is a PN code at about 1 Megachip/second, and the power spectral density is probably comparable to the thermal noise floor of the receiver.


 The counter has an  input sensitivity in
> the order of about -25 dBm -- not sufficient to measure
> directly from an amplified antenna, but perhaps through an
> amplifier.  I am not sure whether the input YIG  tuner
> selectivity is sufficient to separate transmissions from the
> various  satellite's (or are they TDMS?).  What do you think?

All the satellites are at the same frequency, and they are CDMA (each satellite has a different PN sequence on its signal)



From hmurray at megapathdsl.net  Tue Nov 11 18:10:19 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Tue, 11 Nov 2008 10:10:19 -0800
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: Message from "Lux, James P" <james.p.lux@jpl.nasa.gov> of "Tue,
	11 Nov 2008 09:39:21 PST."
	<ECE7A93BD093E1439C20020FBE87C47FEB55C3037A@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>


> All the satellites are at the same frequency, and they are CDMA (each
> satellite has a different PN sequence on its signal) 

What's the bandwidth of an individual satellite?

It may have been a different thread, but the Doppler shift is up to 2 KHz.  
Even if you could tune to an individual satellite signal, you still have to 
go through the whole GPS calculation in order to correct for Doppler.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From james.p.lux at jpl.nasa.gov  Tue Nov 11 18:28:18 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Tue, 11 Nov 2008 10:28:18 -0800
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
References: Message from "Lux, James P" <james.p.lux@jpl.nasa.gov> of "Tue,
	11 Nov 2008 09:39:21 PST."
	<ECE7A93BD093E1439C20020FBE87C47FEB55C3037A@ALTPHYEMBEVSP20.RES.AD.JPL>
	<20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <ECE7A93BD093E1439C20020FBE87C47FEB55C30390@ALTPHYEMBEVSP20.RES.AD.JPL>


> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray
> Sent: Tuesday, November 11, 2008 10:10 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Checking the Frequency of a Rubidium
> Oscillator
>
>
> > All the satellites are at the same frequency, and they are
> CDMA (each
> > satellite has a different PN sequence on its signal)
>
> What's the bandwidth of an individual satellite?
Megahertz (the 1 MHz C/A code + the 10MHz P/Y code)

>
> It may have been a different thread, but the Doppler shift is
> up to 2 KHz.
> Even if you could tune to an individual satellite signal, you
> still have to go through the whole GPS calculation in order
> to correct for Doppler.

A GPS receiver actually solves for the state vector of the receiver (including the local clock error) using the raw observables from the tracking loop (code phase).  The nav equations calculate (apparent) range and range rate from the known state vector of each satellite and the (estimated) state vector of the receiver.  Range rate is the doppler.

The 1.xxx Megachip/second C/A code is 1023 bits long, so the classical approach is to step the receiver through all possible phases of the code, integrating at each one to see if it can detect the signal.  If your integration time is, say, 10 milliseconds, it takes 10 seconds to step through them all. Once the signal is detected, the PN tracking loop tracks that signal.

If you have some a-priori knowledge of the expected code phase, that reduces your search space quite a bit.
You can also search for multiple codes at once with parallel receivers (really, parallel code tracking loops, because the RF receiver is usually just a single bit quantizer, and the same bits go to all loops), either acquiring different satellites in parallel, or speeding up the acquisition of a single satellite.

This is where the proprietary nature of each manufacturer really comes in, because time spent acquiring is time not deriving a nav fix, and in a energy sensitive design (which many GPS receivers are.. E.g. in cell phones or battery powered), time is of the essence.

For instance, if you know your approximate position and date/time, you can not bother trying to search for satellites that aren't above the horizon. If you've characterized your local oscillator properties, you might be able to do a more clever acquisition by modeling the drift.

If the cellular system can tell the receiver in the phone an approximate position and estimated range/range rate, it can greatly reduce the acquisition time. (in fact, most phones don't actually implement a full GPS receiver.. They use assistance from the cell site to acquire, and just return the raw observables, and the centralized system turns that into a position)

All very interesting stuff..

Jim


From vogelchr at vogel.cx  Tue Nov 11 18:29:05 2008
From: vogelchr at vogel.cx (Christian Vogel)
Date: Tue, 11 Nov 2008 19:29:05 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <4919CEF1.5040702@vogel.cx>

Hi Hal,
> What's the bandwidth of an individual satellite?
the bandwidth is defined by the ~ 1 MHz "chipping" rate that 
phase-modulates the carrier, so it's roughly 1 MHz to both sides of the 
carrier (for the civilian signal). Search google images for "gps 
spectrum" to see plots... :-)

    Chris



From bg at lysator.liu.se  Tue Nov 11 18:32:45 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Tue, 11 Nov 2008 19:32:45 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <1226428365.20299.37.camel@bg-desktop>


On Tue, 2008-11-11 at 10:10 -0800, Hal Murray wrote:
> > All the satellites are at the same frequency, and they are CDMA (each
> > satellite has a different PN sequence on its signal) 
> 
> What's the bandwidth of an individual satellite?

As said before. The carrier is chopped by a 1.023MHz PRN sequence on C/A
and a 10.23MHz chipping rate on P(Y).

--

   Bj?rn



From bg at lysator.liu.se  Tue Nov 11 18:37:27 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Tue, 11 Nov 2008 19:37:27 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <ECE7A93BD093E1439C20020FBE87C47FEB55C30390@ALTPHYEMBEVSP20.RES.AD.JPL>
References: Message from "Lux, James P" <james.p.lux@jpl.nasa.gov> of "Tue,
	11 Nov 2008 09:39:21 PST."
	<ECE7A93BD093E1439C20020FBE87C47FEB55C3037A@ALTPHYEMBEVSP20.RES.AD.JPL>
	<20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>
	<ECE7A93BD093E1439C20020FBE87C47FEB55C30390@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <1226428647.20299.41.camel@bg-desktop>


On Tue, 2008-11-11 at 10:28 -0800, Lux, James P wrote:
> 
> A GPS receiver actually solves for the state vector of the receiver (including the local clock error) using the raw observables from the tracking loop (code phase).  The nav equations calculate (apparent) range and range rate from the known state vector of each satellite and the (estimated) state vector of the receiver.  Range rate is the doppler.
> 
> The 1.xxx Megachip/second C/A code is 1023 bits long, so the classical approach is to step the receiver through all possible phases of the code, integrating at each one to see if it can detect the signal.  If your integration time is, say, 10 milliseconds, it takes 10 seconds to step through them all. Once the signal is detected, the PN tracking loop tracks that signal.

You also need to check different doppler bins. 500Hz bins are a classic
choice.

--

   Bj?rn



From brooke at pacific.net  Tue Nov 11 19:12:21 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Tue, 11 Nov 2008 11:12:21 -0800
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <d31.41a80dfe.364b1a9e@aol.com>
References: <d31.41a80dfe.364b1a9e@aol.com>
Message-ID: <4919D915.8000601@pacific.net>

Hi Bruce:

It's my understanding that if you look at the signal from a common GPS antenna 
and feed it into a spectrum analyzer you will not see the signal.  My guess is 
that when developed by the military it was designed to be a stealth system. 
GPS is what's called a Spread spectrum signal.

Also the best possible s/n radio is determined by how orthogonal the different 
PN codes are to each other.  These are described in ICD-GPS-200 which is on 
line at:
http://www.navcen.uscg.gov/gps/geninfo/
along with other GPS info.

Here's a National Instruments page about GPS signal generation:
http://zone.ni.com/devzone/cda/tut/p/id/8015
The definitions on this page for the various Time To First Fix flavors may not 
be accurate.

Have Fun,

Brooke Clarke
http://www.prc68.com

Brucekareen at aol.com wrote:
>  
> I  have an EIP Model 548 counter with a YIG-tuned front end that can be 
> programmed  to scan over narrow frequency ranges.  By feeding the rubidium 
> oscillator under test into the 10 MHz clock input  of the counter, is there any 
> reasonably simple way to directly measure the  frequency of a GPS satellite 
> transmission so as to ascertain the accuracy of the  rubidium source?  The counter has 
> an  input sensitivity in the order of about ?25 dBm -- not sufficient to 
> measure  directly from an amplified antenna, but perhaps through an amplifier.  I 
> am not sure whether the input YIG  tuner selectivity is sufficient to separate 
> transmissions from the various  satellite?s (or are they TDMS?).  What do you 
> think?   
> Bruce,  KG6OJI
> **************AOL Search: Your one stop for directions, recipes and all other 
> Holiday needs. Search Now. 
> (http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays-from
> -aol-search/?ncid=emlcntussear00000001)
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From magnus at rubidium.dyndns.org  Wed Nov 12 00:19:23 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Wed, 12 Nov 2008 01:19:23 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <1226428647.20299.41.camel@bg-desktop>
References: Message from "Lux, James P" <james.p.lux@jpl.nasa.gov> of "Tue,
	11 Nov 2008 09:39:21
	PST."	<ECE7A93BD093E1439C20020FBE87C47FEB55C3037A@ALTPHYEMBEVSP20.RES.AD.JPL>	<20081111181020.B775ABCD5@ip-64-139-1-69.sjc.megapath.net>	<ECE7A93BD093E1439C20020FBE87C47FEB55C30390@ALTPHYEMBEVSP20.RES.AD.JPL>
	<1226428647.20299.41.camel@bg-desktop>
Message-ID: <491A210B.30401@rubidium.dyndns.org>

Bj?rn Gabrielsson skrev:
> On Tue, 2008-11-11 at 10:28 -0800, Lux, James P wrote:
>> A GPS receiver actually solves for the state vector of the receiver (including the local clock error) using the raw observables from the tracking loop (code phase).  The nav equations calculate (apparent) range and range rate from the known state vector of each satellite and the (estimated) state vector of the receiver.  Range rate is the doppler.
>>
>> The 1.xxx Megachip/second C/A code is 1023 bits long, so the classical approach is to step the receiver through all possible phases of the code, integrating at each one to see if it can detect the signal.  If your integration time is, say, 10 milliseconds, it takes 10 seconds to step through them all. Once the signal is detected, the PN tracking loop tracks that signal.
> 
> You also need to check different doppler bins. 500Hz bins are a classic
> choice.

To elaborate on that. The C/A code is 1023 chips long, at 1,023 
MChips/s which cause a cycle period of 1 ms. If you now consider 
sampling at 1 ms, the sampling rate is 1 kHz giving the Nyquist 
frequency of 500 Hz and thus 500 Hz doppler bins. For a earth bound GPS 
receiver, as extreme as 6 kHz doppler offsets can be seen on the 
carrier. The chipping rate shift is 1/1540 as low, so it can be almost 
neglected in comparision.

The traditional search is a two-dimensional search in doppler bins +/- 
6000 Hz in 500 Hz blocks and 0-1022 phase stages for each of 1-32 PRN 
codes. a search space totaling of 818400 combinations taking 818,4 s for 
a single integrator and 1/N for N integrators so roughly a minute or two 
for a now classic receiver of 8 to 12 channels. A more efficient 
algorithm is to sample the signal, FFT it and make the correlation in 
the frequency domain. It will crank out the phase and correlation 
amplitude for each PRN attempted with much less processing. This needs 
ot be performed for each doppler bin, but is certainly worthwhile the 
effort. Extending the search for all the WAAS/EGNOS sats is trivial and 
worthwhile.

Once doppler bin and phase has been achieved for each PRN, picking the 
top N correlations and initiate channels is a quick process. The 
correlation phase can be initiated into the channel together with a 
rought initial frequency guess from the doppler bin and phase locking is 
quickly achieved in a traditional correlation channel. Data channel 
phase locking is the next thing, but that hunt is quickly achieved. This 
  can be aided by having an existing total lock in which case even 
fundamental things such as bit phase on pseudo-code has a very limitied 
range between sats. A very rought idea of current position can give a 
correct model of full subcode phase.

A sat based receiver must handle higher doppler offsets due to its 
higher speed, but as long as the per channel mix-down carrier NCO can be 
set wide enought, and that search patterns include the needed range, it 
will not be much of a problem. Naturally, tracking PLLs needs to handle 
the higher dynamics. As the orbit is fairly stable, orbit predictions 
can be fed into loop for better performance as it allows tighter bandwidth.

The full benefit of code and carrier phase measurements should be used. 
Also, considering L2C is becomming more and more common, it should also 
be used. Preparation for L1C should also be done.

As for signal bandwidth, while the C/A chiping rate is 1,023 MChips/s, 
we can expect a 2,046 MHz range between the first nulls offset from the 
carrier. However, the traditional sats uses a full 20,46 MHz bandwidth 
since it also transmitts the P(Y) code. Buliding a receiver that uses 
the full bandwidth provides certain benefits, but standard off the shelf 
chips usually stays within 2,046 MHz. The front end design is basically 
the same thought, just 10 MHz higher bandwidth. For civilian receivers, 
only code-less tracking receivers usually have that bandwidht.

Modern GPS signals extend to a 24 MHz bandwidth. It is especially the 
M-code that mandates this shift. The M-code should be of no major 
interest for civilian receivers.

Sorry for the short write-up, but there is certainly more to tell about 
this.

Cheers,
Magnus


From phk at phk.freebsd.dk  Wed Nov 12 01:23:48 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 01:23:48 +0000
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: Your message of "Wed, 12 Nov 2008 01:19:23 +0100."
	<491A210B.30401@rubidium.dyndns.org> 
Message-ID: <86963.1226453028@critter.freebsd.dk>

In message <491A210B.30401 at rubidium.dyndns.org>, Magnus Danielson writes:

> Once doppler bin and phase has been achieved for each PRN, [...]

Just a footnote to say that as soon as you start receiving ephemerides
from the first sat, the search-space can be significantly reduced
if you care to do the, rather longhaired, trignometric math.

>A sat based receiver must handle higher doppler offsets due to its 
>higher speed, [...]

While this is true for any non-geo-stationary satellite, it may not
be true for the project the initial poster talked about.

As I remember it, he said that the mission would be in an earth-following
orbit, ie: in the same orbit as the earth around the sun, but
trailing it by some distance.

Given that the distance in GPS terms is "vast" and furthermore that
the GPS orbits have a pretty steep angle relative to the earths
orbital path, I would expect the doppler offsets to be much smaller
than here on earth.

Obviously, getting a position fix will suck with the worst
DOP seen to date, but a frequency fix should not be out
of the question.

Obviously, the situation on the way to the final orbit is entirely
different, and there I would expect doppler to be totally out
of the lower end of the window.

Remember to figure out the relevant relativistic corrections.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From wb6bnq at cox.net  Wed Nov 12 01:59:45 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Tue, 11 Nov 2008 17:59:45 -0800
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
References: <86963.1226453028@critter.freebsd.dk>
Message-ID: <491A3891.82AD53CC@cox.net>

GEEZ,

After all this discussion, it sounds like he should consider 2 Cs space devices,
one main and a secondary.

Bill....WB6BNQ


Poul-Henning Kamp wrote:

> In message <491A210B.30401 at rubidium.dyndns.org>, Magnus Danielson writes:
>
> > Once doppler bin and phase has been achieved for each PRN, [...]
>
> Just a footnote to say that as soon as you start receiving ephemerides
> from the first sat, the search-space can be significantly reduced
> if you care to do the, rather longhaired, trignometric math.
>
> >A sat based receiver must handle higher doppler offsets due to its
> >higher speed, [...]
>
> While this is true for any non-geo-stationary satellite, it may not
> be true for the project the initial poster talked about.
>
> As I remember it, he said that the mission would be in an earth-following
> orbit, ie: in the same orbit as the earth around the sun, but
> trailing it by some distance.
>
> Given that the distance in GPS terms is "vast" and furthermore that
> the GPS orbits have a pretty steep angle relative to the earths
> orbital path, I would expect the doppler offsets to be much smaller
> than here on earth.
>
> Obviously, getting a position fix will suck with the worst
> DOP seen to date, but a frequency fix should not be out
> of the question.
>
> Obviously, the situation on the way to the final orbit is entirely
> different, and there I would expect doppler to be totally out
> of the lower end of the window.
>
> Remember to figure out the relevant relativistic corrections.
>
> Poul-Henning
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From magnus at rubidium.dyndns.org  Wed Nov 12 07:33:34 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Wed, 12 Nov 2008 08:33:34 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <86963.1226453028@critter.freebsd.dk>
References: <86963.1226453028@critter.freebsd.dk>
Message-ID: <491A86CE.6010100@rubidium.dyndns.org>

Poul-Henning Kamp skrev:
> In message <491A210B.30401 at rubidium.dyndns.org>, Magnus Danielson writes:
> 
>> Once doppler bin and phase has been achieved for each PRN, [...]
> 
> Just a footnote to say that as soon as you start receiving ephemerides
> from the first sat, the search-space can be significantly reduced
> if you care to do the, rather longhaired, trignometric math.

True, but breaking into the code phase for each sat is nowdays fairly 
quick, and after setting up the receive channels the rest is much more 
parallelized. It is simply just quicker to do the code phase break in 
and start tracking than receiving the ephemerides data from the first 
sat. The time it takes for a calender to be received is fairly long.

>> A sat based receiver must handle higher doppler offsets due to its 
>> higher speed, [...]
> 
> While this is true for any non-geo-stationary satellite, it may not
> be true for the project the initial poster talked about.
> 
> As I remember it, he said that the mission would be in an earth-following
> orbit, ie: in the same orbit as the earth around the sun, but
> trailing it by some distance.

That was never clear in my mind. Ah well, if so then that part would not 
need any specific modifications, not that they are particular hard.

However, which ever orbit we are discussing, the doppler aspect needs to 
be studied.

> Given that the distance in GPS terms is "vast" and furthermore that
> the GPS orbits have a pretty steep angle relative to the earths
> orbital path, I would expect the doppler offsets to be much smaller
> than here on earth.

Another aspect to remember is that there is usually a earth bound 
assumption used to bootstrap the position calculation. This would 
naturally need to be adapted. Fortunately it can be adapted and tested 
very easily if needed.

> Obviously, getting a position fix will suck with the worst
> DOP seen to date, but a frequency fix should not be out
> of the question.
> 
> Obviously, the situation on the way to the final orbit is entirely
> different, and there I would expect doppler to be totally out
> of the lower end of the window.

Actually, you can expect both ends of the doppler spectrum. As long as 
you are below the GPS sats, you will also see high positive dopplers as 
you goes towards them and negative from those you are leaving behind. As 
you go past them, all will show up on the negative side. However, those 
closest to you will not be looking at you any more due to directivity of 
the antenna array.

> Remember to figure out the relevant relativistic corrections.

There are several relativistic corrections that needs to be considered. 
Also, while the sat is in transit to its final orbit one can expect 
these to be with a higher dynamic than a circular orbit. An elliptic 
orbit would always need orbit-based relativistic correction for that 
extra correctness.

The intended orbit and transit-orbit is certainly of great importance 
for a number of key processing requirements. It is however not extremely 
hard to handle it.

Cheers,
Magnus


From magnus at rubidium.dyndns.org  Wed Nov 12 07:40:11 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Wed, 12 Nov 2008 08:40:11 +0100
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
In-Reply-To: <491A3891.82AD53CC@cox.net>
References: <86963.1226453028@critter.freebsd.dk> <491A3891.82AD53CC@cox.net>
Message-ID: <491A885B.7050104@rubidium.dyndns.org>

WB6BNQ skrev:
> GEEZ,
> 
> After all this discussion, it sounds like he should consider 2 Cs space devices,
> one main and a secondary.

Actually, I would pick rubidium sources unless extreme stability and 
offset is needed. The longer lifetime and less weight compared to Cs 
devices would be a better fit. Another option would be to use an OCXO 
and tune it over the telemetry channel which may prove sufficient if 
telemetry is timely spaced such that worst case drifts can be 
compensated out. The benefit in weight of such a solution is even 
greater. Weight and power budget is much more limiting factor than any 
of the labs we guys run.

Cheers,
Magnus


From Brucekareen at aol.com  Wed Nov 12 15:57:58 2008
From: Brucekareen at aol.com (Brucekareen at aol.com)
Date: Wed, 12 Nov 2008 10:57:58 EST
Subject: [time-nuts] Checking the Frequency of a Rubidium Oscillator
Message-ID: <d3f.3630e2dd.364c5706@aol.com>

 
Thanks to all that  explained the hopelessness of measuring GPS satellite 
transmission frequencies  directly with a simple counter.  I  should have known 
better, but probably have been retired too long.   
Bruce,  KG6OJI 

**************Get movies delivered to your mailbox. One month free from 
blockbuster.com 
(http://pr.atwola.com/promoclk/100000075x1212639737x1200784900/aol?redir=https://www.blockbuster.com/signup/y/reg/p.26978/r.email_footer)

From pabloalvarezsanchez at gmail.com  Wed Nov 12 16:25:30 2008
From: pabloalvarezsanchez at gmail.com (pablo alvarez)
Date: Wed, 12 Nov 2008 17:25:30 +0100
Subject: [time-nuts] Fine delay generator
In-Reply-To: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
Message-ID: <2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>

Dear nuts,

I am designing a card that should be able to delay a trigger from 25ns
up to several seconds in 10ps steps. The card will use an external
10MHz as frequency reference.

I have thought of two architectures. One is a counter clocked by a
keyed oscillator followed by a fine delay and the other is based on a
Time interval meter (TIM), a  counter clocked by a TCXO followed by a
fine delay. Let me just explain a bit more about both options.

 1. Keyed oscillator Counter + fine delay. The keyed oscillator starts
oscillating phase allinged to the input trigger and frequency locked
to the external 10MHz.   This is a beautiful scheme, but sofar I have
not found any comercial keyed oscillator or startable oscillator. Do
you know of a design that could do the job? Keeping an stable
oscillator phase and the frequency locked to an external reference at
the same time is not an easy job.  An example of module that does it
is the V850 by highland:
http://www.highlandtechnology.com/DSS/V850DS.html

The fine delay can be implemented with a digital delay line such as
ON's MC100EP196B or Micrel's SY89297U.
http://www.onsemi.com/pub_link/Collateral/MC100EP196B-D.PDF
http://www.micrel.com/page.do?page=/product-info/products/sy89297u.jsp

A bad point is that the time interval between trigger's cannot be
smaller than the generated delay.
A very nice feature is that its monotonicity is garanteed by design.

 2. Time interval meter + TCXO Counter + fine delay
In this scheme I measure the trigger phase respect to the internal
TCXO and calculate the corresponding fine delay that I have to add to
the counter ouput. I expect the time interval measurement latency to
be of the order of 200ns-300ns, so for small delays it would be
necessary to use a separeted fine delay and multiplex the outputs.
Locking the TCXO to the external 10MHz should not be a problem.

For the TIM I could use a ACAM's TDC-GPX which offers 10ps resolution.
http://www.acam-usa.com/Content/English/gpx/gpx_1.html

As an analogue option I was thinking of latching the input trigger
with a flip-flop, low pass filter it and sample it with a high speed
ADC such as the  AD9626. The TIM could be callibrated at the startup,
but I do not have a feeling of how stable it can be.

http://www.analog.com/en/analog-to-digital-converters/ad-converters/AD9626/products/product.html

Generating the small fine delays from 25ns up to 300ns is perhaps the
most diffucult one IMHO. I am not very sure if the classical scheme of
integrator followed by a comparator can generate delays of up to 300ns
with low jitter.  On the other hand chaining 24 MC100EP196B to
generate a 300ns delay seems a bit scary too...

Thanks in advance for your comments

Cheers

Pablo


From bruce.griffiths at xtra.co.nz  Wed Nov 12 21:02:14 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 13 Nov 2008 10:02:14 +1300
Subject: [time-nuts] Fine delay generator
In-Reply-To: <2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
Message-ID: <491B4456.1000304@xtra.co.nz>

pablo alvarez wrote:
> Dear nuts,
>
> I am designing a card that should be able to delay a trigger from 25ns
> up to several seconds in 10ps steps. The card will use an external
> 10MHz as frequency reference.
>
> I have thought of two architectures. One is a counter clocked by a
> keyed oscillator followed by a fine delay and the other is based on a
> Time interval meter (TIM), a  counter clocked by a TCXO followed by a
> fine delay. Let me just explain a bit more about both options.
>
>  1. Keyed oscillator Counter + fine delay. The keyed oscillator starts
> oscillating phase allinged to the input trigger and frequency locked
> to the external 10MHz.   This is a beautiful scheme, but sofar I have
> not found any comercial keyed oscillator or startable oscillator. Do
> you know of a design that could do the job? Keeping an stable
> oscillator phase and the frequency locked to an external reference at
> the same time is not an easy job.  An example of module that does it
> is the V850 by highland:
> http://www.highlandtechnology.com/DSS/V850DS.html
>
> The fine delay can be implemented with a digital delay line such as
> ON's MC100EP196B or Micrel's SY89297U.
> http://www.onsemi.com/pub_link/Collateral/MC100EP196B-D.PDF
> http://www.micrel.com/page.do?page=/product-info/products/sy89297u.jsp
>
> A bad point is that the time interval between trigger's cannot be
> smaller than the generated delay.
> A very nice feature is that its monotonicity is garanteed by design.
>
>  2. Time interval meter + TCXO Counter + fine delay
> In this scheme I measure the trigger phase respect to the internal
> TCXO and calculate the corresponding fine delay that I have to add to
> the counter ouput. I expect the time interval measurement latency to
> be of the order of 200ns-300ns, so for small delays it would be
> necessary to use a separeted fine delay and multiplex the outputs.
> Locking the TCXO to the external 10MHz should not be a problem.
>
> For the TIM I could use a ACAM's TDC-GPX which offers 10ps resolution.
> http://www.acam-usa.com/Content/English/gpx/gpx_1.html
>
> As an analogue option I was thinking of latching the input trigger
> with a flip-flop, low pass filter it and sample it with a high speed
> ADC such as the  AD9626. The TIM could be callibrated at the startup,
> but I do not have a feeling of how stable it can be.
>
>   
I presume you mean low pass filtering the pulse train whose width is
equal to the input to output delay of a synchroniser.
The dc level depends on the trigger frequency as well as the
synchroniser delay.
> http://www.analog.com/en/analog-to-digital-converters/ad-converters/AD9626/products/product.html
>
> Generating the small fine delays from 25ns up to 300ns is perhaps the
> most diffucult one IMHO. I am not very sure if the classical scheme of
> integrator followed by a comparator can generate delays of up to 300ns
> with low jitter.  On the other hand chaining 24 MC100EP196B to
> generate a 300ns delay seems a bit scary too...
>
>   
> Thanks in advance for your comments
>
> Cheers
>
> Pablo
>
>   
Pablo

1) The HP5359A (and the 5370A/B) used a phase locked startable oscillator.
The classic gated oscillator uses a delay line to determine the
oscillator frequency.
These are commercially available or you can build your own using an
inverting gate and a length of coax or other delay line for higher
performance.

2) The ACAM TDC-GPX has linearity errors much larger than 10ps for short
time intervals (< 120ns).
However if the time interval can be guaranteed to exceed some minimum
(120ns) an integral non linearity of around 10ps is possible.
For longer time intervals the measurement jitter will be significant at
the 10ps level.
The ACAM TDC-GPX has an internal delay locked loop option that allows
the internal delay step size to be locked to an external reference
frequency.

Another delay technique is to use a tapped chain of gates in an FPGA can
be used to implement a fine delay.
A DLL can be used to stabilise the delays.

Another option is to use a pair of ADCs to simultaneously sample a
quadrature pair of 10MHz sinewaves.
Together with a dual phase synchroniser to sample a counter clocked at
10MHz, a resolution on the order of 10ps or so is possible with a range
limited by the counter length.
An LTC1407A-1 dual simultaneous sampling ADC allows sample rates up to
1.5MHz with adequate linearity if driven differentially.
However an inverse tangent calculation is required for each measurement
- this could easily be done in an FPGA within a few tens of nanosec.

To avoid using a fine delay with a large range using a higher frequency
(eg 40MHz or higher) local clock phase locked to 10MHz will reduce the
required fine delay range significantly.

Bruce




From phase3 at wcc.net  Thu Nov 13 01:31:19 2008
From: phase3 at wcc.net (Bill)
Date: Wed, 12 Nov 2008 19:31:19 -0600
Subject: [time-nuts] TBolt disciplined receivers...
Message-ID: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>

Will TAPR be getting anymore of these units, if anyone knows?

 

I'm always a day late and a couple a' dollars short.

 

Bill Mason

W5TP


From bill at iaxs.net  Thu Nov 13 03:27:10 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Wed, 12 Nov 2008 21:27:10 -0600
Subject: [time-nuts] What's all this about violins in the streets?
In-Reply-To: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>
References: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>
Message-ID: <9D0AB0566F9C427FA92F2214F9C37410@cyrus>

My apologies, but I didn't think you'd want to hear about jumps.

My good friend, and software genius, was late for a lunch appointment
today. The "atomic" alarm clock that he has used for years was 3.3
hours behind this morning, but not on any other morning. My WWVB clock
was dead on at 4 PM (in MN, where we both are located).

Anybody got a story about an "atomic" clock messing up like that?

Bill Hawkins

"It's five o'clock somewhere ..." Jimmy Buffet



From bruce.griffiths at xtra.co.nz  Thu Nov 13 03:32:09 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 13 Nov 2008 16:32:09 +1300
Subject: [time-nuts] Fine delay generator
In-Reply-To: <2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
Message-ID: <491B9FB9.2060407@xtra.co.nz>

pablo alvarez wrote:
> Dear nuts,
>
> I am designing a card that should be able to delay a trigger from 25ns
> up to several seconds in 10ps steps. The card will use an external
> 10MHz as frequency reference.
>
>
> As an analogue option I was thinking of latching the input trigger
> with a flip-flop, low pass filter it and sample it with a high speed
> ADC such as the  AD9626. The TIM could be callibrated at the startup,
> but I do not have a feeling of how stable it can be.
>
> http://www.analog.com/en/analog-to-digital-converters/ad-converters/AD9626/products/product.html
>
>   
Pablo

Surely it would be better to sampled the low pass filtered latched
trigger transition with a pipeline ADC clocked at 100MHz or more.
The threshold crossing time of the ADC input can then be calculated from
the ADC samples (using WSK interpolation etc) provided there are
sufficient samples taken during the transition.
The low pass filter delay will have to be taken into account in
determining the actual time of occurrence of the trigger input signal.
A long tailed pair with a differential output could be used to drive a
differential low pass filter connected to the differential ADC input.
A resolution of 10ps or better should be achievable with the offset
stability largely determined by the analog filter delay instability (due
to time, temperature etc).
The slope should be very stable as it is largely determined by the ADC
clock and ADC linearity.

Bruce
> Thanks in advance for your comments
>
> Cheers
>
> Pablo
>
>   



From kirbybq at bellsouth.net  Thu Nov 13 03:33:36 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Wed, 12 Nov 2008 21:33:36 -0600
Subject: [time-nuts] What's all this about violins in the streets?
In-Reply-To: <9D0AB0566F9C427FA92F2214F9C37410@cyrus>
References: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>
	<9D0AB0566F9C427FA92F2214F9C37410@cyrus>
Message-ID: <491BA010.60509@bellsouth.net>

I figure there is no CRC check for the WWV clocks.

I had on lose it for about 3 days in the middle of summer, and then it 
picked it back up and has been OK since.

Maybe local RFI when the clock went to check the signal....

Brian KD4FM



Bill Hawkins wrote:
> My apologies, but I didn't think you'd want to hear about jumps.
> 
> My good friend, and software genius, was late for a lunch appointment
> today. The "atomic" alarm clock that he has used for years was 3.3
> hours behind this morning, but not on any other morning. My WWVB clock
> was dead on at 4 PM (in MN, where we both are located).
> 
> Anybody got a story about an "atomic" clock messing up like that?
> 
> Bill Hawkins
> 
> "It's five o'clock somewhere ..." Jimmy Buffet
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From brooke at pacific.net  Thu Nov 13 03:39:10 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Wed, 12 Nov 2008 19:39:10 -0800
Subject: [time-nuts] What's all this about violins in the streets?
In-Reply-To: <491BA010.60509@bellsouth.net>
References: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>	<9D0AB0566F9C427FA92F2214F9C37410@cyrus>
	<491BA010.60509@bellsouth.net>
Message-ID: <491BA15E.1050500@pacific.net>

Hi Brian:

The WWVB clocks typically want to see 2 or 3 minutes go by where the data 
packets have date and time incrementing by 1 minute.  If you see that then you 
have valid data.  Hard for interference to mess it up.

But a low battery will cause problems, i.e. the clock may miss steps and get 
behind, not sync, etc.  I wonder which way Bill's friend's clock was off?

Have Fun,

Brooke Clarke
http://www.prc68.com

Brian Kirby wrote:
> I figure there is no CRC check for the WWV clocks.
> 
> I had on lose it for about 3 days in the middle of summer, and then it 
> picked it back up and has been OK since.
> 
> Maybe local RFI when the clock went to check the signal....
> 
> Brian KD4FM
> 
> 
> 
> Bill Hawkins wrote:
>> My apologies, but I didn't think you'd want to hear about jumps.
>>
>> My good friend, and software genius, was late for a lunch appointment
>> today. The "atomic" alarm clock that he has used for years was 3.3
>> hours behind this morning, but not on any other morning. My WWVB clock
>> was dead on at 4 PM (in MN, where we both are located).
>>
>> Anybody got a story about an "atomic" clock messing up like that?
>>
>> Bill Hawkins
>>
>> "It's five o'clock somewhere ..." Jimmy Buffet
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From bruce.griffiths at xtra.co.nz  Thu Nov 13 03:59:02 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 13 Nov 2008 16:59:02 +1300
Subject: [time-nuts] Fine delay generator
In-Reply-To: <491B9FB9.2060407@xtra.co.nz>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
	<491B9FB9.2060407@xtra.co.nz>
Message-ID: <491BA606.8010904@xtra.co.nz>


> Pablo
>
> Surely it would be better to sampled the low pass filtered latched
> trigger transition with a pipeline ADC clocked at 100MHz or more.
> The threshold crossing time of the ADC input can then be calculated from
> the ADC samples (using WSK interpolation etc) provided there are
> sufficient samples taken during the transition.
> The low pass filter delay will have to be taken into account in
> determining the actual time of occurrence of the trigger input signal.
> A long tailed pair with a differential output could be used to drive a
> differential low pass filter connected to the differential ADC input.
> A resolution of 10ps or better should be achievable with the offset
> stability largely determined by the analog filter delay instability (due
> to time, temperature etc).
> The slope should be very stable as it is largely determined by the ADC
> clock and ADC linearity.
>
> Bruce
>   

I meant to say that using a higher resolution pipeline ADC than the
AD9626 may be better as the SNR limits the AD9626 to about 10.5 bits at
low input frequencies.
This means that the equivalent timing noise will be around 14ps if the
ADC input has a 10ns transition time and the ADC is clocked at 250MHz.
An ADC with 14 effective bit performance with a 100MHz sampling clock
should have an equivalent timing noise of around 5ps or so when the ADC
input has a 25nS transition time.
An AD9446 should achieve a timing noise level of around 7ps rms or so
when clocked at 100MHz.

A pulse centroid timing technique using an ADC to sample a quasi
Gaussian pulse has been demonstrated to have a stability of 10-20ps or
so after calibration.
A timing technique using WSK interpolation should have somewhat greater
stability as the analog signal processing required is much simpler.

Bruce


From KFIam640 at aol.com  Thu Nov 13 04:35:39 2008
From: KFIam640 at aol.com (KFIam640 at aol.com)
Date: Wed, 12 Nov 2008 23:35:39 EST
Subject: [time-nuts] What's all this about violins in the streets?
Message-ID: <bff.4c9eadf5.364d089b@aol.com>

Yes, mine have shown similar errors from time to time.  Usually a new  
battery fixes the problem.  I have had it happen on AC powered  clocks.  The usually 
go back to proper time after I press the WAVE  button.  I figure they must 
get some interference from something that  causes them to go off time.  Overall, 
they work very well and seldom go off  time.  Going from PST to DST and back 
can be problematic for my  clocks.  I think I have 10 of them around the house 
and I usually have to  put in a new battery or restart 3 or 4 of them at 
PST/PDT time change.  I  am located in the Los Angeles area so the WWVB signal is 
OK here but not as  strong as for a lot of the country.
 
Marvin, W6OQI
 
 
In a message dated 11/12/2008 7:34:08 P.M. Pacific Standard Time,  
kirbybq at bellsouth.net writes:

My good  friend, and software genius, was late for a lunch appointment
> today.  The "atomic" alarm clock that he has used for years was 3.3
> hours  behind this morning, but not on any other morning. My WWVB clock
> was  dead on at 4 PM (in MN, where we both are located).
> 
> Anybody  got a story about an "atomic" clock messing up like  that?


**************Get the Moviefone Toolbar. Showtimes, theaters, movie news & 
more!(http://pr.atwola.com/promoclk/100000075x1212774565x1200812037/aol?redir=htt
p://toolbar.aol.com/moviefone/download.html?ncid=emlcntusdown00000001)

From technoid_tim at comcast.net  Thu Nov 13 07:16:51 2008
From: technoid_tim at comcast.net (Tim Schulz)
Date: Thu, 13 Nov 2008 00:16:51 -0700
Subject: [time-nuts] More HP 5062C cesium beam debugging questions
Message-ID: <491BD463.5080006@comcast.net>

Greetings everyone; I am back on the task of try to figure out what is 
wrong with my 5062C.  Many thanks to Corby for the power supply scans 
and debugging tips so far.  The 18v power supply card seems fine, it is 
not being enabled by the ion pump power supply.  As far as I can tell, 
the ion pump PS is not operating, it is not putting out any HV.  I did 
manage to buy a 5062C carcass minus the cesium beam tube off ebay and 
swapping the ion pump ps didn't change anything.  Some of the readings 
on the status monitor are zeroed out - #4, ion pump, #5, 5mhz, #7 Cs 
oven, #9, beam1, #10, 2nd harmonic, and #11, control.  #6, osc oven, is 
2x the normal reading.  I am just turning the machine on and checking 
things - should I be waiting the 15+ minutes for things to warm up 
before attempting debugging?  Also, considering the age, last serviced 
in '97, is it likely that the Cs tube is shot?  I have found a possible 
local source for a 5061 service manual, is there any chance that it 
would be of any use with the 5062?  Thanks in advance...  tim


From ernieperes at aol.com  Thu Nov 13 10:44:31 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 13 Nov 2008 05:44:31 -0500
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <0966B95C2C344C03B160A47C60E644F3@didierhp>
References: <c9d.37940424.3648fb3b@aol.com>
	<0966B95C2C344C03B160A47C60E644F3@didierhp>
Message-ID: <8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>


Hello,

I am running the HP Z3801A after a long time again, more then 150hrs 
from the new ON status but I have never seen
on the " TI to GPS " small window better figure then 1,5E-9. the 
avarage is 1,3E-8 and seldom goes to 10E-9.
And running parallel the FURY board with a TEMEX OCXO and displays 
+1,6E-10 is the average very often 10E-11 and sometimes for a relative 
short time / 4-5 min / 1,4E-12.

Any idea why the Z3801A not displaying better figure?? Something wrong 
with the HP unit????

Thanks Ernie.

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From bg at lysator.liu.se  Thu Nov 13 11:35:34 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Thu, 13 Nov 2008 12:35:34 +0100
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>
References: <c9d.37940424.3648fb3b@aol.com>
	<0966B95C2C344C03B160A47C60E644F3@didierhp>
	<8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>
Message-ID: <1226576134.20299.102.camel@bg-desktop>


On Thu, 2008-11-13 at 05:44 -0500, ernieperes at aol.com wrote:
> Hello,
> 
> I am running the HP Z3801A after a long time again, more then 150hrs 
> from the new ON status but I have never seen
> on the " TI to GPS " small window better figure then 1,5E-9. the 
> avarage is 1,3E-8 and seldom goes to 10E-9.
> And running parallel the FURY board with a TEMEX OCXO and displays 
> +1,6E-10 is the average very often 10E-11 and sometimes for a relative 
> short time / 4-5 min / 1,4E-12.

Are you comparing apples with apples?  some nanoseconds error in _phase_
(time) seem reasonable (for the HP) . A _frequency_ error in the range
of 1E-10 to 1E-12 is also reasonable (for the FURY).

But then I have neither of the units you compare, so I could have
misunderstood your issue.

--

   Bj?rn



From shoppa at trailing-edge.com  Thu Nov 13 12:32:52 2008
From: shoppa at trailing-edge.com (Tim Shoppa)
Date: Thu, 13 Nov 2008 07:32:52 -0500
Subject: [time-nuts] Fine delay generator
In-Reply-To: <491B4456.1000304@xtra.co.nz>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
	<491B4456.1000304@xtra.co.nz>
Message-ID: <20081113123252.51F0BBA4D4C@mini-me.trailing-edge.com>

Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:
> An LTC1407A-1 dual simultaneous sampling ADC allows sample rates up to
> 1.5MHz with adequate linearity if driven differentially.
> However an inverse tangent calculation is required for each measurement
> - this could easily be done in an FPGA within a few tens of nanosec.

Arctan is the mathematical solution, but by using some extra knowledge
(that the amplitude of both sin and cos can be measured
but are not necessarily exactly equal to the level of DAC resolution) and the
common sense that at some parts of the cycle, cos is changing very slowly
and sin is changing very rapidly, or the other way around, resolution
can be substantially improved (nearly a factor of two).

Giving the slowly changing phase the same weight in the calculation
as the rapidly changing phase is unwise. It is wise to calibrate
the amplitudes and relative phases of sin and cos generators using
the same DAC's as you're going to use to do the measurement.

We were doing all this 30 years ago using CAMAC crates and PDP-8's,
no FPGA for arctan but we spent a good amount of effort in
weighting the calculation to extract
every bit of time resolution given our relatively coarse DAC resolution.

Much of this is in the 1940's Radiation Lab series, there
are extensive sections on sin/cos wave generation, and they
do note when doing the time measurment that you want to move
the trace so you are using the rapidly changing phase.
Of course they weren't necessarily using 10MHz sin/cos generators
back then, mostly they were using custom-wound nonlinear wire-wound pots
and motors driving shafts to make the phases :-).

Tim.


From ernieperes at aol.com  Thu Nov 13 15:14:08 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 13 Nov 2008 10:14:08 -0500
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <1226576134.20299.102.camel@bg-desktop>
References: <c9d.37940424.3648fb3b@aol.com><0966B95C2C344C03B160A47C60E644F3@didierhp><8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>
	<1226576134.20299.102.camel@bg-desktop>
Message-ID: <8CB13B99C0D06C1-8A8-3DF@Webmail-mg14.sim.aol.com>

Hi Bj?rn,

According to HP spec sheet It should be better then just a few 1,5E10-9.

Rgds Ernie.


-----Original Message-----
From: Bj?rn Gabrielsson <bg at lysator.liu.se>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Thu, 13 Nov 2008 12:35 pm
Subject: Re: [time-nuts] HP Z3801A Question



On Thu, 2008-11-13 at 05:44 -0500, ernieperes at aol.com wrote:
> Hello,
>
> I am running the HP Z3801A after a long time again, more then 150hrs
> from the new ON status but I have never seen
> on the " TI to GPS " small window better figure then 1,5E-9. the
> avarage is 1,3E-8 and seldom goes to 10E-9.
> And running parallel the FURY board with a TEMEX OCXO and displays
> +1,6E-10 is the average very often 10E-11 and sometimes for a 
relative
> short time / 4-5 min / 1,4E-12.

Are you comparing apples with apples?  some nanoseconds error in _phase_
(time) seem reasonable (for the HP) . A _frequency_ error in the range
of 1E-10 to 1E-12 is also reasonable (for the FURY).

But then I have neither of the units you compare, so I could have
misunderstood your issue.

--

   Bj?rn


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From bg at lysator.liu.se  Thu Nov 13 15:30:51 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Thu, 13 Nov 2008 16:30:51 +0100
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <8CB13B99C0D06C1-8A8-3DF@Webmail-mg14.sim.aol.com>
References: <c9d.37940424.3648fb3b@aol.com>
	<0966B95C2C344C03B160A47C60E644F3@didierhp>
	<8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>
	<1226576134.20299.102.camel@bg-desktop>
	<8CB13B99C0D06C1-8A8-3DF@Webmail-mg14.sim.aol.com>
Message-ID: <1226590252.20299.104.camel@bg-desktop>


On Thu, 2008-11-13 at 10:14 -0500, ernieperes at aol.com wrote:
> Hi Bj?rn,
> 
> According to HP spec sheet It should be better then just a few 1,5E10-9.
> 
> Rgds Ernie.

In phase or frequency?

--

   Bj?rn



From kirbybq at bellsouth.net  Thu Nov 13 18:00:37 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Thu, 13 Nov 2008 12:00:37 -0600
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <1226590252.20299.104.camel@bg-desktop>
References: <c9d.37940424.3648fb3b@aol.com>	<0966B95C2C344C03B160A47C60E644F3@didierhp>	<8CB1393F0586929-73C-29E5@mblk-d49.sysops.aol.com>	<1226576134.20299.102.camel@bg-desktop>	<8CB13B99C0D06C1-8A8-3DF@Webmail-mg14.sim.aol.com>
	<1226590252.20299.104.camel@bg-desktop>
Message-ID: <491C6B45.3040703@bellsouth.net>

You may be interpting it wrong, if your looking at the 1PPS to GPS, 
thats a time interval measurement referenced to the GPS 1PPS.  -1.5x10-9 
would be 1.5 nanosecond...so 1.5ns over 10 seconds would be 1.5x10-10 
Allan Variance compared to GPS

I do not remember, we made measurements several years ago, I believe the 
Z3801 takes 10 second time interval averages and it updates the 
oscillator via the DAC every 30 seconds, if needed.

There information out there on the unit, either here at Febo.com or 
http://realhamradio.com/cgi-bin/yabb/YaBB.cgi buried in the archives..

Brian





From richiem at hughes.net  Thu Nov 13 18:11:01 2008
From: richiem at hughes.net (Richard Moore)
Date: Thu, 13 Nov 2008 10:11:01 -0800
Subject: [time-nuts] Z3801 outer oven temp?
Message-ID: <527D355F-66FC-4BA7-B1F5-6CA606EF4D62@hughes.net>

Hi folks, wondering if any of you can tell me the outer oven  
temperature of the Z3801. Since the 10811As run in the range of 80-85  
deg C, I'm guessing it might be something like 40 deg C?

Dick Moore


From pabloalvarezsanchez at gmail.com  Thu Nov 13 18:27:09 2008
From: pabloalvarezsanchez at gmail.com (pablo alvarez)
Date: Thu, 13 Nov 2008 19:27:09 +0100
Subject: [time-nuts] Fine delay generator
In-Reply-To: <491B4456.1000304@xtra.co.nz>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>
	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>
	<491B4456.1000304@xtra.co.nz>
Message-ID: <2ae26e4e0811131027s45c55531g186ce4e04b40a68f@mail.gmail.com>

Thanks Tim and Bruce for your info! It is precious.

By the way you will have all the schematics and sources will be on the
web. I will keep you informed.

> 1) The HP5359A (and the 5370A/B) used a phase locked startable oscillator.
> The classic gated oscillator uses a delay line to determine the
> oscillator frequency.
> These are commercially available or you can build your own using an
> inverting gate and a length of coax or other delay line for higher
> performance.

Perhaps the MC100EP196B could be useful an oscillator here. I could
set a total delay of 10ns and try use the analog control input to tune
the period. The phase could be measured with an extra TIM.


> 2) The ACAM TDC-GPX has linearity errors much larger than 10ps for short
> time intervals (< 120ns).
> However if the time interval can be guaranteed to exceed some minimum
> (120ns) an integral non linearity of around 10ps is possible.
> For longer time intervals the measurement jitter will be significant at
> the 10ps level.
> The ACAM TDC-GPX has an internal delay locked loop option that allows
> the internal delay step size to be locked to an external reference
> frequency.
>
> Another delay technique is to use a tapped chain of gates in an FPGA can
> be used to implement a fine delay.
> A DLL can be used to stabilise the delays.

I have thought many times of implementing such a tapped delay line but
always left it for another moment. It is just a bit anoying that ones
has to fix the placement of the taps. On the other hand one could just
let the router place your design and use later statistical code
coverage to calibrate the design at startup.  It may be interesting
replicating the tapped delay lines. The resulting scale would be the
intersection of the original codes.
>
> Another option is to use a pair of ADCs to simultaneously sample a
> quadrature pair of 10MHz sinewaves.
> Together with a dual phase synchroniser to sample a counter clocked at
> 10MHz, a resolution on the order of 10ps or so is possible with a range
> limited by the counter length.
> An LTC1407A-1 dual simultaneous sampling ADC allows sample rates up to
> 1.5MHz with adequate linearity if driven differentially.
> However an inverse tangent calculation is required for each measurement
> - this could easily be done in an FPGA within a few tens of nanosec.

I have seen the paper you are refering to in your site. This method is
not as easy as it seems at the end. You need to generate a perfect
200MHz sine and cosine. You need to monitor its amplitude and to
obtain the maximum performance you need to have a good picture of the
nonlinarities of both sine and cosine. Finally the  LTC1407A-1 latency
is similar to that of the  AD9626.

> To avoid using a fine delay with a large range using a higher frequency
> (eg 40MHz or higher) local clock phase locked to 10MHz will reduce the
> required fine delay range significantly.

Certainly, I will try use a clock as fast as possible.

> Surely it would be better to sampled the low pass filtered latched
> trigger transition with a pipeline ADC clocked at 100MHz or more.
> The threshold crossing time of the ADC input can then be calculated from
> the ADC samples (using WSK interpolation etc) provided there are
> sufficient samples taken during the transition.

Thanks for suggesting the AD9446  and the WSK interpolation. I had
thought of  keeping a normalized waveform of the pulse rising edge
stored in a RAM. By normalized I mean doing the starting points equal
to -.5 and the final points equal to 0.5. I can try to autogenerate
this waveform using a fine delay line and later use statistical code
coverage to do a fine calibration.
By the way I do not understand very well how do you use WSK
interpolation. Normally you use it to find the amplitude level between
two samples, but here we are trying to solve the inverse problem. We
need to know at which moment the signal passed over a given threshold.
How do you solve it?



Pablo
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>


From cdelect at juno.com  Thu Nov 13 18:55:16 2008
From: cdelect at juno.com (Corby Dawson)
Date: Thu, 13 Nov 2008 10:55:16 -0800
Subject: [time-nuts] 5062C trouble
Message-ID: <20081113.105517.2892.0.cdelect@juno.com>


Tim,

The ion pump supply should be on if the unit is plugged in and on.

Remove the HV connector from the supply to remove any load and measure
the divided test point on the bottom of the chassis.

It should read between 2.45 and 3.0 VDC, if not measure from pin 4 of the
ion pump supply to ground. You should have 19VDC.

If HV is good with connector removed and bad with it on, the ion pump is
most likely shorted. If the 19VDC is bad then the regulator between the
+50VDC and the ion pump module is bad. Depends if you have an option 10
or not how it's hooked up but you should be able to trace it.


Corby
____________________________________________________________
Click here to compare rates and find the best deal on renting a car.
http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3nMUn1OOMQpmC43JlqxKWoQZXE64rYNrKeVdmeTS0S431emt/


From bruce.griffiths at xtra.co.nz  Thu Nov 13 20:51:06 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Fri, 14 Nov 2008 09:51:06 +1300
Subject: [time-nuts] Fine delay generator
In-Reply-To: <2ae26e4e0811131027s45c55531g186ce4e04b40a68f@mail.gmail.com>
References: <2ae26e4e0811120641p23a68844i2480c1222853d319@mail.gmail.com>	<2ae26e4e0811120825s4c73297t9a57e6235dc5d4c1@mail.gmail.com>	<491B4456.1000304@xtra.co.nz>
	<2ae26e4e0811131027s45c55531g186ce4e04b40a68f@mail.gmail.com>
Message-ID: <491C933A.9070108@xtra.co.nz>

pablo alvarez wrote:
> Thanks Tim and Bruce for your info! It is precious.
>
> By the way you will have all the schematics and sources will be on the
> web. I will keep you informed.
>
>   
>> 1) The HP5359A (and the 5370A/B) used a phase locked startable oscillator.
>> The classic gated oscillator uses a delay line to determine the
>> oscillator frequency.
>> These are commercially available or you can build your own using an
>> inverting gate and a length of coax or other delay line for higher
>> performance.
>>     
>
> Perhaps the MC100EP196B could be useful an oscillator here. I could
> set a total delay of 10ns and try use the analog control input to tune
> the period. The phase could be measured with an extra TIM.
>
>   
A delay line oscillator should have lower noise.
A varicap can be used to adjust the delay line oscillator frequency
slightly as in the 530A/B or 5359A vernier oscillators.
>   
>> 2) The ACAM TDC-GPX has linearity errors much larger than 10ps for short
>> time intervals (< 120ns).
>> However if the time interval can be guaranteed to exceed some minimum
>> (120ns) an integral non linearity of around 10ps is possible.
>> For longer time intervals the measurement jitter will be significant at
>> the 10ps level.
>> The ACAM TDC-GPX has an internal delay locked loop option that allows
>> the internal delay step size to be locked to an external reference
>> frequency.
>>
>> Another delay technique is to use a tapped chain of gates in an FPGA can
>> be used to implement a fine delay.
>> A DLL can be used to stabilise the delays.
>>     
>
> I have thought many times of implementing such a tapped delay line but
> always left it for another moment. It is just a bit anoying that ones
> has to fix the placement of the taps. On the other hand one could just
> let the router place your design and use later statistical code
> coverage to calibrate the design at startup.  It may be interesting
> replicating the tapped delay lines. The resulting scale would be the
> intersection of the original codes.
>   
>> Another option is to use a pair of ADCs to simultaneously sample a
>> quadrature pair of 10MHz sinewaves.
>> Together with a dual phase synchroniser to sample a counter clocked at
>> 10MHz, a resolution on the order of 10ps or so is possible with a range
>> limited by the counter length.
>> An LTC1407A-1 dual simultaneous sampling ADC allows sample rates up to
>> 1.5MHz with adequate linearity if driven differentially.
>> However an inverse tangent calculation is required for each measurement
>> - this could easily be done in an FPGA within a few tens of nanosec.
>>     
>
> I have seen the paper you are refering to in your site. This method is
> not as easy as it seems at the end. You need to generate a perfect
> 200MHz sine and cosine. You need to monitor its amplitude and to
> obtain the maximum performance you need to have a good picture of the
> nonlinarities of both sine and cosine. Finally the  LTC1407A-1 latency
> is similar to that of the  AD9626.
>
>   
A pair of 10MHz sine and quadrature waveforms will suffice for 10ps
resolution when using an LTC1407A-1.
If the sine and cosine signal amplitudes track slow variations cancel
when using the ratio of the sine and cosine samples.
Calibration could be done by using a suitable input frequency like
17.3447MHz divided by 35 to sample the sine and cosine signals.
Successive samples should then sample the quadrature pair at different
phases allowing measurement of effective gain differences, effective
phase offset between channels, and harmonic amplitudes.
>> To avoid using a fine delay with a large range using a higher frequency
>> (eg 40MHz or higher) local clock phase locked to 10MHz will reduce the
>> required fine delay range significantly.
>>     
>
> Certainly, I will try use a clock as fast as possible.
>
>   
>> Surely it would be better to sampled the low pass filtered latched
>> trigger transition with a pipeline ADC clocked at 100MHz or more.
>> The threshold crossing time of the ADC input can then be calculated from
>> the ADC samples (using WSK interpolation etc) provided there are
>> sufficient samples taken during the transition.
>>     
>
> Thanks for suggesting the AD9446  and the WSK interpolation. I had
> thought of  keeping a normalized waveform of the pulse rising edge
> stored in a RAM. By normalized I mean doing the starting points equal
> to -.5 and the final points equal to 0.5. I can try to autogenerate
> this waveform using a fine delay line and later use statistical code
> coverage to do a fine calibration.
> By the way I do not understand very well how do you use WSK
> interpolation. Normally you use it to find the amplitude level between
> two samples, but here we are trying to solve the inverse problem. We
> need to know at which moment the signal passed over a given threshold.
> How do you solve it?
>
>
>
> Pablo
>   
Pablo

One can use iteration to find the threshold crossing, just as one does
in finding the roots of a polynomial or other function.
WSK interpolation (with a suitable window function) allows one to
calculate the value of the signal at each intermediate point between
samples required by the iteration algorithm (Newton Raphson, binary
search etc).
When one obtains a pair of interpolated points that are sufficiently
close to each other and preferably straddling the threshold crossing
linear interpolation will suffice for the final estimate.
One advantage of this technique is that a model of the signal waveform
isn't required.
The threshold could also be defined as say the average of the 0 and 1
levels as measured by the ADC remote from the transition.
This should significantly reduce the effect of offset and gain variations.

Bruce


From mccorkle at ptialaska.net  Thu Nov 13 21:26:47 2008
From: mccorkle at ptialaska.net (Richard H McCorkle)
Date: Thu, 13 Nov 2008 12:26:47 -0900 (AKST)
Subject: [time-nuts] Z3801 outer oven temp?
In-Reply-To: <527D355F-66FC-4BA7-B1F5-6CA606EF4D62@hughes.net>
References: <527D355F-66FC-4BA7-B1F5-6CA606EF4D62@hughes.net>
Message-ID: <18090.206.174.39.163.1226611607.squirrel@mymail.acsalaska.net>

Hi Dick,

Back in 2004 Stefan Hegnauer reverse engineered the outer oven controller
in the Z3801A and posted the schematics and a PSPICE simulation. Apparently
they are no longer on the web, but his conclusion was:

"The outer oven of the Z3801A GPS disciplined crystal oscillator is used
to keep the ambient of the inner oven of the oscillator (HP10811) at a
roughly constant temperature of somewhere between +60...+65 ?C. The exact
value is not known to me. Because the Z3801A is specified from 0...+50 ?C,
and the HP10811 is specified for ambient temperatures of not more than
+71 ?C,  I think this makes sense."

Hope this helps,

Richard














> Hi folks, wondering if any of you can tell me the outer oven
> temperature of the Z3801. Since the 10811As run in the range of 80-85
> deg C, I'm guessing it might be something like 40 deg C?
>
> Dick Moore
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>




From bruce.griffiths at xtra.co.nz  Thu Nov 13 21:29:24 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Fri, 14 Nov 2008 10:29:24 +1300
Subject: [time-nuts] ADEV secondary standard
Message-ID: <491C9C34.4010504@xtra.co.nz>

When evaluating various methods for measuring ADEV, MDEV etc, it would
be useful to have a secondary standard for ADEV, MDEV etc.
If one splits a low noise signal with a passive splitter and adds
Gaussian noise of known level to one of the outputs, then in principle
if the measurement system noise bandwidth is known, one can calculate
the ADEV of one output with respect to the other.

Are there any other, preferably better, techniques for implementing an
ADEV secondary standard?

Bruce


From SAIDJACK at aol.com  Thu Nov 13 21:41:13 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Thu, 13 Nov 2008 16:41:13 EST
Subject: [time-nuts] HP Z3801A Question
Message-ID: <c72.41c55e5e.364df8f9@aol.com>

Hello Ernie,
 
as Bjoern mentioned I think the HP is indicating Time Interval between GPS  
and OCXO 1PPS in nanoseconds, while the Fury is indicating estimated frequency  
accuracy, a unitless number.
 
The Fury is showing estimated average frequency error over the last 1000  
seconds, similar to AVAR 1000s.
 
You can run GPScon on Fury too, and should be able to compare against the  
graphic you did for the HP unit.
 
Or you could set the LCD of the Fury to show Time Interval to UTC, or probe  
this time interval to UTC with the command ptim:tint? that will return the  
offset in nanoseconds as well.
 
An offset of +/-50ns to UTC seems to be normal for the HP unit. On the  Fury, 
I would expect this to be +/-10ns on a good OCXO.
 
To the benefit of the Z3801A unit: if the HP unit indicates a larger  offset, 
it may also be because it's internal GPS is not as good as the Fury  GPSDO 
receiver. It does not necessarily mean the OCXO is causing the error, it  could 
be that the HP GPS is causing the error, and the HP OCXO is  still dead-on 
because it filters out its higher GPS errors.
 
bye,
Said
 
 
In a message dated 11/13/2008 02:45:57 Pacific Standard Time,  
ernieperes at aol.com writes:

And  running parallel the FURY board with a TEMEX OCXO and displays 
+1,6E-10 is  the average very often 10E-11 and sometimes for a relative 
short time /  4-5 min / 1,4E-12.

Any idea why the Z3801A not displaying better  figure?? Something wrong 
with the HP unit????

Thanks  Ernie.



From jpawlan at pawlan.com  Thu Nov 13 21:55:46 2008
From: jpawlan at pawlan.com (Jeffrey Pawlan)
Date: Thu, 13 Nov 2008 13:55:46 -0800 (PST)
Subject: [time-nuts] ADEV secondary standard
In-Reply-To: <491C9C34.4010504@xtra.co.nz>
References: <491C9C34.4010504@xtra.co.nz>
Message-ID: <Pine.GSO.4.60.0811131354480.6901@jeffrey150.pawlan.com>

You have just described the current preferred method used by NIST for 
calibrating phase noise measurements.





From bruce.griffiths at xtra.co.nz  Thu Nov 13 22:05:36 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Fri, 14 Nov 2008 11:05:36 +1300
Subject: [time-nuts] ADEV secondary standard
In-Reply-To: <Pine.GSO.4.60.0811131354480.6901@jeffrey150.pawlan.com>
References: <491C9C34.4010504@xtra.co.nz>
	<Pine.GSO.4.60.0811131354480.6901@jeffrey150.pawlan.com>
Message-ID: <491CA4B0.3010302@xtra.co.nz>

Jeffrey Pawlan wrote:
> You have just described the current preferred method used by NIST for 
> calibrating phase noise measurements.
>
>
>   
I know, if the phase noise spectrum is known then ADEV can be calculated
from it , if the ADEV measurement system frequency response is known.

The questions are:

1) Is there a better method?

2) Are there any unanticipated problems with the method?

When testing indirect methods of measuring ADEV such a standard would be
useful for checking the measurement system and  its algorithms.

Bruce


From ernieperes at aol.com  Thu Nov 13 22:37:57 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 13 Nov 2008 17:37:57 -0500
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <c72.41c55e5e.364df8f9@aol.com>
References: <c72.41c55e5e.364df8f9@aol.com>
Message-ID: <8CB13F79C1D93AA-DB4-C2D@WEBMAIL-MA11.sysops.aol.com>

Hello Said,

Thanks for the detailed reply, it makes sense.
But both unit , the HP and the FURY board running under the same 
software simultaneously / GPS Con / and I was mentioning the same small 
"windows" TI to GPS, and the FURY displays much better figures then 
HP.....but probably each units gives out / display / different 
data??????
Also the graphic display / BLUE / on the FURY board the max ampl 
between +2,2nsec and -2,0nsec sometimes +0,7nsec ,
-1,7nsec...
the HP unit never goes under +15nsec and -20nsec...... almost 10 times 
worse.....
Anyhow I am happy because it seems to me that the HP is still OK after 
3 years of sleep.....

Rgsa Ernie.


-----Original Message-----
From: SAIDJACK at aol.com
To: time-nuts at febo.com
Sent: Thu, 13 Nov 2008 10:41 pm
Subject: Re: [time-nuts] HP Z3801A Question



Hello Ernie,

as Bjoern mentioned I think the HP is indicating Time Interval between 
GPS
and OCXO 1PPS in nanoseconds, while the Fury is indicating estimated 
frequency
accuracy, a unitless number.

The Fury is showing estimated average frequency error over the last 
1000
seconds, similar to AVAR 1000s.

You can run GPScon on Fury too, and should be able to compare against 
the
graphic you did for the HP unit.

Or you could set the LCD of the Fury to show Time Interval to UTC, or 
probe
this time interval to UTC with the command ptim:tint? that will return 
the
offset in nanoseconds as well.

An offset of +/-50ns to UTC seems to be normal for the HP unit. On the 
Fury,
I would expect this to be +/-10ns on a good OCXO.

To the benefit of the Z3801A unit: if the HP unit indicates a larger 
offset,
it may also be because it's internal GPS is not as good as the Fury 
GPSDO
receiver. It does not necessarily mean the OCXO is causing the error, 
it could
be that the HP GPS is causing the error, and the HP OCXO is still 
dead-on
because it filters out its higher GPS errors.

bye,
Said


In a message dated 11/13/2008 02:45:57 Pacific Standard Time,
ernieperes at aol.com writes:

And running parallel the FURY board with a TEMEX OCXO and displays
+1,6E-10 is the average very often 10E-11 and sometimes for a relative
short time / 4-5 min / 1,4E-12.

Any idea why the Z3801A not displaying better figure?? Something wrong
with the HP unit????

Thanks Ernie.


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From SAIDJACK at aol.com  Thu Nov 13 23:10:33 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Thu, 13 Nov 2008 18:10:33 EST
Subject: [time-nuts] HP Z3801A Question
Message-ID: <d45.345b7d73.364e0de9@aol.com>

Hello Ernie,
 
Glad your HP is still working well.
 
Well it seems you found out how well the Fury is working with an excellent  
OCXO :)
 
The unit running in Mexico achieves similar performance with our standard  
double oven OCXO, see for example:
 
   _http://resco.ucol.mx/Fury/gpsstat.htm_ 
(http://resco.ucol.mx/Fury/gpsstat.htm) 
 
It has not jumped in several days, and the standard deviation is between  
1.7ns to 1.8ns when it doesen't jump during the last 24 hours.
 
Yes, the TI as displayed by GPSCon is much better than the HP  unit. I think 
this is mostly due to the much better GPS receiver in the Fury,  since the 
OCXO of the HP unit is extremely good.
 
Tom and I had discussions about this being caused by the small  sawtooth 
low-pass filtering we do on the TI intervall (Z3801A does the same  thing, 
otherwise you would see the full GPS Sawtooth). The theory was that this  was what 
was causing the Fury to be so much better on GPSCon.
 
To check this, we modified the firmware to completely remove this sawtooth  
filtering, and output the raw data instead, with all the nasty sawtooth  
artifacts on it.

This did not change the result much, I think the max range went from  +/-10ns 
to +/-15ns if I remember correctly.
 
So even if we display true raw capture data, we are still significantly  
better than the Z3801A which displays low-pass sawtooth filtered data.
 
I think this can mostly be attributed to the extremely good  performance of 
the M12M GPS compared to the Oncore GPS in the HP unit.
 
Also, I think you will see that your HP unit will get better over time, as  
the Crystal retraces and ages over the next weeks, and the control voltage  
changes will hopefully get to be smaller and smaller on your unit.
 
bye,
Said
 
 
In a message dated 11/13/2008 14:38:57 Pacific Standard Time,  
ernieperes at aol.com writes:

But both  unit , the HP and the FURY board running under the same 
software  simultaneously / GPS Con / and I was mentioning the same small 
"windows"  TI to GPS, and the FURY displays much better figures then 
HP.....but  probably each units gives out / display / different 
data??????
Also the  graphic display / BLUE / on the FURY board the max ampl 
between +2,2nsec  and -2,0nsec sometimes +0,7nsec ,
-1,7nsec...
the HP unit never goes  under +15nsec and -20nsec...... almost 10 times 
worse.....
Anyhow I am  happy because it seems to me that the HP is still OK after 
3 years of  sleep.....

Rgsa Ernie.


From jpawlan at pawlan.com  Fri Nov 14 00:26:44 2008
From: jpawlan at pawlan.com (Jeffrey Pawlan)
Date: Thu, 13 Nov 2008 16:26:44 -0800 (PST)
Subject: [time-nuts] ADEV secondary standard
In-Reply-To: <491CA4B0.3010302@xtra.co.nz>
References: <491C9C34.4010504@xtra.co.nz>
	<Pine.GSO.4.60.0811131354480.6901@jeffrey150.pawlan.com>
	<491CA4B0.3010302@xtra.co.nz>
Message-ID: <Pine.GSO.4.60.0811131621080.6993@jeffrey150.pawlan.com>

The only difficulty at all is simply the instrument calibration. One must have 
true knowledge about the noise bandwidth of the filter (usually a window) being 
measured.

I do know that HP, NIST, and I have used simple CW carriers instead of noise for 
the calibration. This is a good method for one offset frequency. In fact, it is 
slighty more dependable and accurate being a single tone. Its only disadvantage 
is that one needs to repeat this at every offset you want to calibrate so that 
is why the noise method was invented.


Jeffrey Pawlan



From ch at murgatroid.com  Fri Nov 14 00:57:27 2008
From: ch at murgatroid.com (christopher hoover)
Date: Thu, 13 Nov 2008 16:57:27 -0800
Subject: [time-nuts] Fine delay generator (Tim Shoppa)
In-Reply-To: <mailman.138.1226609478.2542.time-nuts@febo.com>
References: <mailman.138.1226609478.2542.time-nuts@febo.com>
Message-ID: <000f01c945f3$f72e83c0$e58b8b40$@com>

Tim Shoppa wrote:
> mostly they were using custom-wound nonlinear wire-wound pots and 
> motors driving shafts to make the phases :-).

Oh, that is so cool!   And obvious once you think about it.   I love stuff
like that.

Are there pictures?

(It seems like you could do this pretty well with thin film technology
today.)

-ch




From cfharris at erols.com  Fri Nov 14 01:59:32 2008
From: cfharris at erols.com (Chuck Harris)
Date: Thu, 13 Nov 2008 20:59:32 -0500
Subject: [time-nuts] Fine delay generator (Tim Shoppa)
In-Reply-To: <000f01c945f3$f72e83c0$e58b8b40$@com>
References: <mailman.138.1226609478.2542.time-nuts@febo.com>
	<000f01c945f3$f72e83c0$e58b8b40$@com>
Message-ID: <491CDB84.1050804@erols.com>

christopher hoover wrote:
> Tim Shoppa wrote:
>> mostly they were using custom-wound nonlinear wire-wound pots and 
>> motors driving shafts to make the phases :-).
> 
> Oh, that is so cool!   And obvious once you think about it.   I love stuff
> like that.

Actually such things were pretty common in pre-transistor times.
GM used a gizmo, in their buses made in the 1950's, that had 3 such
wire wound pots ganged together, but shifted 120 degrees.  They
connected the pots to a gear on the transmission (in the back of
the bus) and created 3 phase power that was used to drive a
3-phase synchro that ran the speedometer (in the front of the bus).

-Chuck Harris


From shoppa at trailing-edge.com  Fri Nov 14 02:41:17 2008
From: shoppa at trailing-edge.com (Tim Shoppa)
Date: Thu, 13 Nov 2008 21:41:17 -0500
Subject: [time-nuts] Fine delay generator (Tim Shoppa)
In-Reply-To: <000f01c945f3$f72e83c0$e58b8b40$@com>
References: <mailman.138.1226609478.2542.time-nuts@febo.com>
	<000f01c945f3$f72e83c0$e58b8b40$@com>
Message-ID: <20081114024117.6DD60BA4D0D@mini-me.trailing-edge.com>

"christopher hoover" <ch at murgatroid.com> wrote:
> Tim Shoppa wrote:
> > mostly they were using custom-wound nonlinear wire-wound pots and 
> > motors driving shafts to make the phases :-).
>
> Oh, that is so cool!   And obvious once you think about it.   I love stuff
> like that.
>
> Are there pictures?

Yes. IMHO the most interesting volume of the MIT Radiation Lab series
is #19, "Waveforms". Very very hands on for the technology of the 40's.

Millman and Taube (mid-50's?) is pretty cool too.

Tim.


From tractorb at ihug.co.nz  Fri Nov 14 02:39:40 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Fri, 14 Nov 2008 15:39:40 +1300
Subject: [time-nuts] Fine delay generator (Tim Shoppa)
References: <mailman.138.1226609478.2542.time-nuts@febo.com>
	<000f01c945f3$f72e83c0$e58b8b40$@com>
Message-ID: <01ff01c94602$3ed47640$7900a8c0@athlon1200>


----- Original Message ----- 
From: "christopher hoover" <ch at murgatroid.com>
To: <time-nuts at febo.com>
Sent: Friday, November 14, 2008 1:57 PM
Subject: Re: [time-nuts] Fine delay generator (Tim Shoppa)


> Tim Shoppa wrote:
>> mostly they were using custom-wound nonlinear wire-wound pots and
>> motors driving shafts to make the phases :-).
>
> Oh, that is so cool!   And obvious once you think about it.   I love 
> stuff
> like that.
>
> Are there pictures?

Yes- Find a copy of "Waveforms", Chance, Hughes, et al.
It's one of the MIT Rad Lab series.
 Lots of diagrams and pictures.
It was the first one of the series I ever bought, but for other 
reasons!
DaveB, NZ




From tomknox at nist.gov  Fri Nov 14 18:31:06 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Fri, 14 Nov 2008 13:31:06 -0500
Subject: [time-nuts] HP Z3801A Question
In-Reply-To: <d45.345b7d73.364e0de9@aol.com>
References: <d45.345b7d73.364e0de9@aol.com>
Message-ID: <20081114133106.57646ns4rp9hbuga@webmail.nist.gov>

Hi Everyone;
Please excuse me, I am jumping in a little late. This Fury unit is  
interesting, Is the price reasonable? Which MTI oscillator do they  
use? the 5MHz 260-0504? To expand things a bit, how do the Fury,  
Z3801A, Z3805A, Z3811A, Z3816A, 58503A and 58503B compare?  I just  
picked up a Z3811A and plan to characterize it this weekend. If anyone  
is interested I will list results. It has the same 5MHz MTI 260-0624  
that the Z3805A has? Does anyone have specs for this version of the 260?
Best Wishes;
Thomas Knox




Quoting SAIDJACK at aol.com:

> Hello Ernie,
>
> Glad your HP is still working well.
>
> Well it seems you found out how well the Fury is working with an excellent
> OCXO :)
>
> The unit running in Mexico achieves similar performance with our standard
> double oven OCXO, see for example:
>
>    _http://resco.ucol.mx/Fury/gpsstat.htm_
> (http://resco.ucol.mx/Fury/gpsstat.htm)
>
> It has not jumped in several days, and the standard deviation is between
> 1.7ns to 1.8ns when it doesen't jump during the last 24 hours.
>
> Yes, the TI as displayed by GPSCon is much better than the HP  unit. I think
> this is mostly due to the much better GPS receiver in the Fury,  since the
> OCXO of the HP unit is extremely good.
>
> Tom and I had discussions about this being caused by the small  sawtooth
> low-pass filtering we do on the TI intervall (Z3801A does the same  thing,
> otherwise you would see the full GPS Sawtooth). The theory was that  
> this  was what
> was causing the Fury to be so much better on GPSCon.
>
> To check this, we modified the firmware to completely remove this sawtooth
> filtering, and output the raw data instead, with all the nasty sawtooth
> artifacts on it.
>
> This did not change the result much, I think the max range went from  +/-10ns
> to +/-15ns if I remember correctly.
>
> So even if we display true raw capture data, we are still significantly
> better than the Z3801A which displays low-pass sawtooth filtered data.
>
> I think this can mostly be attributed to the extremely good  performance of
> the M12M GPS compared to the Oncore GPS in the HP unit.
>
> Also, I think you will see that your HP unit will get better over time, as
> the Crystal retraces and ages over the next weeks, and the control voltage
> changes will hopefully get to be smaller and smaller on your unit.
>
> bye,
> Said
>
>
> In a message dated 11/13/2008 14:38:57 Pacific Standard Time,
> ernieperes at aol.com writes:
>
> But both  unit , the HP and the FURY board running under the same
> software  simultaneously / GPS Con / and I was mentioning the same small
> "windows"  TI to GPS, and the FURY displays much better figures then
> HP.....but  probably each units gives out / display / different
> data??????
> Also the  graphic display / BLUE / on the FURY board the max ampl
> between +2,2nsec  and -2,0nsec sometimes +0,7nsec ,
> -1,7nsec...
> the HP unit never goes  under +15nsec and -20nsec...... almost 10 times
> worse.....
> Anyhow I am  happy because it seems to me that the HP is still OK after
> 3 years of  sleep.....
>
> Rgsa Ernie.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



From jim77742 at gmail.com  Sun Nov 16 13:38:57 2008
From: jim77742 at gmail.com (Jim Palfreyman)
Date: Mon, 17 Nov 2008 00:38:57 +1100
Subject: [time-nuts] Oh the horror
Message-ID: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>

Only this group will understand and suffer with this news...

Our observatory has recently had three Russian hydrogen masers arrive (along
with some Russians to install them).

It turns out that one of the masers had a rough trip from Russia to
Australia.

It looks like the entire shipping case has been dropped or turned over from
a reasonable height. The 7mm thick internal glass cylinder has been
shattered and inside that the glass bulb has been smashed to bits.

The whole unit is completely destroyed and useless.

It's enough to make a grown man cry.

My girlfriend just doesn't understand...

From ernieperes at aol.com  Sun Nov 16 14:01:13 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Sun, 16 Nov 2008 09:01:13 -0500
Subject: [time-nuts] Oh the horror
In-Reply-To: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
Message-ID: <8CB160AEB642F22-E2C-1720@webmail-me17.sysops.aol.com>

Hi Jim,

No wonder, my girlfriend would do the same...

Rgds Ernie.


-----Original Message-----
From: Jim Palfreyman <jim77742 at gmail.com>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Sun, 16 Nov 2008 2:38 pm
Subject: [time-nuts] Oh the horror



Only this group will understand and suffer with this news...

Our observatory has recently had three Russian hydrogen masers arrive 
(along
with some Russians to install them).

It turns out that one of the masers had a rough trip from Russia to
Australia.

It looks like the entire shipping case has been dropped or turned over 
from
a reasonable height. The 7mm thick internal glass cylinder has been
shattered and inside that the glass bulb has been smashed to bits.

The whole unit is completely destroyed and useless.

It's enough to make a grown man cry.

My girlfriend just doesn't understand...
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From rfnuts at arcor.de  Sun Nov 16 15:19:39 2008
From: rfnuts at arcor.de (Adrian)
Date: Sun, 16 Nov 2008 16:19:39 +0100
Subject: [time-nuts] Oh the horror
In-Reply-To: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
Message-ID: <49203A0B.7090700@arcor.de>

sounds like an interesting parts unit... ;)

Jim Palfreyman schrieb:
> Only this group will understand and suffer with this news...
>
> Our observatory has recently had three Russian hydrogen masers arrive (along
> with some Russians to install them).
>
> It turns out that one of the masers had a rough trip from Russia to
> Australia.
>
> It looks like the entire shipping case has been dropped or turned over from
> a reasonable height. The 7mm thick internal glass cylinder has been
> shattered and inside that the glass bulb has been smashed to bits.
>
> The whole unit is completely destroyed and useless.
>
> It's enough to make a grown man cry.
>
> My girlfriend just doesn't understand...
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>   



From holrum at hotmail.com  Sun Nov 16 16:39:10 2008
From: holrum at hotmail.com (Mark Sims)
Date: Sun, 16 Nov 2008 16:39:10 +0000
Subject: [time-nuts] Oh the horror
In-Reply-To: <mailman.3.1226750401.2767.time-nuts@febo.com>
References: <mailman.3.1226750401.2767.time-nuts@febo.com>
Message-ID: <BLU125-W337242F64B6703A24AF8E8CE100@phx.gbl>


A little duct tape and a dash of superglue and she'll be humming along just fine...
_________________________________________________________________
Get 5 GB of storage with Windows Live Hotmail.
http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_5gb_112008

From magnus at rubidium.dyndns.org  Sun Nov 16 20:29:14 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sun, 16 Nov 2008 21:29:14 +0100
Subject: [time-nuts] Oh the horror
In-Reply-To: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
Message-ID: <4920829A.6090008@rubidium.dyndns.org>

Dear Jim,

Jim Palfreyman wrote:
> Only this group will understand and suffer with this news...
> 
> Our observatory has recently had three Russian hydrogen masers arrive (along
> with some Russians to install them).

Care to detail what model/specs it is? Elaborate some of how they are to 
be used. We love the details as you very well know. :)

> It turns out that one of the masers had a rough trip from Russia to
> Australia.
> 
> It looks like the entire shipping case has been dropped or turned over from
> a reasonable height. The 7mm thick internal glass cylinder has been
> shattered and inside that the glass bulb has been smashed to bits.
> 
> The whole unit is completely destroyed and useless.
> 
> It's enough to make a grown man cry.
> 
> My girlfriend just doesn't understand...

Do cry, do cry... we understand.

Hope insurance etc work out.

Cheers,
Magnus


From n1jez at burlingtontelecom.net  Sun Nov 16 21:42:04 2008
From: n1jez at burlingtontelecom.net (n1jez at burlingtontelecom.net)
Date: Sun, 16 Nov 2008 16:42:04 -0500
Subject: [time-nuts] Pinout for Lucent GPSDO
Message-ID: <005101c94834$2ba34770$6901a8c0@Mike2>

Anyone have the pinout for the Lucent KS24019L104C GPSDO? There's a 50 pin 
(3 row) connector on the rear. Unit has what looks like an Oncore GT ? GPS, 
Datum 10 MHz OCXO and the usual 15 MHz Cell output.

TIA,

73,
Mike, N1JEZ
"A closed mouth gathers no feet" 



From hmurray at megapathdsl.net  Sun Nov 16 21:51:24 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 16 Nov 2008 13:51:24 -0800
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
In-Reply-To: Message from <n1jez@burlingtontelecom.net> of "Sun,
	16 Nov 2008 16:42:04 EST." <005101c94834$2ba34770$6901a8c0@Mike2> 
Message-ID: <20081116215125.B82E0BCD6@ip-64-139-1-69.sjc.megapath.net>

> and the usual 15 MHz Cell output.

My Z3801A has a 10 MHz output.  I thought that was normal.  It seems like a 
nice round convenient number.

So why did cell phone towers switch to 15 MHz?  Or is it just Lucent that 
switched?


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From bg at lysator.liu.se  Sun Nov 16 22:03:15 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Sun, 16 Nov 2008 23:03:15 +0100
Subject: [time-nuts] Oh the horror
In-Reply-To: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
Message-ID: <1226872995.20299.120.camel@bg-desktop>


On Mon, 2008-11-17 at 00:38 +1100, Jim Palfreyman wrote:
> Only this group will understand and suffer with this news...
> 
> Our observatory has recently had three Russian hydrogen masers arrive (along
> with some Russians to install them).
> 
> It turns out that one of the masers had a rough trip from Russia to
> Australia.
> 
> It looks like the entire shipping case has been dropped or turned over from
> a reasonable height. The 7mm thick internal glass cylinder has been
> shattered and inside that the glass bulb has been smashed to bits.
> 
> The whole unit is completely destroyed and useless.
> 
> It's enough to make a grown man cry.

On a much smaller scale... but the "incident" shown in the attached
picture was no fun either... two old BVAs came the standard (brutal)
post service packed like in the picture.

One of the two got its glass bottle broken. :-(

Thanks to lucky circumstances it later got repaired and a good new
home.  :-))

--

    Bj?rn
-------------- next part --------------
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From brooke at pacific.net  Sun Nov 16 22:22:28 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sun, 16 Nov 2008 14:22:28 -0800
Subject: [time-nuts] Oh the horror
In-Reply-To: <1226872995.20299.120.camel@bg-desktop>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
	<1226872995.20299.120.camel@bg-desktop>
Message-ID: <49209D24.8040801@pacific.net>

Hi:

I've had my share of disaster shipments and most of them were the fault of the 
sender's packaging, not the carrier.  See:
http://www.prc68.com/I/Pack.shtml#WgW
Including an FTS4060 band strapped to a pallet! (it did not survive)

Have Fun,

Brooke Clarke
http://www.prc68.com


From cgreen at quartzlock.com  Sun Nov 16 22:43:58 2008
From: cgreen at quartzlock.com (Clive Green)
Date: Sun, 16 Nov 2008 22:43:58 -0000
Subject: [time-nuts] Oh the horror
Message-ID: <001e01c9483c$d09baa30$71d2fe90$@com>

Having sold, delivered, installed, commissioned some 50 Active & Passive
Hydrogen Maser?s around the world, with the attendant paperwork, for these
?controlled? timepieces, end user obligations etc etc, I can fully feel for
the lab awaiting a successful delivery.

The insurance claim will be interesting. The repair will be long winded, but
nothing can be expected otherwise. Having your own backing vacuum pump,
turbo molecular vacuum pump, helium leak detector & the attendant
connections & vacuum valves will help a local rather than a back-to-base
fix.

Then, look forward to e-15 / 100s AVAR & not being able to live without
them. If you have problems, QSY & contact me.  

Look out for a breath of fresh air on the H Maser front.

Clive Green

CEO 

Quartzlock 

+ Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England

(: +44 (0) 1803 862 062 7: +44 (0) 1803 867 962

?:  <mailto:nlaw at quartzlock.com> cgreen at quartzlock.com ?:
<http://www.quartzlock.com> www.quartzlock.com

Skype: clive.green.skype Messenger: cgreen at quartzlock.com

Registered office: Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England
Registered in England

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This is an e-mail from Quartzlock (UK) Limited, its contents (including all
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Opinions, conclusions and other information expressed in this message are
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by an authorised representative independent of this message.

 


From n1jez at burlingtontelecom.net  Sun Nov 16 22:57:21 2008
From: n1jez at burlingtontelecom.net (n1jez at burlingtontelecom.net)
Date: Sun, 16 Nov 2008 17:57:21 -0500
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
References: <20081116215125.B82E0BCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <008501c9483e$e228d9b0$6901a8c0@Mike2>

Not exactly sure why they use 15 MHz, but a good buddy of mine who's a 
Verizon Wireless tech says 15 MHz it is.

Mike
----- Original Message ----- 
From: "Hal Murray" <hmurray at megapathdsl.net>

>> and the usual 15 MHz Cell output.
>
> My Z3801A has a 10 MHz output.  I thought that was normal.  It seems like 
> a
> nice round convenient number.
>
> So why did cell phone towers switch to 15 MHz?  Or is it just Lucent that
> switched?
>
>
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From hmurray at megapathdsl.net  Sun Nov 16 23:01:23 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 16 Nov 2008 15:01:23 -0800
Subject: [time-nuts] Oh the horror
In-Reply-To: Message from "Jim Palfreyman" <jim77742@gmail.com> of "Mon,
	17 Nov 2008 00:38:57 +1100."
	<f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com> 
Message-ID: <20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>


jim77742 at gmail.com said:
> It looks like the entire shipping case has been dropped or turned over
> from a reasonable height. The 7mm thick internal glass cylinder has
> been shattered and inside that the glass bulb has been smashed to
> bits.

> The whole unit is completely destroyed and useless. 

Sigh.  It hurts even from many thousand miles away...

> My girlfriend just doesn't understand...

There must be some way to explain it.  Does she have a garden?  How about a 
cloth collection?

How would she feel if a herd of elephants danced on her garden?  Or a bucket 
of tar got poured over her best box of cloth?

----------

Many years ago, we were writing some software for Pacific Telephone.  I got 
to BS with one of their old timers.  He told a tale that is roughly...

Pacific Telephone used a lot of IBM 7040s.  IBM was getting out of that 
business.  The last one off the refurbishing line was air freighted out to 
California.  That was Friday afternoon.  Monday morning they were going to 
start tearing down the line.

After the plane arrived in California, the CPU got dropped between the 
airplane and the truck.  The frame was bent about 15 degrees.

Somebody made a quick phone call.  The refurbishing line stayed open long 
enough to process that machine again.    It worked fine.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From alan.melia at btinternet.com  Sun Nov 16 23:56:05 2008
From: alan.melia at btinternet.com (Alan Melia)
Date: Sun, 16 Nov 2008 23:56:05 -0000
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
References: <20081116215125.B82E0BCD6@ip-64-139-1-69.sjc.megapath.net>
	<008501c9483e$e228d9b0$6901a8c0@Mike2>
Message-ID: <00e901c94847$86357ce0$0900a8c0@AM>

Some of the ex Telcom units I have seen have 10MHz Rb or OCXO (Datum or
Lucent) and a 10 to 15MHz converter in a milled cover externally....some
frequencies are more easily generated from 15MHz.

Alan G3NYK

----- Original Message -----
From: <n1jez at burlingtontelecom.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Sunday, November 16, 2008 10:57 PM
Subject: Re: [time-nuts] Why/when did cell towers switch to 15 MHz?


> Not exactly sure why they use 15 MHz, but a good buddy of mine who's a
> Verizon Wireless tech says 15 MHz it is.
>
> Mike
there.



From ka2cdk at cox.net  Mon Nov 17 00:43:18 2008
From: ka2cdk at cox.net (Thomas A. Frank)
Date: Sun, 16 Nov 2008 19:43:18 -0500
Subject: [time-nuts] Oh the horror
In-Reply-To: <20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>
References: <20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <597FF329-9C99-4959-8405-DCE3E9DC6A65@cox.net>

Since we're telling horror stories...

Circa 1990, I had a really nice strip chart recorder in a half height  
roll-around rack.  Shipped it to the field for some work, everything  
was fine.  Shipped it back; it made it all the way to our facilities  
heavy freight guys in perfect condition.  It was the last item all  
the way at the front of a 40 foot tractor-trailer...

Guy A rolls it quite vigorously toward the back of the truck where  
Guy B is waiting...and B watches and does nothing as it rolls right  
past him, off the end, and falls 4 feet to the pavement.  He then  
hops down, rights the now bent 45 degree rack, and rolls it into the  
building like nothing happened.  While several of were watching the  
whole incident with slack jaws!

My management talks to their management...and I'm still without a  
strip chart recorder to this day.

Tom Frank, KA2CDK




From max at maxsmusicplace.com  Mon Nov 17 03:15:44 2008
From: max at maxsmusicplace.com (Max Robinson)
Date: Sun, 16 Nov 2008 21:15:44 -0600
Subject: [time-nuts] Oh the horror
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com><1226872995.20299.120.camel@bg-desktop>
	<49209D24.8040801@pacific.net>
Message-ID: <B6B7ACAE9014463B9A9F3A6215A0CAE2@BACKROOM>

Many times I have received shipments from well known electronics companies 
in which there was cushioning around and on top of the item but it was 
sitting on the bottom of the box.  No sign that the packing had shifted, it 
had been packed that way.

Regards.

Max.  K 4 O D S.

Email: max at maxsmusicplace.com

Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Music site: http://www.maxsmusicplace.com

To subscribe to the fun with tubes group send an email to,
funwithtubes-subscribe at yahoogroups.com

----- Original Message ----- 
From: "Brooke Clarke" <brooke at pacific.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Sunday, November 16, 2008 4:22 PM
Subject: Re: [time-nuts] Oh the horror


> Hi:
>
> I've had my share of disaster shipments and most of them were the fault of 
> the
> sender's packaging, not the carrier.  See:
> http://www.prc68.com/I/Pack.shtml#WgW
> Including an FTS4060 band strapped to a pallet! (it did not survive)
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
> 



From hmurray at megapathdsl.net  Mon Nov 17 03:21:42 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 16 Nov 2008 19:21:42 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
Message-ID: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>

Is anybody running ntpd with their Z3801A?

If so, please check your log files and tell me if you see a bogus leap second 
at the end of the past several months.  I've seen them for Aug, Sep, and Oct. 
 I think they are coming from my Z3801A, but it might be something else.

The GPS satellites are now announcing a leap second that will happen at the 
end of the year.   The refclock driver passes that to ntpd and ntpd passes it 
to the kernel and magic happens.

I think the refclock-ntpd interface assumes the leap second will happen at 
the end of the current month.  NIST only announces leap seconds a month ahead 
on WWVB and ACTS.

The Oncore refclock driver has a filter to wait until the current month to 
pass the info to ntpd.  I'm working on something similar for the HP driver.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From garnere at gmail.com  Mon Nov 17 04:02:26 2008
From: garnere at gmail.com (Eric Garner)
Date: Sun, 16 Nov 2008 20:02:26 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>

Ascending from Lurk Mode, I have a (possibly stupid) question: according to

http://tycho.usno.navy.mil/leapsec.html

and Tony Jones's book "The Story of Atomic Time" GPS time does not
account for leap seconds, So why does it alert you to them?

-eric

On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> Is anybody running ntpd with their Z3801A?
>
> If so, please check your log files and tell me if you see a bogus leap second
> at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
>  I think they are coming from my Z3801A, but it might be something else.
>
> The GPS satellites are now announcing a leap second that will happen at the
> end of the year.   The refclock driver passes that to ntpd and ntpd passes it
> to the kernel and magic happens.
>
> I think the refclock-ntpd interface assumes the leap second will happen at
> the end of the current month.  NIST only announces leap seconds a month ahead
> on WWVB and ACTS.
>
> The Oncore refclock driver has a filter to wait until the current month to
> pass the info to ntpd.  I'm working on something similar for the HP driver.
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
--Eric
_________________________________________
Eric Garner


From brooke at pacific.net  Mon Nov 17 04:08:57 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sun, 16 Nov 2008 20:08:57 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
Message-ID: <4920EE59.9050803@pacific.net>

Hi Eric:

So that you can figure out UTC.  But there's no DST bit on any of the 
satellites so for that you need a local time broadcast.


Have Fun,

Brooke Clarke
http://www.prc68.com

Eric Garner wrote:
> Ascending from Lurk Mode, I have a (possibly stupid) question: according to
> 
> http://tycho.usno.navy.mil/leapsec.html
> 
> and Tony Jones's book "The Story of Atomic Time" GPS time does not
> account for leap seconds, So why does it alert you to them?
> 
> -eric
> 
> On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>> Is anybody running ntpd with their Z3801A?
>>
>> If so, please check your log files and tell me if you see a bogus leap second
>> at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
>>  I think they are coming from my Z3801A, but it might be something else.
>>
>> The GPS satellites are now announcing a leap second that will happen at the
>> end of the year.   The refclock driver passes that to ntpd and ntpd passes it
>> to the kernel and magic happens.
>>
>> I think the refclock-ntpd interface assumes the leap second will happen at
>> the end of the current month.  NIST only announces leap seconds a month ahead
>> on WWVB and ACTS.
>>
>> The Oncore refclock driver has a filter to wait until the current month to
>> pass the info to ntpd.  I'm working on something similar for the HP driver.
>>
>> --
>> These are my opinions, not necessarily my employer's.  I hate spam.
>>
>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> 
> 
> 


From smace at intt.net  Mon Nov 17 04:09:00 2008
From: smace at intt.net (Scott Mace)
Date: Sun, 16 Nov 2008 22:09:00 -0600
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <4920EE5C.80000@intt.net>

Yes, I noticed this as well and modified the refclock driver to filter
it as it does in the oncore refclock.

	Scott

Hal Murray wrote:
> Is anybody running ntpd with their Z3801A?
> 
> If so, please check your log files and tell me if you see a bogus leap second 
> at the end of the past several months.  I've seen them for Aug, Sep, and Oct. 
>  I think they are coming from my Z3801A, but it might be something else.
> 
> The GPS satellites are now announcing a leap second that will happen at the 
> end of the year.   The refclock driver passes that to ntpd and ntpd passes it 
> to the kernel and magic happens.
> 
> I think the refclock-ntpd interface assumes the leap second will happen at 
> the end of the current month.  NIST only announces leap seconds a month ahead 
> on WWVB and ACTS.
> 
> The Oncore refclock driver has a filter to wait until the current month to 
> pass the info to ntpd.  I'm working on something similar for the HP driver.
> 


From smace at intt.net  Mon Nov 17 04:11:09 2008
From: smace at intt.net (Scott Mace)
Date: Sun, 16 Nov 2008 22:11:09 -0600
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <4920EE5C.80000@intt.net>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
	<4920EE5C.80000@intt.net>
Message-ID: <4920EEDD.3000205@intt.net>

Here's the diff based on 4.2.4p4

--- ntp-4.2.4p4.orig/ntpd/refclock_hpgps.c      2006-06-06 15:16:51.000000000 -0500
+++ ntp-4.2.4p4/ntpd/refclock_hpgps.c   2008-08-25 09:56:29.000000000 -0500
@@ -535,7 +535,8 @@
                 switch (leapchar) {

                     case '+':
-                       pp->leap = LEAP_ADDSECOND;
+                       if ((month == 6) || (month == 12))
+                           pp->leap = LEAP_ADDSECOND;
                         break;

                     case '0':
@@ -543,7 +544,8 @@
                         break;

                     case '-':
-                       pp->leap = LEAP_DELSECOND;
+                       if ((month == 6) || (month == 12))
+                           pp->leap = LEAP_DELSECOND;
                         break;

                     default:




Scott Mace wrote:
> Yes, I noticed this as well and modified the refclock driver to filter
> it as it does in the oncore refclock.
> 
> 	Scott
> 
> Hal Murray wrote:
>> Is anybody running ntpd with their Z3801A?
>>
>> If so, please check your log files and tell me if you see a bogus leap second 
>> at the end of the past several months.  I've seen them for Aug, Sep, and Oct. 
>>  I think they are coming from my Z3801A, but it might be something else.
>>
>> The GPS satellites are now announcing a leap second that will happen at the 
>> end of the year.   The refclock driver passes that to ntpd and ntpd passes it 
>> to the kernel and magic happens.
>>
>> I think the refclock-ntpd interface assumes the leap second will happen at 
>> the end of the current month.  NIST only announces leap seconds a month ahead 
>> on WWVB and ACTS.
>>
>> The Oncore refclock driver has a filter to wait until the current month to 
>> pass the info to ntpd.  I'm working on something similar for the HP driver.
>>
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From garnere at gmail.com  Mon Nov 17 04:28:25 2008
From: garnere at gmail.com (Eric Garner)
Date: Sun, 16 Nov 2008 20:28:25 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <4920EE59.9050803@pacific.net>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
	<4920EE59.9050803@pacific.net>
Message-ID: <fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>

Sorry for not forming my question better. I guess what I wanted to
know is that given that the first leap second was in 1972 and that the
first GPS satellite was launched in 1993. why was it decided to not
incorporate leap seconds into how GPS "tells" time, but still alerts
you to the fact that they are coming up? Or why was the decision made
to have UTC-GPS different than UTC. My understanding is that they
"tick" simultaneously but "tell" different times.(sorry for the
overuse of quotes)  Is there some navigational reason? Is it actually
intentional?

-eric

On Sun, Nov 16, 2008 at 8:08 PM, Brooke Clarke <brooke at pacific.net> wrote:
> Hi Eric:
>
> So that you can figure out UTC.  But there's no DST bit on any of the
> satellites so for that you need a local time broadcast.
>
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> Eric Garner wrote:
>> Ascending from Lurk Mode, I have a (possibly stupid) question: according to
>>
>> http://tycho.usno.navy.mil/leapsec.html
>>
>> and Tony Jones's book "The Story of Atomic Time" GPS time does not
>> account for leap seconds, So why does it alert you to them?
>>
>> -eric
>>
>> On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>> Is anybody running ntpd with their Z3801A?
>>>
>>> If so, please check your log files and tell me if you see a bogus leap second
>>> at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
>>>  I think they are coming from my Z3801A, but it might be something else.
>>>
>>> The GPS satellites are now announcing a leap second that will happen at the
>>> end of the year.   The refclock driver passes that to ntpd and ntpd passes it
>>> to the kernel and magic happens.
>>>
>>> I think the refclock-ntpd interface assumes the leap second will happen at
>>> the end of the current month.  NIST only announces leap seconds a month ahead
>>> on WWVB and ACTS.
>>>
>>> The Oncore refclock driver has a filter to wait until the current month to
>>> pass the info to ntpd.  I'm working on something similar for the HP driver.
>>>
>>> --
>>> These are my opinions, not necessarily my employer's.  I hate spam.
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>
>>
>>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
--Eric
_________________________________________
Eric Garner


From tvb at LeapSecond.com  Mon Nov 17 04:34:11 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Sun, 16 Nov 2008 20:34:11 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
Message-ID: <EEE034D67D2D41959F2BE22A6CCD7D3F@pc52>

> Ascending from Lurk Mode, I have a (possibly stupid) question: according to
> http://tycho.usno.navy.mil/leapsec.html
> and Tony Jones's book "The Story of Atomic Time" GPS time does not
> account for leap seconds, So why does it alert you to them?

Eric,

"Does not account for" maybe isn't quite what happens, but
right, GPS time rolls along continuously without regard to
variations in astronomical time.

A leap second adjustment count is included in the GPS data
stream so that receivers can output true UTC time stamps, if
that conversion is required.

Some level of advanced warning of a leap second is necessary
so that when the moment arrives the receiver can either delete
the UTC second called 23:59:59 (negative leap second) or insert
an extra UTC second called 23:59:60 (positive leap second).

Theoretically, a GPS receiver might only need one second of
advanced warning to do the right thing in the last UTC second
of the last day of the month, but for a variety of good reasons,
a couple of days or even a couple of months of advanced
notice is better for everyone involved.

/tvb



From brooke at pacific.net  Mon Nov 17 04:34:57 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sun, 16 Nov 2008 20:34:57 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>	<4920EE59.9050803@pacific.net>
	<fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>
Message-ID: <4920F471.60709@pacific.net>

Hi Eric:

The GPS time scale can not have any jumps or there would be corresponding 
position jumps.

Have Fun,

Brooke Clarke
http://www.prc68.com

Eric Garner wrote:
> Sorry for not forming my question better. I guess what I wanted to
> know is that given that the first leap second was in 1972 and that the
> first GPS satellite was launched in 1993. why was it decided to not
> incorporate leap seconds into how GPS "tells" time, but still alerts
> you to the fact that they are coming up? Or why was the decision made
> to have UTC-GPS different than UTC. My understanding is that they
> "tick" simultaneously but "tell" different times.(sorry for the
> overuse of quotes)  Is there some navigational reason? Is it actually
> intentional?
> 
> -eric
> 
> On Sun, Nov 16, 2008 at 8:08 PM, Brooke Clarke <brooke at pacific.net> wrote:
>> Hi Eric:
>>
>> So that you can figure out UTC.  But there's no DST bit on any of the
>> satellites so for that you need a local time broadcast.
>>
>>
>> Have Fun,
>>
>> Brooke Clarke
>> http://www.prc68.com
>>
>> Eric Garner wrote:
>>> Ascending from Lurk Mode, I have a (possibly stupid) question: according to
>>>
>>> http://tycho.usno.navy.mil/leapsec.html
>>>
>>> and Tony Jones's book "The Story of Atomic Time" GPS time does not
>>> account for leap seconds, So why does it alert you to them?
>>>
>>> -eric
>>>
>>> On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>>> Is anybody running ntpd with their Z3801A?
>>>>
>>>> If so, please check your log files and tell me if you see a bogus leap second
>>>> at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
>>>>  I think they are coming from my Z3801A, but it might be something else.
>>>>
>>>> The GPS satellites are now announcing a leap second that will happen at the
>>>> end of the year.   The refclock driver passes that to ntpd and ntpd passes it
>>>> to the kernel and magic happens.
>>>>
>>>> I think the refclock-ntpd interface assumes the leap second will happen at
>>>> the end of the current month.  NIST only announces leap seconds a month ahead
>>>> on WWVB and ACTS.
>>>>
>>>> The Oncore refclock driver has a filter to wait until the current month to
>>>> pass the info to ntpd.  I'm working on something similar for the HP driver.
>>>>
>>>> --
>>>> These are my opinions, not necessarily my employer's.  I hate spam.
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com
>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>>>
>>>
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> 
> 
> 


From jltran at worldnet.att.net  Mon Nov 17 04:43:34 2008
From: jltran at worldnet.att.net (J. L. Trantham)
Date: Sun, 16 Nov 2008 22:43:34 -0600
Subject: [time-nuts] 5061A Manual
Message-ID: <9F1160B0CCD4490F9991CE80EA2DAB8B@S0028384766>

Does anyone know of a link to a 5061A Service Manual?  I found the
'Temporary Operating Manual' at the Agilent website.

Thanks,

Joe



From hmurray at megapathdsl.net  Mon Nov 17 04:47:18 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 16 Nov 2008 20:47:18 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: Message from "Eric Garner" <garnere@gmail.com> of "Sun,
	16 Nov 2008 20:02:26 PST."
	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com> 
Message-ID: <20081117044719.4E047BCD6@ip-64-139-1-69.sjc.megapath.net>


> and Tony Jones's book "The Story of Atomic Time" GPS time does not
> account for leap seconds, So why does it alert you to them? 

You end up needing both with and without leap seconds.

GPS time is without leap seconds.  It also distributes the number of leap 
seconds that have been inserted since GPS started so you can translate GPS 
time into UTC.  So then you need a warning if one is coming up soon.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From imp at bsdimp.com  Mon Nov 17 04:56:14 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sun, 16 Nov 2008 21:56:14 -0700 (MST)
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net>
	<fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
Message-ID: <20081116.215614.179959991.imp@bsdimp.com>

In message: <fbddc0730811162002l2e83889am8ec50910d4c3df35 at mail.gmail.com>
            "Eric Garner" <garnere at gmail.com> writes:
: Ascending from Lurk Mode, I have a (possibly stupid) question: according to
: 
: http://tycho.usno.navy.mil/leapsec.html
: 
: and Tony Jones's book "The Story of Atomic Time" GPS time does not
: account for leap seconds, So why does it alert you to them?

GPS's almanac contains the GPS to UTC offset (current, and future).
It is repeated every 20 minutes, which means it can take 20 minutes
for a cold startup to learn the current number of leapseconds...

Warner

: -eric
: 
: On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
: > Is anybody running ntpd with their Z3801A?
: >
: > If so, please check your log files and tell me if you see a bogus leap second
: > at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
: >  I think they are coming from my Z3801A, but it might be something else.
: >
: > The GPS satellites are now announcing a leap second that will happen at the
: > end of the year.   The refclock driver passes that to ntpd and ntpd passes it
: > to the kernel and magic happens.
: >
: > I think the refclock-ntpd interface assumes the leap second will happen at
: > the end of the current month.  NIST only announces leap seconds a month ahead
: > on WWVB and ACTS.
: >
: > The Oncore refclock driver has a filter to wait until the current month to
: > pass the info to ntpd.  I'm working on something similar for the HP driver.
: >
: > --
: > These are my opinions, not necessarily my employer's.  I hate spam.
: >
: >
: >
: >
: > _______________________________________________
: > time-nuts mailing list -- time-nuts at febo.com
: > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
: > and follow the instructions there.
: >
: 
: 
: 
: -- 
: --Eric
: _________________________________________
: Eric Garner
: 
: _______________________________________________
: time-nuts mailing list -- time-nuts at febo.com
: To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
: and follow the instructions there.
: 
: 


From imp at bsdimp.com  Mon Nov 17 05:01:41 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sun, 16 Nov 2008 22:01:41 -0700 (MST)
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>
References: <fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com>
	<4920EE59.9050803@pacific.net>
	<fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>
Message-ID: <20081116.220141.-1303463008.imp@bsdimp.com>

In message: <fbddc0730811162028o44c0f8fcl185ac139794f5b53 at mail.gmail.com>
            "Eric Garner" <garnere at gmail.com> writes:
: Sorry for not forming my question better. I guess what I wanted to
: know is that given that the first leap second was in 1972 and that the
: first GPS satellite was launched in 1993. why was it decided to not
: incorporate leap seconds into how GPS "tells" time, but still alerts
: you to the fact that they are coming up? Or why was the decision made
: to have UTC-GPS different than UTC. My understanding is that they
: "tick" simultaneously but "tell" different times.(sorry for the
: overuse of quotes)  Is there some navigational reason? Is it actually
: intentional?

Leap seconds suck.  There's no reason to have them unless you need
time to sync up with the way that the earth is pointing.  GPS doesn't
need to synchronize to the earth's directions to solve for location,
so it saves a ton of hassles by just counting seconds since an
arbitrary epoch.  Since UTC is important, GPS's almanac gives the
conversion from GPS to UTC.

Warner


: -eric
: 
: On Sun, Nov 16, 2008 at 8:08 PM, Brooke Clarke <brooke at pacific.net> wrote:
: > Hi Eric:
: >
: > So that you can figure out UTC.  But there's no DST bit on any of the
: > satellites so for that you need a local time broadcast.
: >
: >
: > Have Fun,
: >
: > Brooke Clarke
: > http://www.prc68.com
: >
: > Eric Garner wrote:
: >> Ascending from Lurk Mode, I have a (possibly stupid) question: according to
: >>
: >> http://tycho.usno.navy.mil/leapsec.html
: >>
: >> and Tony Jones's book "The Story of Atomic Time" GPS time does not
: >> account for leap seconds, So why does it alert you to them?
: >>
: >> -eric
: >>
: >> On Sun, Nov 16, 2008 at 7:21 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
: >>> Is anybody running ntpd with their Z3801A?
: >>>
: >>> If so, please check your log files and tell me if you see a bogus leap second
: >>> at the end of the past several months.  I've seen them for Aug, Sep, and Oct.
: >>>  I think they are coming from my Z3801A, but it might be something else.
: >>>
: >>> The GPS satellites are now announcing a leap second that will happen at the
: >>> end of the year.   The refclock driver passes that to ntpd and ntpd passes it
: >>> to the kernel and magic happens.
: >>>
: >>> I think the refclock-ntpd interface assumes the leap second will happen at
: >>> the end of the current month.  NIST only announces leap seconds a month ahead
: >>> on WWVB and ACTS.
: >>>
: >>> The Oncore refclock driver has a filter to wait until the current month to
: >>> pass the info to ntpd.  I'm working on something similar for the HP driver.
: >>>
: >>> --
: >>> These are my opinions, not necessarily my employer's.  I hate spam.
: >>>
: >>>
: >>>
: >>>
: >>> _______________________________________________
: >>> time-nuts mailing list -- time-nuts at febo.com
: >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
: >>> and follow the instructions there.
: >>>
: >>
: >>
: >>
: >
: > _______________________________________________
: > time-nuts mailing list -- time-nuts at febo.com
: > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
: > and follow the instructions there.
: >
: 
: 
: 
: -- 
: --Eric
: _________________________________________
: Eric Garner
: 
: _______________________________________________
: time-nuts mailing list -- time-nuts at febo.com
: To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
: and follow the instructions there.
: 
: 


From sar10538 at gmail.com  Mon Nov 17 05:57:56 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Mon, 17 Nov 2008 18:57:56 +1300
Subject: [time-nuts] Oh the horror
In-Reply-To: <BLU125-W337242F64B6703A24AF8E8CE100@phx.gbl>
References: <mailman.3.1226750401.2767.time-nuts@febo.com>
	<BLU125-W337242F64B6703A24AF8E8CE100@phx.gbl>
Message-ID: <1231b6a80811162157o38f44c63sbf2780af1417a751@mail.gmail.com>

2008/11/17 Mark Sims <holrum at hotmail.com>:
>
> A little duct tape and a dash of superglue and she'll be humming along just fine...

Kia Ora!

Don't forget some number 8 wire to hold it all together mate.

73 for ZL land,
Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From tvb at LeapSecond.com  Mon Nov 17 06:06:58 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Sun, 16 Nov 2008 22:06:58 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
References: <20081117032143.7F67BBCD6@ip-64-139-1-69.sjc.megapath.net><fbddc0730811162002l2e83889am8ec50910d4c3df35@mail.gmail.com><4920EE59.9050803@pacific.net>
	<fbddc0730811162028o44c0f8fcl185ac139794f5b53@mail.gmail.com>
Message-ID: <C321315DBB4D47A683DB67B0591CDA3B@pc52>

> Sorry for not forming my question better. I guess what I wanted to
> know is that given that the first leap second was in 1972 and that the
> first GPS satellite was launched in 1993. why was it decided to not
> incorporate leap seconds into how GPS "tells" time, but still alerts
> you to the fact that they are coming up? Or why was the decision made
> to have UTC-GPS different than UTC. My understanding is that they
> "tick" simultaneously but "tell" different times.(sorry for the
> overuse of quotes)  Is there some navigational reason? Is it actually
> intentional?
> 
> -eric

Oh yes, very intentional. Having to handle leap seconds in an
operational system is a real pain.

Systems that need an autonomous or continuous time scale
typically do not use UTC internally but translate to/from UTC
(e.g., in software). This holds for everything from a wristwatch
to a laptop to a GPS satellite.

/tvb



From stenn at ntp.org  Mon Nov 17 07:11:18 2008
From: stenn at ntp.org (Harlan Stenn)
Date: Mon, 17 Nov 2008 07:11:18 +0000
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: Message from Scott Mace <smace@intt.net> 
	of "Sun, 16 Nov 2008 22:09:00 CST." <4920EE5C.80000@intt.net> 
Message-ID: <20081117071124.1EDF839F35@mail1.ntp.org>

Scott wrote:
> Yes, I noticed this as well and modified the refclock driver to filter
> it as it does in the oncore refclock.
> 
> 	Scott

If you submitted this patch to the NTP Project I didn't see it.

If you didn't submit it, I invite you to do so.

H


From stenn at ntp.org  Mon Nov 17 07:12:11 2008
From: stenn at ntp.org (Harlan Stenn)
Date: Mon, 17 Nov 2008 07:12:11 +0000
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: Message from Scott Mace <smace@intt.net> 
	of "Sun, 16 Nov 2008 22:11:09 CST." <4920EEDD.3000205@intt.net> 
Message-ID: <20081117071217.6D59A39F35@mail1.ntp.org>

OK, so thanks for posting this, and I sitll invite you to submit a patch
via http://bug.ntp.org .

H


From hmurray at megapathdsl.net  Mon Nov 17 08:02:00 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Mon, 17 Nov 2008 00:02:00 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: Message from Harlan Stenn <stenn@ntp.org> of "Mon,
	17 Nov 2008 07:11:18 GMT." <20081117071124.1EDF839F35@mail1.ntp.org> 
Message-ID: <20081117080201.552F5BCD6@ip-64-139-1-69.sjc.megapath.net>

>  If you didn't submit it, I invite you to do so.

I'll have one ready soon.  It's http://bugs.ntp.org/1090



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From wje at quackers.net  Mon Nov 17 12:10:52 2008
From: wje at quackers.net (wje)
Date: Mon, 17 Nov 2008 07:10:52 -0500
Subject: [time-nuts] 5061A Manual
In-Reply-To: <9F1160B0CCD4490F9991CE80EA2DAB8B@S0028384766>
References: <9F1160B0CCD4490F9991CE80EA2DAB8B@S0028384766>
Message-ID: <49215F4C.7000303@quackers.net>

Artekmedia has a very nicely scanned manual for about $10.
There's also a copy floating around on one of the member's sites, but I 
don't remember which one offhand. A Google search and some persistence 
will locate it.

Along these lines, none of the manuals I've found cover the late-model 
DC oven controller, which one of my clocks has.
Anyone have any leads on a schematic?

Bill Ezell
----------
They said 'Windows or better'
so I used Linux.



J. L. Trantham wrote:
> Does anyone know of a link to a 5061A Service Manual?  I found the
> 'Temporary Operating Manual' at the Agilent website.
>
> Thanks,
>
> Joe
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>   


From jltran at worldnet.att.net  Mon Nov 17 15:35:27 2008
From: jltran at worldnet.att.net (J. L. Trantham)
Date: Mon, 17 Nov 2008 09:35:27 -0600
Subject: [time-nuts] 5061A Manual
In-Reply-To: <49215F4C.7000303@quackers.net>
Message-ID: <F4D4074F173E4111ADCB2EF1FE17F5F4@S0028384766>

Found it!

I looked on the Artek Media website but did not see it listed.  However, I
did find it at http://www.leapsecond.com/museum/hp5061a/5061a.pdf.  What a
resource that is!  Thanks Tom.  

I just didn't know how to search the archives of the mailing list.  When I
figured that out, I saw the link.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of wje
Sent: Monday, November 17, 2008 6:11 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5061A Manual

Artekmedia has a very nicely scanned manual for about $10.
There's also a copy floating around on one of the member's sites, but I 
don't remember which one offhand. A Google search and some persistence 
will locate it.

Along these lines, none of the manuals I've found cover the late-model 
DC oven controller, which one of my clocks has.
Anyone have any leads on a schematic?

Bill Ezell
----------
They said 'Windows or better'
so I used Linux.



J. L. Trantham wrote:
> Does anyone know of a link to a 5061A Service Manual?  I found the
> 'Temporary Operating Manual' at the Agilent website.
>
> Thanks,
>
> Joe
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>   

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From garnere at gmail.com  Mon Nov 17 17:17:44 2008
From: garnere at gmail.com (Eric Garner)
Date: Mon, 17 Nov 2008 09:17:44 -0800
Subject: [time-nuts] Leap second glitches on NTP using Z3801A
In-Reply-To: <20081117080201.552F5BCD6@ip-64-139-1-69.sjc.megapath.net>
References: <stenn@ntp.org> <20081117071124.1EDF839F35@mail1.ntp.org>
	<20081117080201.552F5BCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <fbddc0730811170917r6aff8376h4e4dc928d7b15876@mail.gmail.com>

Thanks for the explanation everyone. Hopefully one of these days I'll
have all my pennies saved at the same time that TAPR does another
thunderbolt buy, and I can start playing around with this stuff.

-Eric

On Mon, Nov 17, 2008 at 12:02 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>  If you didn't submit it, I invite you to do so.
>
> I'll have one ready soon.  It's http://bugs.ntp.org/1090
>
>
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
--Eric
_________________________________________
Eric Garner


From robert8rpi at yahoo.co.uk  Mon Nov 17 17:56:33 2008
From: robert8rpi at yahoo.co.uk (Robert Atkinson)
Date: Mon, 17 Nov 2008 17:56:33 +0000 (GMT)
Subject: [time-nuts] Oh the horror
In-Reply-To: <1231b6a80811162157o38f44c63sbf2780af1417a751@mail.gmail.com>
Message-ID: <373413.70746.qm@web27104.mail.ukl.yahoo.com>


Are we talking about the maser or the girlfriend?
?
G8RPI.
--- On Mon, 17/11/08, Steve Rooke <sar10538 at gmail.com> wrote:

From: Steve Rooke <sar10538 at gmail.com>
Subject: Re: [time-nuts] Oh the horror
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Monday, 17 November, 2008, 5:57 AM

2008/11/17 Mark Sims <holrum at hotmail.com>:
>
> A little duct tape and a dash of superglue and she'll be humming along
just fine...

Kia Ora!

Don't forget some number 8 wire to hold it all together mate.

73 for ZL land,
Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



      

From magnus at rubidium.dyndns.org  Mon Nov 17 18:42:19 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Mon, 17 Nov 2008 19:42:19 +0100
Subject: [time-nuts] Oh the horror
In-Reply-To: <373413.70746.qm@web27104.mail.ukl.yahoo.com>
References: <373413.70746.qm@web27104.mail.ukl.yahoo.com>
Message-ID: <4921BB0B.90906@rubidium.dyndns.org>

Robert Atkinson wrote:
> Are we talking about the maser or the girlfriend?

The maser... the maser... when did you hit your head????
What else shines pink at all times when operated?

Cheers,
Magnus - lacks H-maser...

> G8RPI.
> --- On Mon, 17/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
> 
> From: Steve Rooke <sar10538 at gmail.com>
> Subject: Re: [time-nuts] Oh the horror
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> Date: Monday, 17 November, 2008, 5:57 AM
> 
> 2008/11/17 Mark Sims <holrum at hotmail.com>:
>> A little duct tape and a dash of superglue and she'll be humming along
> just fine...
> 
> Kia Ora!
> 
> Don't forget some number 8 wire to hold it all together mate.
> 
> 73 for ZL land,
> Steve


From SAIDJACK at aol.com  Mon Nov 17 19:03:10 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Mon, 17 Nov 2008 14:03:10 EST
Subject: [time-nuts] Oh the horror
Message-ID: <ccc.43f3f0f8.365319ee@aol.com>

Is it time to get a Russian girlfriend along with their Masers :) ?
 
 
In a message dated 11/17/2008 10:43:13 Pacific Standard Time,  
magnus at rubidium.dyndns.org writes:

Robert  Atkinson wrote:
> Are we talking about the maser or the  girlfriend?

The maser... the maser... when did you hit your  head????
What else shines pink at all times when  operated?

Cheers,
Magnus - lacks 


From wb6bnq at cox.net  Mon Nov 17 19:21:09 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Mon, 17 Nov 2008 11:21:09 -0800
Subject: [time-nuts] Oh the horror
References: <373413.70746.qm@web27104.mail.ukl.yahoo.com>
	<4921BB0B.90906@rubidium.dyndns.org>
Message-ID: <4921C424.E74A648D@cox.net>

Magnus Danielson wrote:

>
> What else shines pink at all times when operated?
>
> Cheers,
> Magnus - lacks H-maser...
>

I think I will leave that one alone !

Bill....WB6BNQ




From tomknox at nist.gov  Mon Nov 17 20:08:19 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Mon, 17 Nov 2008 15:08:19 -0500
Subject: [time-nuts] 5061A Manual
In-Reply-To: <9F1160B0CCD4490F9991CE80EA2DAB8B@S0028384766>
References: <9F1160B0CCD4490F9991CE80EA2DAB8B@S0028384766>
Message-ID: <20081117150819.133637rwug8l3x2r@webmail.nist.gov>

Hi Joe;
I think I have a hard copy I can send you to use or copy if you can't  
find a PDF.
Best Wishes;
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting "J. L. Trantham" <jltran at worldnet.att.net>:

> Does anyone know of a link to a 5061A Service Manual?  I found the
> 'Temporary Operating Manual' at the Agilent website.
>
> Thanks,
>
> Joe
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>




From tomknox at nist.gov  Mon Nov 17 20:29:21 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Mon, 17 Nov 2008 15:29:21 -0500
Subject: [time-nuts] Pinout for Lucent GPSDO
In-Reply-To: <005101c94834$2ba34770$6901a8c0@Mike2>
References: <005101c94834$2ba34770$6901a8c0@Mike2>
Message-ID: <20081117152921.15082hzulaeb9u75@webmail.nist.gov>

Hi Mike;
I think I may. Is this the white units with a heat sink front, Datum  
part 103300-001/002/003?
If so I could fax it to you.
Best Wishes;
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting n1jez at burlingtontelecom.net:

> Anyone have the pinout for the Lucent KS24019L104C GPSDO? There's a 50 pin
> (3 row) connector on the rear. Unit has what looks like an Oncore GT ? GPS,
> Datum 10 MHz OCXO and the usual 15 MHz Cell output.
>
> TIA,
>
> 73,
> Mike, N1JEZ
> "A closed mouth gathers no feet"
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>




From jltran at worldnet.att.net  Tue Nov 18 03:32:59 2008
From: jltran at worldnet.att.net (J. L. Trantham)
Date: Mon, 17 Nov 2008 21:32:59 -0600
Subject: [time-nuts] 5061A Manual
In-Reply-To: <20081117150819.133637rwug8l3x2r@webmail.nist.gov>
Message-ID: <C982D69B430E437290A5EF67C0117B95@S0028384766>

Tom,

Thanks for the offer but I found a .PDF copy at leapsecond.com.  It just
took a while to chase down.

Once I get several other projects put to bed, I will be opening up that can
of worms and will very likely be back seeking all kinds of help.  It was
advertised a having all sorts of problems and may turn out to be just a
great source of spare parts.  However the price was too good to pass up.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of tomknox at nist.gov
Sent: Monday, November 17, 2008 2:08 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5061A Manual

Hi Joe;
I think I have a hard copy I can send you to use or copy if you can't  
find a PDF.
Best Wishes;
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting "J. L. Trantham" <jltran at worldnet.att.net>:

> Does anyone know of a link to a 5061A Service Manual?  I found the
> 'Temporary Operating Manual' at the Agilent website.
>
> Thanks,
>
> Joe
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From N3IZN at aol.com  Tue Nov 18 03:55:22 2008
From: N3IZN at aol.com (N3IZN at aol.com)
Date: Mon, 17 Nov 2008 22:55:22 EST
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
Message-ID: <c57.4726e5e9.365396aa@aol.com>

 
Who said 10Mhz was a standard? If it was all ham radios would have a 10 Mhz  
input to replace the internal reference.
 
Every manufacture will have there own reference frequency. With GPSDO 10  Mhz 
is the most common, but I've seen 100 Mhz and things like 7.998 Mhz.
 
Lucent didn't use the 10 Mhz output on their series II products but it was  
there for a test output.

> and  the usual 15 MHz Cell output.

My Z3801A has a 10 MHz output.  I  thought that was normal.  It seems like a 
nice round convenient  number.

So why did cell phone towers switch to 15 MHz?  Or is it  just Lucent that 
switched?




**************You Rock! One month of free movies delivered by mail from 
blockbuster.com 
(http://pr.atwola.com/promoclk/100000075x1212639737x1200784900/aol?redir=https://www.blockbuster.com/signup/y/reg/p.26978/r.email_footer)

From kd1sq at spamcop.net  Tue Nov 18 04:20:21 2008
From: kd1sq at spamcop.net (Lee Reynolds)
Date: Mon, 17 Nov 2008 23:20:21 -0500
Subject: [time-nuts] 10Mhz source?
Message-ID: <b426770a0811172020t67ea55a9q4d2c515d62831b9@mail.gmail.com>

Hi, people.

I'm in need of an extremely accurate 10MHz signal source (doing some
alignment of receiver TXCOs.)

Would anyone know of a source I could either visit or borrow in NH/VT?

Failing that, what's a reasonable plan for buying one that won't break my
piggy bank? I see that there are a fair number of those Trimble GPS clock
units showing up on eBay but have no idea of their utility...

TIA,
     Lee

From hmurray at megapathdsl.net  Tue Nov 18 05:23:26 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Mon, 17 Nov 2008 21:23:26 -0800
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
In-Reply-To: Message from N3IZN@aol.com 
	of "Mon, 17 Nov 2008 22:55:22 EST." <c57.4726e5e9.365396aa@aol.com> 
Message-ID: <20081118052327.595B7BCD6@ip-64-139-1-69.sjc.megapath.net>


> Who said 10Mhz was a standard? If it was all ham radios would have a
> 10 Mhz input to replace the internal reference. 

I was thinking of de facto standard rather than official/legal standard.


Both the Z3801A (and more recent HP/Spectracom units) and the Trimble 
Thunderbolt have 10 MHz outputs.

All the low cost telco Rubidium boxes I've read about have a 10 MHz output.

Lots and lots of lab gear uses 10 MHz, both in and out.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From nospam at oceanfree.net  Tue Nov 18 09:32:06 2008
From: nospam at oceanfree.net (Eamon Skelton)
Date: Tue, 18 Nov 2008 09:32:06 +0000
Subject: [time-nuts] 10Mhz source?
In-Reply-To: <b426770a0811172020t67ea55a9q4d2c515d62831b9@mail.gmail.com>
References: <b426770a0811172020t67ea55a9q4d2c515d62831b9@mail.gmail.com>
Message-ID: <49228B96.4010903@oceanfree.net>

Lee Reynolds wrote:
> Hi, people.
> 
> I'm in need of an extremely accurate 10MHz signal source (doing some
> alignment of receiver TXCOs.)
> 
> Would anyone know of a source I could either visit or borrow in NH/VT?

How accurate does it need to be? An OCXO tuned to
zero beat with WWV will easily get you within 1Hz.

10MHz OCXOs are easy to find on eBay.

> Failing that, what's a reasonable plan for buying one that won't break my
> piggy bank? I see that there are a fair number of those Trimble GPS clock
> units showing up on eBay but have no idea of their utility...
> 
> TIA,
>      Lee

There are a few GPSDOs with a 10MHz output. The Trimble units
would be ideal. Also look at the Navsync CW12-TIM.

If you fancy a bit of homebrew, see James Miller's excellent
design: http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm




-- 
Linux 2.6.26


From wje at quackers.net  Tue Nov 18 11:58:25 2008
From: wje at quackers.net (wje)
Date: Tue, 18 Nov 2008 06:58:25 -0500
Subject: [time-nuts] 10Mhz source?
In-Reply-To: <b426770a0811172020t67ea55a9q4d2c515d62831b9@mail.gmail.com>
References: <b426770a0811172020t67ea55a9q4d2c515d62831b9@mail.gmail.com>
Message-ID: <4922ADE1.7050307@quackers.net>

I'm in Southern NH. I have GPS and Rubidium 10 Mhz sources, and a 5 Mhz 
Cesium source. Le me know if you'd like to drop in, I'm near Peterborough.

Bill Ezell
----------
They said 'Windows or better'
so I used Linux.



Lee Reynolds wrote:
> Hi, people.
>
> I'm in need of an extremely accurate 10MHz signal source (doing some
> alignment of receiver TXCOs.)
>
> Would anyone know of a source I could either visit or borrow in NH/VT?
>
> Failing that, what's a reasonable plan for buying one that won't break my
> piggy bank? I see that there are a fair number of those Trimble GPS clock
> units showing up on eBay but have no idea of their utility...
>
> TIA,
>      Lee
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>   


From yuri at ostry.ru  Tue Nov 18 11:59:39 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Tue, 18 Nov 2008 14:59:39 +0300
Subject: [time-nuts] Rb lamp lifetime...
In-Reply-To: <490D1F14.DD39B9F2@cox.net>
References: <1393325470.20081102052155@ostry.ru> <490D1F14.DD39B9F2@cox.net>
Message-ID: <344885466.20081118145939@ostry.ru>

Hello,

Sunday, November 2, 2008, 6:31:32, WB6BNQ wrote:

W> Hi Yuri,

W> Unless you need the longer term stability of an undisciplined Rb source, I think
W> you would be better served to get one of the ?Timenuts group? Trimble Thunderbolt
W> GPS units to use as a home standard.  It is available via this page:

W> http://www.tapr.org/kits_thunder.html

W> and info about the unit is available at this URL:

W> http://www.leapsecond.com/tbolt-faq.htm

W> Add an external very high quality crystal oscillator locked to the Trimble and
W> you will have the same stability of a good Rb source.  Most would use a high
W> quality Rb source, undisciplined, as a tool for comparing or generating
W> specifications of crystal oscillators.

Unfortunately, I'm currently living in a place that have problems with
good location for GPS antenna. The best place available provides less than
40% of open sky view and a lot of buildings around, lots of reflected
signals. No access to roof, security is tightened heavily after 9/11
and terror acts in Moscow, so it is big problem to get access to
attics or cellars of residental buildings.

I curently have uBlox LEA-5S (SuperSense nav module) connected to this
antenna.... Not very promising... Fix is available about 70% of time
but drifting heavily (due to multipath?), often I see coordinates
about 400-500 m away from real location.

I have Motorola Oncore M12+T module as well (purchased it with
intention to build GPSDO controller), but (IMHO) it will be nearly
useless in such conditions with original W5OJM controller design.

I thinked about some FLL implementation where microcontroller
constantly monitor output of GPS for T-RAIM solution status and
discard measurement cycles that have T-RAIM alarms, restarting cycle
once T-RAIM reports good timing solution again... Will be fun project,
of course, but will take some time. And it will be a good reason to
familiarize myself with new 16-bit PIC24 series... Their cascadable up
to 32 bits timers/counters with input capture looks quite promising...

-- 
Best regards,
 Yuri, UA3ATQ/KI7XJ                 mailto:yuri at ostry.ru



From sebastian.stolp at k-s.ch  Tue Nov 18 12:10:40 2008
From: sebastian.stolp at k-s.ch (Sebastian Stolp)
Date: Tue, 18 Nov 2008 13:10:40 +0100
Subject: [time-nuts] looking for a swiss time nut
Message-ID: <0503AF7B-654D-406A-AFBE-33B557123852@k-s.ch>

hi time nuts,
i had contact with juerg from sins here in switzerland 2 years ago or  
so.
juerg? are you still out there? or in german: hallo juerg, bitte melde  
dich mal!

best regards,
sebastian


From mikes at flatsurface.com  Tue Nov 18 13:18:48 2008
From: mikes at flatsurface.com (Mike S)
Date: Tue, 18 Nov 2008 08:18:48 -0500
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
In-Reply-To: <20081116215125.B82E0BCD6@ip-64-139-1-69.sjc.megapath.net>
References: <20081116215125.B82E0BCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <20081118131850.B979D1165C3@hamburg.alientech.net>

At 04:51 PM 11/16/2008, Hal Murray wrote...
>So why did cell phone towers switch to 15 MHz?  Or is it just Lucent 
>that switched?

Ultimately, CDMA base stations need a precise 1.2288 MHz clock, as that 
is the chip clock rate. A PLL locked to a 10 MHz GPSDO (like the 
Tribles and HP Z3801s, which came out of Nortel BSC/BTS CDMA base 
stations and were known as GPSRs) were probably used originally simply 
because of easy commercial availability.

Some newer units (Nortel GPSTM, used in their newer Metrocell base 
stations) output 9.8304 MHz, which is an 8X multiple of the chip rate. 
These also put out 10 MHz and 0.5 Hz (even-second) signals.

Did Lucent switch, or have they always locked to a 15 MHz source? I've 
only seen the 15 MHz units.

Any Timenuts have an Endrun Tycho CDMA-derived frequency reference? 
http://www.endruntechnologies.com/pdf/TychoCDMA.pdf
http://www.endruntechnologies.com/pdf/PTTI2001_WhitePaper.pdf 



From james.p.lux at jpl.nasa.gov  Tue Nov 18 14:30:36 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Tue, 18 Nov 2008 06:30:36 -0800
Subject: [time-nuts] Why/when did cell towers switch to 15 MHz?
In-Reply-To: <c57.4726e5e9.365396aa@aol.com>
Message-ID: <C548118C.2A1F%James.P.Lux@jpl.nasa.gov>




On 11/17/08 7:55 PM, "N3IZN at aol.com" <N3IZN at aol.com> wrote:

>
>
> Who said 10Mhz was a standard? If it was all ham radios would have a 10 Mhz
> input to replace the internal reference.

Ham radios (or "radio boxes" in general) aren't test equipment, and don't
have external reference inputs in the first place.  Most test equipment
these days uses 10 MHz as the reference input, although, historically, 1 and
5 MHz have also been used.
>
>
> Every manufacture will have there own reference frequency. With GPSDO 10  Mhz
> is the most common, but I've seen 100 Mhz and things like 7.998 Mhz.

Interestingly, the GPS receiver itself probably does NOT use 10 MHz
internally (some frequency related to the chip rate/carrier frequency is
more common).  The 10 MHz is just because the aforementioned test equipment
uses 10MHz as an input.

>
> Lucent didn't use the 10 Mhz output on their series II products but it was
> there for a test output.
>
>> and  the usual 15 MHz Cell output.
>
> My Z3801A has a 10 MHz output.  I  thought that was normal.  It seems like a
> nice round convenient  number.
>
> So why did cell phone towers switch to 15 MHz?  Or is it  just Lucent that
> switched?
>

Probably because it was convenient for their system.  When you're ordering
hundreds of something, it doesn't add much to the cost to make the frequency
what you need, and if some other equipment has a base frequency that's
different than 10, you might save overall.

Jim



From brad at shinji.net  Tue Nov 18 18:13:17 2008
From: brad at shinji.net (Brad Stockdale)
Date: Tue, 18 Nov 2008 13:13:17 -0500
Subject: [time-nuts] Where to find surplus telecom standards
Message-ID: <mailman.5.1227032006.2539.time-nuts@febo.com>

Hello all,

    I'm somewhat new to the list (long time lurker, first time 
poster). I guess I should introduce myself. My name is Brad. I live 
in Pennsylvania. Always been interested in electronics of various 
types (specifically lasers, high voltage, computer interfacing, and 
PIC uC's). Long ago I figured out that for some reason, I have a 
fascination with accurate time. I can't explain it, really, since I'm 
notouriously late and never plan things out, but yet I love to have 
very accurate time... Lol... In any case, back when the market was 
flooded with HP Z3801's, I snatched up four of them, along with some 
mating antenna's. I've ran a couple of them for several years, and 
have used them for my NTP server. I've built a few PIC based clocks 
that utilize my 'house standard' outputs from one of my Z3801's as 
its reference.

    In any case, I am interested in finding some other surplus 
telecom type standards... Specifically, units such as:

	o HP Z3815A
	o HP Z3816A
	o Lucent RFG-RB
	o Lucent RFG-XO

    Where can us time nuts find such units? I'm sure that if I 
watched eBay long enough, I might stumble across them, but thus far, 
I haven't been successful... Even Z3801A's seem to be few and far 
between now... Also, what are reasonable prices for the above type equipment?

    If anyone has any leads on where I should be watching for these, 
please let me know... I'd like to get a few more standards to experiment with.

Thank you,
Brad



From wb6bnq at cox.net  Tue Nov 18 18:23:45 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Tue, 18 Nov 2008 10:23:45 -0800
Subject: [time-nuts] Rb lamp lifetime...
References: <1393325470.20081102052155@ostry.ru> <490D1F14.DD39B9F2@cox.net>
	<344885466.20081118145939@ostry.ru>
Message-ID: <49230831.76591740@cox.net>

Yuri Ostry wrote:

> Hello,
>
> Sunday, November 2, 2008, 6:31:32, WB6BNQ wrote:
>
> W> Hi Yuri,
>
> W> Unless you need the longer term stability of an undisciplined Rb source, I think
> W> you would be better served to get one of the ?Timenuts group? Trimble Thunderbolt
> W> GPS units to use as a home standard.  It is available via this page:
>
> W> http://www.tapr.org/kits_thunder.html
>
> W> and info about the unit is available at this URL:
>
> W> http://www.leapsecond.com/tbolt-faq.htm
>
> W> Add an external very high quality crystal oscillator locked to the Trimble and
> W> you will have the same stability of a good Rb source.  Most would use a high
> W> quality Rb source, undisciplined, as a tool for comparing or generating
> W> specifications of crystal oscillators.
>
> Unfortunately, I'm currently living in a place that have problems with
> good location for GPS antenna. The best place available provides less than
> 40% of open sky view and a lot of buildings around, lots of reflected
> signals. No access to roof, security is tightened heavily after 9/11
> and terror acts in Moscow, so it is big problem to get access to
> attics or cellars of residental buildings.
>
> I curently have uBlox LEA-5S (SuperSense nav module) connected to this
> antenna.... Not very promising... Fix is available about 70% of time
> but drifting heavily (due to multipath?), often I see coordinates
> about 400-500 m away from real location.
>
> I have Motorola Oncore M12+T module as well (purchased it with
> intention to build GPSDO controller), but (IMHO) it will be nearly
> useless in such conditions with original W5OJM controller design.
>
> I thinked about some FLL implementation where microcontroller
> constantly monitor output of GPS for T-RAIM solution status and
> discard measurement cycles that have T-RAIM alarms, restarting cycle
> once T-RAIM reports good timing solution again... Will be fun project,
> of course, but will take some time. And it will be a good reason to
> familiarize myself with new 16-bit PIC24 series... Their cascadable up
> to 32 bits timers/counters with input capture looks quite promising...
>
> --
> Best regards,
>  Yuri, UA3ATQ/KI7XJ                 mailto:yuri at ostry.ru

Hi Yuri,

Someone correct me if I am wrong, but I think the M12+ is like the UT+ and uses one
bird, at a time in the time mode, to do the timing process after you got a position
fix.  If that is true then maybe it will yeild a better result ?  I think it would be
worth a try.  So, put the Shera controller together with your M12+ and see what happens.

I am wondering if limiting the antenna's view would help with the multipath ?  For
instance, what happens if you build a cone shaped skirt that is pretty tall such that it
prevents a majority of the side view energy from reaching the antenna ?

Worst case, you could use the M12+/Shera arrangement with a Rb unit and go to a park or
other open space for a day, or if camping is available, maybe a weekend camping trip
would be in order.  Then compare the Rb oscillator, setting it if need be, and then take
it home.  Not an ideal solution, but with the much better holdover of the Rb source you
would, maybe, at least have perhaps a few parts in 10E-10th for a month or so before
having to do it again.

Bill....WB6BNQ




From brad at shinji.net  Tue Nov 18 18:29:48 2008
From: brad at shinji.net (Brad Stockdale)
Date: Tue, 18 Nov 2008 13:29:48 -0500
Subject: [time-nuts] Where to find surplus telecom standards
In-Reply-To: <E1L2V4o-00009x-Pe@meow.febo.com>
References: <E1L2V4o-00009x-Pe@meow.febo.com>
Message-ID: <mailman.6.1227033000.2539.time-nuts@febo.com>

Hello,

    Kinda bad form to reply to your own threads right away, but here goes...

    I just checked on eBay right now and there are some Lucent units 
up for auction. Of course, I don't have money right this second, but 
now I know that the lucent units seem to be more prevalant than the 
HP ones... I'll setup some saved searches so I can hopefully grab a 
few more of these standards to play with...

    On a slightly different subject, albeit somewhat related... Does 
anyone know what HP Z3801A's are worth nowadays? I remember when they 
first came on the market, they were around $250, then up to about 
$400 or so when supplies got scarce. Not sure what happened after 
that... Just kinda curious if I could make some extra money by 
selling a couple of my Z3801's and using the profits to buy some 
other units to 'play' with...

Thanks,
Brad



From ryanbytes at gmail.com  Tue Nov 18 18:45:24 2008
From: ryanbytes at gmail.com (Ryan)
Date: Tue, 18 Nov 2008 12:45:24 -0600
Subject: [time-nuts] CPU frequency and NTP crazyness.
In-Reply-To: <dc1901680801052134i5052e7d0q9f444d9016ef122f@mail.gmail.com>
References: <dc1901680801040845w3376893eqf2d7c83d314ea636@mail.gmail.com>
	<477E7D56.4060103@vogel.cx>
	<dc1901680801041844t7e6ac5a6p6451b909284a7eb@mail.gmail.com>
	<dc1901680801052008q71551a83m67a632002232f546@mail.gmail.com>
	<2ad2af430801052124n2834e3ban4c94a800f3081617@mail.gmail.com>
	<dc1901680801052134i5052e7d0q9f444d9016ef122f@mail.gmail.com>
Message-ID: <dc1901680811181045y2ca196cav9aa3c4c08b75629d@mail.gmail.com>

Sorry for the months later response but I figured out my problem with
NTP not working correctly on my Athlon XP machine running Windows XP.
Too much time on my hands and the struggle for some perfection in my
life at the moment led me to NTP again. As I did before I used the
Meinberg windows install for the NTP package. I can't remember if
there was an option to disable the multimedia timer in the setup on
the installer of the older package but on the latest release there
was. I disabled the multimedia timer for the hell of it and let NTP
go. So far it looks like NTP is working great. There are no insane
jumps in offset like there was before. Everything is converging nicely
making me one happy camper.


From w1ksz at earthlink.net  Tue Nov 18 19:15:37 2008
From: w1ksz at earthlink.net (Richard W. Solomon)
Date: Tue, 18 Nov 2008 12:15:37 -0700 (GMT-07:00)
Subject: [time-nuts] Where to find surplus telecom standards
Message-ID: <32017378.1227035737765.JavaMail.root@elwamui-muscovy.atl.sa.earthlink.net>

Use the Advanced Search to check Closed Sales. You will be
pleasantly surprised. They were a better investment than the
Stock Market !!

73, Dick, W1KSZ

-----Original Message-----
>From: Brad Stockdale <brad at shinji.net>
>Sent: Nov 18, 2008 11:29 AM
>To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
>Subject: Re: [time-nuts] Where to find surplus telecom standards
>
>Hello,
>
>    Kinda bad form to reply to your own threads right away, but here goes...
>
>    I just checked on eBay right now and there are some Lucent units 
>up for auction. Of course, I don't have money right this second, but 
>now I know that the lucent units seem to be more prevalant than the 
>HP ones... I'll setup some saved searches so I can hopefully grab a 
>few more of these standards to play with...
>
>    On a slightly different subject, albeit somewhat related... Does 
>anyone know what HP Z3801A's are worth nowadays? I remember when they 
>first came on the market, they were around $250, then up to about 
>$400 or so when supplies got scarce. Not sure what happened after 
>that... Just kinda curious if I could make some extra money by 
>selling a couple of my Z3801's and using the profits to buy some 
>other units to 'play' with...
>
>Thanks,
>Brad
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.



From bruce.griffiths at xtra.co.nz  Tue Nov 18 19:50:42 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Wed, 19 Nov 2008 08:50:42 +1300
Subject: [time-nuts] Rb lamp lifetime...
In-Reply-To: <49230831.76591740@cox.net>
References: <1393325470.20081102052155@ostry.ru>
	<490D1F14.DD39B9F2@cox.net>	<344885466.20081118145939@ostry.ru>
	<49230831.76591740@cox.net>
Message-ID: <49231C92.8040606@xtra.co.nz>

WB6BNQ wrote:
> Yuri Ostry wrote:
>
>   
>> Hello,
>>
>> Sunday, November 2, 2008, 6:31:32, WB6BNQ wrote:
>>
>> W> Hi Yuri,
>>
>> W> Unless you need the longer term stability of an undisciplined Rb source, I think
>> W> you would be better served to get one of the ?Timenuts group? Trimble Thunderbolt
>> W> GPS units to use as a home standard.  It is available via this page:
>>
>> W> http://www.tapr.org/kits_thunder.html
>>
>> W> and info about the unit is available at this URL:
>>
>> W> http://www.leapsecond.com/tbolt-faq.htm
>>
>> W> Add an external very high quality crystal oscillator locked to the Trimble and
>> W> you will have the same stability of a good Rb source.  Most would use a high
>> W> quality Rb source, undisciplined, as a tool for comparing or generating
>> W> specifications of crystal oscillators.
>>
>> Unfortunately, I'm currently living in a place that have problems with
>> good location for GPS antenna. The best place available provides less than
>> 40% of open sky view and a lot of buildings around, lots of reflected
>> signals. No access to roof, security is tightened heavily after 9/11
>> and terror acts in Moscow, so it is big problem to get access to
>> attics or cellars of residental buildings.
>>
>> I curently have uBlox LEA-5S (SuperSense nav module) connected to this
>> antenna.... Not very promising... Fix is available about 70% of time
>> but drifting heavily (due to multipath?), often I see coordinates
>> about 400-500 m away from real location.
>>
>> I have Motorola Oncore M12+T module as well (purchased it with
>> intention to build GPSDO controller), but (IMHO) it will be nearly
>> useless in such conditions with original W5OJM controller design.
>>
>> I thinked about some FLL implementation where microcontroller
>> constantly monitor output of GPS for T-RAIM solution status and
>> discard measurement cycles that have T-RAIM alarms, restarting cycle
>> once T-RAIM reports good timing solution again... Will be fun project,
>> of course, but will take some time. And it will be a good reason to
>> familiarize myself with new 16-bit PIC24 series... Their cascadable up
>> to 32 bits timers/counters with input capture looks quite promising...
>>
>> --
>> Best regards,
>>  Yuri, UA3ATQ/KI7XJ                 mailto:yuri at ostry.ru
>>     
>
> Hi Yuri,
>
> Someone correct me if I am wrong, but I think the M12+ is like the UT+ and uses one
> bird, at a time in the time mode, to do the timing process after you got a position
> fix.  If that is true then maybe it will yeild a better result ?  I think it would be
> worth a try.  So, put the Shera controller together with your M12+ and see what happens.
>
> I am wondering if limiting the antenna's view would help with the multipath ?  For
> instance, what happens if you build a cone shaped skirt that is pretty tall such that it
> prevents a majority of the side view energy from reaching the antenna ?
>
> Worst case, you could use the M12+/Shera arrangement with a Rb unit and go to a park or
> other open space for a day, or if camping is available, maybe a weekend camping trip
> would be in order.  Then compare the Rb oscillator, setting it if need be, and then take
> it home.  Not an ideal solution, but with the much better holdover of the Rb source you
> would, maybe, at least have perhaps a few parts in 10E-10th for a month or so before
> having to do it again.
>
> Bill....WB6BNQ
>
>   
Bill

The M12+T uses all SVs above the user defined altitude limit to compute
the timing solution.
However the individual time offsets for each SV from the global solution
are available, so in principle one can remove one or more SV's from the
solution.
This requires either hardware or software timing error correction to do
this.
Thus, in principle, one could implement a much more complex SV selection
algorithm than a simple altitude limit.

Since switching to holdover mode will be relatively frequent a more
versatile controller than Shera controller will be required.
If you use an appropriate micro most of the required hardware is built
in to the chip.
Neither external counters nor auxiliary oscillators are necessary as
everything can be clocked at 10MHz.

Bruce


From stanley_reynolds at yahoo.com  Tue Nov 18 20:10:09 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Tue, 18 Nov 2008 12:10:09 -0800 (PST)
Subject: [time-nuts] Where to find surplus telecom standards
References: <E1L2V4o-00009x-Pe@meow.febo.com> <E1L2VKr-0000V5-L8@meow.febo.com>
Message-ID: <934064.85145.qm@web30306.mail.mud.yahoo.com>

I have purchased a few things from Ebay, but it is seldom you get the best price. You will see some items that don't get a bid or sell at a lower price. Check that sellers feedback and shipping cost for why no one is bidding. That said with buyers needing their money?for other?things with uncertain economic times ahead some buys may appear but I think the sellers are just listing less stuff now.

You were also asking about selling which can be a problem if you don't have a good reputation / feedback because of the problem above.

As many on this list has reported ( "Oh the horror") bad packing and shipping is a real concern and is yet another risk with Ebay. When you add the Ebay fees and paypal fees and labor it is hard to see how anyone makes money or on the other side gets a good deal. 

Another source is govautions but that has problems as well, paper work and shipping are even more of a problem. Often the items you want have items you don't want in the same lot.

Hamfest and want ads on club web sites is another source.

Just like any other addiction go slow and think ahead about how to store all your good stuff or how to hide it from your better half. You may not be truly effected yet as you are thinking of selling old stuff to by new.

Stanley

?



________________________________
From: Brad Stockdale <brad at shinji.net>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Tuesday, November 18, 2008 12:29:48 PM
Subject: Re: [time-nuts] Where to find surplus telecom standards

Hello,

? ? Kinda bad form to reply to your own threads right away, but here goes...

? ? I just checked on eBay right now and there are some Lucent units 
up for auction. Of course, I don't have money right this second, but 
now I know that the lucent units seem to be more prevalant than the 
HP ones... I'll setup some saved searches so I can hopefully grab a 
few more of these standards to play with...

? ? On a slightly different subject, albeit somewhat related... Does 
anyone know what HP Z3801A's are worth nowadays? I remember when they 
first came on the market, they were around $250, then up to about 
$400 or so when supplies got scarce. Not sure what happened after 
that... Just kinda curious if I could make some extra money by 
selling a couple of my Z3801's and using the profits to buy some 
other units to 'play' with...

Thanks,
Brad


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From brad at shinji.net  Tue Nov 18 20:54:44 2008
From: brad at shinji.net (Brad Stockdale)
Date: Tue, 18 Nov 2008 15:54:44 -0500
Subject: [time-nuts] Where to find surplus telecom standards
In-Reply-To: <32017378.1227035737765.JavaMail.root@elwamui-muscovy.atl.s
	a.earthlink.net>
References: <32017378.1227035737765.JavaMail.root@elwamui-muscovy.atl.sa.earthlink.net>
Message-ID: <mailman.7.1227041690.2539.time-nuts@febo.com>

Good idea! I've used eBay on and off since 1999, and never even knew 
I was able to search closed auctions! Ya learn something new every 
day! Thank you for the idea.

I did indeed find some closed Z3801 and related auctions. My, the 
price has gone up on them.

Thanks,
Brad


At 02:15 PM 11/18/2008, you wrote:
>Use the Advanced Search to check Closed Sales. You will be
>pleasantly surprised. They were a better investment than the
>Stock Market !!
>
>73, Dick, W1KSZ
>
>-----Original Message-----
> >From: Brad Stockdale <brad at shinji.net>
> >Sent: Nov 18, 2008 11:29 AM
> >To: Discussion of precise time and frequency measurement 
> <time-nuts at febo.com>
> >Subject: Re: [time-nuts] Where to find surplus telecom standards
> >
> >Hello,
> >
> >    Kinda bad form to reply to your own threads right away, but here goes...
> >
> >    I just checked on eBay right now and there are some Lucent units
> >up for auction. Of course, I don't have money right this second, but
> >now I know that the lucent units seem to be more prevalant than the
> >HP ones... I'll setup some saved searches so I can hopefully grab a
> >few more of these standards to play with...
> >
> >    On a slightly different subject, albeit somewhat related... Does
> >anyone know what HP Z3801A's are worth nowadays? I remember when they
> >first came on the market, they were around $250, then up to about
> >$400 or so when supplies got scarce. Not sure what happened after
> >that... Just kinda curious if I could make some extra money by
> >selling a couple of my Z3801's and using the profits to buy some
> >other units to 'play' with...
> >
> >Thanks,
> >Brad
> >
> >
> >_______________________________________________
> >time-nuts mailing list -- time-nuts at febo.com
> >To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >and follow the instructions there.
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
>
>__________ Information from ESET NOD32 Antivirus, version of virus 
>signature database 3622 (20081118) __________
>
>The message was checked by ESET NOD32 Antivirus.
>
>http://www.eset.com



From stephan at rrsg.ee.uct.ac.za  Wed Nov 19 14:29:59 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Wed, 19 Nov 2008 16:29:59 +0200
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
Message-ID: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>

Hi All,

Up until now we've been interfacing my Motorola M12+T's using the Oncore
software. However, at this point we are trying to have it interfaced
directly to a FPGA. To my mind this should be simple - the commands are
discriminated (framed) by looking at the start and terminating bytes
sequences when they enter the FIFO, check summed, decoded etc.

However, I noted something very peculiar about the motorola ASCII protocol:
The start bytes @@ and he terminating byte <CR><LF> aren't unique with
respect to the data bytes. For instance one could receive a time of 13hrs
and 10mins which would look identical to the terminating characters.
Initially I thought it made sense since the data is also sent in ascii
format. It appears not to be the case.

It seems to me that the only way in which a command could be robustly
identified and check summed is when the interface knows the length of the
expected return.  Obviously, the data lengths are dependent on both the
actual command and the specific request. This type of intelligence is
cumbersome to implement in FPGAs.

It would be of great help if you could point me in the right direction here.
I feel rather stupid in asking such a simple question, but at this point I
can't seem to see the light. I'm flabbergasted...

Best regards,

Stephan

From stanley_reynolds at yahoo.com  Wed Nov 19 15:34:27 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Wed, 19 Nov 2008 07:34:27 -0800 (PST)
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <964475.11768.qm@web30307.mail.mud.yahoo.com>

Looking at the user guide which is the extent of my experience. Would the position version of the M12+ be a better choice for your application ? That is trade NMEA-0183 for all the timing features ?

Stanley

Link to user guide : 
http://www.synergy-gps.com/images/stories/guides/m12+userguide.pdf


?



________________________________
From: Stephan Sandenbergh <stephan at rrsg.ee.uct.ac.za>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Wednesday, November 19, 2008 8:29:59 AM
Subject: [time-nuts] M12+T ASCII interface - I'm confused?

Hi All,

Up until now we've been interfacing my Motorola M12+T's using the Oncore
software. However, at this point we are trying to have it interfaced
directly to a FPGA. To my mind this should be simple - the commands are
discriminated (framed) by looking at the start and terminating bytes
sequences when they enter the FIFO, check summed, decoded etc.

However, I noted something very peculiar about the motorola ASCII protocol:
The start bytes @@ and he terminating byte <CR><LF> aren't unique with
respect to the data bytes. For instance one could receive a time of 13hrs
and 10mins which would look identical to the terminating characters.
Initially I thought it made sense since the data is also sent in ascii
format. It appears not to be the case.

It seems to me that the only way in which a command could be robustly
identified and check summed is when the interface knows the length of the
expected return.? Obviously, the data lengths are dependent on both the
actual command and the specific request. This type of intelligence is
cumbersome to implement in FPGAs.

It would be of great help if you could point me in the right direction here.
I feel rather stupid in asking such a simple question, but at this point I
can't seem to see the light. I'm flabbergasted...

Best regards,

Stephan
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From david.partridge at dsl.pipex.com  Wed Nov 19 15:44:47 2008
From: david.partridge at dsl.pipex.com (David C. Partridge)
Date: Wed, 19 Nov 2008 15:44:47 -0000
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <85C99562C7C74DE3B2B307715E377112@APOLLO>

Aren't potential terminating chars doubled up if in the datastream?

Check the protocol specification very carefully.

Cheers
Dave 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Stephan Sandenbergh
Sent: 19 November 2008 14:30
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] M12+T ASCII interface - I'm confused?

Hi All,

Up until now we've been interfacing my Motorola M12+T's using the Oncore
software. However, at this point we are trying to have it interfaced
directly to a FPGA. To my mind this should be simple - the commands are
discriminated (framed) by looking at the start and terminating bytes
sequences when they enter the FIFO, check summed, decoded etc.

However, I noted something very peculiar about the motorola ASCII protocol:
The start bytes @@ and he terminating byte <CR><LF> aren't unique with
respect to the data bytes. For instance one could receive a time of 13hrs
and 10mins which would look identical to the terminating characters.
Initially I thought it made sense since the data is also sent in ascii
format. It appears not to be the case.



From david.partridge at dsl.pipex.com  Wed Nov 19 15:50:57 2008
From: david.partridge at dsl.pipex.com (David C. Partridge)
Date: Wed, 19 Nov 2008 15:50:57 -0000
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <8742721C9702408DB0DA6BFF68B30321@APOLLO>

I have just the beast for you - an HP 4951C with serial adapter!!! That well
let you really see what's in the datastream.

Dave



From brooke at pacific.net  Wed Nov 19 16:21:01 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Wed, 19 Nov 2008 08:21:01 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <49243CED.4060400@pacific.net>

Hi Stephan:

Check the manual for "stuffing", it's not a Thanksgiving term here but has to 
do with what happens when a byte in a binary data stream (the data in the 
Motorola protocol is all binary, not ASCII) is the same as the ASCII "@" 
character.  This means that the length of a packet is variable and depends on 
the actual data inside the packet.  But you know the minimum length if you know 
the packet ID.

To start look for the string <CR><LF>@@ and the next characters (maybe 2 or 4 
hex characters) are the packet ID.  Sometimes this happens inside a packet 
because that's what the data looks like.  But go with it and if it's wrong the 
program will cycle around to where you are on packet boundaries.


Have Fun,

Brooke Clarke
http://www.prc68.com

Stephan Sandenbergh wrote:
> Hi All,
> 
> Up until now we've been interfacing my Motorola M12+T's using the Oncore
> software. However, at this point we are trying to have it interfaced
> directly to a FPGA. To my mind this should be simple - the commands are
> discriminated (framed) by looking at the start and terminating bytes
> sequences when they enter the FIFO, check summed, decoded etc.
> 
> However, I noted something very peculiar about the motorola ASCII protocol:
> The start bytes @@ and he terminating byte <CR><LF> aren't unique with
> respect to the data bytes. For instance one could receive a time of 13hrs
> and 10mins which would look identical to the terminating characters.
> Initially I thought it made sense since the data is also sent in ascii
> format. It appears not to be the case.
> 
> It seems to me that the only way in which a command could be robustly
> identified and check summed is when the interface knows the length of the
> expected return.  Obviously, the data lengths are dependent on both the
> actual command and the specific request. This type of intelligence is
> cumbersome to implement in FPGAs.
> 
> It would be of great help if you could point me in the right direction here.
> I feel rather stupid in asking such a simple question, but at this point I
> can't seem to see the light. I'm flabbergasted...
> 
> Best regards,
> 
> Stephan
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From aa8k at comcast.net  Wed Nov 19 18:34:57 2008
From: aa8k at comcast.net (Mike Naruta AA8K)
Date: Wed, 19 Nov 2008 13:34:57 -0500
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call
Message-ID: <49245C51.8040601@comcast.net>



I love my new Trimble Thunderbolt.
Thank you TAPR and Time-Nuts!


I was thinking of putting insulation
all around the Thunderbolt to thermally
stabilize it.  It's in my basement and
the temperature there rarely gets above
18 C.

That would also help with my dedicated
power supply, as the 12 volt sags when
the Thunderbolt is started.  The power
supply is beautiful one from a 1985 HP
fiber optic mux.


The manual says that operating temperature
is up to 60 C.  If extra-insulated, is the
oven plus other power going to raise the
whole unit temperature too high?

Would insulating the Thunderbolt and
raising its temperature lead to a shorter
MTBF?

Should I tuck some foam around the oven
instead?

Should I just run it ambient and let the
oven do all the work?


Mike - AA8K



From jmfranke at cox.net  Wed Nov 19 18:49:44 2008
From: jmfranke at cox.net (John Franke)
Date: Wed, 19 Nov 2008 13:49:44 -0500
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call
References: <49245C51.8040601@comcast.net>
Message-ID: <FCF4B4E6B7294264891E7F0EB7BF1D4A@youre7075dc078>

The problem is knowing how much insulation.  If you use too much insulation, 
the Thunderbolt will overheat.  I would just block any direct drafts and let 
the unit do what it was designed to do.

John  WA4WDL

----- Original Message ----- 
From: "Mike Naruta AA8K" <aa8k at comcast.net>
To: <time-nuts at febo.com>
Sent: Wednesday, November 19, 2008 1:34 PM
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call


>
>
> I love my new Trimble Thunderbolt.
> Thank you TAPR and Time-Nuts!
>
>
> I was thinking of putting insulation
> all around the Thunderbolt to thermally
> stabilize it.  It's in my basement and
> the temperature there rarely gets above
> 18 C.
>
> That would also help with my dedicated
> power supply, as the 12 volt sags when
> the Thunderbolt is started.  The power
> supply is beautiful one from a 1985 HP
> fiber optic mux.
>
>
> The manual says that operating temperature
> is up to 60 C.  If extra-insulated, is the
> oven plus other power going to raise the
> whole unit temperature too high?
>
> Would insulating the Thunderbolt and
> raising its temperature lead to a shorter
> MTBF?
>
> Should I tuck some foam around the oven
> instead?
>
> Should I just run it ambient and let the
> oven do all the work?
>
>
> Mike - AA8K
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From tvb at LeapSecond.com  Wed Nov 19 19:05:44 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Wed, 19 Nov 2008 11:05:44 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <41A373D58AE14BC4A1315499616BADC5@pc52>

Stephan,

Ah, it's not a stupid question -- I think all of us who have written
code to interface with GPS receivers have had to deal with this.

Some GPS protocols use escape characters, but the Oncore
binary protocol doesn't. There are five clues to robustly parsing
a complete message:

1) starts with @@
2) ends with <cr><lf>
3) message length is known, based on message header
4) valid checksum
5) there may be a pause between sentences

You can use all of these clues to "sync" to a serial data stream
and accurately determine the start of the next message.

As you already observed, just looking for @@ or <cr><lf> is
not sufficient. Checking for <cr><lf>@@ is better, but still not
perfect. To do it right you also need to include message length
and checksum into the calculation. The length is knowable by
looking at the message type in the header as it arrives.

If you use a millisecond-level serial timeout that can help even
more (since if the first two bytes after a pause are @@ you
know it is a message start, not 16-bits of 0x4040 embedded
binary data). There is a timing gap between some, but not all
messages, so use this technique with care. You can also use
the 1PPS pulse as a start of message hint.

True, a robust solution is not FPGA-friendly, but probably not
impossible, either. If you can't solve it, consider using a $1
microcontroller (where this sort of message handling is trivial)
between the receiver and your FPGA which would parse, edit,
or reformat the messages to the FPGA's liking.

/tvb


> Hi All,
> 
> Up until now we've been interfacing my Motorola M12+T's using the Oncore
> software. However, at this point we are trying to have it interfaced
> directly to a FPGA. To my mind this should be simple - the commands are
> discriminated (framed) by looking at the start and terminating bytes
> sequences when they enter the FIFO, check summed, decoded etc.
> 
> However, I noted something very peculiar about the motorola ASCII protocol:
> The start bytes @@ and he terminating byte <CR><LF> aren't unique with
> respect to the data bytes. For instance one could receive a time of 13hrs
> and 10mins which would look identical to the terminating characters.
> Initially I thought it made sense since the data is also sent in ascii
> format. It appears not to be the case.
> 
> It seems to me that the only way in which a command could be robustly
> identified and check summed is when the interface knows the length of the
> expected return.  Obviously, the data lengths are dependent on both the
> actual command and the specific request. This type of intelligence is
> cumbersome to implement in FPGAs.
> 
> It would be of great help if you could point me in the right direction here.
> I feel rather stupid in asking such a simple question, but at this point I
> can't seem to see the light. I'm flabbergasted...
> 
> Best regards,
> 
> Stephan




From hmurray at megapathdsl.net  Wed Nov 19 19:16:57 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Wed, 19 Nov 2008 11:16:57 -0800
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call
In-Reply-To: Message from Mike Naruta AA8K <aa8k@comcast.net> 
	of "Wed, 19 Nov 2008 13:34:57 EST." <49245C51.8040601@comcast.net> 
Message-ID: <20081119191658.BDEFEBCD5@ip-64-139-1-69.sjc.megapath.net>


> I was thinking of putting insulation all around the Thunderbolt to
> thermally stabilize it.  It's in my basement and the temperature there
> rarely gets above 18 C.

> That would also help with my dedicated power supply, as the 12 volt
> sags when the Thunderbolt is started.  The power supply is beautiful
> one from a 1985 HP fiber optic mux. 

Running things hotter reduces lifetime.

Insulation isn't going to solve the problem of startup sag if the TBolt has 
been off for a long time.  It will just change the time scale on "long".  Are 
you expecting to unplug it and leave it off for a while (say 1/2 hour) and 
then plug it back in very often?  If not, why worry about that case?

Does the current setup work OK after it's warmed up?  What's the rating on 
the power supply?  Tom's web page says it takes 160 mA.  I expect it would be 
lower at a higher temperature.  (That might be fun to measure.)


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From tvb at LeapSecond.com  Wed Nov 19 19:21:30 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Wed, 19 Nov 2008 11:21:30 -0800
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call
References: <49245C51.8040601@comcast.net>
Message-ID: <F592490D5DCD4936B0B2943E1363E5F7@pc52>

I think "isolation" may work better than "insulation". The latter
attenuates external temperature variations from getting in but
at the same time also necessarily restricts heat flow going out.
The result is gradual overheating.

You might first want to determine just how temperature sensitive
your TBolt is or isn't. Also see if the response is quite different
between rapid and slow temperature changes.

It's possible that just putting it inside a air sealed metal box would
do the trick. And the thicker the metal the better (thermal mass).

Note that unlike a standalone OCXO, most GPSDO are less
sensitive to temperature changes. This is because they are a
closed system -- drift due to gradual changes in temperature are
simply swept away by the OCXO-GPS servo loop. It's the short
mechanical shock or temperature spikes that cause trouble, not
any slow smooth gradual environmental change.

Take all this with a grain of salt because I've not done tempco
work on the TBolt yet. If anyone else has data, now would be
a good time to give a report.

Thanks,
/tvb

----- Original Message ----- 
From: "Mike Naruta AA8K" <aa8k at comcast.net>
To: <time-nuts at febo.com>
Sent: Wednesday, November 19, 2008 10:34 AM
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call


> 
> 
> I love my new Trimble Thunderbolt.
> Thank you TAPR and Time-Nuts!
> 
> 
> I was thinking of putting insulation
> all around the Thunderbolt to thermally
> stabilize it.  It's in my basement and
> the temperature there rarely gets above
> 18 C.
> 
> That would also help with my dedicated
> power supply, as the 12 volt sags when
> the Thunderbolt is started.  The power
> supply is beautiful one from a 1985 HP
> fiber optic mux.
> 
> 
> The manual says that operating temperature
> is up to 60 C.  If extra-insulated, is the
> oven plus other power going to raise the
> whole unit temperature too high?
> 
> Would insulating the Thunderbolt and
> raising its temperature lead to a shorter
> MTBF?
> 
> Should I tuck some foam around the oven
> instead?
> 
> Should I just run it ambient and let the
> oven do all the work?
> 
> 
> Mike - AA8K




From Murray.Greenman at rakon.com  Wed Nov 19 19:47:43 2008
From: Murray.Greenman at rakon.com (Murray Greenman)
Date: Thu, 20 Nov 2008 08:47:43 +1300
Subject: [time-nuts] Coddling your TBOLT
In-Reply-To: <mailman.194.1227121579.2542.time-nuts@febo.com>
References: <mailman.194.1227121579.2542.time-nuts@febo.com>
Message-ID: <BE50C3A72EBA61449C804B2C8B4AE381D05A56@NEPTUNE.rakon.net>

Personally, I'd just leave the TBOLT to get on with the job.

It's probably a good idea to exclude draughts, but adding further
insulation will probably not help matters and may hinder them. I'm
thinking specifically of what happens to the ambient compensation of
OCXOs when the insulation thermal resistance (and thus the thermal
gradient to ambient) differs materially from when the unit was
calibrated.

Murray ZL1BPU



From david at endor.com  Wed Nov 19 20:06:29 2008
From: david at endor.com (David McGaw)
Date: Wed, 19 Nov 2008 15:06:29 -0500
Subject: [time-nuts] CHU: do not stay tuned...
In-Reply-To: <797939.32819.qm@web50715.mail.yahoo.com>
References: <7.0.1.0.0.20070303172741.0421ecc0@endor.com>
	<797939.32819.qm@web50715.mail.yahoo.com>
Message-ID: <200811192006.mAJK6US8029996@mailhub2.dartmouth.edu>

It appears that CHU on 7.335MHz will soon be moved.  While CNRC can 
keep transmitting on the frequency, so can broadcasters in other 
countries now use it.  I have been hearing World
Harvest Radio WHRI in the United States broadcasting on top of it at 
times.  The word I got from NRC-INMS is that there will be an 
announcement soon of a frequency change.

Be ready to retune,

David McGaw




From jmfranke at cox.net  Wed Nov 19 20:24:35 2008
From: jmfranke at cox.net (John Franke)
Date: Wed, 19 Nov 2008 15:24:35 -0500
Subject: [time-nuts] CHU: do not stay tuned...
References: <7.0.1.0.0.20070303172741.0421ecc0@endor.com><797939.32819.qm@web50715.mail.yahoo.com>
	<200811192006.mAJK6US8029996@mailhub2.dartmouth.edu>
Message-ID: <87DBDC56DD3F4FFB8E6D87214DFC17E0@youre7075dc078>

Thanks for the heads up!

John WA4WDL

----- Original Message ----- 
From: "David McGaw" <david at endor.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Wednesday, November 19, 2008 3:06 PM
Subject: [time-nuts] CHU: do not stay tuned...


> It appears that CHU on 7.335MHz will soon be moved.  While CNRC can
> keep transmitting on the frequency, so can broadcasters in other
> countries now use it.  I have been hearing World
> Harvest Radio WHRI in the United States broadcasting on top of it at
> times.  The word I got from NRC-INMS is that there will be an
> announcement soon of a frequency change.
>
> Be ready to retune,
>
> David McGaw
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From bruce.griffiths at xtra.co.nz  Wed Nov 19 21:12:21 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 20 Nov 2008 10:12:21 +1300
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <41A373D58AE14BC4A1315499616BADC5@pc52>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<41A373D58AE14BC4A1315499616BADC5@pc52>
Message-ID: <49248135.9040203@xtra.co.nz>

Tom Van Baak wrote:
> Stephan,
>
> Ah, it's not a stupid question -- I think all of us who have written
> code to interface with GPS receivers have had to deal with this.
>
> Some GPS protocols use escape characters, but the Oncore
> binary protocol doesn't. There are five clues to robustly parsing
> a complete message:
>
> 1) starts with @@
> 2) ends with <cr><lf>
> 3) message length is known, based on message header
> 4) valid checksum
> 5) there may be a pause between sentences
>
> You can use all of these clues to "sync" to a serial data stream
> and accurately determine the start of the next message.
>
> As you already observed, just looking for @@ or <cr><lf> is
> not sufficient. Checking for <cr><lf>@@ is better, but still not
> perfect. To do it right you also need to include message length
> and checksum into the calculation. The length is knowable by
> looking at the message type in the header as it arrives.
>
> If you use a millisecond-level serial timeout that can help even
> more (since if the first two bytes after a pause are @@ you
> know it is a message start, not 16-bits of 0x4040 embedded
> binary data). There is a timing gap between some, but not all
> messages, so use this technique with care. You can also use
> the 1PPS pulse as a start of message hint.
>
> True, a robust solution is not FPGA-friendly, but probably not
> impossible, either. If you can't solve it, consider using a $1
> microcontroller (where this sort of message handling is trivial)
> between the receiver and your FPGA which would parse, edit,
> or reformat the messages to the FPGA's liking.
>
> /tvb
>
>
>   
No need to use an external processor just implement a processor within
the FPGA.
VHDL code for suitable processors is readily available.

Bruce

Bruce


From jgd at johngsbbq.com  Thu Nov 20 04:16:37 2008
From: jgd at johngsbbq.com (Neon John)
Date: Wed, 19 Nov 2008 23:16:37 -0500
Subject: [time-nuts] What's all this about violins in the streets?
In-Reply-To: <9D0AB0566F9C427FA92F2214F9C37410@cyrus>
References: <000c01c9452f$8d8e6a30$b500a8c0@billcomp>
	<9D0AB0566F9C427FA92F2214F9C37410@cyrus>
Message-ID: <h0p9i456ssnls69kghl1tcj846f3ood1sk@4ax.com>

On Wed, 12 Nov 2008 21:27:10 -0600, "Bill Hawkins" <bill at iaxs.net> wrote:

>My apologies, but I didn't think you'd want to hear about jumps.
>
>My good friend, and software genius, was late for a lunch appointment
>today. The "atomic" alarm clock that he has used for years was 3.3
>hours behind this morning, but not on any other morning. My WWVB clock
>was dead on at 4 PM (in MN, where we both are located).
>
>Anybody got a story about an "atomic" clock messing up like that?

Yup.  I have an "Atomix" brand wall mounted clock that picks up the wrong time
by a random amount about once a week.  I have "atomic" clocks all over the
place (would anyone on this list expect any less? :-) so I had to put a little
label on it that says "this clock is not accurate".  I keep it around mainly
for entertainment and because it reads one of my outdoor temperature sensors.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Nothing in life is to be feared. It is only to be understood. -Marie Curie



From jgd at johngsbbq.com  Thu Nov 20 04:22:01 2008
From: jgd at johngsbbq.com (Neon John)
Date: Wed, 19 Nov 2008 23:22:01 -0500
Subject: [time-nuts] Oh the horror
In-Reply-To: <1226872995.20299.120.camel@bg-desktop>
References: <f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
	<1226872995.20299.120.camel@bg-desktop>
Message-ID: <kbp9i45imqpf02s1amf4lla7p81qerm0m9@4ax.com>

On Sun, 16 Nov 2008 23:03:15 +0100, Bj?rn Gabrielsson <bg at lysator.liu.se>
wrote:


>On a much smaller scale... but the "incident" shown in the attached
>picture was no fun either... two old BVAs came the standard (brutal)
>post service packed like in the picture.

Do y'all have UPS down there?  That sounds like a standard high priority extra
special treatment job - run over the package with BOTH the fork lift and the
semi truck.  This is what a UPS's X-ray tube looks like

http://www.neon-john.com/Nuke/xray_tube.jpg

JOhn
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Ignorance more frequently begets confidence than does knowledge. -Darwin



From jgd at johngsbbq.com  Thu Nov 20 04:29:06 2008
From: jgd at johngsbbq.com (Neon John)
Date: Wed, 19 Nov 2008 23:29:06 -0500
Subject: [time-nuts] Oh the horror
In-Reply-To: <20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>
References: <jim77742@gmail.com> of "Mon, 17 Nov 2008 00:38:57 +1100."
	<f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com>
	<20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <ghp9i4hq6jjqh44j7ig7gi9jehn19ap4gv@4ax.com>

On Sun, 16 Nov 2008 15:01:23 -0800, Hal Murray <hmurray at megapathdsl.net>
wrote:

>
>jim77742 at gmail.com said:
>> It looks like the entire shipping case has been dropped or turned over
>> from a reasonable height. The 7mm thick internal glass cylinder has
>> been shattered and inside that the glass bulb has been smashed to
>> bits.
>
>> The whole unit is completely destroyed and useless. 
>
>Sigh.  It hurts even from many thousand miles away...
>
>> My girlfriend just doesn't understand...
>
>There must be some way to explain it.  Does she have a garden?  How about a 
>cloth collection?

First off, I feel yer pain.  Second, there may be a problem in the
specification for the standard issue girlfriend.  One very important
specification for any time-nut-destined Mk1 girlfriend is the ability to feel
blue smoke and released vacuum pain.

My lovely ex of 27 years (and after a 5 year fling, maybe to be current again)
certainly conformed perfectly to that specification.  Of course, she worked
with both hot and cold glass so she had pain to feel too.  LIke lifting a
piece out of the annealing oven, now at room temperature, laying it on the
counter to prepare it for shipping and hearing that characteristic little
"tink" of a stress crack.  I'm reasonably sure that she created a hostile work
environment in our shared shop more than once due to the sound pressure level.

When the aroma of blue smoke wafted through the air, I'd usually get company
for some commiseration, a good back rub and sometimes other condolences.  A
properly spec'ced wife-mate is worth more than even a hydrogen maser.  


IMO of course.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
I'm so cool, I'm afraid to catch cold.



From df6jb at ulrich-bangert.de  Thu Nov 20 07:34:38 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Thu, 20 Nov 2008 08:34:38 +0100
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
Message-ID: <472B05D634454161A0C61DD767C2AF49@athlon>

Stephan,

can you give us a clue what it is all about? What happens with the data
after being decoded by the FPGA? 

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Stephan Sandenbergh
> Gesendet: Mittwoch, 19. November 2008 15:30
> An: Discussion of precise time and frequency measurement
> Betreff: [time-nuts] M12+T ASCII interface - I'm confused?
> 
> 
> Hi All,
> 
> Up until now we've been interfacing my Motorola M12+T's using 
> the Oncore software. However, at this point we are trying to 
> have it interfaced directly to a FPGA. To my mind this should 
> be simple - the commands are discriminated (framed) by 
> looking at the start and terminating bytes sequences when 
> they enter the FIFO, check summed, decoded etc.
> 
> However, I noted something very peculiar about the motorola 
> ASCII protocol: The start bytes @@ and he terminating byte 
> <CR><LF> aren't unique with respect to the data bytes. For 
> instance one could receive a time of 13hrs and 10mins which 
> would look identical to the terminating characters. Initially 
> I thought it made sense since the data is also sent in ascii 
> format. It appears not to be the case.
> 
> It seems to me that the only way in which a command could be 
> robustly identified and check summed is when the interface 
> knows the length of the expected return.  Obviously, the data 
> lengths are dependent on both the actual command and the 
> specific request. This type of intelligence is cumbersome to 
> implement in FPGAs.
> 
> It would be of great help if you could point me in the right 
> direction here. I feel rather stupid in asking such a simple 
> question, but at this point I can't seem to see the light. 
> I'm flabbergasted...
> 
> Best regards,
> 
> Stephan
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From ernieperes at aol.com  Thu Nov 20 09:20:46 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 20 Nov 2008 04:20:46 -0500
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: <d45.345b7d73.364e0de9@aol.com>
References: <d45.345b7d73.364e0de9@aol.com>
Message-ID: <8CB190867C4C87A-5FC-1A8D@FWM-D13.sysops.aol.com>


Hello,

I am fighting to get 1PPS from my Trimble Tbolt GPSDO. Self-survey 
completed and via software the 1PPS also activated
but no1PPS output on the BNC connector. Already tried all the software 
possibilities but no help....
the 1PPS 74HC04 driver IC does does not get any input signal.
On the Tbolt Monitor program no any fault....
Any idea???

Thanks and regards,
Ernie.


From ernieperes at aol.com  Thu Nov 20 09:45:02 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 20 Nov 2008 04:45:02 -0500
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: <8CB190867C4C87A-5FC-1A8D@FWM-D13.sysops.aol.com>
References: <d45.345b7d73.364e0de9@aol.com>
	<8CB190867C4C87A-5FC-1A8D@FWM-D13.sysops.aol.com>
Message-ID: <8CB190BCBA7E0B2-4EC-1DB4@webmail-me13.sysops.aol.com>

Sorry but forget to mention the Unit NOT from TAPR


-----Original Message-----
From: ernieperes at aol.com
To: time-nuts at febo.com
Sent: Thu, 20 Nov 2008 10:20 am
Subject: Re: [time-nuts] Trimble 1 PPS



Hello,

I am fighting to get 1PPS from my Trimble Tbolt GPSDO. Self-survey
completed and via software the 1PPS also activated
but no1PPS output on the BNC connector. Already tried all the software
possibilities but no help....
the 1PPS 74HC04 driver IC does does not get any input signal.
On the Tbolt Monitor program no any fault....
Any idea???

Thanks and regards,
Ernie.

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From hmurray at megapathdsl.net  Thu Nov 20 09:59:04 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 01:59:04 -0800
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: Message from ernieperes@aol.com of "Thu,
	20 Nov 2008 04:45:02 EST."
	<8CB190BCBA7E0B2-4EC-1DB4@webmail-me13.sysops.aol.com> 
Message-ID: <20081120095905.367E4BCD5@ip-64-139-1-69.sjc.megapath.net>

> the 1PPS 74HC04 driver IC does does not get any input signal.

What are you looking at it with?

The pulse is only 10 microseconds wide.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From stephan at rrsg.ee.uct.ac.za  Thu Nov 20 10:36:10 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Thu, 20 Nov 2008 12:36:10 +0200
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <41A373D58AE14BC4A1315499616BADC5@pc52>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<41A373D58AE14BC4A1315499616BADC5@pc52>
Message-ID: <ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com>

Tom,

Thank you for the valuable inputs. I was quietly hoping that I was
misunderstanding the protocol in some way.

My gut tells me that  <Checksum><cr><lf><@><@> would be believable more than
say 95% (if not 99%) of the time. I've got the following observations:

- 95% is a bad number in accurate timing applications.

- the checksum is one of the few things that are easy to do in VHDL.

- one would always miss the first most data stream at startup (not a
problem).

- the last message in the data stream will always only be decoded on the
next second when the new streams are coming through (a potential problem)

Thus, I agree: The only real reliable way is to have a lookup of header
bytes and data length. Disappointing protocol I must add.

I so hoped that this won't be the case. Such is life.

Regards,

Stephan.

2008/11/19 Tom Van Baak <tvb at leapsecond.com>

> Stephan,
>
> Ah, it's not a stupid question -- I think all of us who have written
> code to interface with GPS receivers have had to deal with this.
>
> Some GPS protocols use escape characters, but the Oncore
> binary protocol doesn't. There are five clues to robustly parsing
> a complete message:
>
> 1) starts with @@
> 2) ends with <cr><lf>
> 3) message length is known, based on message header
> 4) valid checksum
> 5) there may be a pause between sentences
>
> You can use all of these clues to "sync" to a serial data stream
> and accurately determine the start of the next message.
>
> As you already observed, just looking for @@ or <cr><lf> is
> not sufficient. Checking for <cr><lf>@@ is better, but still not
> perfect. To do it right you also need to include message length
> and checksum into the calculation. The length is knowable by
> looking at the message type in the header as it arrives.
>
> If you use a millisecond-level serial timeout that can help even
> more (since if the first two bytes after a pause are @@ you
> know it is a message start, not 16-bits of 0x4040 embedded
> binary data). There is a timing gap between some, but not all
> messages, so use this technique with care. You can also use
> the 1PPS pulse as a start of message hint.
>
> True, a robust solution is not FPGA-friendly, but probably not
> impossible, either. If you can't solve it, consider using a $1
> microcontroller (where this sort of message handling is trivial)
> between the receiver and your FPGA which would parse, edit,
> or reformat the messages to the FPGA's liking.
>
> /tvb
>
>
> > Hi All,
> >
> > Up until now we've been interfacing my Motorola M12+T's using the Oncore
> > software. However, at this point we are trying to have it interfaced
> > directly to a FPGA. To my mind this should be simple - the commands are
> > discriminated (framed) by looking at the start and terminating bytes
> > sequences when they enter the FIFO, check summed, decoded etc.
> >
> > However, I noted something very peculiar about the motorola ASCII
> protocol:
> > The start bytes @@ and he terminating byte <CR><LF> aren't unique with
> > respect to the data bytes. For instance one could receive a time of 13hrs
> > and 10mins which would look identical to the terminating characters.
> > Initially I thought it made sense since the data is also sent in ascii
> > format. It appears not to be the case.
> >
> > It seems to me that the only way in which a command could be robustly
> > identified and check summed is when the interface knows the length of the
> > expected return.  Obviously, the data lengths are dependent on both the
> > actual command and the specific request. This type of intelligence is
> > cumbersome to implement in FPGAs.
> >
> > It would be of great help if you could point me in the right direction
> here.
> > I feel rather stupid in asking such a simple question, but at this point
> I
> > can't seem to see the light. I'm flabbergasted...
> >
> > Best regards,
> >
> > Stephan
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From stephan at rrsg.ee.uct.ac.za  Thu Nov 20 10:38:10 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Thu, 20 Nov 2008 12:38:10 +0200
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <49248135.9040203@xtra.co.nz>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<41A373D58AE14BC4A1315499616BADC5@pc52> <49248135.9040203@xtra.co.nz>
Message-ID: <ca708d410811200238g452358e2rd9904ffb1766bafb@mail.gmail.com>

Hi Bruce,

Yes - at this point an external processor is not a real option.

Are you aware of open source code that I could try out?

In hind sight, I should've put a microprocessor core onto the FPGA to do all
the management kind of tasks.

Regards,

Stephan.

No need to use an external processor just implement a processor within
the FPGA.
VHDL code for suitable processors is readily available.

Bruce

Bruce



2008/11/19 Bruce Griffiths <bruce.griffiths at xtra.co.nz>

> Tom Van Baak wrote:
> > Stephan,
> >
> > Ah, it's not a stupid question -- I think all of us who have written
> > code to interface with GPS receivers have had to deal with this.
> >
> > Some GPS protocols use escape characters, but the Oncore
> > binary protocol doesn't. There are five clues to robustly parsing
> > a complete message:
> >
> > 1) starts with @@
> > 2) ends with <cr><lf>
> > 3) message length is known, based on message header
> > 4) valid checksum
> > 5) there may be a pause between sentences
> >
> > You can use all of these clues to "sync" to a serial data stream
> > and accurately determine the start of the next message.
> >
> > As you already observed, just looking for @@ or <cr><lf> is
> > not sufficient. Checking for <cr><lf>@@ is better, but still not
> > perfect. To do it right you also need to include message length
> > and checksum into the calculation. The length is knowable by
> > looking at the message type in the header as it arrives.
> >
> > If you use a millisecond-level serial timeout that can help even
> > more (since if the first two bytes after a pause are @@ you
> > know it is a message start, not 16-bits of 0x4040 embedded
> > binary data). There is a timing gap between some, but not all
> > messages, so use this technique with care. You can also use
> > the 1PPS pulse as a start of message hint.
> >
> > True, a robust solution is not FPGA-friendly, but probably not
> > impossible, either. If you can't solve it, consider using a $1
> > microcontroller (where this sort of message handling is trivial)
> > between the receiver and your FPGA which would parse, edit,
> > or reformat the messages to the FPGA's liking.
> >
> > /tvb
> >
> >
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From stephan at rrsg.ee.uct.ac.za  Thu Nov 20 10:47:32 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Thu, 20 Nov 2008 12:47:32 +0200
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <472B05D634454161A0C61DD767C2AF49@athlon>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<472B05D634454161A0C61DD767C2AF49@athlon>
Message-ID: <ca708d410811200247h73024201o874943e1c02b9810@mail.gmail.com>

Hi Ulrich,

Sure - among other things the FPGA keeps a real-time clock. It ticks away on
a disciplined clock, but the time and date value is constantly kept in sync
with what the GPS spits out as UTC.

So, the FPGA catches some of the GPS messages, but also allow for a straight
path through to a PC. Everything that comes in is passed on the the PC -
this way existing software could still be used to interface with the GPS
etc.

Stephan.

2008/11/20 Ulrich Bangert <df6jb at ulrich-bangert.de>

> Stephan,
>
> can you give us a clue what it is all about? What happens with the data
> after being decoded by the FPGA?
>
> Best regards
> Ulrich Bangert
>
> > -----Ursprungliche Nachricht-----
> > Von: time-nuts-bounces at febo.com
> > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Stephan Sandenbergh
> > Gesendet: Mittwoch, 19. November 2008 15:30
> > An: Discussion of precise time and frequency measurement
> > Betreff: [time-nuts] M12+T ASCII interface - I'm confused?
> >
> >
> > Hi All,
> >
> > Up until now we've been interfacing my Motorola M12+T's using
> > the Oncore software. However, at this point we are trying to
> > have it interfaced directly to a FPGA. To my mind this should
> > be simple - the commands are discriminated (framed) by
> > looking at the start and terminating bytes sequences when
> > they enter the FIFO, check summed, decoded etc.
> >
> > However, I noted something very peculiar about the motorola
> > ASCII protocol: The start bytes @@ and he terminating byte
> > <CR><LF> aren't unique with respect to the data bytes. For
> > instance one could receive a time of 13hrs and 10mins which
> > would look identical to the terminating characters. Initially
> > I thought it made sense since the data is also sent in ascii
> > format. It appears not to be the case.
> >
> > It seems to me that the only way in which a command could be
> > robustly identified and check summed is when the interface
> > knows the length of the expected return.  Obviously, the data
> > lengths are dependent on both the actual command and the
> > specific request. This type of intelligence is cumbersome to
> > implement in FPGAs.
> >
> > It would be of great help if you could point me in the right
> > direction here. I feel rather stupid in asking such a simple
> > question, but at this point I can't seem to see the light.
> > I'm flabbergasted...
> >
> > Best regards,
> >
> > Stephan
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> > and
> > follow the instructions there.
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From stephan at rrsg.ee.uct.ac.za  Thu Nov 20 10:50:05 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Thu, 20 Nov 2008 12:50:05 +0200
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <964475.11768.qm@web30307.mail.mud.yahoo.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<964475.11768.qm@web30307.mail.mud.yahoo.com>
Message-ID: <ca708d410811200250s765fec34u731e9ba64215e793@mail.gmail.com>

Hi,

NMEA would have been nice - but this is a timing application.

Stephan.

2008/11/19 Stanley Reynolds <stanley_reynolds at yahoo.com>

> Looking at the user guide which is the extent of my experience. Would the
> position version of the M12+ be a better choice for your application ? That
> is trade NMEA-0183 for all the timing features ?
>
> Stanley
>
> Link to user guide :
> http://www.synergy-gps.com/images/stories/guides/m12+userguide.pdf
>
>
>
>
>
>
> ________________________________
> From: Stephan Sandenbergh <stephan at rrsg.ee.uct.ac.za>
> To: Discussion of precise time and frequency measurement <
> time-nuts at febo.com>
> Sent: Wednesday, November 19, 2008 8:29:59 AM
> Subject: [time-nuts] M12+T ASCII interface - I'm confused?
>
> Hi All,
>
> Up until now we've been interfacing my Motorola M12+T's using the Oncore
> software. However, at this point we are trying to have it interfaced
> directly to a FPGA. To my mind this should be simple - the commands are
> discriminated (framed) by looking at the start and terminating bytes
> sequences when they enter the FIFO, check summed, decoded etc.
>
> However, I noted something very peculiar about the motorola ASCII protocol:
> The start bytes @@ and he terminating byte <CR><LF> aren't unique with
> respect to the data bytes. For instance one could receive a time of 13hrs
> and 10mins which would look identical to the terminating characters.
> Initially I thought it made sense since the data is also sent in ascii
> format. It appears not to be the case.
>
> It seems to me that the only way in which a command could be robustly
> identified and check summed is when the interface knows the length of the
> expected return.  Obviously, the data lengths are dependent on both the
> actual command and the specific request. This type of intelligence is
> cumbersome to implement in FPGAs.
>
> It would be of great help if you could point me in the right direction
> here.
> I feel rather stupid in asking such a simple question, but at this point I
> can't seem to see the light. I'm flabbergasted...
>
> Best regards,
>
> Stephan
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From hmurray at megapathdsl.net  Thu Nov 20 11:19:37 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 03:19:37 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: Message from "Stephan Sandenbergh" <stephan@rrsg.ee.uct.ac.za> 
	of "Thu, 20 Nov 2008 12:36:10 +0200."
	<ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com> 
Message-ID: <20081120111938.D4202BCD5@ip-64-139-1-69.sjc.megapath.net>


> My gut tells me that  <Checksum><cr><lf><@><@> would be believable
> more than say 95% (if not 99%) of the time. I've got the following
> observations: 

I suggest that you debug things in software and then figure out how to 
implement that algorithm in the FPGA.  You can rearrange code and try again 
to make it easier to move your code to the FPGA.

Searching for <cr><lf><@><@> means you will wait for the start of the next 
packet before processing the current one.

> the checksum is one of the few things that are easy to do in VHDL.

So what.  What are you going to do with the rest of the data?

In the old days (TTL DIPs) we used to build microcoded machines rather than 
real CPUs.  They were tuned to the specific problem.  That was before c took 
over, at least with the people I worked with.  That general style actually 
fits fairly well into a FPGA.  The key idea is that it lets you think of the 
problem as software rather than hardware.  That's usually a lot simpler if 
your state machine has many states that mostly map to something like a 
program counter.  I'll say more if anybody wants.  I think Xilinx had an app 
note.  You have to write the microcode and you probably have to write an 
assembler.  (We just grabbed one from a previous project and hacked it to fit 
our new machine.)  These days it may be better to through a few more gates at 
the problem and use a real CPU that runs c.




RS-232 shouldn't make any bit errors if you are running at sensible 
speed/distances.  It shouldn't get any byte errors unless your hardware/OS is 
broken or your user code can't get enough CPU cycles.  So it's reasonable to 
assume that most of the data will be clean.  (not perfect, but good enough so 
you don't have to even think about complicated error recovery.)

If I wanted to process that stuff, I'd have a mode bit: hunt vs in-sync.  
(This is assuming I really do understand the packet format.)

In hunt mode, I'd scan for <cr><lf>@@, assume that was the start of a packet, 
then grab the command bytes, lookup the length, and read that much.  If the 
checksum matched, and the next two bytes were <cr><lf>, I'd switch to in-sync 
and process the packet.  If not, go back and try again.  If I didn't 
recognize the command bytes, stay in hunt mode and go back to looking for <cr>
<lf>@@.

When in-sync mode, I'd read two bytes, check for @@, grab the command bytes, 
lookup the length, read that much, check the checksum, check for <cr><lf>...  
If anything didn't check, I'd raise a flag and switch back to hunt mode.  
That flag shouldn't ever go off.

That mode bit is mostly for thinking.  The code may fold together so you 
don't need it.  But something similar may be needed for debugging.  You want 
to flag an error if something goes wrong after you have gotten in sync.  You 
don't want to raise an alarm until you do get in sync.




-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From df6jb at ulrich-bangert.de  Thu Nov 20 11:48:40 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Thu, 20 Nov 2008 12:48:40 +0100
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200247h73024201o874943e1c02b9810@mail.gmail.com>
Message-ID: <3DFE1146A28F482391D0035C35AA20DE@athlon>

Hi Stephan,

I have been asking my question because I wanted to learn whether an FPGA
was really needed. Don't understand me wrong, I am a dedicated user of
XILINX and ALTERA FPGAs and CPLDs myself, but sometimes a $2
microcontroller will do the job better than any FPGA. It is correct that
you may put a 32 bit micro + numerous peripherals say in an XC3S400 and
still it is half-empty for other purposes. I also use technology like
that. However it is not ALWAYS better. Even the bigger FPGAs do not have
enough RAM as that you could hold the embedded firmware + the RAM needed
for the application in it. That calls for external RAM. Also be prepared
NOT to fit the complete firmware into the FPGA's configuration device.
One must be lucky if a kind of bootloader fits into the FPGA
configuration that enables the FPGA (once that it is configured) to load
the "real" firmware from an external memory device like a serial EEPROM.
You see that there are a number of trade offs and one has to think very
carefully which solution is the best overall compromise.

Best regards
Ulrich Bangert  

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Stephan Sandenbergh
> Gesendet: Donnerstag, 20. November 2008 11:48
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] M12+T ASCII interface - I'm confused?
> 
> 
> Hi Ulrich,
> 
> Sure - among other things the FPGA keeps a real-time clock. 
> It ticks away on a disciplined clock, but the time and date 
> value is constantly kept in sync with what the GPS spits out as UTC.
> 
> So, the FPGA catches some of the GPS messages, but also allow 
> for a straight path through to a PC. Everything that comes in 
> is passed on the the PC - this way existing software could 
> still be used to interface with the GPS etc.
> 
> Stephan.
> 
> 2008/11/20 Ulrich Bangert <df6jb at ulrich-bangert.de>
> 
> > Stephan,
> >
> > can you give us a clue what it is all about? What happens with the 
> > data after being decoded by the FPGA?
> >
> > Best regards
> > Ulrich Bangert
> >
> > > -----Ursprungliche Nachricht-----
> > > Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] 
> > > Im Auftrag von Stephan Sandenbergh
> > > Gesendet: Mittwoch, 19. November 2008 15:30
> > > An: Discussion of precise time and frequency measurement
> > > Betreff: [time-nuts] M12+T ASCII interface - I'm confused?
> > >
> > >
> > > Hi All,
> > >
> > > Up until now we've been interfacing my Motorola M12+T's using the 
> > > Oncore software. However, at this point we are trying to have it 
> > > interfaced directly to a FPGA. To my mind this should be simple - 
> > > the commands are discriminated (framed) by looking at the 
> start and 
> > > terminating bytes sequences when they enter the FIFO, 
> check summed, 
> > > decoded etc.
> > >
> > > However, I noted something very peculiar about the motorola ASCII 
> > > protocol: The start bytes @@ and he terminating byte 
> <CR><LF> aren't 
> > > unique with respect to the data bytes. For instance one could 
> > > receive a time of 13hrs and 10mins which would look 
> identical to the 
> > > terminating characters. Initially I thought it made sense 
> since the 
> > > data is also sent in ascii format. It appears not to be the case.
> > >
> > > It seems to me that the only way in which a command could be 
> > > robustly identified and check summed is when the 
> interface knows the 
> > > length of the expected return.  Obviously, the data lengths are 
> > > dependent on both the actual command and the specific 
> request. This 
> > > type of intelligence is cumbersome to implement in FPGAs.
> > >
> > > It would be of great help if you could point me in the right 
> > > direction here. I feel rather stupid in asking such a simple 
> > > question, but at this point I can't seem to see the light. I'm 
> > > flabbergasted...
> > >
> > > Best regards,
> > >
> > > Stephan
> > > _______________________________________________
> > > time-nuts mailing list -- time-nuts at febo.com
> > > To unsubscribe, go to
> > > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts and
> > > follow the instructions there.
> > >
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From bruce.griffiths at xtra.co.nz  Thu Nov 20 11:51:52 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Fri, 21 Nov 2008 00:51:52 +1300
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200238g452358e2rd9904ffb1766bafb@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<41A373D58AE14BC4A1315499616BADC5@pc52>
	<49248135.9040203@xtra.co.nz>
	<ca708d410811200238g452358e2rd9904ffb1766bafb@mail.gmail.com>
Message-ID: <49254F58.6040905@xtra.co.nz>

Stephan Sandenbergh wrote:
> Hi Bruce,
>
> Yes - at this point an external processor is not a real option.
>
> Are you aware of open source code that I could try out?
>
> In hind sight, I should've put a microprocessor core onto the FPGA to do all
> the management kind of tasks.
>
> Regards,
>
> Stephan.
>   
Stephan

If you dont wish to use Alteras Nios processor or Xilinx's Picoblaze or
Microblaze, VHDL for a Forth processor has been posted at:
http://www.ultratechnology.com/4thvhdl.htm

Other open source cores can be found here:

http://www.opencores.org/browse.cgi/filter/category_microprocessor


Bruce



From ernieperes at aol.com  Thu Nov 20 12:20:30 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 20 Nov 2008 07:20:30 -0500
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: <20081120095905.367E4BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <8CB1921834B7D6F-F74-120B@WEBMAIL-DG15.sim.aol.com>

100MHz HP digital scope.


-----Original Message-----
From: Hal Murray <hmurray at megapathdsl.net>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Thu, 20 Nov 2008 10:59 am
Subject: Re: [time-nuts] Trimble 1 PPS



> the 1PPS 74HC04 driver IC does does not get any input signal.

What are you looking at it with?

The pulse is only 10 microseconds wide.

--
These are my opinions, not necessarily my employer's.  I hate spam.




_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
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From Jean-Louis.Oneto at obs-azur.fr  Thu Nov 20 13:02:36 2008
From: Jean-Louis.Oneto at obs-azur.fr (Jean-Louis Oneto)
Date: Thu, 20 Nov 2008 13:02:36 -0000
Subject: [time-nuts] Oh the horror
References: <jim77742@gmail.com> of "Mon, 17 Nov 2008 00:38:57
	+1100."<f616e0f80811160538n36fce421j5dfd385a37ca9ad3@mail.gmail.com><20081116230124.8D575BCD6@ip-64-139-1-69.sjc.megapath.net>
	<ghp9i4hq6jjqh44j7ig7gi9jehn19ap4gv@4ax.com>
Message-ID: <71F012E3E69140C6821789B9481BBFCC@pcreopt>


----- Original Message ----- 
From: "Neon John" <jgd at johngsbbq.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, November 20, 2008 4:29 AM
Subject: Re: [time-nuts] Oh the horror


[...]
>
> When the aroma of blue smoke wafted through the air, I'd usually get 
> company
> for some commiseration, a good back rub and sometimes other condolences. 
> A
> properly spec'ced wife-mate is worth more than even a hydrogen maser.

Especially if her has long-term stability as well...

>
>
> IMO of course.
>
> John
> --
> John De Armond
> See my website for my current email address
> http://www.neon-john.com
> http://www.johndearmond.com <-- best little blog on the net!
> Tellico Plains, Occupied TN
> I'm so cool, I'm afraid to catch cold.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 



From ernieperes at aol.com  Thu Nov 20 14:07:47 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 20 Nov 2008 09:07:47 -0500
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: <8CB190BCBA7E0B2-4EC-1DB4@webmail-me13.sysops.aol.com>
References: <d45.345b7d73.364e0de9@aol.com><8CB190867C4C87A-5FC-1A8D@FWM-D13.sysops.aol.com>
	<8CB190BCBA7E0B2-4EC-1DB4@webmail-me13.sysops.aol.com>
Message-ID: <8CB19307FE7EEB0-640-F6D@WEBMAIL-MC21.sysops.aol.com>




-----Original Message-----
From: ernieperes at aol.com
To: time-nuts at febo.com
Sent: Thu, 20 Nov 2008 10:45 am
Subject: Re: [time-nuts] Trimble 1 PPS



Sorry but forget to mention the Unit NOT from TAPR


-----Original Message-----
From: ernieperes at aol.com
To: time-nuts at febo.com
Sent: Thu, 20 Nov 2008 10:20 am
Subject: Re: [time-nuts] Trimble 1 PPS



Hello,

I am fighting to get 1PPS from my Trimble Tbolt GPSDO. Self-survey
completed and via software the 1PPS also activated
but no1PPS output on the BNC connector. Already tried all the software
possibilities but no help....
the 1PPS 74HC04 driver IC does does not get any input signal.
On the Tbolt Monitor program no any fault....
Any idea???

Thanks and regards,
Ernie.

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
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and follow the instructions there.


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and follow the instructions there.



From tvb at LeapSecond.com  Thu Nov 20 14:08:55 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Thu, 20 Nov 2008 06:08:55 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com><41A373D58AE14BC4A1315499616BADC5@pc52>
	<ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com>
Message-ID: <0B21646114CB4EFF9D05B9FF590AF1C5@pc52>

> Tom,
> 
> Thank you for the valuable inputs. I was quietly hoping that I was
> misunderstanding the protocol in some way.
> 
> My gut tells me that  <Checksum><cr><lf><@><@> would be believable more than
> say 95% (if not 99%) of the time. I've got the following observations:
> 
> - 95% is a bad number in accurate timing applications.

You misunderstand. You can get as close to 100% as you
want. Some of us have logged data from M12+ receivers without
error for weeks or months -- gigabytes, error-free.

> - the checksum is one of the few things that are easy to do in VHDL.
> 
> - one would always miss the first most data stream at startup (not a
> problem).

Correct, not a problem. Note NMEA, TSIP, and any other
GPS protocol has the same feature, right?

> - the last message in the data stream will always only be decoded on the
> next second when the new streams are coming through (a potential problem)

Not true. You can process the entire message as soon as
the checksum matches. Do you see why?

If you're brave you can process the message, byte by byte,
field by field, as it arrives in real time and use the checksum
as a commit.

> Thus, I agree: The only real reliable way is to have a lookup of header
> bytes and data length. Disappointing protocol I must add.

A protocol like NMEA (ascii at 4800 baud) doesn't have
sufficient bandwidth to accomodate all the data from a timing
receiver. So Motorola (and Trimble, etc.) all have binary
protocols (~2x the density of ascii) and higher baudrates.

> I so hoped that this won't be the case. Such is life.
> 
> Regards,
> 
> Stephan.

/tvb



From ernieperes at aol.com  Thu Nov 20 14:10:28 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Thu, 20 Nov 2008 09:10:28 -0500
Subject: [time-nuts] Trimble 1 PPS
In-Reply-To: <20081120095905.367E4BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <8CB1930E0618E0F-640-FA5@WEBMAIL-MC21.sysops.aol.com>

I have to apologize because it was my failure to set up this Digital 
storage HP scope. Now I got the 1 PPS.....it is working.

Rgds Ernie.


-----Original Message-----
From: Hal Murray <hmurray at megapathdsl.net>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Thu, 20 Nov 2008 10:59 am
Subject: Re: [time-nuts] Trimble 1 PPS



> the 1PPS 74HC04 driver IC does does not get any input signal.

What are you looking at it with?

The pulse is only 10 microseconds wide.

--
These are my opinions, not necessarily my employer's. I hate spam.




_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From stephan at rrsg.ee.uct.ac.za  Thu Nov 20 15:16:40 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Thu, 20 Nov 2008 17:16:40 +0200
Subject: [time-nuts] Fwd:  M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200712i40de450er39cc9fae48dbde83@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<41A373D58AE14BC4A1315499616BADC5@pc52>
	<ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com>
	<0B21646114CB4EFF9D05B9FF590AF1C5@pc52>
	<ca708d410811200712i40de450er39cc9fae48dbde83@mail.gmail.com>
Message-ID: <ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>

Hi,

Now I'm slightly confused:

>
> > My gut tells me that  <Checksum><cr><lf><@><@> would be believable more than
> > say 95% (if not 99%) of the time. I've got the following observations:

In the above I assumed no data length checking is employed.

> >
> > - 95% is a bad number in accurate timing applications.
>
> You misunderstand. You can get as close to 100% as you
> want. Some of us have logged data from M12+ receivers without
> error for weeks or months -- gigabytes, error-free.

Sure, I assume you refer to the case when you check the data length as
well? I meant that the <Checksum><cr><lf><@><@> byte string could also
potentially exist in the data itself, but only in very rare cases
(from there the 95% thumb suck).

>
> > - the checksum is one of the few things that are easy to do in VHDL.
> >
> > - one would always miss the first most data stream at startup (not a
> > problem).
>
> Correct, not a problem. Note NMEA, TSIP, and any other
> GPS protocol has the same feature, right?
>
> > - the last message in the data stream will always only be decoded on the
> > next second when the new streams are coming through (a potential problem)
>
> Not true. You can process the entire message as soon as
> the checksum matches. Do you see why?
>
> If you're brave you can process the message, byte by byte,
> field by field, as it arrives in real time and use the checksum
> as a commit.

Again, the checksum could be part of the data string - so without
checking the data length you'll be waiting for the @@ (less probable
to exist in data).

>
> > Thus, I agree: The only real reliable way is to have a lookup of header
> > bytes and data length. Disappointing protocol I must add.
>

Stephan


From cfharris at erols.com  Thu Nov 20 15:33:46 2008
From: cfharris at erols.com (Chuck Harris)
Date: Thu, 20 Nov 2008 10:33:46 -0500
Subject: [time-nuts] Fwd:  M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<41A373D58AE14BC4A1315499616BADC5@pc52>	<ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com>	<0B21646114CB4EFF9D05B9FF590AF1C5@pc52>	<ca708d410811200712i40de450er39cc9fae48dbde83@mail.gmail.com>
	<ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>
Message-ID: <4925835A.4070500@erols.com>

Stephan Sandenbergh wrote:
> Hi,
> 
> Now I'm slightly confused:
> 
>>> My gut tells me that  <Checksum><cr><lf><@><@> would be believable more than
>>> say 95% (if not 99%) of the time. I've got the following observations:
> 
> In the above I assumed no data length checking is employed.
> 
>>> - 95% is a bad number in accurate timing applications.
>> You misunderstand. You can get as close to 100% as you
>> want. Some of us have logged data from M12+ receivers without
>> error for weeks or months -- gigabytes, error-free.
> 
> Sure, I assume you refer to the case when you check the data length as
> well? I meant that the <Checksum><cr><lf><@><@> byte string could also
> potentially exist in the data itself, but only in very rare cases
> (from there the 95% thumb suck).

No it cannot.  It would be:<checksum><cr><cr><lf><lf><@><@><@><@>...

As I understand it, they use a byte stuff code, where any of the "special"
bytes must be doubled if they are in the data.... And, there must be a
data area length check or you could get into some truly pathological situations.

-Chuck Harris


From brooke at pacific.net  Thu Nov 20 17:04:51 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 20 Nov 2008 09:04:51 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200250s765fec34u731e9ba64215e793@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<964475.11768.qm@web30307.mail.mud.yahoo.com>
	<ca708d410811200250s765fec34u731e9ba64215e793@mail.gmail.com>
Message-ID: <492598B3.5000104@pacific.net>

Hi Stephan:

I've heard from Art at Synergy that the latest i-Lotus versions of the M12+T 
receivers have NMEA enabled.  That's to say you can switch to that protocol.

Have Fun,

Brooke Clarke
http://www.prc68.com

Stephan Sandenbergh wrote:
> Hi,
> 
> NMEA would have been nice - but this is a timing application.
> 
> Stephan.
> 
> 2008/11/19 Stanley Reynolds <stanley_reynolds at yahoo.com>
> 
>> Looking at the user guide which is the extent of my experience. Would the
>> position version of the M12+ be a better choice for your application ? That
>> is trade NMEA-0183 for all the timing features ?
>>
>> Stanley
>>
>> Link to user guide :
>> http://www.synergy-gps.com/images/stories/guides/m12+userguide.pdf
>>
>>
>>
>>
>>
>>
>> ________________________________
>> From: Stephan Sandenbergh <stephan at rrsg.ee.uct.ac.za>
>> To: Discussion of precise time and frequency measurement <
>> time-nuts at febo.com>
>> Sent: Wednesday, November 19, 2008 8:29:59 AM
>> Subject: [time-nuts] M12+T ASCII interface - I'm confused?
>>
>> Hi All,
>>
>> Up until now we've been interfacing my Motorola M12+T's using the Oncore
>> software. However, at this point we are trying to have it interfaced
>> directly to a FPGA. To my mind this should be simple - the commands are
>> discriminated (framed) by looking at the start and terminating bytes
>> sequences when they enter the FIFO, check summed, decoded etc.
>>
>> However, I noted something very peculiar about the motorola ASCII protocol:
>> The start bytes @@ and he terminating byte <CR><LF> aren't unique with
>> respect to the data bytes. For instance one could receive a time of 13hrs
>> and 10mins which would look identical to the terminating characters.
>> Initially I thought it made sense since the data is also sent in ascii
>> format. It appears not to be the case.
>>
>> It seems to me that the only way in which a command could be robustly
>> identified and check summed is when the interface knows the length of the
>> expected return.  Obviously, the data lengths are dependent on both the
>> actual command and the specific request. This type of intelligence is
>> cumbersome to implement in FPGAs.
>>
>> It would be of great help if you could point me in the right direction
>> here.
>> I feel rather stupid in asking such a simple question, but at this point I
>> can't seem to see the light. I'm flabbergasted...
>>
>> Best regards,
>>
>> Stephan
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From kyrrin at bluefeathertech.com  Thu Nov 20 17:15:18 2008
From: kyrrin at bluefeathertech.com (Bruce Lane)
Date: Thu, 20 Nov 2008 09:15:18 -0800
Subject: [time-nuts] I'm back! And I need a receiver...
Message-ID: <200811200915180795.02337FAD@192.168.42.129>

Fellow clock-tickers,

	I have returned from a most worthwhile Mexico vacation! It was great fun, but I'm glad to be home.

	With that said - Murphy struck, hard, the day before I left by taking out the GPS receiver (again!) in my Odetics 425 clock. I'm beginning to wonder if this was a common failure for these units.

	In any case -- Does anyone have a spare Magellan model OEM 5000 module that I could convince you to part with?

	Failing that -- I'm not optimistic about being able to modify the Odetics to work from a more modern NMEA-output module, so it is likely that I would have to replace it. What I'd be looking for is a rackmounted unit, no more than 4U high, that can put out disciplined 10MHz and IRIG-B time code. A Trak Systems 882x series would be nice, but I know how popular those are.

	Thanks much.


-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
"Quid Malmborg in Plano..."



From tvb at LeapSecond.com  Thu Nov 20 17:44:05 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Thu, 20 Nov 2008 09:44:05 -0800
Subject: [time-nuts] Fwd:  M12+T ASCII interface - I'm confused?
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com><41A373D58AE14BC4A1315499616BADC5@pc52><ca708d410811200236y25cc2499v263c267842f0967b@mail.gmail.com><0B21646114CB4EFF9D05B9FF590AF1C5@pc52><ca708d410811200712i40de450er39cc9fae48dbde83@mail.gmail.com>
	<ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>
Message-ID: <F0FE2D7584F04F67BF0D900F08B60B00@pc52>

>> You misunderstand. You can get as close to 100% as you
>> want. Some of us have logged data from M12+ receivers without
>> error for weeks or months -- gigabytes, error-free.
> 
> Sure, I assume you refer to the case when you check the data length as
> well? I meant that the <Checksum><cr><lf><@><@> byte string could also
> potentially exist in the data itself, but only in very rare cases
> (from there the 95% thumb suck).

Yes, you must use the data length. These are *packets*; all
of which have their own fixed length. See pages 30, 31 of the
M12+ user manual.

>> If you're brave you can process the message, byte by byte,
>> field by field, as it arrives in real time and use the checksum
>> as a commit.
> 
> Again, the checksum could be part of the data string - so without
> checking the data length you'll be waiting for the @@ (less probable
> to exist in data).

No no, the checksum is a designated byte at a known offset
within the packet. You first read the whole packet. Then you
validate the checksum byte and/or do other sanity checks on
the data. You don't just go looking through all the bytes in the
packet for any old byte that equals some value.

Maybe re-read Hal's message where he talked about a hunt
and sync mode. That got the point across nicely.

I hope you end up liking the binary format; I'm not sure how it
could be improved.

/tvb



From danrae at verizon.net  Thu Nov 20 17:57:48 2008
From: danrae at verizon.net (Dan Rae)
Date: Thu, 20 Nov 2008 09:57:48 -0800
Subject: [time-nuts] To improve a Tbolt?
Message-ID: <4925A51C.2010602@verizon.net>

I have been reading with interest John Miles' page about his Tbolt 
'upgrade'.

http://www.thegleam.com/ke5fx/tbolt.htm

I have a newly acquired Tbolt here, and also have lying around an almost 
identical 10811-60111 OCXO which I am considering using with it, exactly 
as John describes.  However my Tbolt is of a later vintage than John's 
(2005 date code) and I wonder if that would show as big an improvement 
as John reports.  The on board OCXO on this one has a Trimble sticker on 
it, but otherwise looks similar to the one pictured on John's page.  The 
GPS receiver area of my board also looks very different, but I don't 
think this would have any effect.

Not having the sort of phase noise measuring facilities here to be able 
to test it, I am wondering if anyone else has done this with a similar 
vintage Tbolt, and could say if it is likely to show as big an 
improvement as John seems to be getting.

I was a little surprised at the amount of short term variation, of the 
order of minutes duration, that I was seeing on another Tbolt when using 
it to set a Rb standard. 

The obvious answer to my question is to try it and see, but I'd 
appreciate hearing from anyone who has tried it!

Dan



From GandalfG8 at aol.com  Thu Nov 20 18:33:35 2008
From: GandalfG8 at aol.com (GandalfG8 at aol.com)
Date: Thu, 20 Nov 2008 13:33:35 EST
Subject: [time-nuts] I'm back! And I need a receiver...
Message-ID: <c2a.3dfed60e.3657077f@aol.com>

 
In a message dated 20/11/2008 17:16:18 GMT Standard Time,  
kyrrin at bluefeathertech.com writes:

What I'd  be looking for is a rackmounted unit, no more than 4U high, that 
can put out  disciplined 10MHz and IRIG-B time code. A Trak Systems 882x series 
would be  nice, but I know how popular those are.



---------------------
I thought that too but make sure you're getting what you expect.
 
At the end of last month I bought a Trak 8821B-7 via the usual place,  others 
here may well have bid on it too, it didn't have the display but I'd  already 
got an IRIG-B display unit so no problem there, or so I thought.
It turned out to be a base station special, with an original Trak fitted  
16.384MHz oscillator and with the IRIG-B and divided frequency outputs not  
fitted.
 
Bit of an expensive mistake that one:-(
 
Sorry to hear the 5000 module didn't survive too long.
 
regards
 
Nigel
GM8PZR
 

From brad at shinji.net  Thu Nov 20 18:40:31 2008
From: brad at shinji.net (Brad Stockdale)
Date: Thu, 20 Nov 2008 13:40:31 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
Message-ID: <mailman.8.1227206438.2539.time-nuts@febo.com>

Hello all,

    Thank you to everyone that has helped (and some that continue to 
help) me with my GPSDO equipment post... I've got a few leads out 
there and hopefully I'll be able to get ahold of some of these units 
soon... I really am looking forward to getting to work with some other GPSDO's.

    Anyway, on to the reason for this post... I'd like to get some 
receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I 
know that HEARING them may not be a 'normal' request, but I just 
would like to monitor the audio as well as being able to decode the signals...

    I guess the first thing to take care of is receiving the signals. 
Can anyone recommend decent receivers for these stations? I guess the 
list of frequencies would be:

	o WWVB = 60 KHz
	o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
	o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz

    Hmm, I just noticed that WWV and WWVH overlap... How in the heck 
do you differentiate between the two stations if they broadcast on 
all the same channels?

    Anyway, I wouldn't mind a kit type of project that would let me 
receive these signals... Maybe I'll check out Ramsey Electronics, 
Rainbow Kits, Velleman, et al. Surely one of them has kits for these 
broadcast ranges.

    Can anyone suggest a kit, or project listed online with 
schematics and parts lists, or I guess even reasonably priced commercial units?

    If I can't get radios that have built in decoders for these 
stations, I'd be happy just receiving their audio and then trying to 
build my own decoder using a PIC or something...

    Thanks for any advice.

Brad




From jra at febo.com  Thu Nov 20 18:55:24 2008
From: jra at febo.com (John Ackermann N8UR)
Date: Thu, 20 Nov 2008 13:55:24 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESF-0002F3-5R@meow.febo.com>
References: <E1L3ESF-0002F3-5R@meow.febo.com>
Message-ID: <4925B29C.2070605@febo.com>

Brad Stockdale wrote:
[ ... ]
>     Anyway, on to the reason for this post... I'd like to get some 
> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I 
> know that HEARING them may not be a 'normal' request, but I just 
> would like to monitor the audio as well as being able to decode the signals...
broadcast ranges.

[ ... ]
>     Can anyone suggest a kit, or project listed online with 
> schematics and parts lists, or I guess even reasonably priced commercial units?
> 
>     If I can't get radios that have built in decoders for these 
> stations, I'd be happy just receiving their audio and then trying to 
> build my own decoder using a PIC or something...

If you don't mind a big, heavy box, the HP 3586[A,B,C] selective 
voltmeters are absolutely wonderful tools for any sort of LF/HF 
measurement.  They tune from 20 Hz to 32 MHz and have narrow 20 and 400 
Hz filter bandwidths, as well as a voice-bandwidth filter (the width 
depends on the model and option).  They read amplitude to 0.01 dB and 
can count a received carrier to 0.1 Hz frequency resolution.

They have a speaker and line-level audio output, but no decoder.  They 
also have a GPIB connector, so you can use a computer to tune and read 
frequency and amplitude.

The "C" model is the best for lab use, because it has 50/75/600 ohm 
input options, and uses standard BNC and binding post input connectors. 
  The A and B models were designed for telco use and have slightly weird 
input impedances and connectors, but nothing to stop them from still 
being very useful.

They sometimes go on eBay for <$200, which is a steal in my book.  They 
weigh about 50 pounds, though, so aren't exactly portable.

John


From chris.kuethe at gmail.com  Thu Nov 20 18:55:36 2008
From: chris.kuethe at gmail.com (Chris Kuethe)
Date: Thu, 20 Nov 2008 10:55:36 -0800
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESF-0002F3-3H@meow.febo.com>
References: <E1L3ESF-0002F3-3H@meow.febo.com>
Message-ID: <91981b3e0811201055s116f2222r2a8094fa6a1673cc@mail.gmail.com>

On Thu, Nov 20, 2008 at 10:40 AM, Brad Stockdale <brad at shinji.net> wrote:
>        o WWVB = 60 KHz

I bought a nice little module from digi-key to handle this.
561-1014-ND, under $11 including the ferrite antenna.

>        o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
>        o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz
>
>    Hmm, I just noticed that WWV and WWVH overlap... How in the heck
> do you differentiate between the two stations if they broadcast on
> all the same channels?

different gender of voice, and they don't talk at the same time.

>    Can anyone suggest a kit, or project listed online with
> schematics and parts lists, or I guess even reasonably priced commercial units?

See the above digi-key module. hang it off an arduino or something...

>    If I can't get radios that have built in decoders for these
> stations, I'd be happy just receiving their audio and then trying to
> build my own decoder using a PIC or something...

lots of existing work to build on
http://www.siwawi.arubi.uni-kl.de/avr_projects/arm_projects/glcd_dcf77/index.html
http://www.schatenseite.de/binaryclock.html?&L=2


-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?


From jmfranke at cox.net  Thu Nov 20 18:58:38 2008
From: jmfranke at cox.net (John Franke)
Date: Thu, 20 Nov 2008 13:58:38 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
References: <E1L3ESE-0002F3-WE@meow.febo.com>
Message-ID: <97FDE17575C84A7DA7DAF11B15F3B09F@youre7075dc078>

The ticks are diferent frequency tines.

From: http://tf.nist.gov/timefreq/general/pdf/1383.pdf :

The most frequent sounds heard on WWV and WWVH are the seconds pulses. These 
pulses

are heard every second except on the 29th and 59th seconds of each minute.

The first pulse of each hour is an 800 ms pulse of 1500 Hz. The first pulse 
of each minute

is an 800 ms pulse of 1000 Hz at WWV and 1200 Hz at WWVH. The remaining 
second

pulses are short audio bursts (5 ms pulses of 1000 Hz at WWV and 1200 Hz at 
WWVH)

that sound like the ticking of a clock.


John WA4WDL

----- Original Message ----- 
From: "Brad Stockdale" <brad at shinji.net>
To: <time-nuts at febo.com>
Sent: Thursday, November 20, 2008 1:40 PM
Subject: Re: [time-nuts] WWV / WWVH / WWVB


> Hello all,
>
>    Thank you to everyone that has helped (and some that continue to
> help) me with my GPSDO equipment post... I've got a few leads out
> there and hopefully I'll be able to get ahold of some of these units
> soon... I really am looking forward to getting to work with some other 
> GPSDO's.
>
>    Anyway, on to the reason for this post... I'd like to get some
> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
> know that HEARING them may not be a 'normal' request, but I just
> would like to monitor the audio as well as being able to decode the 
> signals...
>
>    I guess the first thing to take care of is receiving the signals.
> Can anyone recommend decent receivers for these stations? I guess the
> list of frequencies would be:
>
> o WWVB = 60 KHz
> o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
> o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz
>
>    Hmm, I just noticed that WWV and WWVH overlap... How in the heck
> do you differentiate between the two stations if they broadcast on
> all the same channels?
>
>    Anyway, I wouldn't mind a kit type of project that would let me
> receive these signals... Maybe I'll check out Ramsey Electronics,
> Rainbow Kits, Velleman, et al. Surely one of them has kits for these
> broadcast ranges.
>
>    Can anyone suggest a kit, or project listed online with
> schematics and parts lists, or I guess even reasonably priced commercial 
> units?
>
>    If I can't get radios that have built in decoders for these
> stations, I'd be happy just receiving their audio and then trying to
> build my own decoder using a PIC or something...
>
>    Thanks for any advice.
>
> Brad
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From k1ggi at arrl.net  Thu Nov 20 19:08:51 2008
From: k1ggi at arrl.net (Ed, k1ggi)
Date: Thu, 20 Nov 2008 14:08:51 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESF-0002F3-1n@meow.febo.com>
References: <E1L3ESF-0002F3-1n@meow.febo.com>
Message-ID: <0c5201c94b43$711392d0$0a01a8c0@ATHLONXP1700>

Brad Stockdale wrote:
<snip>
How in the heck do you differentiate between the two stations if they
broadcast on all the same channels?
<snip>

Brad -
Regarding WWV and WWVH, take a look at
http://tf.nist.gov/timefreq/general/broadcast.htm#1
and
http://tf.nist.gov/timefreq/general/broadcast.htm#7

Ed




From bill at iaxs.net  Thu Nov 20 19:11:15 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Thu, 20 Nov 2008 13:11:15 -0600
Subject: [time-nuts] I'm back! And I need a receiver...
In-Reply-To: <200811200915180795.02337FAD@192.168.42.129>
References: <200811200915180795.02337FAD@192.168.42.129>
Message-ID: <C51E39175ABE46FA88732C8BDD9699DA@cyrus>

Bruce,

Four years ago, I planned to build a three-rack time standard system
similar to the one at Fort Collins. It was "a bridge too far" and now
I have a surplus of Datum time code generators in the 9100, 9200, and
9300 series. Many of them do IRIG-B and have an external input for 1
MHz.
The three best units would have been the system clock displays.

They do not have disciplined oscillators, but there are empty card
sockets for anything you care to add, like a divide by ten for 10 MHz. 

Units are less than 4U, some are only 1U high.

Units are available for a third of a C note, or four for the whole note.

Bill Hawkins


-----Original Message-----
From: Bruce Lane
Sent: Thursday, November 20, 2008 11:15 AM

	Failing that -- I'm not optimistic about being able to modify
the Odetics to work from a more modern NMEA-output module, so it is
likely that I would have to replace it. What I'd be looking for is a
rackmounted unit, no more than 4U high, that can put out disciplined
10MHz and IRIG-B time code. A Trak Systems 882x series would be nice,
but I know how popular those are.




From holrum at hotmail.com  Thu Nov 20 19:23:45 2008
From: holrum at hotmail.com (Mark Sims)
Date: Thu, 20 Nov 2008 19:23:45 +0000
Subject: [time-nuts] I'm back! And I need a receiver...
In-Reply-To: <mailman.214.1227208168.2542.time-nuts@febo.com>
References: <mailman.214.1227208168.2542.time-nuts@febo.com>
Message-ID: <BLU125-W462DF717AE6F47E3221274CE0C0@phx.gbl>


Do you need the one with the two boards piggypacked  (main board and smaller RF voard) or the single board version.I tried to email you directly,  but your overly paranoid email blocker gets in the way...
_________________________________________________________________
Color coding for safety: Windows Live Hotmail alerts you to suspicious email.
http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_safety_112008 

From bill at iaxs.net  Thu Nov 20 19:24:56 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Thu, 20 Nov 2008 13:24:56 -0600
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESE-0002F3-WE@meow.febo.com>
References: <E1L3ESE-0002F3-WE@meow.febo.com>
Message-ID: <0030C9F0B4C0420686B8D447014812EB@cyrus>

Are you open to vacuum tube equipment?

I have a set with a 2" scope tube that let me see the phase shift
between WWV and WWVH when propagation conditions brought them both
to Minneapolis. Also a Specific Products WWV receiver.

Also have an HP 117A VLF Comparator, but not the preamp and loop.

Bill Hawkins

-----Original Message-----
From: Brad Stockdale
Sent: Thursday, November 20, 2008 12:41 PM

    Anyway, on to the reason for this post... I'd like to get some
receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
know that HEARING them may not be a 'normal' request, but I just would
like to monitor the audio as well as being able to decode the signals...




From hmurray at megapathdsl.net  Thu Nov 20 19:43:22 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 11:43:22 -0800
Subject: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
In-Reply-To: Message from "Stephan Sandenbergh" <stephan@rrsg.ee.uct.ac.za> 
	of "Thu, 20 Nov 2008 17:16:40 +0200."
	<ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com> 
Message-ID: <20081120194323.CB6CFBCD6@ip-64-139-1-69.sjc.megapath.net>


> Sure, I assume you refer to the case when you check the data length as
> well? I meant that the <Checksum><cr><lf><@><@> byte string could also
> potentially exist in the data itself, but only in very rare cases
> (from there the 95% thumb suck). 

The checksum byte can have any value.  You can't use it to help you get in 
sync since you don't know (and can't compute) what it is unless you have the 
rest of the packet and then you are already in sync.

Once you get in sync, you don't look for any patterns inside the packet.  You 
read a few byes to figure out how long the packet is, read the rest of the 
packet, then do some sanity checks.

Since the RS-232 level stuff should be error free, the sanity checks will 
almost never fail.  If they do, it means somebody tripped over a cable or a 
lightning bolt hit.  (Or you have a bug in your software.)  Flag an error, 
somehow, so you know you have a problem.  I'm thinking of something like a 
LED with a software or pushbutton reset.  Then go back to the beginning and 
try to get in sync again.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From hmurray at megapathdsl.net  Thu Nov 20 19:47:15 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 11:47:15 -0800
Subject: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
In-Reply-To: Message from "Tom Van Baak" <tvb@LeapSecond.com> of "Thu,
	20 Nov 2008 09:44:05 PST." <F0FE2D7584F04F67BF0D900F08B60B00@pc52>
Message-ID: <20081120194716.B153FBCD5@ip-64-139-1-69.sjc.megapath.net>


> I hope you end up liking the binary format; I'm not sure how it could
> be improved. 

It's a bit ugly that you have to do a table lookup in the packet type to get 
the length.  That makes it harder to split the transport layer out into a 
separate chunk of software.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From pico.2008 at sbcglobal.net  Thu Nov 20 19:47:49 2008
From: pico.2008 at sbcglobal.net (Peter Putnam)
Date: Thu, 20 Nov 2008 11:47:49 -0800
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <0030C9F0B4C0420686B8D447014812EB@cyrus>
References: <E1L3ESE-0002F3-WE@meow.febo.com>
	<0030C9F0B4C0420686B8D447014812EB@cyrus>
Message-ID: <4925BEE5.8010608@sbcglobal.net>

Greetings...

I have a used, untested 60 KHz preamp board (no case) for the hp 117A 
VLF receiver.

It is the early model using two 13CW4 nuvistors and a mechanical filter.

If anyone is interested, please contact me directly.

Regards,
Peter




Bill Hawkins wrote:
> Are you open to vacuum tube equipment?
>
> I have a set with a 2" scope tube that let me see the phase shift
> between WWV and WWVH when propagation conditions brought them both
> to Minneapolis. Also a Specific Products WWV receiver.
>
> Also have an HP 117A VLF Comparator, but not the preamp and loop.
>
> Bill Hawkins
>
> -----Original Message-----
> From: Brad Stockdale
> Sent: Thursday, November 20, 2008 12:41 PM
>
>     Anyway, on to the reason for this post... I'd like to get some
> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
> know that HEARING them may not be a 'normal' request, but I just would
> like to monitor the audio as well as being able to decode the signals...
>
>
>
>
>   


From scmcgrath at gmail.com  Thu Nov 20 20:00:49 2008
From: scmcgrath at gmail.com (Scott McGrath)
Date: Thu, 20 Nov 2008 15:00:49 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESF-0002F3-3H@meow.febo.com>
References: <E1L3ESF-0002F3-3H@meow.febo.com>
Message-ID: <c9ffea950811201200x5e6ac0e0l595b370cb7baebf@mail.gmail.com>

That is due to the wonders of HF propagation.    WWV is in Ft Collins
WWVH is in Hawaii   so coverage is largely restricted to Asia/Pacific
region
somewhere on NIST's site there is a propagation prediction for all the stations.

On Thu, Nov 20, 2008 at 1:40 PM, Brad Stockdale <brad at shinji.net> wrote:
> Hello all,
>
>    Thank you to everyone that has helped (and some that continue to
> help) me with my GPSDO equipment post... I've got a few leads out
> there and hopefully I'll be able to get ahold of some of these units
> soon... I really am looking forward to getting to work with some other GPSDO's.
>
>    Anyway, on to the reason for this post... I'd like to get some
> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
> know that HEARING them may not be a 'normal' request, but I just
> would like to monitor the audio as well as being able to decode the signals...
>
>    I guess the first thing to take care of is receiving the signals.
> Can anyone recommend decent receivers for these stations? I guess the
> list of frequencies would be:
>
>        o WWVB = 60 KHz
>        o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
>        o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz
>
>    Hmm, I just noticed that WWV and WWVH overlap... How in the heck
> do you differentiate between the two stations if they broadcast on
> all the same channels?
>
>    Anyway, I wouldn't mind a kit type of project that would let me
> receive these signals... Maybe I'll check out Ramsey Electronics,
> Rainbow Kits, Velleman, et al. Surely one of them has kits for these
> broadcast ranges.
>
>    Can anyone suggest a kit, or project listed online with
> schematics and parts lists, or I guess even reasonably priced commercial units?
>
>    If I can't get radios that have built in decoders for these
> stations, I'd be happy just receiving their audio and then trying to
> build my own decoder using a PIC or something...
>
>    Thanks for any advice.
>
> Brad
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>


From brooke at pacific.net  Thu Nov 20 20:14:43 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 20 Nov 2008 12:14:43 -0800
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3ESE-0002F3-WE@meow.febo.com>
References: <E1L3ESE-0002F3-WE@meow.febo.com>
Message-ID: <4925C533.5080501@pacific.net>

Hi Brad:

To get the best s/n radio you need to have good narrow filters.  The NRD-545 
uses DSP for the IF filters and so can be adjusted to a 10 Hz bandwidth.  This 
is the lowest IF bandwidth I know of in any HF receiver including the high end 
and military models.  The only things with narrower bandwidths are the 
HP/Agilent 4395A in spectrum analyzer mode where there is a 1 Hz bandwidth or 
the PC sound card spectrum analyzers where you can get sub Hertz bandwidths.
http://www.prc68.com/I/NRD545.shtml
http://www.prc68.com/I/4395A.shtml#SA

The 114BR Time Comparator was used with WWV and WWVH in conjunction with a 
receiver and scope.  http://www.prc68.com/I/TF_rack.html
You could duplicate the function of the HP 114 using a variable time delay for 
phase comparison.

The antenna is about as important as the receiver for HF and LF signals.  For 
HF I really like the B&W Terminated Folded dipoles.  Chirp receiver testing 
showed them to be far superior to every thing else.
http://www.prc68.com/I/RCS-5A.shtml#Ant

The trick to getting a PIC to decode the subcarrier data would be best done by 
audio filtering prior to amplitude detection.  I haven't worked with the DSPics 
but that would allow doing better filtering in the PIC. 
http://www.prc68.com/I/TF_rack.html

For WWVB the amplitude changes but the carrier is always there.  Starting Jan 1 
2006 the modulation depth was changed from 10 to 17 dB, see:
http://tf.nist.gov/timefreq/general/pdf/2139.pdf
It's very important that you filter out close by RF signals.  Here is a 0 to 
200 kHz spectrum plot:   http://www.prc68.com/I/Spec_0002.shtml
you can see that there are plenty of signals there.

Have Fun,

Brooke Clarke
http://www.prc68.com

Brad Stockdale wrote:
> Hello all,
> 
>     Thank you to everyone that has helped (and some that continue to 
> help) me with my GPSDO equipment post... I've got a few leads out 
> there and hopefully I'll be able to get ahold of some of these units 
> soon... I really am looking forward to getting to work with some other GPSDO's.
> 
>     Anyway, on to the reason for this post... I'd like to get some 
> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I 
> know that HEARING them may not be a 'normal' request, but I just 
> would like to monitor the audio as well as being able to decode the signals...
> 
>     I guess the first thing to take care of is receiving the signals. 
> Can anyone recommend decent receivers for these stations? I guess the 
> list of frequencies would be:
> 
> 	o WWVB = 60 KHz
> 	o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
> 	o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz
> 
>     Hmm, I just noticed that WWV and WWVH overlap... How in the heck 
> do you differentiate between the two stations if they broadcast on 
> all the same channels?
> 
>     Anyway, I wouldn't mind a kit type of project that would let me 
> receive these signals... Maybe I'll check out Ramsey Electronics, 
> Rainbow Kits, Velleman, et al. Surely one of them has kits for these 
> broadcast ranges.
> 
>     Can anyone suggest a kit, or project listed online with 
> schematics and parts lists, or I guess even reasonably priced commercial units?
> 
>     If I can't get radios that have built in decoders for these 
> stations, I'd be happy just receiving their audio and then trying to 
> build my own decoder using a PIC or something...
> 
>     Thanks for any advice.
> 
> Brad
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From brooke at pacific.net  Thu Nov 20 20:18:37 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 20 Nov 2008 12:18:37 -0800
Subject: [time-nuts] M12+T ASCII interface - I'm confused?
In-Reply-To: <49243CED.4060400@pacific.net>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<49243CED.4060400@pacific.net>
Message-ID: <4925C61D.3080706@pacific.net>

Hi Stephan:

I was wrong about the stuffing.  Got confused with other protocols.
All the Motorola @@ packets are a fixed length.

Have Fun,

Brooke Clarke
http://www.prc68.com

Brooke Clarke wrote:
> Hi Stephan:
> 
> Check the manual for "stuffing", it's not a Thanksgiving term here but has to 
> do with what happens when a byte in a binary data stream (the data in the 
> Motorola protocol is all binary, not ASCII) is the same as the ASCII "@" 
> character.  This means that the length of a packet is variable and depends on 
> the actual data inside the packet.  But you know the minimum length if you know 
> the packet ID.
> 
> To start look for the string <CR><LF>@@ and the next characters (maybe 2 or 4 
> hex characters) are the packet ID.  Sometimes this happens inside a packet 
> because that's what the data looks like.  But go with it and if it's wrong the 
> program will cycle around to where you are on packet boundaries.
> 
> 
> Have Fun,
> 
> Brooke Clarke
> http://www.prc68.com
> 
> Stephan Sandenbergh wrote:
>> Hi All,
>>
>> Up until now we've been interfacing my Motorola M12+T's using the Oncore
>> software. However, at this point we are trying to have it interfaced
>> directly to a FPGA. To my mind this should be simple - the commands are
>> discriminated (framed) by looking at the start and terminating bytes
>> sequences when they enter the FIFO, check summed, decoded etc.
>>
>> However, I noted something very peculiar about the motorola ASCII protocol:
>> The start bytes @@ and he terminating byte <CR><LF> aren't unique with
>> respect to the data bytes. For instance one could receive a time of 13hrs
>> and 10mins which would look identical to the terminating characters.
>> Initially I thought it made sense since the data is also sent in ascii
>> format. It appears not to be the case.
>>
>> It seems to me that the only way in which a command could be robustly
>> identified and check summed is when the interface knows the length of the
>> expected return.  Obviously, the data lengths are dependent on both the
>> actual command and the specific request. This type of intelligence is
>> cumbersome to implement in FPGAs.
>>
>> It would be of great help if you could point me in the right direction here.
>> I feel rather stupid in asking such a simple question, but at this point I
>> can't seem to see the light. I'm flabbergasted...
>>
>> Best regards,
>>
>> Stephan
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From brad at shinji.net  Thu Nov 20 20:37:50 2008
From: brad at shinji.net (Brad Stockdale)
Date: Thu, 20 Nov 2008 15:37:50 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <4925B29C.2070605@febo.com>
References: <E1L3ESF-0002F3-5R@meow.febo.com>
 <4925B29C.2070605@febo.com>
Message-ID: <mailman.9.1227213476.2539.time-nuts@febo.com>

Oh my... The HP 3586 looks like a gorgeous piece of equipment. It'd 
look very impressive in my (hopefully) growing rack of time/frequency gear...

I just checked on eBay right now and didn't see any available right 
this second, but I will put in a saved search for them so I can get 
email alerts...

Do you know of any good (reasonably priced) used equipment dealers 
that I should also be looking at for HP test equipment? I know 
there's shops that specialize in used test gear, but I just don't 
know their addresses... I'll google around right now and see what I 
can come up with, but if anyone has any suggestions that they have 
delt with before and been satisfied, I'd like to hear.

Thanks for the great idea! I hope I can track one of these down 
sooner or later.

Regards,
Brad


At 01:55 PM 11/20/2008, you wrote:
>Brad Stockdale wrote:
>[ ... ]
> >     Anyway, on to the reason for this post... I'd like to get some
> > receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
> > know that HEARING them may not be a 'normal' request, but I just
> > would like to monitor the audio as well as being able to decode 
> the signals...
>broadcast ranges.
>
>[ ... ]
> >     Can anyone suggest a kit, or project listed online with
> > schematics and parts lists, or I guess even reasonably priced 
> commercial units?
> >
> >     If I can't get radios that have built in decoders for these
> > stations, I'd be happy just receiving their audio and then trying to
> > build my own decoder using a PIC or something...
>
>If you don't mind a big, heavy box, the HP 3586[A,B,C] selective
>voltmeters are absolutely wonderful tools for any sort of LF/HF
>measurement.  They tune from 20 Hz to 32 MHz and have narrow 20 and 400
>Hz filter bandwidths, as well as a voice-bandwidth filter (the width
>depends on the model and option).  They read amplitude to 0.01 dB and
>can count a received carrier to 0.1 Hz frequency resolution.
>
>They have a speaker and line-level audio output, but no decoder.  They
>also have a GPIB connector, so you can use a computer to tune and read
>frequency and amplitude.
>
>The "C" model is the best for lab use, because it has 50/75/600 ohm
>input options, and uses standard BNC and binding post input connectors.
>   The A and B models were designed for telco use and have slightly weird
>input impedances and connectors, but nothing to stop them from still
>being very useful.
>
>They sometimes go on eBay for <$200, which is a steal in my book.  They
>weigh about 50 pounds, though, so aren't exactly portable.
>
>John
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
>
>__________ Information from ESET NOD32 Antivirus, version of virus 
>signature database 3628 (20081120) __________
>
>The message was checked by ESET NOD32 Antivirus.
>
>http://www.eset.com



From jra at febo.com  Thu Nov 20 20:44:16 2008
From: jra at febo.com (John Ackermann N8UR)
Date: Thu, 20 Nov 2008 15:44:16 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3GHl-0005GE-AS@meow.febo.com>
References: <E1L3ESF-0002F3-5R@meow.febo.com> <4925B29C.2070605@febo.com>
	<E1L3GHl-0005GE-AS@meow.febo.com>
Message-ID: <4925CC20.2000305@febo.com>

Tucker Electronics is probably the biggest US used test gear vendor, but 
there are others.  I've dealt once or twice with TekNet with good results.

However, most of the used equipment folks are selling to commercial 
entities and their prices can be large multiples of the eBay going rate. 
  So be prepared for sticker shock.

BTW, I used a couple of 3586s to record audio from the 2005 leap second 
event -- One was tuned to 60 kHz for WWVB and the other to CHU.  (Having 
run out of 3586s at that point, I used my ham gear for WWV 5 and 10 MHz. 
  You can see and hear the results at 
http://www.febo.com/pages/leapsecond_2005/

John
----

Brad Stockdale wrote:
> Oh my... The HP 3586 looks like a gorgeous piece of equipment. It'd 
> look very impressive in my (hopefully) growing rack of time/frequency gear...
> 
> I just checked on eBay right now and didn't see any available right 
> this second, but I will put in a saved search for them so I can get 
> email alerts...
> 
> Do you know of any good (reasonably priced) used equipment dealers 
> that I should also be looking at for HP test equipment? I know 
> there's shops that specialize in used test gear, but I just don't 
> know their addresses... I'll google around right now and see what I 
> can come up with, but if anyone has any suggestions that they have 
> delt with before and been satisfied, I'd like to hear.
> 
> Thanks for the great idea! I hope I can track one of these down 
> sooner or later.
> 
> Regards,
> Brad
> 
> 
> At 01:55 PM 11/20/2008, you wrote:
>> Brad Stockdale wrote:
>> [ ... ]
>>>     Anyway, on to the reason for this post... I'd like to get some
>>> receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
>>> know that HEARING them may not be a 'normal' request, but I just
>>> would like to monitor the audio as well as being able to decode 
>> the signals...
>> broadcast ranges.
>>
>> [ ... ]
>>>     Can anyone suggest a kit, or project listed online with
>>> schematics and parts lists, or I guess even reasonably priced 
>> commercial units?
>>>     If I can't get radios that have built in decoders for these
>>> stations, I'd be happy just receiving their audio and then trying to
>>> build my own decoder using a PIC or something...
>> If you don't mind a big, heavy box, the HP 3586[A,B,C] selective
>> voltmeters are absolutely wonderful tools for any sort of LF/HF
>> measurement.  They tune from 20 Hz to 32 MHz and have narrow 20 and 400
>> Hz filter bandwidths, as well as a voice-bandwidth filter (the width
>> depends on the model and option).  They read amplitude to 0.01 dB and
>> can count a received carrier to 0.1 Hz frequency resolution.
>>
>> They have a speaker and line-level audio output, but no decoder.  They
>> also have a GPIB connector, so you can use a computer to tune and read
>> frequency and amplitude.
>>
>> The "C" model is the best for lab use, because it has 50/75/600 ohm
>> input options, and uses standard BNC and binding post input connectors.
>>   The A and B models were designed for telco use and have slightly weird
>> input impedances and connectors, but nothing to stop them from still
>> being very useful.
>>
>> They sometimes go on eBay for <$200, which is a steal in my book.  They
>> weigh about 50 pounds, though, so aren't exactly portable.
>>
>> John
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>> __________ Information from ESET NOD32 Antivirus, version of virus 
>> signature database 3628 (20081120) __________
>>
>> The message was checked by ESET NOD32 Antivirus.
>>
>> http://www.eset.com
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From brad at shinji.net  Thu Nov 20 20:46:58 2008
From: brad at shinji.net (Brad Stockdale)
Date: Thu, 20 Nov 2008 15:46:58 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3GHl-0005GE-4G@meow.febo.com>
References: <E1L3ESF-0002F3-5R@meow.febo.com> <4925B29C.2070605@febo.com>
	<E1L3GHl-0005GE-4G@meow.febo.com>
Message-ID: <mailman.10.1227214024.2539.time-nuts@febo.com>

At 03:37 PM 11/20/2008, you wrote:

>I just checked on eBay right now and didn't see any available right
>this second, but I will put in a saved search for them so I can get
>email alerts...

I take it back... There are a few. Sorry about that!

Brad



From brad at shinji.net  Thu Nov 20 20:51:16 2008
From: brad at shinji.net (Brad Stockdale)
Date: Thu, 20 Nov 2008 15:51:16 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <91981b3e0811201055s116f2222r2a8094fa6a1673cc@mail.gmail.co
 m>
References: <E1L3ESF-0002F3-3H@meow.febo.com>
	<91981b3e0811201055s116f2222r2a8094fa6a1673cc@mail.gmail.com>
Message-ID: <mailman.11.1227214281.2539.time-nuts@febo.com>



At 01:55 PM 11/20/2008, you wrote:

>I bought a nice little module from digi-key to handle this.
>561-1014-ND, under $11 including the ferrite antenna.


Interesting little module. Cheap too! Looking over the datasheet 
right now. Thanks for the pointer.

Brad



From brad at shinji.net  Thu Nov 20 20:54:38 2008
From: brad at shinji.net (Brad Stockdale)
Date: Thu, 20 Nov 2008 15:54:38 -0500
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <0030C9F0B4C0420686B8D447014812EB@cyrus>
References: <E1L3ESE-0002F3-WE@meow.febo.com>
	<0030C9F0B4C0420686B8D447014812EB@cyrus>
Message-ID: <mailman.12.1227214483.2539.time-nuts@febo.com>

At 02:24 PM 11/20/2008, you wrote:

>Are you open to vacuum tube equipment?

Surely. Tubes are another interest of mine, but I only really deal 
with audio stuff. One of my ham friends tried to ease my fear of RF 
equipment by telling me that RF gear was basically just audio gear 
with chokes/coils and tuned circuits. Didn't help aleviate my 
hesitation of getting into it. Haha.

>I have a set with a 2" scope tube that let me see the phase shift
>between WWV and WWVH when propagation conditions brought them both
>to Minneapolis. Also a Specific Products WWV receiver.

Do you happen to have a make/model of this neat sounding receiver 
with the scope built in?

Thanks,
Brad



From bg at lysator.liu.se  Thu Nov 20 21:49:18 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Thu, 20 Nov 2008 22:49:18 +0100
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3GUj-0005rC-Eu@meow.febo.com>
References: <E1L3ESF-0002F3-3H@meow.febo.com>
	<91981b3e0811201055s116f2222r2a8094fa6a1673cc@mail.gmail.com>
	<E1L3GUj-0005rC-Eu@meow.febo.com>
Message-ID: <1227217758.20299.141.camel@bg-desktop>


On Thu, 2008-11-20 at 15:51 -0500, Brad Stockdale wrote:
> 
> At 01:55 PM 11/20/2008, you wrote:
> 
> >I bought a nice little module from digi-key to handle this.
> >561-1014-ND, under $11 including the ferrite antenna.
> 
> 
> Interesting little module. Cheap too! Looking over the datasheet 
> right now. Thanks for the pointer.

Here is a euro-alternative that for a multitude of frequencies

   http://www.hkw-elektronik.de/englisch/products/assemblys.php

I built a few receivers from this design

    http://www.buzzard.me.uk/jonathan/radioclock.html

using HKW-modules.

--

    Bj?rn



From bill at iaxs.net  Thu Nov 20 22:06:22 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Thu, 20 Nov 2008 16:06:22 -0600
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <E1L3GXz-00060L-H4@meow.febo.com>
References: <E1L3ESE-0002F3-WE@meow.febo.com><0030C9F0B4C0420686B8D447014812EB@cyrus>
	<E1L3GXz-00060L-H4@meow.febo.com>
Message-ID: <8C3BC370530B47649A6FB5D077B44BE3@cyrus>

Brad,

I started with audio in 1950, got into receivers, never got into
transmitters, except some carrier current stuff. Only real difference
in receivers is the concept of tuned circuits for selectivity as
opposed to wide-band audio.

Well, there's also detection and AGC. Um, and mixing (hetrodyning)
or regeneration. Probably other stuff as well. Actually, audio amps
are pretty simple compared to 25 tube military receivers of the 50s.
And receivers are simpler than Caesium or Rubidium standards, or
precision frequency synthesizers.

The receiver that showed phase shift is a Lavoie LA800, s/n 125.
Receives WWV or WWVH on 5 or 15 MHz. Takes 0.05 to 10 MHz from
your standard and generates 10 MHz for the circular sweep. Beam
is intensity modulated by received signal cleverly converted to
10 MHz. Easier to see phase shift than Lissajous method.

The Specific Products receiver is the WWVC, with filters. Receives
WWV/H on 2.5, 5, 10, 15 and 20 MHz. Filters 400 or 600 Hz tones,
or ticks, or open for voice. Has audio output.

Both have 2" scope and speaker. The WWVC just has X and Y for
Lissajous figures. Have manual for each.

Bill Hawkins


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brad Stockdale
Sent: Thursday, November 20, 2008 2:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWV / WWVH / WWVB

At 02:24 PM 11/20/2008, you wrote:

>Are you open to vacuum tube equipment?

Surely. Tubes are another interest of mine, but I only really deal with
audio stuff. One of my ham friends tried to ease my fear of RF equipment
by telling me that RF gear was basically just audio gear with
chokes/coils and tuned circuits. Didn't help aleviate my hesitation of
getting into it. Haha.

>I have a set with a 2" scope tube that let me see the phase shift 
>between WWV and WWVH when propagation conditions brought them both to 
>Minneapolis. Also a Specific Products WWV receiver.

Do you happen to have a make/model of this neat sounding receiver with
the scope built in?

Thanks,
Brad




From hmurray at megapathdsl.net  Thu Nov 20 22:27:53 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 14:27:53 -0800
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: Message from Brad Stockdale <brad@shinji.net> 
	of "Thu, 20 Nov 2008 13:40:31 EST." <E1L3ESE-0002F3-WE@meow.febo.com> 
Message-ID: <20081120222754.34CD8BCD5@ip-64-139-1-69.sjc.megapath.net>


>     If I can't get radios that have built in decoders for these
> stations, I'd be happy just receiving their audio and then trying to
> build my own decoder using a PIC or something... 

The typical short wave radio will give you audio on WWV/H.

WWVB is 60 KHz.  Most radios don't go that low.  The tiny modules only give 
you a carrier.  If you wanted to hear anything more than clicks, you would 
have to use that to gate a tone.

ntpd has a refclock driver for WWV/H.  I've never played with it.
  http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver36.html

From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.13.1227220077.2539.time-nuts@febo.com>


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From richiem at hughes.net  Thu Nov 20 23:27:45 2008
From: richiem at hughes.net (Richard Moore)
Date: Thu, 20 Nov 2008 15:27:45 -0800
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <mailman.218.1227212295.2542.time-nuts@febo.com>
References: <mailman.218.1227212295.2542.time-nuts@febo.com>
Message-ID: <794F0D3A-F6D6-449F-8195-BF5CA750E20A@hughes.net>

Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in  
China. He nicely gave me the time-nuts discount, and also included a  
power connector with pigtail leads. Including shipping, it was $175  
and it took 7 days to get here in W. Wash. You can find him and these  
units on eBay at:  http://stores.ebay.com/High-precision-Osc-from-China

It's date code is 3/19/05.
The App Ver is 3.00  6/27/2.
GPS Core is 10.02  11/14/1.
ID is 96.
s/n is 82331036  3/7/5.

It's up and running in a top-of-bench way, and I have a few Qs:
1)  What are good params to use for the loop to get best frequency  
acc'y and stability?
2)  Is there a firmware upgrade you recommend?
3)  What V/Hz figure do you all recommend? It's at what must be a  
default of -5...
4)  DAC voltage is +0.0633...  Is this a fairly normal value?
5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB  
adapter, but DSPMon does not see the data at all -- no TX or RX. Does  
it not work with this vintage/version of TBolt?

Best,
Dick Moore


From hmurray at megapathdsl.net  Thu Nov 20 23:31:42 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 15:31:42 -0800
Subject: [time-nuts] Where to find surplus telecom standards
In-Reply-To: Message from Brad Stockdale <brad@shinji.net> 
	of "Tue, 18 Nov 2008 13:29:48 EST." <E1L2VKr-0000V5-FR@meow.febo.com> 
Message-ID: <20081120233143.2A2B7BCD5@ip-64-139-1-69.sjc.megapath.net>


>     On a slightly different subject, albeit somewhat related... Does
> anyone know what HP Z3801A's are worth nowadays? I remember when they
> first came on the market, they were around $250, then up to about
> $400 or so when supplies got scarce. Not sure what happened after
> that... Just kinda curious if I could make some extra money by
> selling a couple of my Z3801's and using the profits to buy some
> other units to 'play' with... 

There are a couple for sale at $400 plus $120 shipping from Hong Kong.  Since 
they are still for sale, I'd say the current price is under $500.

Assuming it's in reasonable shape, I'll offer  $400 plus reasonable shipping. 
 (You save the ebay fees.)






-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From brooke at pacific.net  Thu Nov 20 23:36:48 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 20 Nov 2008 15:36:48 -0800
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <794F0D3A-F6D6-449F-8195-BF5CA750E20A@hughes.net>
References: <mailman.218.1227212295.2542.time-nuts@febo.com>
	<794F0D3A-F6D6-449F-8195-BF5CA750E20A@hughes.net>
Message-ID: <4925F490.90506@pacific.net>

Hi Dick:

Did you set the COM port number?
Right click with the cursor on the window.
http://www.prc68.com/I/ThunderBolt.shtml#TBM

Have Fun,

Brooke Clarke
http://www.prc68.com

Richard Moore wrote:
> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in  
> China. He nicely gave me the time-nuts discount, and also included a  
> power connector with pigtail leads. Including shipping, it was $175  
> and it took 7 days to get here in W. Wash. You can find him and these  
> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from-China
> 
> It's date code is 3/19/05.
> The App Ver is 3.00  6/27/2.
> GPS Core is 10.02  11/14/1.
> ID is 96.
> s/n is 82331036  3/7/5.
> 
> It's up and running in a top-of-bench way, and I have a few Qs:
> 1)  What are good params to use for the loop to get best frequency  
> acc'y and stability?
> 2)  Is there a firmware upgrade you recommend?
> 3)  What V/Hz figure do you all recommend? It's at what must be a  
> default of -5...
> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB  
> adapter, but DSPMon does not see the data at all -- no TX or RX. Does  
> it not work with this vintage/version of TBolt?
> 
> Best,
> Dick Moore
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From jmiles at pop.net  Thu Nov 20 23:44:49 2008
From: jmiles at pop.net (John Miles)
Date: Thu, 20 Nov 2008 15:44:49 -0800
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <794F0D3A-F6D6-449F-8195-BF5CA750E20A@hughes.net>
Message-ID: <PKEGJHPHLLBACEOICCBJMEGEPDAB.jmiles@pop.net>

Unless you are going to use a different OCXO, there is nothing to do except
perhaps tell it to save the self-survey results and set your "foilage mode"
if desired.  They are plug and play.

-5 V/Hz is the correct kvco parameter; any changes will either degrade the
phase margin and give you a "hump" in your loop response, or lengthen the
loop response.  And it wouldn't be advisable to alter the loop-time and
damping parameters without taking a series of ADEV plots under various GPS
reception conditions to make sure you're actually improving things.

The DAC voltage on mine is sitting at 0.608664V, with a corresponding DAC
value of 8F49D.  This is a 20-bit value centered at 0x80000.  As long as you
are between 0x10000 (a bit more than -5V) and 0xF0000 (a bit less than +5V)
your oscillator has sufficient control range.  If it goes closer to 0x00000
or 0xFFFFF it means you're about to hit the rails, and would need a new
OCXO.  This *might* happen if you left it running for 30 years.

-- john, KE5FX


> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of Richard Moore
> Sent: Thursday, November 20, 2008 3:28 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] TBolt in the house!
>
>
> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in
> China. He nicely gave me the time-nuts discount, and also included a
> power connector with pigtail leads. Including shipping, it was $175
> and it took 7 days to get here in W. Wash. You can find him and these
> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from-China
>
> It's date code is 3/19/05.
> The App Ver is 3.00  6/27/2.
> GPS Core is 10.02  11/14/1.
> ID is 96.
> s/n is 82331036  3/7/5.
>
> It's up and running in a top-of-bench way, and I have a few Qs:
> 1)  What are good params to use for the loop to get best frequency
> acc'y and stability?
> 2)  Is there a firmware upgrade you recommend?
> 3)  What V/Hz figure do you all recommend? It's at what must be a
> default of -5...
> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB
> adapter, but DSPMon does not see the data at all -- no TX or RX. Does
> it not work with this vintage/version of TBolt?
>
> Best,
> Dick Moore
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



From rvassar at rob-vassar.com  Fri Nov 21 00:16:32 2008
From: rvassar at rob-vassar.com (Robert Vassar)
Date: Thu, 20 Nov 2008 18:16:32 -0600
Subject: [time-nuts] WWV / WWVH / WWVB
In-Reply-To: <20081120222754.34CD8BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081120222754.34CD8BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <490E8414-E77A-4578-805B-59DEF99FCDD8@rob-vassar.com>


On Nov 20, 2008, at 4:27 PM, Hal Murray wrote:

>
>
> ntpd has a refclock driver for WWV/H.  I've never played with it.
>   http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver36.html
>>


I played with it back in the 90's, I hooked up the audio line out  
from my Yaesu FT-840 to a SPARCstation 20.  It does in fact work.   
But as I remember it consumed pretty much 100% of a 75Mhz SuperSPARC- 
II CPU.  I'm sure a modern CPU would do a much better job.


Keep in mind the F/F1/F2 layer that the HF signals use to propagate  
tends to move around a bit.  This introduces a variable propagation  
delay that cannot be entirely corrected.


Rob



From kyrrin at bluefeathertech.com  Fri Nov 21 00:46:21 2008
From: kyrrin at bluefeathertech.com (Bruce Lane)
Date: Thu, 20 Nov 2008 16:46:21 -0800
Subject: [time-nuts] I'm back! And I need a receiver...
In-Reply-To: <C51E39175ABE46FA88732C8BDD9699DA@cyrus>
References: <200811200915180795.02337FAD@192.168.42.129>
	<C51E39175ABE46FA88732C8BDD9699DA@cyrus>
Message-ID: <200811201646210343.03D0738E@192.168.42.129>

Hi, Bill,

	Thanks for the offer, but I also have a goodly number of the Datum 9300's and similar units.

	What I really need at the moment is at least a partial "turnkey" solution. Ideally, I want to fix the Odetics clock as it has been very reliable outside of the GPS receiver.

	I know if I look long enough, I'll find something.

*********** REPLY SEPARATOR  ***********

On 20-Nov-08 at 13:11 Bill Hawkins wrote:

>Bruce,
>
>Four years ago, I planned to build a three-rack time standard system
>similar to the one at Fort Collins. It was "a bridge too far" and now
>I have a surplus of Datum time code generators in the 9100, 9200, and
>9300 series. Many of them do IRIG-B and have an external input for 1
>MHz.
>The three best units would have been the system clock displays.
>
>They do not have disciplined oscillators, but there are empty card
>sockets for anything you care to add, like a divide by ten for 10 MHz. 
>
>Units are less than 4U, some are only 1U high.
>
>Units are available for a third of a C note, or four for the whole note.
>
>Bill Hawkins
>
>
>-----Original Message-----
>From: Bruce Lane
>Sent: Thursday, November 20, 2008 11:15 AM
>
>	Failing that -- I'm not optimistic about being able to modify
>the Odetics to work from a more modern NMEA-output module, so it is
>likely that I would have to replace it. What I'd be looking for is a
>rackmounted unit, no more than 4U high, that can put out disciplined
>10MHz and IRIG-B time code. A Trak Systems 882x series would be nice,
>but I know how popular those are.
>
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to
>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.


-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
"Quid Malmborg in Plano..."



From GDowd at symmetricom.com  Fri Nov 21 01:30:46 2008
From: GDowd at symmetricom.com (Greg Dowd)
Date: Thu, 20 Nov 2008 17:30:46 -0800
Subject: [time-nuts] Do any regulations or laws require time to be
	accurate within 'x' seconds?
In-Reply-To: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
References: <4fdb424f0811030903q579f12a1l10f74835d2f4a164@mail.gmail.com>
Message-ID: <CB45EB047BD43041BF1F4CC7D6DB21BF01AF69CB@sjmail2.symmetricom.com>

This is about the most I've found.
http://tf.nist.gov/timefreq/general/pdf/2125.pdf

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Gretchen Baxter
Sent: Monday, November 03, 2008 9:03 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Do any regulations or laws require time to be
accurate within 'x' seconds?

Greetings,

There are a lot of regulations that mandate synchronized time.

But do any of these regulations or laws require time to be accurate
within
'x' seconds?  Such as, 'time much be synchronized within 5 seconds of
GPS
time.

Thanx,

Gretchen
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.


From ch at murgatroid.com  Fri Nov 21 02:09:36 2008
From: ch at murgatroid.com (christopher hoover)
Date: Thu, 20 Nov 2008 18:09:36 -0800
Subject: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
In-Reply-To: <mailman.218.1227212295.2542.time-nuts@febo.com>
References: <mailman.218.1227212295.2542.time-nuts@febo.com>
Message-ID: <001801c94b7e$33e9e9a0$9bbdbce0$@com>

tvb wrote:
> I hope you end up liking the binary format; I'm not sure how it could
> be improved.

IIRC, there's no length field in the packet; so you have to know the length
of all the messages you might possibly rx, even if you are interested in
just a few of them.

-ch




From imp at bsdimp.com  Fri Nov 21 02:44:13 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Thu, 20 Nov 2008 19:44:13 -0700 (MST)
Subject: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
In-Reply-To: <001801c94b7e$33e9e9a0$9bbdbce0$@com>
References: <mailman.218.1227212295.2542.time-nuts@febo.com>
	<001801c94b7e$33e9e9a0$9bbdbce0$@com>
Message-ID: <20081120.194413.161865311.imp@bsdimp.com>

In message: <001801c94b7e$33e9e9a0$9bbdbce0$@com>
            "christopher hoover" <ch at murgatroid.com> writes:
: tvb wrote:
: > I hope you end up liking the binary format; I'm not sure how it could
: > be improved.
: 
: IIRC, there's no length field in the packet; so you have to know the length
: of all the messages you might possibly rx, even if you are interested in
: just a few of them.

IIRC, you just have to know...

Warner


From hmurray at megapathdsl.net  Fri Nov 21 04:03:56 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 20 Nov 2008 20:03:56 -0800
Subject: [time-nuts] Do any regulations or laws require time to
	be	accurate within 'x' seconds?
Message-ID: <20081121040357.7A7C4BCD5@ip-64-139-1-69.sjc.megapath.net>

http://www.oup.com/us/pdf/houp/10_3.pdf
OATS Reporting Technical Specifications, NASD
OATS == Order Audit Trail System

All computer system clocks and mechanical time stamping devices must be 
synchronized to within three seconds of the National Institute of Standards 
and Technology (NIST) atomic clock. Any time provider may be used for 
synchronization, however, all clocks and time stamping devices must remain 
accurate within a three-second tolerance of the NIST clock.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From normn3ykf at stny.rr.com  Fri Nov 21 05:58:36 2008
From: normn3ykf at stny.rr.com (Norman J McSweyn)
Date: Fri, 21 Nov 2008 00:58:36 -0500
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <4925C61D.3080706@pacific.net>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net>
	<4925C61D.3080706@pacific.net>
Message-ID: <49264E0C.3070809@stny.rr.com>

Gentlemen:
Why would the M12+T swap the order of messages?

I write @@Hn and @@Eq in that order to the board and it gives it back to 
  me in reverse order.

Tried @@Cf then resending the messages. Still the same. Then did it AND 
swapped the order of the messages. Still the same.

The manual says it's first in, first out regarding the serial buffer.

I'm using Labview 8.

Norm n3ykf



From richiem at hughes.net  Fri Nov 21 06:19:21 2008
From: richiem at hughes.net (Richard Moore)
Date: Thu, 20 Nov 2008 22:19:21 -0800
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <mailman.229.1227247121.2542.time-nuts@febo.com>
References: <mailman.229.1227247121.2542.time-nuts@febo.com>
Message-ID: <607A7840-C2D1-4746-9235-9BFEA56C44E1@hughes.net>

> Message: 2
> Date: Thu, 20 Nov 2008 15:36:48 -0800
> From: Brooke Clarke <brooke at pacific.net>
> Subject: Re: [time-nuts] TBolt in the house!
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <4925F490.90506 at pacific.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Dick:
>
> Did you set the COM port number?
> Right click with the cursor on the window.
> http://www.prc68.com/I/ThunderBolt.shtml#TBM
>

Yep, Brooke, I did. My ATEN 232>USB adapter looks like Com Port 6 to  
my windows box, which regularly thinks that it is a Microsoft Ball  
Point, whatever that is and it's a real pain to straighten that out.  
I'd like to get rid of the MS Ball Point driver completely if I could  
find it; any help with that appreciated.

> Richard Moore wrote:
>> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in
>> China. He nicely gave me the time-nuts discount, and also included a
>> power connector with pigtail leads. Including shipping, it was $175
>> and it took 7 days to get here in W. Wash. You can find him and these
>> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from- 
>> China
>>
>> It's date code is 3/19/05.
>> The App Ver is 3.00  6/27/2.
>> GPS Core is 10.02  11/14/1.
>> ID is 96.
>> s/n is 82331036  3/7/5.
>>
>> It's up and running in a top-of-bench way, and I have a few Qs:
>> 1)  What are good params to use for the loop to get best frequency
>> acc'y and stability?
>> 2)  Is there a firmware upgrade you recommend?
>> 3)  What V/Hz figure do you all recommend? It's at what must be a
>> default of -5...
>> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
>> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB
>> adapter, but DSPMon does not see the data at all -- no TX or RX. Does
>> it not work with this vintage/version of TBolt?
>> ------------------------------


> Message: 3
> Date: Thu, 20 Nov 2008 15:44:49 -0800
> From: "John Miles" <jmiles at pop.net>
> Subject: Re: [time-nuts] TBolt in the house!
> To: "Discussion of precise time and frequency measurement"
> 	<time-nuts at febo.com>
> Message-ID: <PKEGJHPHLLBACEOICCBJMEGEPDAB.jmiles at pop.net>
> Content-Type: text/plain; charset="us-ascii"
>
> Unless you are going to use a different OCXO, there is nothing to  
> do except
> perhaps tell it to save the self-survey results and set your  
> "foilage mode"
> if desired.  They are plug and play.
>
> -5 V/Hz is the correct kvco parameter; any changes will either  
> degrade the
> phase margin and give you a "hump" in your loop response, or  
> lengthen the
> loop response.  And it wouldn't be advisable to alter the loop-time  
> and
> damping parameters without taking a series of ADEV plots under  
> various GPS
> reception conditions to make sure you're actually improving things.

John, thanks for the feedback. I'll leave the V/Hz alone, Any advice  
on loop time constant and damping?

>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
>> bounces at febo.com]On
>> Behalf Of Richard Moore
>> Sent: Thursday, November 20, 2008 3:28 PM
>> To: time-nuts at febo.com
>> Subject: [time-nuts] TBolt in the house!
>>
>>
>> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in
>> China. He nicely gave me the time-nuts discount, and also included a
>> power connector with pigtail leads. Including shipping, it was $175
>> and it took 7 days to get here in W. Wash. You can find him and these
>> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from- 
>> China
>>
>> It's date code is 3/19/05.
>> The App Ver is 3.00  6/27/2.
>> GPS Core is 10.02  11/14/1.
>> ID is 96.
>> s/n is 82331036  3/7/5.
>>
>> It's up and running in a top-of-bench way, and I have a few Qs:
>> 1)  What are good params to use for the loop to get best frequency
>> acc'y and stability?
>> 2)  Is there a firmware upgrade you recommend?
>> 3)  What V/Hz figure do you all recommend? It's at what must be a
>> default of -5...
>> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
>> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB
>> adapter, but DSPMon does not see the data at all -- no TX or RX. Does
>> it not work with this vintage/version of TBolt?


From normn3ykf at stny.rr.com  Fri Nov 21 06:25:38 2008
From: normn3ykf at stny.rr.com (Norman J McSweyn)
Date: Fri, 21 Nov 2008 01:25:38 -0500
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <607A7840-C2D1-4746-9235-9BFEA56C44E1@hughes.net>
References: <mailman.229.1227247121.2542.time-nuts@febo.com>
	<607A7840-C2D1-4746-9235-9BFEA56C44E1@hughes.net>
Message-ID: <49265462.8090600@stny.rr.com>

Give this a try!
http://www.synergy-gps.com/images/stories/ShopTalk/disabling%20detection%20of%20microsoft%20ballpoint%20mouse.pdf
The serial mouse issue drove me nuts for a while.
Norm


From brooke at pacific.net  Fri Nov 21 07:10:26 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 20 Nov 2008 23:10:26 -0800
Subject: [time-nuts] TBolt in the house!
In-Reply-To: <607A7840-C2D1-4746-9235-9BFEA56C44E1@hughes.net>
References: <mailman.229.1227247121.2542.time-nuts@febo.com>
	<607A7840-C2D1-4746-9235-9BFEA56C44E1@hughes.net>
Message-ID: <49265EE2.20605@pacific.net>

Hi Dick:

Not only the port number but also the serial parameters, see:
http://www.prc68.com/I/ThunderBolt.shtml#TBM
That's why I gave you the right click hint.


Have Fun,

Brooke Clarke
http://www.prc68.com

Richard Moore wrote:
>> Message: 2
>> Date: Thu, 20 Nov 2008 15:36:48 -0800
>> From: Brooke Clarke <brooke at pacific.net>
>> Subject: Re: [time-nuts] TBolt in the house!
>> To: Discussion of precise time and frequency measurement
>> 	<time-nuts at febo.com>
>> Message-ID: <4925F490.90506 at pacific.net>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Hi Dick:
>>
>> Did you set the COM port number?
>> Right click with the cursor on the window.
>> http://www.prc68.com/I/ThunderBolt.shtml#TBM
>>
> 
> Yep, Brooke, I did. My ATEN 232>USB adapter looks like Com Port 6 to  
> my windows box, which regularly thinks that it is a Microsoft Ball  
> Point, whatever that is and it's a real pain to straighten that out.  
> I'd like to get rid of the MS Ball Point driver completely if I could  
> find it; any help with that appreciated.
> 
>> Richard Moore wrote:
>>> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in
>>> China. He nicely gave me the time-nuts discount, and also included a
>>> power connector with pigtail leads. Including shipping, it was $175
>>> and it took 7 days to get here in W. Wash. You can find him and these
>>> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from- 
>>> China
>>>
>>> It's date code is 3/19/05.
>>> The App Ver is 3.00  6/27/2.
>>> GPS Core is 10.02  11/14/1.
>>> ID is 96.
>>> s/n is 82331036  3/7/5.
>>>
>>> It's up and running in a top-of-bench way, and I have a few Qs:
>>> 1)  What are good params to use for the loop to get best frequency
>>> acc'y and stability?
>>> 2)  Is there a firmware upgrade you recommend?
>>> 3)  What V/Hz figure do you all recommend? It's at what must be a
>>> default of -5...
>>> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
>>> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB
>>> adapter, but DSPMon does not see the data at all -- no TX or RX. Does
>>> it not work with this vintage/version of TBolt?
>>> ------------------------------
> 
> 
>> Message: 3
>> Date: Thu, 20 Nov 2008 15:44:49 -0800
>> From: "John Miles" <jmiles at pop.net>
>> Subject: Re: [time-nuts] TBolt in the house!
>> To: "Discussion of precise time and frequency measurement"
>> 	<time-nuts at febo.com>
>> Message-ID: <PKEGJHPHLLBACEOICCBJMEGEPDAB.jmiles at pop.net>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Unless you are going to use a different OCXO, there is nothing to  
>> do except
>> perhaps tell it to save the self-survey results and set your  
>> "foilage mode"
>> if desired.  They are plug and play.
>>
>> -5 V/Hz is the correct kvco parameter; any changes will either  
>> degrade the
>> phase margin and give you a "hump" in your loop response, or  
>> lengthen the
>> loop response.  And it wouldn't be advisable to alter the loop-time  
>> and
>> damping parameters without taking a series of ADEV plots under  
>> various GPS
>> reception conditions to make sure you're actually improving things.
> 
> John, thanks for the feedback. I'll leave the V/Hz alone, Any advice  
> on loop time constant and damping?
> 
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
>>> bounces at febo.com]On
>>> Behalf Of Richard Moore
>>> Sent: Thursday, November 20, 2008 3:28 PM
>>> To: time-nuts at febo.com
>>> Subject: [time-nuts] TBolt in the house!
>>>
>>>
>>> Hi, nuts -- I just got my TBolt from h-whole-bunch-of-b's-bob in
>>> China. He nicely gave me the time-nuts discount, and also included a
>>> power connector with pigtail leads. Including shipping, it was $175
>>> and it took 7 days to get here in W. Wash. You can find him and these
>>> units on eBay at:  http://stores.ebay.com/High-precision-Osc-from- 
>>> China
>>>
>>> It's date code is 3/19/05.
>>> The App Ver is 3.00  6/27/2.
>>> GPS Core is 10.02  11/14/1.
>>> ID is 96.
>>> s/n is 82331036  3/7/5.
>>>
>>> It's up and running in a top-of-bench way, and I have a few Qs:
>>> 1)  What are good params to use for the loop to get best frequency
>>> acc'y and stability?
>>> 2)  Is there a firmware upgrade you recommend?
>>> 3)  What V/Hz figure do you all recommend? It's at what must be a
>>> default of -5...
>>> 4)  DAC voltage is +0.0633...  Is this a fairly normal value?
>>> 5)  I downloaded Tboltmon v. 2.60 and it works great with my 232>USB
>>> adapter, but DSPMon does not see the data at all -- no TX or RX. Does
>>> it not work with this vintage/version of TBolt?
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From df6jb at ulrich-bangert.de  Fri Nov 21 10:56:04 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Fri, 21 Nov 2008 11:56:04 +0100
Subject: [time-nuts] Fwd:  M12+T ASCII interface - I'm confused?
In-Reply-To: <ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>
Message-ID: <BDC53D8FF4934A06A8642C1807A85FC7@athlon>

Stephan,

for me the following rules have turned to be optimal for M12+ decoding:

1) Program the M12+ to auto-send all information that you are interested
in at a one second update rate.

2) During serial reception do nothing else than to put the received data
into a buffer of sufficient length.

3) Wait for the PPS to appear. After the positive slope of the PPS you
can be sure that EVERYTHING that relates to the second which's start is
indicated by the PPS is in your buffer.

4) Start a counter that addresses bytes in your buffer and search for
"@@". Don't look for "<cr><lf>@@", that would make it necessary that the
end of the messages of the LAST second is still in the buffer in order
to detect the first first new packet, what you do not want. Note: Since
you will reset the pointer that indicates where in the buffer the next
received byte will be written to the start of the buffer after having
decoded all packets it is very likely that your buffer starts with "@@"
and no lengthy search is necessary.

5) If a "@@" is detected read the next two charcters and using a table
decide whether they make a correct packet header and find out the length
of the according packet.

6) Use the packet length information to find out whether the <cr><lf>
sequence is to be found at a matching location of your buffer. If that
is the case then perform the crc calculation. If this is ok too you have
found a valid packet and may decode it's contents.

7) Set your "@@" search counter to the end of this packet and goto 4)

8) Repeat this until all packets of interest have been found or until
you have reached the end of your buffer.

9) Reset the pointer which indicates where the next received byte shall
be written in the buffer to the start of the buffer. Also important: Set
all bytes in your buffer to an known initial state, otherwise artefacs
of the LAST transmission could pretend a succesfull reception for the
current second. Then goto 3)

For the whole action you have abt. 30 ms time (an eternity for today
technology) because abt. 30 ms after the positive slope of the PPS the
M12+ starts to transmit packets belonging to the NEXT PPS. If one of the
conditions for a valid packet is NOT given simply disregard it and
increment the counter until the next "@@".

In my GPSDO I use a log mechanism that logs errors in packet detection &
decoding. Sometimes there ARE errors. It does not need a pulled cable or
a direct lighning stroke. Any sufficient big spike on your power lines
will do. For that reason you should not rely on the idea that the serial
reception is practically error-free. However, errors of that kind are
very seldom. For me they appear once every few months.

Best regards
Ulrich

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Stephan Sandenbergh
> Gesendet: Donnerstag, 20. November 2008 16:17
> An: Discussion of precise time and frequency measurement
> Betreff: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
> 
> 
> Hi,
> 
> Now I'm slightly confused:
> 
> >
> > > My gut tells me that  <Checksum><cr><lf><@><@> would be 
> believable 
> > > more than say 95% (if not 99%) of the time. I've got the 
> following 
> > > observations:
> 
> In the above I assumed no data length checking is employed.
> 
> > >
> > > - 95% is a bad number in accurate timing applications.
> >
> > You misunderstand. You can get as close to 100% as you
> > want. Some of us have logged data from M12+ receivers without error 
> > for weeks or months -- gigabytes, error-free.
> 
> Sure, I assume you refer to the case when you check the data 
> length as well? I meant that the <Checksum><cr><lf><@><@> 
> byte string could also potentially exist in the data itself, 
> but only in very rare cases (from there the 95% thumb suck).
> 
> >
> > > - the checksum is one of the few things that are easy to 
> do in VHDL.
> > >
> > > - one would always miss the first most data stream at 
> startup (not a 
> > > problem).
> >
> > Correct, not a problem. Note NMEA, TSIP, and any other
> > GPS protocol has the same feature, right?
> >
> > > - the last message in the data stream will always only be 
> decoded on 
> > > the next second when the new streams are coming through 
> (a potential 
> > > problem)
> >
> > Not true. You can process the entire message as soon as
> > the checksum matches. Do you see why?
> >
> > If you're brave you can process the message, byte by byte, field by 
> > field, as it arrives in real time and use the checksum as a commit.
> 
> Again, the checksum could be part of the data string - so 
> without checking the data length you'll be waiting for the @@ 
> (less probable to exist in data).
> 
> >
> > > Thus, I agree: The only real reliable way is to have a lookup of 
> > > header bytes and data length. Disappointing protocol I must add.
> >
> 
> Stephan
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From df6jb at ulrich-bangert.de  Fri Nov 21 10:57:59 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Fri, 21 Nov 2008 11:57:59 +0100
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <4925A51C.2010602@verizon.net>
Message-ID: <B0A62A7A0B0E4AE28BB7B71AB338D931@athlon>

I would be interested in this information as well!

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Dan Rae
> Gesendet: Donnerstag, 20. November 2008 18:58
> An: time-nuts at febo.com
> Betreff: [time-nuts] To improve a Tbolt?
> 
> 
> I have been reading with interest John Miles' page about his Tbolt 
> 'upgrade'.
> 
http://www.thegleam.com/ke5fx/tbolt.htm

I have a newly acquired Tbolt here, and also have lying around an almost

identical 10811-60111 OCXO which I am considering using with it, exactly

as John describes.  However my Tbolt is of a later vintage than John's 
(2005 date code) and I wonder if that would show as big an improvement 
as John reports.  The on board OCXO on this one has a Trimble sticker on

it, but otherwise looks similar to the one pictured on John's page.  The

GPS receiver area of my board also looks very different, but I don't 
think this would have any effect.

Not having the sort of phase noise measuring facilities here to be able 
to test it, I am wondering if anyone else has done this with a similar 
vintage Tbolt, and could say if it is likely to show as big an 
improvement as John seems to be getting.

I was a little surprised at the amount of short term variation, of the 
order of minutes duration, that I was seeing on another Tbolt when using

it to set a Rb standard. 

The obvious answer to my question is to try it and see, but I'd 
appreciate hearing from anyone who has tried it!

Dan


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From phill.r1 at btinternet.com  Fri Nov 21 11:28:17 2008
From: phill.r1 at btinternet.com (Roy Phillips)
Date: Fri, 21 Nov 2008 11:28:17 -0000
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
Message-ID: <A7E911DD7DAD459085782CFF4A79D16F@LapTop>

Dear Members

I have the Trimble NTPX26AB-06 and I have established that the I/O port (25 way D connector) has the same pin-outs as the Z3801A. Can any owners/users of these units advise me on a suitable (proved to work) interface adaptor from the RS-422  to RS-232. The unit works fine and is producing its 10 MHz output with very good accuracy, but I am looking forward to "seeing it" through its interface with TBolt Mon. 
Thanks

Roy Phillips

From phill.r1 at btinternet.com  Fri Nov 21 12:00:41 2008
From: phill.r1 at btinternet.com (Roy Phillips)
Date: Fri, 21 Nov 2008 12:00:41 -0000
Subject: [time-nuts] Lucent Rb/GPS
Message-ID: <818BC855A60B4B059CA02EEF546C8DE5@LapTop>

Gentlemen

Is there a member out there that recognizes the LUCENT unit that is currently being offered. This is the dual RTFG-m-RB and RTFG-m-XO. The only number that appears is L105B. This appears to be part of an AT&T system. The question is - - can the interface software be obtained easily ? Any other information on this item would be useful to know.

Roy

From sar10538 at gmail.com  Fri Nov 21 12:21:16 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sat, 22 Nov 2008 01:21:16 +1300
Subject: [time-nuts] Off-Topic: On Wavetek 3010 lever thumbwheel switches
	and manual
Message-ID: <1231b6a80811210421x30c58cbt22ea48e2d6906055@mail.gmail.com>

I have bought one of these but all (yes ALL) the frequency selection
lever thumbwheel switches are broken. I've been looking around for
them but with no luck as yet. Ideally I'd like to pick up used to save
money but I'll look at anything. They are labeld L20-36AD, L20-37AD
and L20-17AJ and the unit uses various quantities of each to form a
switch bank. Can anyone let me know if they can be obtained somewhere
or substituted with another more available type?

I've also trawled the Net to find a freely downloadable manual (user
and servicing) but to no avail. If anyone has a copy or could point me
in the right direction, I would be most grateful.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From stephan at rrsg.ee.uct.ac.za  Fri Nov 21 13:06:23 2008
From: stephan at rrsg.ee.uct.ac.za (Stephan Sandenbergh)
Date: Fri, 21 Nov 2008 15:06:23 +0200
Subject: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
In-Reply-To: <BDC53D8FF4934A06A8642C1807A85FC7@athlon>
References: <ca708d410811200716u6232d57ehbbebd088dfc084dc@mail.gmail.com>
	<BDC53D8FF4934A06A8642C1807A85FC7@athlon>
Message-ID: <ca708d410811210506t15ad62caye869b63e3a6b5e20@mail.gmail.com>

Hi,

Thanks all - I think I've got a pretty good grasp of the protocol now.
Ulrich thanks for the rule set. I'm quite sure the remaining issues are just
us speaking past one another. Maybe the [time-nuts] could get a white board
for block diagrams? :)

One more thing: The M12+ automatically throws out faulty messages - does it
remove those messages from the input buffer to make space for valid ones?
Or, are the faulty messages kept in the buffer but not processed?

The reason I'm asking: If the former is true I will be able to have the M12+
share the RX part of the RS232 link with another device. Messages destined
for the other device will be discarded. Same goes for the other device. If
the latter is true the M12+ buffer would probably always be full with
garbage destined for the other device.

Does anyone know the answer to this?

Regards,

Stephan

On 21/11/2008, Ulrich Bangert <df6jb at ulrich-bangert.de> wrote:
>
> Stephan,
>
> for me the following rules have turned to be optimal for M12+ decoding:
>
> 1) Program the M12+ to auto-send all information that you are interested
> in at a one second update rate.
>
> 2) During serial reception do nothing else than to put the received data
> into a buffer of sufficient length.
>
> 3) Wait for the PPS to appear. After the positive slope of the PPS you
> can be sure that EVERYTHING that relates to the second which's start is
> indicated by the PPS is in your buffer.
>
> 4) Start a counter that addresses bytes in your buffer and search for
> "@@". Don't look for "<cr><lf>@@", that would make it necessary that the
> end of the messages of the LAST second is still in the buffer in order
> to detect the first first new packet, what you do not want. Note: Since
> you will reset the pointer that indicates where in the buffer the next
> received byte will be written to the start of the buffer after having
> decoded all packets it is very likely that your buffer starts with "@@"
> and no lengthy search is necessary.
>
> 5) If a "@@" is detected read the next two charcters and using a table
> decide whether they make a correct packet header and find out the length
> of the according packet.
>
> 6) Use the packet length information to find out whether the <cr><lf>
> sequence is to be found at a matching location of your buffer. If that
> is the case then perform the crc calculation. If this is ok too you have
> found a valid packet and may decode it's contents.
>
> 7) Set your "@@" search counter to the end of this packet and goto 4)
>
> 8) Repeat this until all packets of interest have been found or until
> you have reached the end of your buffer.
>
> 9) Reset the pointer which indicates where the next received byte shall
> be written in the buffer to the start of the buffer. Also important: Set
> all bytes in your buffer to an known initial state, otherwise artefacs
> of the LAST transmission could pretend a succesfull reception for the
> current second. Then goto 3)
>
> For the whole action you have abt. 30 ms time (an eternity for today
> technology) because abt. 30 ms after the positive slope of the PPS the
> M12+ starts to transmit packets belonging to the NEXT PPS. If one of the
> conditions for a valid packet is NOT given simply disregard it and
> increment the counter until the next "@@".
>
> In my GPSDO I use a log mechanism that logs errors in packet detection &
> decoding. Sometimes there ARE errors. It does not need a pulled cable or
> a direct lighning stroke. Any sufficient big spike on your power lines
> will do. For that reason you should not rely on the idea that the serial
> reception is practically error-free. However, errors of that kind are
> very seldom. For me they appear once every few months.
>
> Best regards
> Ulrich
>
>
> > -----Ursprungliche Nachricht-----
> > Von: time-nuts-bounces at febo.com
> > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Stephan Sandenbergh
>
> > Gesendet: Donnerstag, 20. November 2008 16:17
> > An: Discussion of precise time and frequency measurement
> > Betreff: [time-nuts] Fwd: M12+T ASCII interface - I'm confused?
>
> >
> >
> > Hi,
> >
> > Now I'm slightly confused:
> >
> > >
> > > > My gut tells me that  <Checksum><cr><lf><@><@> would be
> > believable
> > > > more than say 95% (if not 99%) of the time. I've got the
> > following
> > > > observations:
> >
> > In the above I assumed no data length checking is employed.
> >
> > > >
> > > > - 95% is a bad number in accurate timing applications.
> > >
> > > You misunderstand. You can get as close to 100% as you
> > > want. Some of us have logged data from M12+ receivers without error
> > > for weeks or months -- gigabytes, error-free.
> >
> > Sure, I assume you refer to the case when you check the data
> > length as well? I meant that the <Checksum><cr><lf><@><@>
> > byte string could also potentially exist in the data itself,
> > but only in very rare cases (from there the 95% thumb suck).
> >
> > >
> > > > - the checksum is one of the few things that are easy to
> > do in VHDL.
> > > >
> > > > - one would always miss the first most data stream at
> > startup (not a
> > > > problem).
> > >
> > > Correct, not a problem. Note NMEA, TSIP, and any other
> > > GPS protocol has the same feature, right?
> > >
> > > > - the last message in the data stream will always only be
> > decoded on
> > > > the next second when the new streams are coming through
> > (a potential
> > > > problem)
> > >
> > > Not true. You can process the entire message as soon as
> > > the checksum matches. Do you see why?
> > >
> > > If you're brave you can process the message, byte by byte, field by
> > > field, as it arrives in real time and use the checksum as a commit.
> >
> > Again, the checksum could be part of the data string - so
> > without checking the data length you'll be waiting for the @@
> > (less probable to exist in data).
> >
> > >
> > > > Thus, I agree: The only real reliable way is to have a lookup of
> > > > header bytes and data length. Disappointing protocol I must add.
> > >
> >
> > Stephan
> >
>
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> > and
> > follow the instructions there.
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From APBIDDLE at UNITED.NET  Fri Nov 21 15:11:47 2008
From: APBIDDLE at UNITED.NET (Alan P. Biddle)
Date: Fri, 21 Nov 2008 09:11:47 -0600
Subject: [time-nuts] Finding a good antenna location?
Message-ID: <BBA3B3C46E764914B8A81DB1FFF44FF5@WA4SCA>

I recently picked up a Thunderbolt on eBay.  For the present, I will be
using it with the antenna inside, and have been experimenting with various
window locations for the best signals.  Even small changes in position make
a significant difference in the individual satellite signals, though
fortunately there are several locations which are qualitatively good in
terms of the number with acceptable signal strengths.

My question is whether there is a general "goodness of reception" parameter,
or process, which would allow me to at least semi-quantitatively find the
"best" antenna location?  The constant motion of the satellites seems to
preclude the normal "tune for maximum" approach.

Apologies if I missed this, and thanks for the great info I did find in the
archives. 


Alan
WA4SCA




From yuri at ostry.ru  Fri Nov 21 15:43:16 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Fri, 21 Nov 2008 18:43:16 +0300
Subject: [time-nuts] Finding a good antenna location?
In-Reply-To: <BBA3B3C46E764914B8A81DB1FFF44FF5@WA4SCA>
References: <BBA3B3C46E764914B8A81DB1FFF44FF5@WA4SCA>
Message-ID: <24008955.20081121184316@ostry.ru>

Hello, Alan.

Friday, November 21, 2008, 18:11:47, you wrote:

A> I recently picked up a Thunderbolt on eBay.  For the present, I will be
A> using it with the antenna inside, and have been experimenting with various
A> window locations for the best signals.  Even small changes in position make
A> a significant difference in the individual satellite signals, though
A> fortunately there are several locations which are qualitatively good in
A> terms of the number with acceptable signal strengths.

A> My question is whether there is a general "goodness of reception" parameter,
A> or process, which would allow me to at least semi-quantitatively find the
A> "best" antenna location?  The constant motion of the satellites seems to
A> preclude the normal "tune for maximum" approach.

A> Apologies if I missed this, and thanks for the great info I did find in the
A> archives. 


A> Alan
A> WA4SCA

Rule of thumb for GPS antenna location - more unobstructed sky view is better. Less
reflective objects around antenna is better.

Sometimes nearby transmiting antennas may represent problem, if there
is oxidized compression joints that may act as "frequency multiplier"
(non-linearity).

Height is not so critical, unobstructed sky view is much more important...



-- 
Best regards,
 Yuri  UA3ATQ/KI7XJ                        mailto:yuri at ostry.ru



From mike.clapp at gmail.com  Fri Nov 21 19:03:41 2008
From: mike.clapp at gmail.com (Mike Clapp)
Date: Fri, 21 Nov 2008 14:03:41 -0500
Subject: [time-nuts] Do any regulations or laws require time to be
	accurate within 'x' seconds?
In-Reply-To: <20081121040357.7A7C4BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081121040357.7A7C4BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <230c2f110811211103j5b18ab5cnf4e0884eafd56010@mail.gmail.com>

The North American Electric Reliability Corporation (NERC) under federal law
can fine of up to $1 million a day.

Standard BAL-005-0 ? Automatic Generation Control
Requirement 17. Each Balancing Authority shall at least annually check and
calibrate its time error and
frequency devices against a common reference. The Balancing Authority shall
adhere to the
minimum values for measuring devices as listed below:

Device Accuracy

Digital frequency transducer ? 0.001 Hz

From bill at iaxs.net  Fri Nov 21 20:16:53 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Fri, 21 Nov 2008 14:16:53 -0600
Subject: [time-nuts] Do any regulations or laws require time to
	beaccurate within 'x' seconds?
In-Reply-To: <230c2f110811211103j5b18ab5cnf4e0884eafd56010@mail.gmail.com>
References: <20081121040357.7A7C4BCD5@ip-64-139-1-69.sjc.megapath.net>
	<230c2f110811211103j5b18ab5cnf4e0884eafd56010@mail.gmail.com>
Message-ID: <E608A7B47765431FADDF644C6EE8F2B9@cyrus>

That's an interesting reference. Google finds it.

Assuming that the digital frequency transducer measures the 60 Hz line
frequency, the required accuracy is somewhat less than 2 parts in 10E-5.

Analog transducers, like Watts, Volts, and VARs, require 0.25% of scale
accuracy. Calibration is annual.

This is nothing like the 10E-15 sought by time nuts.

Bill Hawkins


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Mike Clapp
Sent: Friday, November 21, 2008 1:04 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Do any regulations or laws require time to
beaccurate within 'x' seconds?

The North American Electric Reliability Corporation (NERC) under federal
law can fine of up to $1 million a day.

Standard BAL-005-0 - Automatic Generation Control Requirement 17. Each
Balancing Authority shall at least annually check and calibrate its time
error and frequency devices against a common reference. The Balancing
Authority shall adhere to the minimum values for measuring devices as
listed below:

Device Accuracy

Digital frequency transducer ? 0.001 Hz
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From tvb at LeapSecond.com  Fri Nov 21 20:42:16 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 21 Nov 2008 12:42:16 -0800
Subject: [time-nuts] Do any regulations or laws require time
	tobeaccurate within 'x' seconds?
References: <20081121040357.7A7C4BCD5@ip-64-139-1-69.sjc.megapath.net><230c2f110811211103j5b18ab5cnf4e0884eafd56010@mail.gmail.com>
	<E608A7B47765431FADDF644C6EE8F2B9@cyrus>
Message-ID: <9F10238B28664C51B8AAE2075E0E4231@pc52>

http://www.nerc.com/files/BAL-005-0.pdf
http://www.nerc.com/files/BAL-005-1.pdf

It would appear these documents are just talking about annual
calibration requirements of the *transducer* (the control room
test equipment used to measure line frequency) and do not
imply a specification of line frequency itself.

Does anyone know which NERC document specifies power line
phase or frequency? (and note that a frequency measurement
implies an averaging time).

See http://leapsecond.com/pages/mains/ for the ADEV of power
line frequency. It's ~2e-5 at one day. So does NERC owe me a
million bucks or not?

/tvb

----- Original Message ----- 
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Friday, November 21, 2008 12:16 PM
Subject: Re: [time-nuts] Do any regulations or laws require time tobeaccurate within 'x' seconds?


> That's an interesting reference. Google finds it.
> 
> Assuming that the digital frequency transducer measures the 60 Hz line
> frequency, the required accuracy is somewhat less than 2 parts in 10E-5.
> 
> Analog transducers, like Watts, Volts, and VARs, require 0.25% of scale
> accuracy. Calibration is annual.
> 
> This is nothing like the 10E-15 sought by time nuts.
> 
> Bill Hawkins
> 
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Mike Clapp
> Sent: Friday, November 21, 2008 1:04 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Do any regulations or laws require time to
> beaccurate within 'x' seconds?
> 
> The North American Electric Reliability Corporation (NERC) under federal
> law can fine of up to $1 million a day.
> 
> Standard BAL-005-0 - Automatic Generation Control Requirement 17. Each
> Balancing Authority shall at least annually check and calibrate its time
> error and frequency devices against a common reference. The Balancing
> Authority shall adhere to the minimum values for measuring devices as
> listed below:
> 
> Device Accuracy
> 
> Digital frequency transducer ? 0.001 Hz




From jmiles at pop.net  Fri Nov 21 20:42:43 2008
From: jmiles at pop.net (John Miles)
Date: Fri, 21 Nov 2008 12:42:43 -0800
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <B0A62A7A0B0E4AE28BB7B71AB338D931@athlon>
Message-ID: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>

I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
the performance of my Thunderbolt from the TAPR group buy (in orange) next
to the traces for my older unit before and after the 10811 upgrade.

There is no upside to tinkering with the OCXO on the TAPR units, unless you
have something that can beat a 10811.  You could replace it with a rubidium
source and get better short-term stability, but I don't think swapping one
quartz OCXO for another would be a useful thing to do.

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of Ulrich Bangert
> Sent: Friday, November 21, 2008 2:58 AM
> To: Time nuts
> Subject: Re: [time-nuts] To improve a Tbolt?
>
>
> I would be interested in this information as well!
>
> Best regards
> Ulrich Bangert
>
> > -----Ursprungliche Nachricht-----
> > Von: time-nuts-bounces at febo.com
> > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Dan Rae
> > Gesendet: Donnerstag, 20. November 2008 18:58
> > An: time-nuts at febo.com
> > Betreff: [time-nuts] To improve a Tbolt?
> >
> >
> > I have been reading with interest John Miles' page about his Tbolt
> > 'upgrade'.
> >
> http://www.thegleam.com/ke5fx/tbolt.htm
>
> I have a newly acquired Tbolt here, and also have lying around an almost
>
> identical 10811-60111 OCXO which I am considering using with it, exactly
>
> as John describes.  However my Tbolt is of a later vintage than John's
> (2005 date code) and I wonder if that would show as big an improvement
> as John reports.  The on board OCXO on this one has a Trimble sticker on
>
> it, but otherwise looks similar to the one pictured on John's page.  The
>
> GPS receiver area of my board also looks very different, but I don't
> think this would have any effect.
>
> Not having the sort of phase noise measuring facilities here to be able
> to test it, I am wondering if anyone else has done this with a similar
> vintage Tbolt, and could say if it is likely to show as big an
> improvement as John seems to be getting.
>
> I was a little surprised at the amount of short term variation, of the
> order of minutes duration, that I was seeing on another Tbolt when using
>
> it to set a Rb standard.
>
> The obvious answer to my question is to try it and see, but I'd
> appreciate hearing from anyone who has tried it!
>
> Dan
>
>



From danrae at verizon.net  Fri Nov 21 21:26:09 2008
From: danrae at verizon.net (Dan Rae)
Date: Fri, 21 Nov 2008 13:26:09 -0800
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>
References: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>
Message-ID: <49272771.9020208@verizon.net>

John Miles wrote:
> I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
> the performance of my Thunderbolt from the TAPR group buy (in orange) next
> to the traces for my older unit before and after the 10811 upgrade.
>   

Thanks John, it looks like the Tapr ones have a very good oven fitted 
already, and thus I will leave well alone.  There must be something else 
I can use the 10811 for :^)

Dan



From hmurray at megapathdsl.net  Fri Nov 21 21:27:49 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Fri, 21 Nov 2008 13:27:49 -0800
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: Message from "Roy Phillips" <phill.r1@btinternet.com> of "Fri,
	21 Nov 2008 11:28:17 GMT." <A7E911DD7DAD459085782CFF4A79D16F@LapTop> 
Message-ID: <20081121212750.E5047BCD5@ip-64-139-1-69.sjc.megapath.net>


> I have the Trimble NTPX26AB-06 and I have established that the I/O
> port (25 way D connector) has the same pin-outs as the Z3801A. Can any
> owners/users of these units advise me on a suitable (proved to work)
> interface adaptor from the RS-422  to RS-232. The unit works fine and
> is producing its 10 MHz output with very good accuracy, but I am
> looking forward to "seeing it" through its interface with TBolt Mon.  

The Z3801A has both RS-422 and RS-232 level conversion chips inside.  What 
gets routed to to the connector is determined by either some jumpers on a 
header or some zero ohm resistors.  So it's easy to modify the unit to 
directly speak RS-232.

I don't know what's in the NTPX26AB, but looking to see if there is an RS-232 
chip seems like a good excuse to open it up and look around.  :)  (If you 
haven't done it already.)

If you want to build an external converter box, I have schematics I found on 
the web many years ago.  They use LTC1318 or MAX3162.  I'm sure there are 
many other chips, but those are probably a reasonable place to start.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From tvb at LeapSecond.com  Fri Nov 21 21:33:17 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 21 Nov 2008 13:33:17 -0800
Subject: [time-nuts] To improve a Tbolt?
References: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>
Message-ID: <95641BFAAA0946FFBEEF2693D565DC03@pc52>

> I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
> the performance of my Thunderbolt from the TAPR group buy (in orange) next
> to the traces for my older unit before and after the 10811 upgrade.
> 
> There is no upside to tinkering with the OCXO on the TAPR units, unless you
> have something that can beat a 10811.  You could replace it with a rubidium
> source and get better short-term stability, but I don't think swapping one
> quartz OCXO for another would be a useful thing to do.
> 
> -- john, KE5FX

Hi John,

Very nice work and I mostly agree with your conclusions. The
OCXO inside the TAPR TBolts is really quite good. And those
that aren't that good are not sent to TAPR for sale (my pile of
TBolt rejects is growing; more on that later).

So, yes, the typical TBolt OCXO is in the same ballpark as many
10811, which is why replacing one with the other may be futile.

A problem here is that 10811 are all over the map. There are
variants of 10811; and even those with the same part number or
part number suffix will vary. Some 10811 get way down in the
-13's and are thus much better than any TBolt I've seen (which
is also one reason that some HP 58503* or Z38* series GPSDO
command such a price). Also, some 10811 have much better
phase noise specs than other. Some people are after better PN
rather than better ADEV.

So if you have the ability to measure each 10811, or measure
an assortment of good OCXO, clearly you can pick a superior
one and thus improve your TBolt performance.

On your rubidium comment, one needs to be a little careful about
expectations. For short tau (say 0.1 to 10 seconds) your average
cheap eBay surplus telecom Rb will have far less performance
than a good OCXO. Yet mid-term (say 10 to 10^4 seconds), a
Rb-GPSDO will win. However, long-term the LO makes much less
difference since GPS always wins. And GPS aside, clearly the
holdover performance of Rb will blow away OCXO.

So it all depends on ones need. I guess my main point is that a
typical rubidium-based TBolt is not necessarily, just because it's
"atomic", automatically better than a stock TBolt at every point.

If you'd like to test an FRS or LPRO version of a TBolt for me let
me know. I'd rather see your plots than my words.

Thanks,
/tvb



From w1ksz at earthlink.net  Fri Nov 21 21:52:38 2008
From: w1ksz at earthlink.net (Richard W. Solomon)
Date: Fri, 21 Nov 2008 14:52:38 -0700 (GMT-07:00)
Subject: [time-nuts] To improve a Tbolt?
Message-ID: <9540430.1227304358613.JavaMail.root@elwamui-norfolk.atl.sa.earthlink.net>

I have a 10811 floating around here somewhere. What about marrying up
one of your reject TAPR's to it ? 

73, Dick, W1KSZ

-----Original Message-----
>From: Tom Van Baak <tvb at LeapSecond.com>
>Sent: Nov 21, 2008 2:33 PM
>To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
>Subject: Re: [time-nuts] To improve a Tbolt?
>
>> I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
>> the performance of my Thunderbolt from the TAPR group buy (in orange) next
>> to the traces for my older unit before and after the 10811 upgrade.
>> 
>> There is no upside to tinkering with the OCXO on the TAPR units, unless you
>> have something that can beat a 10811.  You could replace it with a rubidium
>> source and get better short-term stability, but I don't think swapping one
>> quartz OCXO for another would be a useful thing to do.
>> 
>> -- john, KE5FX
>
>Hi John,
>
>Very nice work and I mostly agree with your conclusions. The
>OCXO inside the TAPR TBolts is really quite good. And those
>that aren't that good are not sent to TAPR for sale (my pile of
>TBolt rejects is growing; more on that later).
>
>So, yes, the typical TBolt OCXO is in the same ballpark as many
>10811, which is why replacing one with the other may be futile.
>
>A problem here is that 10811 are all over the map. There are
>variants of 10811; and even those with the same part number or
>part number suffix will vary. Some 10811 get way down in the
>-13's and are thus much better than any TBolt I've seen (which
>is also one reason that some HP 58503* or Z38* series GPSDO
>command such a price). Also, some 10811 have much better
>phase noise specs than other. Some people are after better PN
>rather than better ADEV.
>
>So if you have the ability to measure each 10811, or measure
>an assortment of good OCXO, clearly you can pick a superior
>one and thus improve your TBolt performance.
>
>On your rubidium comment, one needs to be a little careful about
>expectations. For short tau (say 0.1 to 10 seconds) your average
>cheap eBay surplus telecom Rb will have far less performance
>than a good OCXO. Yet mid-term (say 10 to 10^4 seconds), a
>Rb-GPSDO will win. However, long-term the LO makes much less
>difference since GPS always wins. And GPS aside, clearly the
>holdover performance of Rb will blow away OCXO.
>
>So it all depends on ones need. I guess my main point is that a
>typical rubidium-based TBolt is not necessarily, just because it's
>"atomic", automatically better than a stock TBolt at every point.
>
>If you'd like to test an FRS or LPRO version of a TBolt for me let
>me know. I'd rather see your plots than my words.
>
>Thanks,
>/tvb
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.



From smace at intt.net  Fri Nov 21 21:57:23 2008
From: smace at intt.net (Scott Mace)
Date: Fri, 21 Nov 2008 15:57:23 -0600
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: <A7E911DD7DAD459085782CFF4A79D16F@LapTop>
References: <A7E911DD7DAD459085782CFF4A79D16F@LapTop>
Message-ID: <49272EC3.7000409@intt.net>

On the Z3801a, if you want to use the 1-PPS or 10MHz signals that are on the DB-25 you will need
to convert the PECL outputs.  I build a little converter based on the on-semi MC100ELT23 dual PECL
to TTL translator.  I also built a simple RS422 to RS232 converter using a DS275 and 75179
All of these were done on 16SOIC surfboards that fit inside a DB25-DB25 shell.

I wanted to keep my z3801a boxes completely unmodified.

	Scott

Roy Phillips wrote:
> Dear Members
> 
> I have the Trimble NTPX26AB-06 and I have established that the I/O port (25 way D connector) has the same pin-outs as the Z3801A. Can any owners/users of these units advise me on a suitable (proved to work) interface adaptor from the RS-422  to RS-232. The unit works fine and is producing its 10 MHz output with very good accuracy, but I am looking forward to "seeing it" through its interface with TBolt Mon. 
> Thanks
> 
> Roy Phillips
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From kc0ukk at msosborn.com  Fri Nov 21 21:57:40 2008
From: kc0ukk at msosborn.com (Matt Osborn)
Date: Fri, 21 Nov 2008 15:57:40 -0600
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <49264E0C.3070809@stny.rr.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net>
	<4925C61D.3080706@pacific.net> <49264E0C.3070809@stny.rr.com>
Message-ID: <fhbei49g7dh7ppva49ataktts2lr1412vk@4ax.com>

I'm not a Labview expert, but I've seen Labview do that with messages
from other devices. Labview (or more likely, its programmer) has
issues dealing with threading issues.
 
On Fri, 21 Nov 2008 00:58:36 -0500, Norman J McSweyn
<normn3ykf at stny.rr.com> wrote:

>Gentlemen:
>Why would the M12+T swap the order of messages?
>
>I write @@Hn and @@Eq in that order to the board and it gives it back to 
>  me in reverse order.
>
>Tried @@Cf then resending the messages. Still the same. Then did it AND 
>swapped the order of the messages. Still the same.
>
>The manual says it's first in, first out regarding the serial buffer.
>
>I'm using Labview 8.
>
>Norm n3ykf
>
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.

-- kc0ukk at msosborn dot com


From jmiles at pop.net  Fri Nov 21 22:00:36 2008
From: jmiles at pop.net (John Miles)
Date: Fri, 21 Nov 2008 14:00:36 -0800
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <95641BFAAA0946FFBEEF2693D565DC03@pc52>
Message-ID: <PKEGJHPHLLBACEOICCBJIEMHPDAB.jmiles@pop.net>


> On your rubidium comment, one needs to be a little careful about
> expectations. For short tau (say 0.1 to 10 seconds) your average
> cheap eBay surplus telecom Rb will have far less performance
> than a good OCXO. Yet mid-term (say 10 to 10^4 seconds), a
> Rb-GPSDO will win. However, long-term the LO makes much less
> difference since GPS always wins. And GPS aside, clearly the
> holdover performance of Rb will blow away OCXO.
>

Good point, there's a big piece of the curve where simply upgrading a
quartz-based GPS standard to drive an Rb would not be a win.  Two pieces,
actually, since Efratom (at least) doesn't seem to care much about phase
noise.

> So it all depends on ones need. I guess my main point is that a
> typical rubidium-based TBolt is not necessarily, just because it's
> "atomic", automatically better than a stock TBolt at every point.
>
> If you'd like to test an FRS or LPRO version of a TBolt for me let
> me know. I'd rather see your plots than my words.

I could graft a rubidium source onto the original Thunderbolt platform I
used for the OCXO tests, but I currently don't have a good way to look at
Allan deviation compared to the TSC/maser setup you've got.  I can measure
the phase noise easily enough but it'd be better to get it back to you for
longer-term tests, especially if the loop parameters need to be adjusted
iteratively.  That would be a heat-death-of-the-Universe process on a
3048A...

-- john, KE5FX



From bruce.griffiths at xtra.co.nz  Fri Nov 21 22:06:30 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sat, 22 Nov 2008 11:06:30 +1300
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>
References: <PKEGJHPHLLBACEOICCBJGEMAPDAB.jmiles@pop.net>
Message-ID: <492730E6.3040403@xtra.co.nz>

John Miles wrote:
> I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
> the performance of my Thunderbolt from the TAPR group buy (in orange) next
> to the traces for my older unit before and after the 10811 upgrade.
>
> There is no upside to tinkering with the OCXO on the TAPR units, unless you
> have something that can beat a 10811.  You could replace it with a rubidium
> source and get better short-term stability, but I don't think swapping one
> quartz OCXO for another would be a useful thing to do.
>
> -- john, KE5FX
>   
John

What power supply did the TAPR Thunderbolt use?
Have you considered using a variant of the Wenzel supply filters to
cleanup the spurs in the 1-10kHz region.
This is trivial with the low current -12V supply but would require some
design effort for the +12V and +5V supplies.
Using a more modern opamp (simplifies biasing) to augment the
performance of such a filter for the higher current supplies would be
worthwhile.
Even dropping the spur level by 20dB is probably worthwhile.

Bruce


From normn3ykf at stny.rr.com  Fri Nov 21 22:32:07 2008
From: normn3ykf at stny.rr.com (Norman J McSweyn)
Date: Fri, 21 Nov 2008 17:32:07 -0500
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <fhbei49g7dh7ppva49ataktts2lr1412vk@4ax.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net>	<4925C61D.3080706@pacific.net>
	<49264E0C.3070809@stny.rr.com>
	<fhbei49g7dh7ppva49ataktts2lr1412vk@4ax.com>
Message-ID: <492736E7.4070003@stny.rr.com>

Matt Osborn wrote:
> I'm not a Labview expert, but I've seen Labview do that with messages
> from other devices. Labview (or more likely, its programmer) has
> issues dealing with threading issues.
>  
> On Fri, 21 Nov 2008 00:58:36 -0500, Norman J McSweyn
> <normn3ykf at stny.rr.com> wrote:
> 
>> Gentlemen:
>> Why would the M12+T swap the order of messages?
>>
>> I write @@Hn and @@Eq in that order to the board and it gives it back to 
>>  me in reverse order.
>>
>> Tried @@Cf then resending the messages. Still the same. Then did it AND 
>> swapped the order of the messages. Still the same.
>>
>> The manual says it's first in, first out regarding the serial buffer.
>>
>> I'm using Labview 8.
>>
>> Norm n3ykf
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> -- kc0ukk at msosborn dot com
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
Matt,
Could be a loose nut issue. However, using different messages as a test 
reveals that "first in first out" in different circumstances is the 
behaviour.

The first part of this .vi just writes a string to the device.
The second reads the buffer (and loops).
After reading the buffer, I flush it. Just to make sure that I will get 
a clean read next iteration.

Any pointers to troubleshooting will be greatly appreciated.

Why would threading have anything to do with it?

Just for giggles, I'll try not closing the Visa session until the .vi 
completes.
73 de Norm n3ykf


From jmiles at pop.net  Fri Nov 21 22:50:06 2008
From: jmiles at pop.net (John Miles)
Date: Fri, 21 Nov 2008 14:50:06 -0800
Subject: [time-nuts] To improve a Tbolt?
In-Reply-To: <492730E6.3040403@xtra.co.nz>
Message-ID: <PKEGJHPHLLBACEOICCBJAEMNPDAB.jmiles@pop.net>


> What power supply did the TAPR Thunderbolt use?

The green, orange, and red traces used the supply module that came with the
TAPR order.  You can see the characteristic hump around 3 kHz that appears
in many of Tom's plots with this supply as well.

The blue trace was the old-style packaged Thunderbolt with the integrated
switching supply.

> Have you considered using a variant of the Wenzel supply filters to
> cleanup the spurs in the 1-10kHz region.

It couldn't hurt.  However, I don't tend to take spurs below -120 dBc very
seriously, because they can come from so many different sources outside my
control.  The HP 3048A system components were scattered all over the room at
the time these graphs were taken, and I had a strong cellular/pager
transmitter on the building immediately next door.  In any event the 3048A's
own spur-level specification is about -115 dBc.

I try not to lose sleep over low-level spurs unless/until they interfere
with an actual application, then I look into the specific one(s) that are
causing trouble.  Sloppy, perhaps, but ars longa, vita brevis and all that
good stuff...

> This is trivial with the low current -12V supply but would require some
> design effort for the +12V and +5V supplies.
> Using a more modern opamp (simplifies biasing) to augment the
> performance of such a filter for the higher current supplies would be
> worthwhile.
> Even dropping the spur level by 20dB is probably worthwhile.

I think the best way to deal with wideband noise and spurs is at the
architectural level.  Wall off the GPS clock and its supplies entirely, and
use its 10 MHz output to phase lock the clock you're actually using to drive
critical stuff.  That clock would be fed with a clean supply and tightly
integrated with its application, as opposed to mounted 20 feet away on
another rack.

With that philosophy, the GPS clock's performance at 10 Hz and below is
worth sweating out, but phase noise and spurs at wider offsets may not be.

-- john, KE5FX




From brooke at pacific.net  Fri Nov 21 22:53:24 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Fri, 21 Nov 2008 14:53:24 -0800
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <492736E7.4070003@stny.rr.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net>	<4925C61D.3080706@pacific.net>	<49264E0C.3070809@stny.rr.com>	<fhbei49g7dh7ppva49ataktts2lr1412vk@4ax.com>
	<492736E7.4070003@stny.rr.com>
Message-ID: <49273BE4.3040907@pacific.net>

Hi Norman:

Can you save the LV program to run with version 7 and email it program to me?

Have Fun,

Brooke Clarke
http://www.prc68.com

Norman J McSweyn wrote:
> Matt Osborn wrote:
>> I'm not a Labview expert, but I've seen Labview do that with messages
>> from other devices. Labview (or more likely, its programmer) has
>> issues dealing with threading issues.
>>  
>> On Fri, 21 Nov 2008 00:58:36 -0500, Norman J McSweyn
>> <normn3ykf at stny.rr.com> wrote:
>>
>>> Gentlemen:
>>> Why would the M12+T swap the order of messages?
>>>
>>> I write @@Hn and @@Eq in that order to the board and it gives it back to 
>>>  me in reverse order.
>>>
>>> Tried @@Cf then resending the messages. Still the same. Then did it AND 
>>> swapped the order of the messages. Still the same.
>>>
>>> The manual says it's first in, first out regarding the serial buffer.
>>>
>>> I'm using Labview 8.
>>>
>>> Norm n3ykf
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> -- kc0ukk at msosborn dot com
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> Matt,
> Could be a loose nut issue. However, using different messages as a test 
> reveals that "first in first out" in different circumstances is the 
> behaviour.
> 
> The first part of this .vi just writes a string to the device.
> The second reads the buffer (and loops).
> After reading the buffer, I flush it. Just to make sure that I will get 
> a clean read next iteration.
> 
> Any pointers to troubleshooting will be greatly appreciated.
> 
> Why would threading have anything to do with it?
> 
> Just for giggles, I'll try not closing the Visa session until the .vi 
> completes.
> 73 de Norm n3ykf
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From tvb at LeapSecond.com  Fri Nov 21 23:06:16 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 21 Nov 2008 15:06:16 -0800
Subject: [time-nuts] M12+T more confusion
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net><4925C61D.3080706@pacific.net>
	<49264E0C.3070809@stny.rr.com>
Message-ID: <52B513258A16404389B74802DDFA9CDE@pc52>

> Gentlemen:
> Why would the M12+T swap the order of messages?
> 
> I write @@Hn and @@Eq in that order to the board and it gives it back to 
>  me in reverse order.

What parameter(s) are you passing the @@Hn and @@Eq
and how quickly are you sending them? Page 31 talks about
this.

> Tried @@Cf then resending the messages. Still the same. Then did it AND 
> swapped the order of the messages. Still the same.

You are enabling output messages, right? Sounds like the
order in which you individually *enable* one or more messages
is unrelated to the order in which, once a second(*), all selected
messages are *output*. I've never confirmed if they are output
alphabetically or by size or priority or what. Does someone know
for sure? Or does it matter?

> The manual says it's first in, first out regarding the serial buffer.

Right, but the commands you are sending are merely enabling
commands. Send as many as you want in any order. You don't
see responses until the top of the next second. Just a guess,
though, since my M12+T is not available to confirm this.

> 
> I'm using Labview 8.
> 
> Norm n3ykf




From chris.kuethe at gmail.com  Fri Nov 21 23:29:03 2008
From: chris.kuethe at gmail.com (Chris Kuethe)
Date: Fri, 21 Nov 2008 15:29:03 -0800
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <52B513258A16404389B74802DDFA9CDE@pc52>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>
	<49243CED.4060400@pacific.net> <4925C61D.3080706@pacific.net>
	<49264E0C.3070809@stny.rr.com> <52B513258A16404389B74802DDFA9CDE@pc52>
Message-ID: <91981b3e0811211529t6e2bd687p865c9cbf0ef3ab34@mail.gmail.com>

On Fri, Nov 21, 2008 at 3:06 PM, Tom Van Baak <tvb at leapsecond.com> wrote:
> You are enabling output messages, right? Sounds like the
> order in which you individually *enable* one or more messages
> is unrelated to the order in which, once a second(*), all selected
> messages are *output*. I've never confirmed if they are output
> alphabetically or by size or priority or what. Does someone know
> for sure? Or does it matter?

i've not seen a gps yet that doesn't act like there's a big,
fixed-order list against which the enabled output messages are checked
once per reporting cycle. it's not impossible to dynamically schedule
a specific order of messages at a certain rate by building an array of
function calls, but that sounds like more work... the first way can be
done with a single char comparison per message.

some messages are certainly more expensive to generate (GSV vs GLL)
and are probably less interesting - so long has there is a good fix
and a navigation solution the average user probably won't care too
much about satellite locations. And the fix data will be more relevant
if you can output location immediately after it's calculated, rather
than delaying it 200ms for a satellite status report. Some receivers
do have certain message types triggered at set time - I hear SiRF's
ZDA message is supposed to be sync'd with the top of the second.


-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?


From normn3ykf at stny.rr.com  Fri Nov 21 23:32:42 2008
From: normn3ykf at stny.rr.com (Norman J McSweyn)
Date: Fri, 21 Nov 2008 18:32:42 -0500
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <52B513258A16404389B74802DDFA9CDE@pc52>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net><4925C61D.3080706@pacific.net>	<49264E0C.3070809@stny.rr.com>
	<52B513258A16404389B74802DDFA9CDE@pc52>
Message-ID: <4927451A.2030303@stny.rr.com>

Tom Van Baak wrote:
>> Gentlemen:
>> Why would the M12+T swap the order of messages?
>>
>> I write @@Hn and @@Eq in that order to the board and it gives it back to 
>>  me in reverse order.
> 
> What parameter(s) are you passing the @@Hn and @@Eq
> and how quickly are you sending them? Page 31 talks about
> this.
Tom,
Each message is written so as to get the board to output once per second.

The program is structured such that it writes once, then drops down and 
loops , reading the buffer (I've disabled the termination character) 
when XX bytes have accumulated.
> 
>> Tried @@Cf then resending the messages. Still the same. Then did it AND 
>> swapped the order of the messages. Still the same.
> 
> You are enabling output messages, right? Sounds like the
> order in which you individually *enable* one or more messages
> is unrelated to the order in which, once a second(*), all selected
> messages are *output*. I've never confirmed if they are output
> alphabetically or by size or priority or what. Does someone know
> for sure? Or does it matter?
I'm suspecting this is the case. Need to power off the board to confirm 
that there's nothing being stored
Just did that. Then reset the board with @@Cf. Then wrote @@Hn and @@Ha 
to the board in that order.
Came back @@Ha then @@ Hn.
If I use @@Hn and @@Eq (ascii position/time message) the same behaviour 
exists.
> 
>> The manual says it's first in, first out regarding the serial buffer.
> 
> Right, but the commands you are sending are merely enabling
> commands. Send as many as you want in any order. You don't
> see responses until the top of the next second. Just a guess,
> though, since my M12+T is not available to confirm this.
> 
I've played with an 8051. Do know a little about micros. Love trying to 
guess what's going on inside the little black box.
>> I'm using Labview 8.
>>
>> Norm n3ykf
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From richiem at hughes.net  Fri Nov 21 23:39:22 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 21 Nov 2008 15:39:22 -0800
Subject: [time-nuts] Wavetek 3010
In-Reply-To: <mailman.238.1227300160.2542.time-nuts@febo.com>
References: <mailman.238.1227300160.2542.time-nuts@febo.com>
Message-ID: <22830685-98BB-43BC-A219-04A8679AC723@hughes.net>


On Nov 21, 2008, at 12:42 PM, time-nuts-request at febo.com wrote:

> Message: 2
> Date: Sat, 22 Nov 2008 01:21:16 +1300
> From: "Steve Rooke" <sar10538 at gmail.com>
> Subject: [time-nuts] Off-Topic: On Wavetek 3010 lever thumbwheel
> 	switches	and manual
> To: "Discussion of precise time and frequency measurement"
> 	<time-nuts at febo.com>
> Message-ID:
> 	<1231b6a80811210421x30c58cbt22ea48e2d6906055 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> snip>>>>

> I've also trawled the Net to find a freely downloadable manual (user
> and servicing) but to no avail. If anyone has a copy or could point me
> in the right direction, I would be most grateful.
>
> 73, Steve
> --  
> Steve Rooke - ZL3TUV & G8KVD
> Omnium finis imminet
>
Steve, I've got a Wavetek 3001/3002 manual that may get you near to  
where you need to go. Contact me at richiem at hughes.net, and let me  
know if that's something you can use. I'd be happy to loan it to you  
for copying.

Best,
Dick Moore


From normn3ykf at stny.rr.com  Fri Nov 21 23:43:47 2008
From: normn3ykf at stny.rr.com (Norman J McSweyn)
Date: Fri, 21 Nov 2008 18:43:47 -0500
Subject: [time-nuts] M12+T more confusion
In-Reply-To: <91981b3e0811211529t6e2bd687p865c9cbf0ef3ab34@mail.gmail.com>
References: <ca708d410811190629i221f323cnbebd8f3f40606dc4@mail.gmail.com>	<49243CED.4060400@pacific.net>
	<4925C61D.3080706@pacific.net>	<49264E0C.3070809@stny.rr.com>
	<52B513258A16404389B74802DDFA9CDE@pc52>
	<91981b3e0811211529t6e2bd687p865c9cbf0ef3ab34@mail.gmail.com>
Message-ID: <492747B3.5000500@stny.rr.com>

Chris Kuethe wrote:
> On Fri, Nov 21, 2008 at 3:06 PM, Tom Van Baak <tvb at leapsecond.com> wrote:
>> You are enabling output messages, right? Sounds like the
>> order in which you individually *enable* one or more messages
>> is unrelated to the order in which, once a second(*), all selected
>> messages are *output*. I've never confirmed if they are output
>> alphabetically or by size or priority or what. Does someone know
>> for sure? Or does it matter?
> 
> i've not seen a gps yet that doesn't act like there's a big,
> fixed-order list against which the enabled output messages are checked
> once per reporting cycle. it's not impossible to dynamically schedule
> a specific order of messages at a certain rate by building an array of
> function calls, but that sounds like more work... the first way can be
> done with a single char comparison per message.
Chris,
I'm not much of a programmer **YET**. The approach you suggest is one 
that I would need to take if I was creating a bulletproof app. Using the 
simple method that I've employed definitely isn't.
Don't get much time to play with this stuff. When I do, I try to get 
something to work. It's like anything else. The more you play with it, 
the less intimidating and more familiar it is, hence, more comfortable.
> 
> some messages are certainly more expensive to generate (GSV vs GLL)
> and are probably less interesting - so long has there is a good fix
> and a navigation solution the average user probably won't care too
> much about satellite locations. And the fix data will be more relevant
> if you can output location immediately after it's calculated, rather
> than delaying it 200ms for a satellite status report. Some receivers
> do have certain message types triggered at set time - I hear SiRF's
> ZDA message is supposed to be sync'd with the top of the second.
> 
> 


From richiem at hughes.net  Fri Nov 21 23:44:55 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 21 Nov 2008 15:44:55 -0800
Subject: [time-nuts] TBolt in the house -- MSFT mouse bug
In-Reply-To: <mailman.3.1227268801.9751.time-nuts@febo.com>
References: <mailman.3.1227268801.9751.time-nuts@febo.com>
Message-ID: <3CAD840C-1072-4887-A614-D3970BE1E4C5@hughes.net>

On Nov 21, 2008, at 4:00 AM, time-nuts-request at febo.com wrote:

> Message: 2
> Date: Fri, 21 Nov 2008 01:25:38 -0500
> From: Norman J McSweyn <normn3ykf at stny.rr.com>
> Subject: Re: [time-nuts] TBolt in the house!
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <49265462.8090600 at stny.rr.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Give this a try!
> http://www.synergy-gps.com/images/stories/ShopTalk/disabling% 
> 20detection%20of%20microsoft%20ballpoint%20mouse.pdf
> The serial mouse issue drove me nuts for a while.
> Norm

Norm, You Da Man!!! The regedit did the trick. Thanks also to Randy  
at Synergy, and Big Thanks to that unnamed customer who figured it  
out. Boy, was I tired of having to constantly disable that BallPoint  
driver. Just another reason to love time-nuts.

Dick


From hmurray at megapathdsl.net  Sat Nov 22 00:10:04 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Fri, 21 Nov 2008 16:10:04 -0800
Subject: [time-nuts] M12+T more confusion
In-Reply-To: Message from "Chris Kuethe" <chris.kuethe@gmail.com> of "Fri,
	21 Nov 2008 15:29:03 PST."
	<91981b3e0811211529t6e2bd687p865c9cbf0ef3ab34@mail.gmail.com> 
Message-ID: <20081122001005.7145ABCD5@ip-64-139-1-69.sjc.megapath.net>


> I hear SiRF's ZDA message is supposed to be sync'd with the top of the
> second.

The manual says something like that.

I've been searching for inexpensive GPS units that work well with ntp.  The 
SiRF sets are inexpensive, but the timing on their NMEA messages sucks.  
There is a lot of jitter and wander.  By wander I mean offset that changes 
slowly so you can't filter it out, hanging bridges.
  http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif

They also have a leap second bug that makes the answer off by a second some 
of the time in some strange pattern over a week.  I assume that's what caused 
it.  It was working OK until the GPS satellites started announcing the next 
leap second.
  http://www.megapathdsl.net/~hmurray/ntp/leap-gps2.gif
(I'll bet there is a good story behind that one.)


The NMEA driver in ntpd defaults to expecting RMC, so that's what I normally 
use.

A while ago, somebody mentioned that ZDA should be better, so I tried it.  I 
couldn't see any difference.





-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From hmurray at megapathdsl.net  Sat Nov 22 06:27:31 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Fri, 21 Nov 2008 22:27:31 -0800
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: Message from Scott Mace <smace@intt.net> 
	of "Fri, 21 Nov 2008 15:57:23 CST." <49272EC3.7000409@intt.net> 
Message-ID: <20081122062732.B2217BCD5@ip-64-139-1-69.sjc.megapath.net>


> On the Z3801a, if you want to use the 1-PPS or 10MHz signals that are
> on the DB-25 you will need to convert the PECL outputs.

If you are willing to lift a pin and cut a trace, you can get the PPS on 
RS-232 without any external level conversion.  The fine print is in here:
  http://support.ntp.org/bin/view/Support/Z3801AReceiverModifications

I used a non-standard pin on the DB-25 in order to avoid cutting a trace, but 
I was building my own 25 to 9 pin adapter so that was easy fix.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From vilgotch at bigpond.net.au  Sat Nov 22 07:52:22 2008
From: vilgotch at bigpond.net.au (Morris Odell)
Date: Sat, 22 Nov 2008 18:52:22 +1100
Subject: [time-nuts] Oncore question
Message-ID: <002101c94c77$40e46960$ad00a8c0@Morris1>

Hi Fellow Nuts,

I've been following the thread on parsing the Motorola receiver code with
 great interest. I have written AVR code to do this but have not gone to
 great trouble making it bullet proof as it was a non critical application 
in
 a Nixie clock. I programmed the receiver to send only one message, and then
 looked for the @@Ba string before I started counting bytes. I used the
 number of SVs byte to decide whether the data was good. Worked fine for me!

 I'm about to start another project with an Oncore so maybe I'll experiment
 with a more complex program this time.

 My question relates to the older Oncore VP receivers. I have one which had 
a
 dead memory battery. The receiver has an on-board battery charger for a
 rechargable Li cell but they are very hard to find down here. In the past
 I've used a conventional Li cell with a schottky diode to prevent the
 charger from forcing current down it's throat. I was wondering if there's
 any reason not to use a super cap. I only need it to support the memory for
 very short periods during power burps. Will the on-board charger be OK for 
a 1F
 super cap?

Any help or opinons much appreciated

Thanks,

Morris 



From iovane at inwind.it  Sat Nov 22 09:54:11 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Sat, 22 Nov 2008 10:54:11 +0100
Subject: [time-nuts] HP 53131A question
Message-ID: <KAQBIB$D3CB3C54D444A51FFC83F8CB7102F303@libero.it>

Hi all,

I'm planning to use a HP 53131A for phase measurements. 
In a limit case, just to understand, suppose that I'm 
reading, say, 100 degrees, and the next reading gives again 
100 degrees, but meanwhile the signal under test jumped 360 
degrees. Is there any way to detect such a case? 

Thanks in advance,
Antonio I8IOV



From kirbybq at bellsouth.net  Sat Nov 22 10:24:48 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Sat, 22 Nov 2008 04:24:48 -0600
Subject: [time-nuts] Oncore question
In-Reply-To: <002101c94c77$40e46960$ad00a8c0@Morris1>
References: <002101c94c77$40e46960$ad00a8c0@Morris1>
Message-ID: <4927DDF0.70605@bellsouth.net>

check http://www.synergy-gps.com/content/view/42/89/  the article on 
battery backup has some info on this....


Brian KD4FM


Morris Odell wrote:
> Hi Fellow Nuts,
> 
> I've been following the thread on parsing the Motorola receiver code with
>  great interest. I have written AVR code to do this but have not gone to
>  great trouble making it bullet proof as it was a non critical application 
> in
>  a Nixie clock. I programmed the receiver to send only one message, and then
>  looked for the @@Ba string before I started counting bytes. I used the
>  number of SVs byte to decide whether the data was good. Worked fine for me!
> 
>  I'm about to start another project with an Oncore so maybe I'll experiment
>  with a more complex program this time.
> 
>  My question relates to the older Oncore VP receivers. I have one which had 
> a
>  dead memory battery. The receiver has an on-board battery charger for a
>  rechargable Li cell but they are very hard to find down here. In the past
>  I've used a conventional Li cell with a schottky diode to prevent the
>  charger from forcing current down it's throat. I was wondering if there's
>  any reason not to use a super cap. I only need it to support the memory for
>  very short periods during power burps. Will the on-board charger be OK for 
> a 1F
>  super cap?
> 
> Any help or opinons much appreciated
> 
> Thanks,
> 
> Morris 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From phill.r1 at btinternet.com  Sat Nov 22 11:29:03 2008
From: phill.r1 at btinternet.com (Roy Phillips)
Date: Sat, 22 Nov 2008 11:29:03 -0000
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: <20081122062732.B2217BCD5@ip-64-139-1-69.sjc.megapath.net>
References: <20081122062732.B2217BCD5@ip-64-139-1-69.sjc.megapath.net>
Message-ID: <09CB132E5B2A4C91BAD441E50658F8C9@LapTop>

Hal
Thanks for your kind help. You are certainly right about the PECL level 
signals from the I/O connector, but this is where the similarity stops, as 
the Trimble unit is to all intents a substitute for the Z3801A, but 
internally its quite different. In the interests of costs, it would seem 
that there is no RS-232 facility. There is a sub PCB that carries the LED's 
at the front of the unit via a connector, and there is a location on this 
PCB for a for a 9-pin D connector!.  If this had been used it would have 
made a serial port available at the front panel. More interesting is that 
there are tracks feeding what would have been pins 2,3 and 5 !
Perhaps there was an intention in the original specification to provide a 
"service" serial port to the front of the unit - but would this have 
provided RS-422 and not RS-232 signals ? Unfortunately, Trimble will not 
offer any information on this unit, as it was made for Nortel, and I have so 
far not been able to find any alternative information except for a brief 
reference in the Z3801A article.

Roy


----- Original Message ----- 
From: "Hal Murray" <hmurray at megapathdsl.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, November 22, 2008 6:27 AM
Subject: Re: [time-nuts] The Trimble NTPX26AB-06 / Z3801A


>
>> On the Z3801a, if you want to use the 1-PPS or 10MHz signals that are
>> on the DB-25 you will need to convert the PECL outputs.
>
> If you are willing to lift a pin and cut a trace, you can get the PPS on
> RS-232 without any external level conversion.  The fine print is in here:
>  http://support.ntp.org/bin/view/Support/Z3801AReceiverModifications
>
> I used a non-standard pin on the DB-25 in order to avoid cutting a trace, 
> but
> I was building my own 25 to 9 pin adapter so that was easy fix.
>
>
>
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 




From hmurray at megapathdsl.net  Sat Nov 22 11:51:53 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sat, 22 Nov 2008 03:51:53 -0800
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: Message from "Roy Phillips" <phill.r1@btinternet.com> of "Sat,
	22 Nov 2008 11:29:03 GMT." <09CB132E5B2A4C91BAD441E50658F8C9@LapTop> 
Message-ID: <20081122115154.C9984BCD5@ip-64-139-1-69.sjc.megapath.net>


> In the interests of costs, it would seem  that there is no RS-232
> facility. There is a sub PCB that carries the LED's  at the front of
> the unit via a connector, and there is a location on this  PCB for a
> for a 9-pin D connector!.  If this had been used it would have  made a
> serial port available at the front panel. More interesting is that
> there are tracks feeding what would have been pins 2,3 and 5 !

Follow the traces and see where they go.

Put a scope on the data-out pin and see if you see anything.


> Unfortunately, Trimble will not  offer any information on this unit,
> as it was made for Nortel, and I have so  far not been able to find
> any alternative information except for a brief  reference in the
> Z3801A article.




-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From bg at lysator.liu.se  Sat Nov 22 11:54:23 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Sat, 22 Nov 2008 12:54:23 +0100
Subject: [time-nuts] The Trimble NTPX26AB-06 / Z3801A
In-Reply-To: <09CB132E5B2A4C91BAD441E50658F8C9@LapTop>
References: <20081122062732.B2217BCD5@ip-64-139-1-69.sjc.megapath.net>
	<09CB132E5B2A4C91BAD441E50658F8C9@LapTop>
Message-ID: <1227354863.20299.151.camel@bg-desktop>

Hi Roy,

On Sat, 2008-11-22 at 11:29 +0000, Roy Phillips wrote:

> at the front of the unit via a connector, and there is a location on this 
> PCB for a for a 9-pin D connector!.  If this had been used it would have 
> made a serial port available at the front panel. More interesting is that 
> there are tracks feeding what would have been pins 2,3 and 5 !

> Perhaps there was an intention in the original specification to provide a 
> "service" serial port to the front of the unit - but would this have 
> provided RS-422 and not RS-232 signals ? 

RS-422 gives you, at least, RX+, RX-, TX+, TX-; your pins (2,3,5) cannot
be RS-422. I would spy voltage levels with a scope, and hope for
RS232-levels or TTL-levels.

TTL is easily shifted with a MAX232 or equiv.

> Roy

--

    Bj?rn



From magnus at rubidium.dyndns.org  Sat Nov 22 14:57:05 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sat, 22 Nov 2008 15:57:05 +0100
Subject: [time-nuts] HP 53131A question
In-Reply-To: <KAQBIB$D3CB3C54D444A51FFC83F8CB7102F303@libero.it>
References: <KAQBIB$D3CB3C54D444A51FFC83F8CB7102F303@libero.it>
Message-ID: <49281DC1.2090107@rubidium.dyndns.org>

iovane at inwind.it skrev:
> Hi all,
> 
> I'm planning to use a HP 53131A for phase measurements. 
> In a limit case, just to understand, suppose that I'm 
> reading, say, 100 degrees, and the next reading gives again 
> 100 degrees, but meanwhile the signal under test jumped 360 
> degrees. Is there any way to detect such a case? 

No. Not really. The counter makes a +/- TI measurement between channel A 
and B and also measures frequency on one of them. The individual count 
on the two channels is lost and thus the slip information. If you divide 
the signals down by say 10, then a signle cycle slip on the original 
signal would show up as a 36 degree shift in reading, while a 10 degree 
shift on the signal would be displayed as a 1 degree shift on reading.

The dividers would hold the state which you don't get directly. Some 
counters allow for simultaneous time-stamping and event counter 
recording of A and B channels. Those counters safe enought state to 
provide phase measurement (through time stamp) and slip difference 
(through event counters). You are interested in absolute phase, so that 
is what you want to do.

Cheers,
Magnus


From tvb at LeapSecond.com  Sat Nov 22 16:54:36 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Sat, 22 Nov 2008 08:54:36 -0800
Subject: [time-nuts] HP 53131A question
References: <KAQBIB$D3CB3C54D444A51FFC83F8CB7102F303@libero.it>
Message-ID: <9503C766715444DCA5BD7774D6767F41@pc52>

> Hi all,
> 
> I'm planning to use a HP 53131A for phase measurements. 
> In a limit case, just to understand, suppose that I'm 
> reading, say, 100 degrees, and the next reading gives again 
> 100 degrees, but meanwhile the signal under test jumped 360 
> degrees. Is there any way to detect such a case? 
> 
> Thanks in advance,
> Antonio I8IOV

That's a good question for the purpose of understanding.

In general, no. So you have to pick your sampling rate to be
somewhat faster than the expected maximum cycle drift rate
(Nyquist has something to say related to this).

As a further example, the same thing would happen to the earth,
if while you were sleeping it quickly sped up 3x normal speed
and slowed back down to normal. You'd wake up, see a sunrise,
and think it was Saturday morning. Instead it would actually be
Sunday morning. You were sleeping; how would you know?

Now if there were a special application where detecting phase
jumps like this was critical you could drive two free-running
counters, one from the input signal, one from a reference clock,
and compare them as often or as infrequent as you wish. A
"continuous count" or "zero dead time" counter works this way.
But a 53131A is isn't of this design.

Magnus' suggestion about dividers is perfect. It is what many of
us do with our clocks -- instead of measuring phase angle between
two 5 MHz RF signals, we divide 5 MHz down to 1 Hz and leisurely
compare the time interval of 1PPS signals, as often as once a
second or even as infrequently as once an hour or day.

/tvb



From magnus at rubidium.dyndns.org  Sat Nov 22 17:32:42 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sat, 22 Nov 2008 18:32:42 +0100
Subject: [time-nuts] HP 53131A question
In-Reply-To: <9503C766715444DCA5BD7774D6767F41@pc52>
References: <KAQBIB$D3CB3C54D444A51FFC83F8CB7102F303@libero.it>
	<9503C766715444DCA5BD7774D6767F41@pc52>
Message-ID: <4928423A.6060108@rubidium.dyndns.org>

Tom Van Baak skrev:
>> Hi all,
>>
>> I'm planning to use a HP 53131A for phase measurements. 
>> In a limit case, just to understand, suppose that I'm 
>> reading, say, 100 degrees, and the next reading gives again 
>> 100 degrees, but meanwhile the signal under test jumped 360 
>> degrees. Is there any way to detect such a case? 
>>
>> Thanks in advance,
>> Antonio I8IOV
> 
> That's a good question for the purpose of understanding.
> 
> In general, no. So you have to pick your sampling rate to be
> somewhat faster than the expected maximum cycle drift rate
> (Nyquist has something to say related to this).
> 
> As a further example, the same thing would happen to the earth,
> if while you were sleeping it quickly sped up 3x normal speed
> and slowed back down to normal. You'd wake up, see a sunrise,
> and think it was Saturday morning. Instead it would actually be
> Sunday morning. You were sleeping; how would you know?
> 
> Now if there were a special application where detecting phase
> jumps like this was critical you could drive two free-running
> counters, one from the input signal, one from a reference clock,
> and compare them as often or as infrequent as you wish. A
> "continuous count" or "zero dead time" counter works this way.
> But a 53131A is isn't of this design.

Hmm... come to think of it, I don't recall that I have seen any 
documentation of the counter core of the HP53131A/53132A.

The "zero dead time" aspect of a counter has been somewhat debated. What 
it means is that the counter makes a pause between two measurements, 
read out the values, resets its counters and arm the trigger circuit for 
the next trigger event. The event counter counts the number of gated 
signal, i.e. for a clock the number of cycles. The time counter counts 
the number of reference clock cycles of the reference clock, so this is 
an event counter for the reference clock. The reference clock is often 
higher than the 10 MHz local reference, but the HP5335A is an example of 
a counter using the 10 MHz directly. Modern counters also use 
interpolators to increase time-resolution, so the interpolated start and 
stop value is also stored.

The problem is that during the pause, you are not monitoring the signal, 
so you can't see if it does any jumps or anything. A zero dead time 
counter solves this by keeping the event counter and time counter 
running continously. Rather, the start and stop events sample the state 
of these counters and store it. By taking the difference between the 
start and stop event counter values, you get the number of events 
between the start and stop, and similarly for the time counter. If you 
now record a number of these into a memory, what is the stop of one 
measurement can be the start of the next, so the same trigger event 
becomes both stop and start. There simply is no dead time. What is 
stored in the memory is the absolute phase of the signal. What many does 
not realize is that the reference input at the back is infact a input 
channel, and that some measurements is better performed directly with 
that. When using two channels it becomes a transfer oscillator with its 
benefits and drawbacks.

A great way to learn about many of the aspects is to read the HP5372A 
programmers manual, since the binary format is really the pure binary 
pattern stored in the 8192 sample long memory. It details how you need 
to process it to get the same result as the display shows when you have 
selected that measurement on the front. It also allows for other forms 
of analysis where the pure TI data is important.

> Magnus' suggestion about dividers is perfect. It is what many of
> us do with our clocks -- instead of measuring phase angle between
> two 5 MHz RF signals, we divide 5 MHz down to 1 Hz and leisurely
> compare the time interval of 1PPS signals, as often as once a
> second or even as infrequently as once an hour or day.

This method simulates much of the continous aspect, as the division 
circuit does not have the dead time of the counter. However, the benefit 
of dividing less is that you can get a quicker update time. Higher 
frequencies of jitter/wander (phase deviations) can be exposed and 
treated separately. The division converts the signal phase it into a 
form which a +/- TI capable counter with dead time can handle. To cover 
dead time, the minimum period of the output signal should be longer than 
the effective deadtime for a complete guarantee, but for many cases 
higher frequencies can be used anyway. 1 Hz is not necessarilly needed.

Cheers,
Magnus


From Arnold.Tibus at gmx.de  Sun Nov 23 00:05:26 2008
From: Arnold.Tibus at gmx.de (Arnold Tibus)
Date: Sun, 23 Nov 2008 01:05:26 +0100
Subject: [time-nuts] Oncore question
In-Reply-To: <002101c94c77$40e46960$ad00a8c0@Morris1>
Message-ID: <mailman.15.1227398758.2539.time-nuts@febo.com>

Hello Morris, 
I am not aware what is the voltage range for the backup battery in the GPS-RX, 
but using a super cap or gold cap instead of a (rechargeable) battery
should be ok for short backup times, Synergy does even propose the use 
of a SuperCap or UltraCapacitor as a backup power source for certain op. conditions.

What is the main difference to the use of batteries?
In capacitors, the voltage does directly follow the charging current amount 
but batteries do hold the voltage in a certain area quite stable. Therfore 
a battery with the same charge is more efficient but need long charging time 
and the special capacitors can be charged very quick.

After your question I did want to know myself for what time these caps would serve.
My result:
For a backup current of 25 ?A and allowing a voltage drop during the backup 
of 0.5 V, the data will be safe for around 5 to 6 hours,

With only 5 ?A backup current the time will be 5 times higher (abt. 27 h) 
not counting for leakage or other discharge factors. 

The very simple numerical assessment:

C = 1 F , U = 5 V (max. 5.5 V in gold caps?)
1 F charged to 5 V : 
Q = 5 As,  
U = I * T / C

Voltage drop per second for C = 1 F loaded to 5 V
U/s = 5 E - 6 * A * 5 V/ 1 A = 25 ?V

Time for 500 mV drop down (from 5 V down to 4.5 V )
at a load current of 25 ?A :
500 *10 ^-3 Vs / 25*10^-6 V = 20,000 s = 5 h 33 min

or:

Q = 5 V F = 5 V * 1 As / V = 5 As = 5 *10^6 ?As = 5.000.000 ?As
10 % of 5 V   => 500,000 ?As
A load of   5 ?A gives 100,000 s = 27 3/4 h
A load of 25 ?A gives   20,000 s =   5 1/2 h

Such big capacitors may be charged within parts of a second, if wanted, 
but don't forget the Voltage Limit!

Good luck and regards
Arnold, DK2WT


On Sat, 22 Nov 2008 18:52:22 +1100, Morris Odell wrote:

>Hi Fellow Nuts,

>I've been following the thread on parsing the Motorola receiver code with
> great interest. I have written AVR code to do this but have not gone to
> great trouble making it bullet proof as it was a non critical application 
>in
> a Nixie clock. I programmed the receiver to send only one message, and then
> looked for the @@Ba string before I started counting bytes. I used the
> number of SVs byte to decide whether the data was good. Worked fine for me!

> I'm about to start another project with an Oncore so maybe I'll experiment
> with a more complex program this time.

> My question relates to the older Oncore VP receivers. I have one which had 
>a
> dead memory battery. The receiver has an on-board battery charger for a
> rechargable Li cell but they are very hard to find down here. In the past
> I've used a conventional Li cell with a schottky diode to prevent the
> charger from forcing current down it's throat. I was wondering if there's
> any reason not to use a super cap. I only need it to support the memory for
> very short periods during power burps. Will the on-board charger be OK for 
>a 1F
> super cap?

>Any help or opinons much appreciated

>Thanks,

>Morris 


>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.







From SAIDJACK at aol.com  Sun Nov 23 00:26:40 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Sat, 22 Nov 2008 19:26:40 EST
Subject: [time-nuts] Oncore question
Message-ID: <bf8.398b4901.3659fd40@aol.com>

Hello Arnold,
 
the current drawn by the Motorola GPS from the backup bat is not linear  
versus voltage.
 
On an M12+, the real time clock takes most of the current, and will stop  
operating after about a day or less on a Supercap. The SRAM memory keeps  
maintaining it's contents for much longer than that.
 
After the RTC crystal stops, the power consumption goes down to extremely  
low discharge rates.
 
I have seen our FireFox units (M12+ with supercap) still maintain position  
and almanac over more than 1.5 weeks! Down to 0.5V or so. The Date is off by  
that amount too of course since the RTC just stops ticking.
 
This presents a serious problem due to a fault in the Motorola firmware (in  
my opinion):
 
The M12+ sees a "valid" Almanac, but the time and date are off due to the  
fact that the RTC crystal just stopped a some point.
 
The M12+ thinks it's a different time/date than it really is, and  
desperately tries to search the sky for a sat constellation that is not  there. It 
doesn't even reset its internal RTC when it sees a couple of  Sats.
 
I have seen instances where it took a day or more for the firmware to catch  
on, and reset the time in the RTC.
 
When using a small coin Lithium battery, the backup time is only 6 months  to 
1 year or so typically, also not a very good performance.
 
Not a good situation, they could have solved that more elegantly for  sure.
 
bye,
Said
 
 
 
 
In a message dated 11/22/2008 16:06:57 Pacific Standard Time,  
Arnold.Tibus at gmx.de writes:

After  your question I did want to know myself for what time these caps would 
 serve.
My result:
For a backup current of 25 ?A and allowing a voltage  drop during the backup 
of 0.5 V, the data will be safe for around 5 to 6  hours,

With only 5 ?A backup current the time will be 5 times higher  (abt. 27 h) 
not counting for leakage or other discharge factors.  



From ian.sheffield1 at tesco.net  Sun Nov 23 15:47:47 2008
From: ian.sheffield1 at tesco.net (Ian Sheffield)
Date: Sun, 23 Nov 2008 15:47:47 -0000
Subject: [time-nuts] EZGPIB error
Message-ID: <006801c94d82$d68bc060$0201a8c0@cookie>

Hello chaps,

A quick question to the assembled multitude rather than bothering Ulrich directly, as some of you must have seen this problem:

What causes the error message Socket Error # 10065
No route to host, when using EZGPIB with my Prologix latest version interface with my laptops?

EZGPIB works fine from my desktop PC but gives this error message with both of my laptops running XP (one XP Home, the other is XP Pro).

The Prologix itself is working fine, as it controls and reads my HP5334 perfectly using the direct Prologix commands. EZGPIB , as stated, also works fine from the Desktop PC.

What is not configured correctly in the laptops?

Many thanks in advance,

Ian.

From bruce.griffiths at xtra.co.nz  Sun Nov 23 20:17:45 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 24 Nov 2008 09:17:45 +1300
Subject: [time-nuts] EZGPIB error
In-Reply-To: <006801c94d82$d68bc060$0201a8c0@cookie>
References: <006801c94d82$d68bc060$0201a8c0@cookie>
Message-ID: <4929BA69.3030803@xtra.co.nz>

Ian Sheffield wrote:
> Hello chaps,
>
> A quick question to the assembled multitude rather than bothering Ulrich directly, as some of you must have seen this problem:
>
> What causes the error message Socket Error # 10065
> No route to host, when using EZGPIB with my Prologix latest version interface with my laptops?
>
> EZGPIB works fine from my desktop PC but gives this error message with both of my laptops running XP (one XP Home, the other is XP Pro).
>
> The Prologix itself is working fine, as it controls and reads my HP5334 perfectly using the direct Prologix commands. EZGPIB , as stated, also works fine from the Desktop PC.
>
> What is not configured correctly in the laptops?
>
> Many thanks in advance,
>
> Ian.
Are you using the latest version of EZGPIB?


Bruce



From Arnold.Tibus at gmx.de  Sun Nov 23 21:02:27 2008
From: Arnold.Tibus at gmx.de (Arnold Tibus)
Date: Sun, 23 Nov 2008 22:02:27 +0100
Subject: [time-nuts] Oncore question
In-Reply-To: <bf8.398b4901.3659fd40@aol.com>
Message-ID: <mailman.16.1227474269.2539.time-nuts@febo.com>

Hi Said,
thank you very much for the additional clarification, very interesting 
behaviour. I think this does confirm roughly my assumption. When only pwr 
fails for a few hours (intermittant) have to be taken into account, super caps 
may be good for safe work during several hours up to perhaps 24 hours, 
but not beyond, is that right? Do you know at what voltage the clock does resign? 
Perhaps this could be improved with a software solving the recovery problem 
when repowering the RX. 
You describe that using LiIon batteries are not yet the ideal way, but why 
cannot higher capacities come into play (space should be not the problem 
for on ground use in fix stations)?

regards,
Arnold






On Sat, 22 Nov 2008 19:26:40 EST, SAIDJACK at aol.com wrote:

>Hello Arnold,
> 
>the current drawn by the Motorola GPS from the backup bat is not linear  
>versus voltage.
> 
>On an M12+, the real time clock takes most of the current, and will stop  
>operating after about a day or less on a Supercap. The SRAM memory keeps  
>maintaining it's contents for much longer than that.
> 
>After the RTC crystal stops, the power consumption goes down to extremely  
>low discharge rates.
> 
>I have seen our FireFox units (M12+ with supercap) still maintain position  
>and almanac over more than 1.5 weeks! Down to 0.5V or so. The Date is off by  
>that amount too of course since the RTC just stops ticking.
> 
>This presents a serious problem due to a fault in the Motorola firmware (in  
>my opinion):
> 
>The M12+ sees a "valid" Almanac, but the time and date are off due to the  
>fact that the RTC crystal just stopped a some point.
> 
>The M12+ thinks it's a different time/date than it really is, and  
>desperately tries to search the sky for a sat constellation that is not  there. It 
>doesn't even reset its internal RTC when it sees a couple of  Sats.
> 
>I have seen instances where it took a day or more for the firmware to catch  
>on, and reset the time in the RTC.
> 
>When using a small coin Lithium battery, the backup time is only 6 months  to 
>1 year or so typically, also not a very good performance.
> 
>Not a good situation, they could have solved that more elegantly for  sure.
> 
>bye,
>Said
> 
> 
> 
> 
>In a message dated 11/22/2008 16:06:57 Pacific Standard Time,  
>Arnold.Tibus at gmx.de writes:

>After  your question I did want to know myself for what time these caps would 
> serve.
>My result:
>For a backup current of 25 ?A and allowing a voltage  drop during the backup 
>of 0.5 V, the data will be safe for around 5 to 6  hours,

>With only 5 ?A backup current the time will be 5 times higher  (abt. 27 h) 
>not counting for leakage or other discharge factors.  


>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.







From pico.2008 at sbcglobal.net  Sun Nov 23 22:08:45 2008
From: pico.2008 at sbcglobal.net (Peter Putnam)
Date: Sun, 23 Nov 2008 14:08:45 -0800
Subject: [time-nuts] GPS Valid Fix Detector
Message-ID: <4929D46D.1090409@sbcglobal.net>

Greetings,

For those interested in a very simple means of determining if the NMEA
data stream from a GPS receiver contains valid fix data, I offer
design details for a "Valid Fix" detector that runs in a Microchip
12F629, an 8-pin DIP device.

No other components are required if the GPS receiver provides CMOS 
output levels:

http://www.ni6e.com/time/GPS_Valid_Fix.html

Regards,
Peter





From jmiles at pop.net  Sun Nov 23 22:07:18 2008
From: jmiles at pop.net (John Miles)
Date: Sun, 23 Nov 2008 14:07:18 -0800
Subject: [time-nuts] EZGPIB error
In-Reply-To: <4929BA69.3030803@xtra.co.nz>
Message-ID: <PKEGJHPHLLBACEOICCBJEEIDPEAB.jmiles@pop.net>

That's a Winsock HOST UNREACHABLE error.  If you're moving the Prologix
board from one subnet to another, are you reconfiguring its IP address?

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of Bruce Griffiths
> Sent: Sunday, November 23, 2008 12:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] EZGPIB error
>
>
> Ian Sheffield wrote:
> > Hello chaps,
> >
> > A quick question to the assembled multitude rather than
> bothering Ulrich directly, as some of you must have seen this problem:
> >
> > What causes the error message Socket Error # 10065
> > No route to host, when using EZGPIB with my Prologix latest
> version interface with my laptops?
> >
> > EZGPIB works fine from my desktop PC but gives this error
> message with both of my laptops running XP (one XP Home, the
> other is XP Pro).
> >
> > The Prologix itself is working fine, as it controls and reads
> my HP5334 perfectly using the direct Prologix commands. EZGPIB ,
> as stated, also works fine from the Desktop PC.
> >
> > What is not configured correctly in the laptops?
> >
> > Many thanks in advance,
> >
> > Ian.
> Are you using the latest version of EZGPIB?
>
>



From warrensjmail-one at yahoo.com  Sun Nov 23 22:18:23 2008
From: warrensjmail-one at yahoo.com (WarrenS Email)
Date: Sun, 23 Nov 2008 14:18:23 -0800
Subject: [time-nuts] GPSDO using 100Hz
Message-ID: <036501c94db9$666f79c0$6401a8c0@WSOffice>

This is my first listing so don't know if I'm doing correctly.

Question is: Has anyone done any work using the 100Hz GPS output, instead of the 1 Hz output?
The reason I ask is because I am in the process of cleaning up my SIMPLE GPS Freq Phase lock tracker breadboard that does about the same as most, but in a different way. By using just a few basic standard  74HCxx IC logic gates and Flip-Flops with RC's I phase lock a low accuracy VCXO to give me a high accuracy 10MHz reference. This is something I built for my own use, to check the accuracy of my 10 MHz freq standard and to check the accuracy of  the 60KHz WWVB signal. 

I found out that the most important trick to keep the GPS tracker simple (GPSDO), fast and low power, and do it without the usual microprocessor stuff,  was to use the 100Hz output instead of the 1HZ output from the Motorola Oncore receiver board.  Basically this allows simple logic circuits to give 10 to 100 times better results, such as phase noise of around 1 ns instead of 100ns from second to second, cold turn on and full accuracy lock of the tracking osc in well under a minute (with GPS left on). It also has the ability to track the GPS phase errors at about a 10 Hz rate which gave me some new interesting insight, such as the 1 sec sawtooth error that the Oncore reports on, that would usually requires the use of a computer to process, is no longer very relevant. 
I found out the 1 second reported phase error is just an alising artifact of a higher freq phase dither that can be completely filtered out with a 1 second Time constant RC. (i.e RC replaces microprocessor).

It generally takes about an hour Tracking time constant to get good 1e-10 Freq stability using the 1 Second GPS signal, and more like 3 to 24 hours as not degrade a really good Oscillator.
I am getting such good results with the simple high speed RC PLL, I am now doing some test to see if there are new ways to reduce the Tracking time. 
It would seem it should be possible to get 1e-10 in more like a 100 seconds instead of an hour. This would then reduce the required stability of the tracking Oscillator by an order of magnitude or better. The simple PLL tracks the 100Hz within about 1 ns and can lock up in 10 seconds, and the GPS signals themselves don't seem to vary by more than about 10 ns with 10 minute and 1Hr average times. (from http://tf.nist.gov/service/gpstrace.htm)
I have not found any GPS signal accuracy data for shorter average times, so that is what I'm presently plotting.
One of the other many benefits of fast GPS tracking may be the possibility of a more mobile Disciplined Oscillator.

If anyone has done any work using the 100Hz Oncore GS signal to do frequency tracking,  I would be very interested in further discussions.

Warren
********

From quenbob5 at pacbell.net  Sun Nov 23 23:12:16 2008
From: quenbob5 at pacbell.net (Bob Q)
Date: Sun, 23 Nov 2008 15:12:16 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <036501c94db9$666f79c0$6401a8c0@WSOffice>
Message-ID: <000701c94dc0$ed9d5320$1801a8c0@BOBCEL1R7>

I have a design based on the Motorola MT12+ receiver that uses a CMOS 
XOR-based PLL.  I will send you the file with write up and schematic.
Bob Q.
----- Original Message ----- 
From: "WarrenS Email" <warrensjmail-one at yahoo.com>
To: <time-nuts at febo.com>
Sent: Sunday, November 23, 2008 2:18 PM
Subject: [time-nuts] GPSDO using 100Hz


> This is my first listing so don't know if I'm doing correctly.
>
> Question is: Has anyone done any work using the 100Hz GPS output, instead 
> of the 1 Hz output?
> The reason I ask is because I am in the process of cleaning up my SIMPLE 
> GPS Freq Phase lock tracker breadboard that does about the same as most, 
> but in a different way. By using just a few basic standard  74HCxx IC 
> logic gates and Flip-Flops with RC's I phase lock a low accuracy VCXO to 
> give me a high accuracy 10MHz reference. This is something I built for my 
> own use, to check the accuracy of my 10 MHz freq standard and to check the 
> accuracy of  the 60KHz WWVB signal.
>
> I found out that the most important trick to keep the GPS tracker simple 
> (GPSDO), fast and low power, and do it without the usual microprocessor 
> stuff,  was to use the 100Hz output instead of the 1HZ output from the 
> Motorola Oncore receiver board.  Basically this allows simple logic 
> circuits to give 10 to 100 times better results, such as phase noise of 
> around 1 ns instead of 100ns from second to second, cold turn on and full 
> accuracy lock of the tracking osc in well under a minute (with GPS left 
> on). It also has the ability to track the GPS phase errors at about a 10 
> Hz rate which gave me some new interesting insight, such as the 1 sec 
> sawtooth error that the Oncore reports on, that would usually requires the 
> use of a computer to process, is no longer very relevant.
> I found out the 1 second reported phase error is just an alising artifact 
> of a higher freq phase dither that can be completely filtered out with a 1 
> second Time constant RC. (i.e RC replaces microprocessor).
>
> It generally takes about an hour Tracking time constant to get good 1e-10 
> Freq stability using the 1 Second GPS signal, and more like 3 to 24 hours 
> as not degrade a really good Oscillator.
> I am getting such good results with the simple high speed RC PLL, I am now 
> doing some test to see if there are new ways to reduce the Tracking time.
> It would seem it should be possible to get 1e-10 in more like a 100 
> seconds instead of an hour. This would then reduce the required stability 
> of the tracking Oscillator by an order of magnitude or better. The simple 
> PLL tracks the 100Hz within about 1 ns and can lock up in 10 seconds, and 
> the GPS signals themselves don't seem to vary by more than about 10 ns 
> with 10 minute and 1Hr average times. (from 
> http://tf.nist.gov/service/gpstrace.htm)
> I have not found any GPS signal accuracy data for shorter average times, 
> so that is what I'm presently plotting.
> One of the other many benefits of fast GPS tracking may be the possibility 
> of a more mobile Disciplined Oscillator.
>
> If anyone has done any work using the 100Hz Oncore GS signal to do 
> frequency tracking,  I would be very interested in further discussions.
>
> Warren
> ********
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 



From rickharold at gmail.com  Mon Nov 24 02:34:23 2008
From: rickharold at gmail.com (Rick Harold)
Date: Sun, 23 Nov 2008 19:34:23 -0700
Subject: [time-nuts] position determination over short distance
Message-ID: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>

All,

I'm planning doing some experiments in distance measurement.  They don't
deal with atomic time directly but with extreme short periods of time.

I need to determine the position of a instrument with a 1mm accuracy or
less.
The instrument is not connected to a mechanical device but is separate &
independent.
The surface which the instrument is positioned on is close to the size of a
11"x11" square.

I thought of using 1 RF transmitters (not sure of freq) on bottom of the
device near the surface.
The surface would have RF receivers on 3 or 4 edges/corners to receive the
signal.

If each of the receivers positions are known and they then send a signal to
a central circuit (again known positions) how can I differentiate the time
of arrival
at the central location?  Does anybody know of a circuit/chip or system
which would determine the time 'difference'.
Obviously this is used to triangulate the position of the instrument.
Light travels 1 mm in ~3.3 picoseconds so I would suspect the differentiator
would have to have that or better resolution.
It could also use some proportional method to extrapolate the position since
the surface has a fixed size.

Any ideas/thoughts?

Thanks in advance.

Rick Harold

From bruce.griffiths at xtra.co.nz  Mon Nov 24 02:46:55 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 24 Nov 2008 15:46:55 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <036501c94db9$666f79c0$6401a8c0@WSOffice>
References: <036501c94db9$666f79c0$6401a8c0@WSOffice>
Message-ID: <492A159F.3070806@xtra.co.nz>

WarrenS Email wrote:
> This is my first listing so don't know if I'm doing correctly.
>
> Question is: Has anyone done any work using the 100Hz GPS output, instead of the 1 Hz output?
> The reason I ask is because I am in the process of cleaning up my SIMPLE GPS Freq Phase lock tracker breadboard that does about the same as most, but in a different way. By using just a few basic standard  74HCxx IC logic gates and Flip-Flops with RC's I phase lock a low accuracy VCXO to give me a high accuracy 10MHz reference. This is something I built for my own use, to check the accuracy of my 10 MHz freq standard and to check the accuracy of  the 60KHz WWVB signal. 
>
> I found out that the most important trick to keep the GPS tracker simple (GPSDO), fast and low power, and do it without the usual microprocessor stuff,  was to use the 100Hz output instead of the 1HZ output from the Motorola Oncore receiver board.  Basically this allows simple logic circuits to give 10 to 100 times better results, such as phase noise of around 1 ns instead of 100ns from second to second, cold turn on and full accuracy lock of the tracking osc in well under a minute (with GPS left on). It also has the ability to track the GPS phase errors at about a 10 Hz rate which gave me some new interesting insight, such as the 1 sec sawtooth error that the Oncore reports on, that would usually requires the use of a computer to process, is no longer very relevant. 
> I found out the 1 second reported phase error is just an alising artifact of a higher freq phase dither that can be completely filtered out with a 1 second Time constant RC. (i.e RC replaces microprocessor).
>
> It generally takes about an hour Tracking time constant to get good 1e-10 Freq stability using the 1 Second GPS signal, and more like 3 to 24 hours as not degrade a really good Oscillator.
> I am getting such good results with the simple high speed RC PLL, I am now doing some test to see if there are new ways to reduce the Tracking time. 
> It would seem it should be possible to get 1e-10 in more like a 100 seconds instead of an hour. This would then reduce the required stability of the tracking Oscillator by an order of magnitude or better. The simple PLL tracks the 100Hz within about 1 ns and can lock up in 10 seconds, and the GPS signals themselves don't seem to vary by more than about 10 ns with 10 minute and 1Hr average times. (from http://tf.nist.gov/service/gpstrace.htm)
> I have not found any GPS signal accuracy data for shorter average times, so that is what I'm presently plotting.
> One of the other many benefits of fast GPS tracking may be the possibility of a more mobile Disciplined Oscillator.
>
> If anyone has done any work using the 100Hz Oncore GS signal to do frequency tracking,  I would be very interested in further discussions.
>
> Warren
> ********
>   
Warren

Its difficult to make much useful comment as you provide few measured
results.

With an M12+T or equivalent the ADEV of the PPS output (without sawtooth
correction) goes below 1E-10 at  Tau > 200 sec or so.
Thus with an optimised GPSDO it wont take an hour or so to achieve 1E-10
stability.
However a single shot phase error measurement system resolution of
around 1ns or so is usually required.
Take a look at the GPSDO ADEV plots at:

http://www.leapsecond.com/pages/gpsdo/

Where the ADEV for various GPSDO remains below 1E-11 over the Tau range
of [0.1s, 100,000s]

The achievable performance also depends a great deal on the quality of
the OCXO used in the GPSDO.

If the "digital" phase error measurement techniques you have been
comparing your system with have inadequate resolution it will tale
longer for the measured ADEV to fall below 1E-10.
If the OCXO used has a relatively high ADEV at low values of tau then it
may well required averaging over very long time intervals to achieve an
ADEV below 1E-10.

More detail is required before an analysis of the performance of your
system is possible.

Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 24 02:52:32 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 24 Nov 2008 15:52:32 +1300
Subject: [time-nuts] position determination over short distance
In-Reply-To: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
Message-ID: <492A16F0.4060502@xtra.co.nz>

Rick Harold wrote:
> All,
>
> I'm planning doing some experiments in distance measurement.  They don't
> deal with atomic time directly but with extreme short periods of time.
>
> I need to determine the position of a instrument with a 1mm accuracy or
> less.
> The instrument is not connected to a mechanical device but is separate &
> independent.
> The surface which the instrument is positioned on is close to the size of a
> 11"x11" square.
>
> I thought of using 1 RF transmitters (not sure of freq) on bottom of the
> device near the surface.
> The surface would have RF receivers on 3 or 4 edges/corners to receive the
> signal.
>
> If each of the receivers positions are known and they then send a signal to
> a central circuit (again known positions) how can I differentiate the time
> of arrival
> at the central location?  Does anybody know of a circuit/chip or system
> which would determine the time 'difference'.
> Obviously this is used to triangulate the position of the instrument.
> Light travels 1 mm in ~3.3 picoseconds so I would suspect the differentiator
> would have to have that or better resolution.
> It could also use some proportional method to extrapolate the position since
> the surface has a fixed size.
>
> Any ideas/thoughts?
>
> Thanks in advance.
>
> Rick Harold
>   
Rick

The techniques used in early geodimeters spring to mind.
Just modulate the RF transmissions with various carriers and make a
sequence of modulation phase shift measurements.

Of course one could also use the same techniques employed in the GPS system.

Are you sure that you cant just use optical techniques with corner cube
reflectors?

Can you not triangulate using 3 or more cameras?

Bruce


From fortime at bellsouth.net  Mon Nov 24 02:58:17 2008
From: fortime at bellsouth.net (phil)
Date: Sun, 23 Nov 2008 21:58:17 -0500
Subject: [time-nuts] position determination over short distance
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
Message-ID: <000c01c94de0$828754d0$a101a8c0@officemail>


----- Original Message ----- 
From: "Rick Harold" <rickharold at gmail.com>
To: <time-nuts at febo.com>
Sent: Sunday, November 23, 2008 9:34 PM
Subject: [time-nuts] position determination over short distance


> All,
>
> I'm planning doing some experiments in distance measurement.  They don't
> deal with atomic time directly but with extreme short periods of time.
>
> I need to determine the position of a instrument with a 1mm accuracy or
> less.
> The instrument is not connected to a mechanical device but is separate &
> independent.
> The surface which the instrument is positioned on is close to the size of 
> a
> 11"x11" square.
>
> I thought of using 1 RF transmitters (not sure of freq) on bottom of the
> device near the surface.
> The surface would have RF receivers on 3 or 4 edges/corners to receive the
> signal.
>
> If each of the receivers positions are known and they then send a signal 
> to
> a central circuit (again known positions) how can I differentiate the time
> of arrival
> at the central location?  Does anybody know of a circuit/chip or system
> which would determine the time 'difference'.
> Obviously this is used to triangulate the position of the instrument.
> Light travels 1 mm in ~3.3 picoseconds so I would suspect the 
> differentiator
> would have to have that or better resolution.
> It could also use some proportional method to extrapolate the position 
> since
> the surface has a fixed size.
>
> Any ideas/thoughts?
>
> Thanks in advance.
>
> Rick Harold

Rather vague as to what you are doing.
Have you considered ultrasonics or even laser rather than RF?



From yuri at ostry.ru  Mon Nov 24 03:21:05 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Mon, 24 Nov 2008 06:21:05 +0300
Subject: [time-nuts] GPS Valid Fix Detector
In-Reply-To: <4929D46D.1090409@sbcglobal.net>
References: <4929D46D.1090409@sbcglobal.net>
Message-ID: <1874045047.20081124062105@ostry.ru>

Hello,

Monday, November 24, 2008, 1:08:45, Peter Putnam wrote:

P> Greetings,

P> For those interested in a very simple means of determining if the NMEA
P> data stream from a GPS receiver contains valid fix data, I offer
P> design details for a "Valid Fix" detector that runs in a Microchip
P> 12F629, an 8-pin DIP device.

P> No other components are required if the GPS receiver provides CMOS 
P> output levels:

P> http://www.ni6e.com/time/GPS_Valid_Fix.html

P> Regards,
P> Peter


Looks like your firmware will need some correction, as there is a lot
of NMEA variations...

Below is examples of GPRMC sentences from several different GPS
receivers. You'll need to pick character after second comma, not by
particular offset, to be compatible. 


uBlox LEA4A (firmware 4):
$GPRMC,214541.00,A,5558.55936,N,03709.54595,E,1.116,104.33,120107,,,A*6A 

Trimble Pathfinder Pro XR
$GPRMC,050945.00,A,3504.227794,N,13545.810149,E,000.0,57.1,140302,6.5,W,A*12

Garmin GPS III Plus
$GPRMC,031655,A,3404.456,N,13531.788,E,000.0,360.0,110101,006.8,W*6D

Garmin GPSMAP 76S
$GPRMC,040014,A,4242.0410,N,14134.2795,E,1.4,51.0,010802,8.0,W,A*35

Blue Logger GPS (Something from Japan)
$GPRMC,021803.751,A,3501.5666,N,13546.9457,E,0.00,212.31,110604,,*07

uBlox SBR-LS (firmware 3.01)
$GPRMC,051250.00,A,5558.55523,N,03709.54211,E,1.177,229.34,080705,,,A*6E

GlobalSat BT-338 (SiRF)
$GPRMC,100643.000,A,5522.9036,N,03710.1282,E,0.16,119.11,200507,,*0D





-- 
Best regards,
 Yuri                          mailto:yuri at ostry.ru



From eb4apl at cembreros.jazztel.es  Mon Nov 24 03:24:27 2008
From: eb4apl at cembreros.jazztel.es (EB4APL)
Date: Mon, 24 Nov 2008 04:24:27 +0100
Subject: [time-nuts] position determination over short distance
In-Reply-To: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
Message-ID: <492A1E6B.10107@cembreros.jazztel.es>

Rick Harold wrote:
> All,
>
> I'm planning doing some experiments in distance measurement.  They don't
> deal with atomic time directly but with extreme short periods of time.
>
> I need to determine the position of a instrument with a 1mm accuracy or
> less.
> The instrument is not connected to a mechanical device but is separate &
> independent.
> The surface which the instrument is positioned on is close to the size of a
> 11"x11" square.
>
> I thought of using 1 RF transmitters (not sure of freq) on bottom of the
> device near the surface.
> The surface would have RF receivers on 3 or 4 edges/corners to receive the
> signal.
>
> If each of the receivers positions are known and they then send a signal to
> a central circuit (again known positions) how can I differentiate the time
> of arrival
> at the central location?  Does anybody know of a circuit/chip or system
> which would determine the time 'difference'.
> Obviously this is used to triangulate the position of the instrument.
> Light travels 1 mm in ~3.3 picoseconds so I would suspect the differentiator
> would have to have that or better resolution.
> It could also use some proportional method to extrapolate the position since
> the surface has a fixed size.
>
> Any ideas/thoughts?
>
> Thanks in advance.
>
> Rick Harold
>
>   
Use a laser distance meter (or homebuild one)
Regards,
Ignacio, EB4APL


From dtmspam at techemail.com  Mon Nov 24 03:31:45 2008
From: dtmspam at techemail.com (David Medin)
Date: Sun, 23 Nov 2008 19:31:45 -0800
Subject: [time-nuts] Any nixie project people out there?
Message-ID: <20081123193145.AD4C2B3E@resin14.mta.everyone.net>


   I appreciate the assistance I've gotten here in getting my Tbolts set
   up and generating that beautiful traceable 10 MHz for my benches at
   home and work.

   I've got a giveback IF someone plans to put it to good use. My
   faithful Ballantine 5700A 9 digit nixie frequency counter isn't
   counting so well in its upper range as of last week, and as much as I
   have some affinity for it (I've had it for over 20 years), I have no
   time to repair it and have a more modern counter with my Tbolt now
   driving the reference. If anyone out there is looking for a nixie
   project for a clock or just simply wanting to use the parts, let me
   know. I'm not really looking for anything for it, but I'd rather just
   drop it off at a UPS shipping store and have them package and send it
   at your cost, and that would be your only obligation. It has a 1 MHz
   (I believe, because the external reference is 1 MHz) ovenized
   oscillator on a PC board, 9 digits of working nixies soldered to the
   PCB, a gate to 10 seconds, and a range of 10 Hz to 512 MHz, although
   the upper octave is not working properly and indicating about twice
   the applied frequency. It is chock full of ECL and TTL including the
   nixie driver TTL, most in sockets, so it should be real accessible for
   those wanting to turn it into something else where just the drivers
   and divider chain would be of use. The case comes together with Dzus
   on top and bottom, and has a few dents and also a spot where the NASA
   inventory tag used to be years ago. It does work, top range aside. I
   do NOT have a manual.

   No takers, and the nixie driver chips will go on ebay, but I'd rather
   give it to someone who can use it in only the whacky way a Time Nut
   can.

   Thanks.

   Dave Medin
     _________________________________________________________________

   Are you a Techie? Get Your Free Tech Email Address Now! Visit
   http://www.TechEmail.com

From tvb at LeapSecond.com  Mon Nov 24 03:41:28 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Sun, 23 Nov 2008 19:41:28 -0800
Subject: [time-nuts] position determination over short distance
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
Message-ID: <D1A2AF1FB4C04E48B8380CF4900A617B@pc52>

> I need to determine the position of a instrument with a 1mm accuracy or less.
> The instrument is not connected to a mechanical device but is separate &
> independent.
> The surface which the instrument is positioned on is close to the size of a
> 11"x11" square.

1 mm or better accuracy on a 300x300 mm surface can be
obtained with a cheap webcam mounted above the surface
and a little bit a creative software.

> Obviously this is used to triangulate the position of the instrument.
> Light travels 1 mm in ~3.3 picoseconds so I would suspect the differentiator
> would have to have that or better resolution.

Sound travels about a million times slower than light. 343 m/s
is 1 mm in 2.9 microseconds. Perhaps this is the way to go?

I remind visitors here that a WWV tick takes the same time to
travel from Ft Collins to Seattle as it does to travel from the SW
radio speaker to your ear.

/tvb



From bruce.griffiths at xtra.co.nz  Mon Nov 24 03:52:42 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 24 Nov 2008 16:52:42 +1300
Subject: [time-nuts] position determination over short distance
In-Reply-To: <D1A2AF1FB4C04E48B8380CF4900A617B@pc52>
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
	<D1A2AF1FB4C04E48B8380CF4900A617B@pc52>
Message-ID: <492A250A.6080405@xtra.co.nz>

Tom Van Baak wrote:
>> I need to determine the position of a instrument with a 1mm accuracy or less.
>> The instrument is not connected to a mechanical device but is separate &
>> independent.
>> The surface which the instrument is positioned on is close to the size of a
>> 11"x11" square.
>>     
>
> 1 mm or better accuracy on a 300x300 mm surface can be
> obtained with a cheap webcam mounted above the surface
> and a little bit a creative software.
>
>   
>> Obviously this is used to triangulate the position of the instrument.
>> Light travels 1 mm in ~3.3 picoseconds so I would suspect the differentiator
>> would have to have that or better resolution.
>>     
>
> Sound travels about a million times slower than light. 343 m/s
> is 1 mm in 2.9 microseconds. Perhaps this is the way to go?
>
> I remind visitors here that a WWV tick takes the same time to
> travel from Ft Collins to Seattle as it does to travel from the SW
> radio speaker to your ear.
>
> /tvb
>
>   
If you use sound then compensation for the temperature, pressure and
humidity dependence of the speed of sound may be required.
If your accuracy requirements are higher then compensating for
variations in the C02 content will also be required.
One of the simpler ways is to use the same techniques to measure a fixed
reference path difference.

Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 24 03:56:05 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 24 Nov 2008 16:56:05 +1300
Subject: [time-nuts] position determination over short distance
In-Reply-To: <D1A2AF1FB4C04E48B8380CF4900A617B@pc52>
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
	<D1A2AF1FB4C04E48B8380CF4900A617B@pc52>
Message-ID: <492A25D5.6080900@xtra.co.nz>

Tom Van Baak wrote:
>> I need to determine the position of a instrument with a 1mm accuracy or less.
>> The instrument is not connected to a mechanical device but is separate &
>> independent.
>> The surface which the instrument is positioned on is close to the size of a
>> 11"x11" square.
>>     
>
> 1 mm or better accuracy on a 300x300 mm surface can be
> obtained with a cheap webcam mounted above the surface
> and a little bit a creative software.
>
> /tvb
>   
Dont forget to calibrate the camera distortion and ensure that this
doesnt over over time.

i.e. lock the focus and ensure the camera position, tilt etc with
respect to the reference surface do not vary.

Bruce


From mmoss at mindspring.com  Mon Nov 24 04:08:54 2008
From: mmoss at mindspring.com (Marvin Moss)
Date: Sun, 23 Nov 2008 23:08:54 -0500
Subject: [time-nuts] Manual for Systron Donner 6152A Freq Counter
Message-ID: <380-22008111244854453@mindspring.com>

I have been unable to locate a 6152A manual.
Does anyone have one they can send me?

Thanks,
Marvin

From holrum at hotmail.com  Mon Nov 24 04:26:22 2008
From: holrum at hotmail.com (Mark Sims)
Date: Mon, 24 Nov 2008 04:26:22 +0000
Subject: [time-nuts] position determination over short distance
In-Reply-To: <mailman.270.1227498768.2542.time-nuts@febo.com>
References: <mailman.270.1227498768.2542.time-nuts@febo.com>
Message-ID: <BLU125-W3CE78D100C108D8DD88CECE080@phx.gbl>


If you can hook your instrument to a device,  a cheap computer mouse should be able to solve your problem for as little as $1...  a few bucks more for a wireless mouse.
_________________________________________________________________
Get more done, have more fun, and stay more connected with Windows Mobile?. 
http://clk.atdmt.com/MRT/go/119642556/direct/01/

From james.p.lux at jpl.nasa.gov  Mon Nov 24 04:26:52 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Sun, 23 Nov 2008 20:26:52 -0800
Subject: [time-nuts] position determination over short distance
In-Reply-To: <492A25D5.6080900@xtra.co.nz>
Message-ID: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>

There's a fair amount of F/OSS software from JPL available to do this sort of calibration. It's used to calibrate cameras used on Mars rovers, among other things. The target pattern for calibration is a bunch of big circular dots on a background.


On 11/23/08 7:56 PM, "Bruce Griffiths" <bruce.griffiths at xtra.co.nz> wrote:

Tom Van Baak wrote:
>> I need to determine the position of a instrument with a 1mm accuracy or less.
>> The instrument is not connected to a mechanical device but is separate &
>> independent.
>> The surface which the instrument is positioned on is close to the size of a
>> 11"x11" square.
>>
>
> 1 mm or better accuracy on a 300x300 mm surface can be
> obtained with a cheap webcam mounted above the surface
> and a little bit a creative software.
>
> /tvb
>
Dont forget to calibrate the camera distortion and ensure that this
doesnt over over time.

i.e. lock the focus and ensure the camera position, tilt etc with
respect to the reference surface do not vary.

Bruce

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.


From yuri at ostry.ru  Mon Nov 24 05:43:15 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Mon, 24 Nov 2008 08:43:15 +0300
Subject: [time-nuts] Oncore question
In-Reply-To: <E1L4M85-0000yw-Qq@meow.febo.com>
References: <bf8.398b4901.3659fd40@aol.com> <E1L4M85-0000yw-Qq@meow.febo.com>
Message-ID: <381945846.20081124084315@ostry.ru>

Hello,

Monday, November 24, 2008, 0:02:27, Arnold Tibus wrote:

A> You describe that using LiIon batteries are not yet the ideal way, but why
A> cannot higher capacities come into play (space should be not the problem
A> for on ground use in fix stations)?

I simply put large rechargeable Lithium-Vanadium pentoxide coin cell
with appropriate charging circuit to GPS carrier board and forgot about
this question...

Another solution is to put CR123 battery holder to carrier PCB, stuff
it with a good quality cell and it will probably last for 15+ years,
driving just clock and CMOS RAM during power outages..

-- 
Best regards,
 Yuri  UA3ATQ/KI7XJ                        mailto:yuri at ostry.ru



From d.seiter at comcast.net  Mon Nov 24 08:38:38 2008
From: d.seiter at comcast.net (d.seiter at comcast.net)
Date: Mon, 24 Nov 2008 08:38:38 +0000
Subject: [time-nuts] Any nixie project people out there?
Message-ID: <112420080838.19904.492A680E0008257E00004DC022007358349D0A9B070A9CD20B@comcast.net>

Hi David-

Any takers yet?  While the last thing I need is another nixie counter (I have 4 or 5 already), I do have a soft spot for nixies, and hate the way so much gear has been chopped up for trendy clocks.  That said, what I'd really like to do is make an accurate, self turning hour glass that drives a nixie clock.  Or maybe a GPS disciplined hour-glass driving a nixie clock.  How the hour-glass could be disciplined, except in turn-over speed, I'm not sure.  It's still in the planning stage.  My purchasing budget has been greatly reduced due to the economy, so I'm looking for deals where I wouldn't have before. 

-Dave
 -------------- Original message ----------------------
From: "David Medin" <dtmspam at techemail.com>
> 
>    I appreciate the assistance I've gotten here in getting my Tbolts set
>    up and generating that beautiful traceable 10 MHz for my benches at
>    home and work.
> 
>    I've got a giveback IF someone plans to put it to good use. My
>    faithful Ballantine 5700A 9 digit nixie frequency counter isn't
>    counting so well in its upper range as of last week, and as much as I
>    have some affinity for it (I've had it for over 20 years), I have no
>    time to repair it and have a more modern counter with my Tbolt now
>    driving the reference. If anyone out there is looking for a nixie
>    project for a clock or just simply wanting to use the parts, let me
>    know. I'm not really looking for anything for it, but I'd rather just
>    drop it off at a UPS shipping store and have them package and send it
>    at your cost, and that would be your only obligation. It has a 1 MHz
>    (I believe, because the external reference is 1 MHz) ovenized
>    oscillator on a PC board, 9 digits of working nixies soldered to the
>    PCB, a gate to 10 seconds, and a range of 10 Hz to 512 MHz, although
>    the upper octave is not working properly and indicating about twice
>    the applied frequency. It is chock full of ECL and TTL including the
>    nixie driver TTL, most in sockets, so it should be real accessible for
>    those wanting to turn it into something else where just the drivers
>    and divider chain would be of use. The case comes together with Dzus
>    on top and bottom, and has a few dents and also a spot where the NASA
>    inventory tag used to be years ago. It does work, top range aside. I
>    do NOT have a manual.
> 
>    No takers, and the nixie driver chips will go on ebay, but I'd rather
>    give it to someone who can use it in only the whacky way a Time Nut
>    can.
> 
>    Thanks.
> 
>    Dave Medin
>      _________________________________________________________________
> 
>    Are you a Techie? Get Your Free Tech Email Address Now! Visit
>    http://www.TechEmail.com
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From GandalfG8 at aol.com  Mon Nov 24 08:47:30 2008
From: GandalfG8 at aol.com (GandalfG8 at aol.com)
Date: Mon, 24 Nov 2008 03:47:30 EST
Subject: [time-nuts] Oncore question
Message-ID: <c47.4896b503.365bc422@aol.com>

 
In a message dated 24/11/2008 05:43:49 GMT Standard Time, yuri at ostry.ru  
writes:

I simply  put large rechargeable Lithium-Vanadium pentoxide coin cell
with  appropriate charging circuit to GPS carrier board and forgot about
this  question...

Another solution is to put CR123 battery holder to carrier  PCB, stuff
it with a good quality cell and it will probably last for 15+  years,
driving just clock and CMOS RAM during power  outages..



----------------
 
And if it's important that the whole system stays working for reasonable  
length drop outs, lead acid gel batteries on a master 12, 24 or 48 volt  
(nominal) power supply, again forgetting batteries at board level, are  still hard to 
beat.
 
regards
 
Nigel
GM8PZR

From df6jb at ulrich-bangert.de  Mon Nov 24 09:43:35 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Mon, 24 Nov 2008 10:43:35 +0100
Subject: [time-nuts] EZGPIB error
In-Reply-To: <006801c94d82$d68bc060$0201a8c0@cookie>
Message-ID: <7B77325DC7064361848BD339A6C284C5@athlon>

Ian,

I will be out of the home today and tomorrow but after that I'll tackle
this problem.

Best regards
Ulrich

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Ian Sheffield
> Gesendet: Sonntag, 23. November 2008 16:48
> An: Discussion of precise time and frequency measurement
> Betreff: [time-nuts] EZGPIB error
> 
> 
> Hello chaps,
> 
> A quick question to the assembled multitude rather than 
> bothering Ulrich directly, as some of you must have seen this problem:
> 
> What causes the error message Socket Error # 10065
> No route to host, when using EZGPIB with my Prologix latest 
> version interface with my laptops?
> 
> EZGPIB works fine from my desktop PC but gives this error 
> message with both of my laptops running XP (one XP Home, the 
> other is XP Pro).
> 
> The Prologix itself is working fine, as it controls and reads 
> my HP5334 perfectly using the direct Prologix commands. 
> EZGPIB , as stated, also works fine from the Desktop PC.
> 
> What is not configured correctly in the laptops?
> 
> Many thanks in advance,
> 
> Ian.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From warrensjmail-one at yahoo.com  Mon Nov 24 09:47:57 2008
From: warrensjmail-one at yahoo.com (WarrenS Email)
Date: Mon, 24 Nov 2008 01:47:57 -0800
Subject: [time-nuts] GPSDO using 100Hz
Message-ID: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>

Bruce Griffiths answered:

Its difficult to make much useful comment as you provide few measured
results.

With an M12+T or equivalent the ADEV of the PPS output (without sawtooth
correction) goes below 1E-10 at  Tau > 200 sec or so.
Thus with an optimized GPSDO it wont take an hour or so to achieve 1E-10
stability.
However a single shot phase error measurement system resolution of
around 1ns or so is usually required.
Take a look at the GPSDO ADEV plots at:

http://www.leapsecond.com/pages/gpsdo/

Where the ADEV for various GPSDO remains below 1E-11 over the Tau range
of [0.1s, 100,000s]

The achievable performance also depends a great deal on the quality of
the OCXO used in the GPSDO.

If the "digital" phase error measurement techniques you have been
comparing your system with have inadequate resolution it will tale
longer for the measured ADEV to fall below 1E-10.
If the OCXO used has a relatively high ADEV at low values of tau then it
may well required averaging over very long time intervals to achieve an
ADEV below 1E-10.

More detail is required before an analysis of the performance of your
system is possible.

Bruce

*********************

Bruce, Thanks for the feedback, Good information to know, 
but you seemed to missed my point and question.

Yes I am comparing to SIMPLE, and home built type, non optimized, 
trackers like  Brooks Shera's "10 Mhz GPS Frequency Standard". 
I understand, and even wrote, NIST reports about  a 10ns uncertainty 
with a 10 minute average, which would give a 1e-8 / 600, or  1.5 parts in 1E-11 
possible in 600 seconds, 1e-10 in 100 seconds.  Its safe to assume NIST is 
not using Shera's unit, which I believe adds an additional  24 ns or is 
it 41.7 ns uncertainty to each 1 second reading. 
Besides asking if anyone is using the 100Hz output, I would like to ask 
why don't the generally available GPSDO use the 100Hz, which can give 
about 1 ns of certainly with a simple PLL and analog RC filter, instead of 
the using the 1 sec which has more like 100 ns of uncorrected uncertainty 
in it and must use a processor?

Also I should comment that on  LeapSecond.com 
http://www.leapsecond.com/pages/gpsdo/
you stated "where the ADEV for various GPSDO remains below 1E-11 
over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
the tracking time constant that the GPSDO is set to, which is usually 
recommended to be set for a TC of several hours for optimal results.
BTW most of what they have plotted is the results of NOT setting the GPSDO 
tracking TC slow enough. This is why the Allan Deviation increases in the tracking 
mode at mid averaging times. The 1 second GPS tracking signal is adding noise, 
which pretty much makes my point that 1 PPS signal is not so good to use 
if you want good fast results.

Warren

From df6jb at ulrich-bangert.de  Mon Nov 24 10:00:45 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Mon, 24 Nov 2008 11:00:45 +0100
Subject: [time-nuts] GPS Valid Fix Detector
In-Reply-To: <1874045047.20081124062105@ostry.ru>
Message-ID: <AE1131EC2B3948E8BAD64AD0766F678B@athlon>

Peter,

in general NMEA decoding involves

1) Message type detection

2) End of message detection

4) Checksum test

5) Looking for what is to be found between comma N and comma N+1, having
in mind that there may also be NOTHING.

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Yuri Ostry
> Gesendet: Montag, 24. November 2008 04:21
> An: Peter Putnam; Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] GPS Valid Fix Detector
> 
> 
> Hello,
> 
> Monday, November 24, 2008, 1:08:45, Peter Putnam wrote:
> 
> P> Greetings,
> 
> P> For those interested in a very simple means of determining if the 
> P> NMEA data stream from a GPS receiver contains valid fix 
> data, I offer 
> P> design details for a "Valid Fix" detector that runs in a Microchip 
> P> 12F629, an 8-pin DIP device.
> 
> P> No other components are required if the GPS receiver provides CMOS
> P> output levels:
> 
> P> http://www.ni6e.com/time/GPS_Valid_Fix.html
> 
> P> Regards,
> P> Peter
> 
> 
> Looks like your firmware will need some correction, as there 
> is a lot of NMEA variations...
> 
> Below is examples of GPRMC sentences from several different 
> GPS receivers. You'll need to pick character after second 
> comma, not by particular offset, to be compatible. 
> 
> 
> uBlox LEA4A (firmware 4): 
> $GPRMC,214541.00,A,5558.55936,N,03709.54595,E,1.116,104.33,120
> 107,,,A*6A 
> 
> Trimble Pathfinder Pro XR 
> $GPRMC,050945.00,A,3504.227794,N,13545.810149,E,000.0,57.1,140
> 302,6.5,W,A*12
> 
> Garmin GPS III Plus 
> $GPRMC,031655,A,3404.456,N,13531.788,E,000.0,360.0,110101,006.8,W*6D
> 
> Garmin GPSMAP 76S 
> $GPRMC,040014,A,4242.0410,N,14134.2795,E,1.4,51.0,010802,8.0,W,A*35
> 
> Blue Logger GPS (Something from Japan) 
> $GPRMC,021803.751,A,3501.5666,N,13546.9457,E,0.00,212.31,110604,,*07
> 
> uBlox SBR-LS (firmware 3.01) 
> $GPRMC,051250.00,A,5558.55523,N,03709.54211,E,1.177,229.34,080
> 705,,,A*6E
> 
> GlobalSat BT-338 (SiRF) 
> $GPRMC,100643.000,A,5522.9036,N,03710.1282,E,0.16,119.11,200507,,*0D
> 
> 
> 
> 
> 
> -- 
> Best regards,
>  Yuri                          mailto:yuri at ostry.ru
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From df6jb at ulrich-bangert.de  Mon Nov 24 10:15:07 2008
From: df6jb at ulrich-bangert.de (Ulrich Bangert)
Date: Mon, 24 Nov 2008 11:15:07 +0100
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
Message-ID: <013A31E636B14693AD2A457E09608EF3@athlon>

Warren,

James Miller, G3RUH, also uses the 100 Hz signal. So it's neither
specifically new nor the philosopher's stone that you may perhaps
believe to have found. The PPS and the 100 Hz signal come from the SAME
oscillator. The jitter in the PPS comes from the fact that the receiver
logic decides WHICH slope of the oscillator signal comes next close to
the TRUE point of time where the PPS should be generated. The key error
in your idea is the assumption that every 100 positive slopes of your
100 Hz is identical with the start of a new second, which is wrong when
you look at it at a second to second base. What is true is that the MEAN
frequency of the 100 Hz is locked to the GPS and that is why your fast
pll works as well as James Miller's.

Best regards
Ulrich Bangert   

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von WarrenS Email
> Gesendet: Montag, 24. November 2008 10:48
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] GPSDO using 100Hz
> 
> 
> Bruce Griffiths answered:
> 
> Its difficult to make much useful comment as you provide few 
> measured results.
> 
> With an M12+T or equivalent the ADEV of the PPS output 
> (without sawtooth
> correction) goes below 1E-10 at  Tau > 200 sec or so.
> Thus with an optimized GPSDO it wont take an hour or so to 
> achieve 1E-10 stability. However a single shot phase error 
> measurement system resolution of around 1ns or so is usually 
> required. Take a look at the GPSDO ADEV plots at:
> 
> http://www.leapsecond.com/pages/gpsdo/
> 
> Where the ADEV for various GPSDO remains below 1E-11 over the 
> Tau range of [0.1s, 100,000s]
> 
> The achievable performance also depends a great deal on the 
> quality of the OCXO used in the GPSDO.
> 
> If the "digital" phase error measurement techniques you have 
> been comparing your system with have inadequate resolution it 
> will tale longer for the measured ADEV to fall below 1E-10. 
> If the OCXO used has a relatively high ADEV at low values of 
> tau then it may well required averaging over very long time 
> intervals to achieve an ADEV below 1E-10.
> 
> More detail is required before an analysis of the performance 
> of your system is possible.
> 
> Bruce
> 
> *********************
> 
> Bruce, Thanks for the feedback, Good information to know, 
> but you seemed to missed my point and question.
> 
> Yes I am comparing to SIMPLE, and home built type, non optimized, 
> trackers like  Brooks Shera's "10 Mhz GPS Frequency Standard". 
> I understand, and even wrote, NIST reports about  a 10ns uncertainty 
> with a 10 minute average, which would give a 1e-8 / 600, or  
> 1.5 parts in 1E-11 
> possible in 600 seconds, 1e-10 in 100 seconds.  Its safe to 
> assume NIST is 
> not using Shera's unit, which I believe adds an additional  
> 24 ns or is 
> it 41.7 ns uncertainty to each 1 second reading. 
> Besides asking if anyone is using the 100Hz output, I would 
> like to ask 
> why don't the generally available GPSDO use the 100Hz, which can give 
> about 1 ns of certainly with a simple PLL and analog RC 
> filter, instead of 
> the using the 1 sec which has more like 100 ns of uncorrected 
> uncertainty 
> in it and must use a processor?
> 
> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING 
> to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal 
> results. BTW most of what they have plotted is the results of 
> NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation 
> increases in the tracking 
> mode at mid averaging times. The 1 second GPS tracking signal 
> is adding noise, 
> which pretty much makes my point that 1 PPS signal is not so 
> good to use 
> if you want good fast results.
> 
> Warren
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> and 
> follow the instructions there.
> 



From Jean-Louis.Oneto at obs-azur.fr  Mon Nov 24 11:22:51 2008
From: Jean-Louis.Oneto at obs-azur.fr (Jean-Louis Oneto)
Date: Mon, 24 Nov 2008 11:22:51 -0000
Subject: [time-nuts] position determination over short distance
References: <cd5103e0811231834o482e124s4359d5ee2135c6ce@mail.gmail.com>
Message-ID: <2C575D8605454CFF82195D15B15C67BB@pcreopt>

Hi,
A graphic tablet (11" square is a common size) should give you about 120 
positions/mm for something like a hundred bucks.
That's not very different from the "mouse" solution, but give you absolute 
position rather than relative.
Regards,
Jean-Louis Oneto

----- Original Message ----- 
From: "Rick Harold" <rickharold at gmail.com>
To: <time-nuts at febo.com>
Sent: Monday, November 24, 2008 2:34 AM
Subject: [time-nuts] position determination over short distance


> All,
>
> I'm planning doing some experiments in distance measurement.  They don't
> deal with atomic time directly but with extreme short periods of time.
>
> I need to determine the position of a instrument with a 1mm accuracy or
> less.
> The instrument is not connected to a mechanical device but is separate &
> independent.
> The surface which the instrument is positioned on is close to the size of 
> a
> 11"x11" square.
>
> I thought of using 1 RF transmitters (not sure of freq) on bottom of the
> device near the surface.
> The surface would have RF receivers on 3 or 4 edges/corners to receive the
> signal.
>
> If each of the receivers positions are known and they then send a signal 
> to
> a central circuit (again known positions) how can I differentiate the time
> of arrival
> at the central location?  Does anybody know of a circuit/chip or system
> which would determine the time 'difference'.
> Obviously this is used to triangulate the position of the instrument.
> Light travels 1 mm in ~3.3 picoseconds so I would suspect the 
> differentiator
> would have to have that or better resolution.
> It could also use some proportional method to extrapolate the position 
> since
> the surface has a fixed size.
>
> Any ideas/thoughts?
>
> Thanks in advance.
>
> Rick Harold
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 



From warrensjmail-one at yahoo.com  Mon Nov 24 11:49:49 2008
From: warrensjmail-one at yahoo.com (WarrenS Email)
Date: Mon, 24 Nov 2008 03:49:49 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <082b01c94e2a$c18e9630$6401a8c0@WSOffice>

Ulrich Bangert  

Thanks for the great Information. 

>UR) James Miller, G3RUH, also uses the 100 Hz signal
Thanks, that is what I was asking for, other people that were using the 100Hz.
Now if I could just figure out how to post a response under an existing 
thread, and not have it start a new one I'd be happy.

Concerning your other comments:
>UR) it's neither specifically new nor ...
I did not mean to imply that the 100Hz was new or its use was discovered by me, 
Mostly I'm wondering why it is so little used, and I'm looking for other people using it.
Something that I can do with the 100Hz that you probable have not seen before is 
the ability to make a GPSDO similar to Brooks Shera's processors based unit 
using just 3 standard off the self 74HC IC's and a pretty crappy Osc.

>UR) The key error in your idea is the assumption that every 100 positive slopes of your
100 Hz is identical with the start of a new second, which is wrong when you look at it at 
a second to second base. 
Correct that my assumption was that every 100 pulses gives a one second pulse at the 
same location.You are incorrect that when this is not true, it is a key error in my idea.
I did see that the 100Hz pulse that comes out at about the time as the 1Hz sawtooth 
correction is updated seems to have the same amount of phase error as reported for 
the 1 Hz, best I could tell. I do know it is sometimes true, I'll check that out better and 
verify that it is not always true on my unit. Thanks for the information. 
BUT, NO matter, because the max jitter error of around 100ns is the same in both of 
the 100Hz and the 1 Hz signal, and the 100Hz error is nonaccumative.
That is when I average 100 points each with an uncertainty of 100ns I get at least the 
Square root of 100 better resolution If they where truly random, which they are not, 
they have the same basic ramp type phase response as the 1 Hz sawtooth, just much faster 
so averaging works much better than if they where random. 
What I have found is that the net effect is for the most part that averaging 100 100Hz 
signals will give about the same error result as averaging 100 One second pulses. 
If you want to proof it to yourself use a digital scope with an average function and look 
at the results. (there are some rare exceptions, I skip over for now)

For another example, consider what the results would be if you just used every 
100th 1 second pulse. You'd end up with 100ns uncertainty in 100 seconds rather 
the under 10 ns  you get by averaging 100 1 second pulses (most of the time).   

UR) What is true is that the MEAN frequency of the 100 Hz is locked to the GPS 
and that is why your fast PLL works as well as James Miller's.
What I tried to state is that the 100Hz is fast enough to make a simple analog PPL, 
something that is not very easy to do with the 1 Hz  signals.
Thanks for the name, I'll check more on how he is doing his simple GPS tracker. 
It looks like he is using the 10KHz output of the Jupiter GPS. 
Unfortunately my oncore does not have a 10KHz output.

Thanks,
Warren

***************************
James Miller, G3RUH, also uses the 100 Hz signal. So it's neither
specifically new nor the philosopher's stone that you may perhaps
believe to have found. The PPS and the 100 Hz signal come from the SAME
oscillator. The jitter in the PPS comes from the fact that the receiver
logic decides WHICH slope of the oscillator signal comes next close to
the TRUE point of time where the PPS should be generated. The key error
in your idea is the assumption that every 100 positive slopes of your
100 Hz is identical with the start of a new second, which is wrong when
you look at it at a second to second base. What is true is that the MEAN
frequency of the 100 Hz is locked to the GPS and that is why your fast
pll works as well as James Miller's.

Best regards
Ulrich Bangert   

From ernieperes at aol.com  Mon Nov 24 13:13:23 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Mon, 24 Nov 2008 08:13:23 -0500
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <082b01c94e2a$c18e9630$6401a8c0@WSOffice>
References: <082b01c94e2a$c18e9630$6401a8c0@WSOffice>
Message-ID: <8CB1C4D8F656B6C-ADC-4AA@WEBMAIL-DC05.sysops.aol.com>

Hii Warren,

have a look on this 
link...http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm

and he is using the 10KHz...rpt 10KHz not the 100Hz......compare with 
your circuit diagram... / I would like to see / or the other solution 
just make the same circuit and with your testing method chk both 
unit.......with the same OCXO....
the jupiter eng board is still available in the German Ebay....

Rgds Ernie.




-----Original Message-----
From: WarrenS Email <warrensjmail-one at yahoo.com>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Mon, 24 Nov 2008 12:49 pm
Subject: [time-nuts] GPSDO using 100Hz



Ulrich Bangert

Thanks for the great Information.

>UR) James Miller, G3RUH, also uses the 100 Hz signal
Thanks, that is what I was asking for, other people that were using the 
100Hz.
Now if I could just figure out how to post a response under an existing
thread, and not have it start a new one I'd be happy.

Concerning your other comments:
>UR) it's neither specifically new nor ...
I did not mean to imply that the 100Hz was new or its use was 
discovered by me,
Mostly I'm wondering why it is so little used, and I'm looking for 
other people
using it.
Something that I can do with the 100Hz that you probable have not seen 
before is

the ability to make a GPSDO similar to Brooks Shera's processors based 
unit
using just 3 standard off the self 74HC IC's and a pretty crappy Osc.

>UR) The key error in your idea is the assumption that every 100 
positive slopes
of your
100 Hz is identical with the start of a new second, which is wrong when 
you look
at it at
a second to second base.
Correct that my assumption was that every 100 pulses gives a one second 
pulse at
the
same location.You are incorrect that when this is not true, it is a key 
error in
my idea.
I did see that the 100Hz pulse that comes out at about the time as the 
1Hz
sawtooth
correction is updated seems to have the same amount of phase error as 
reported
for
the 1 Hz, best I could tell. I do know it is sometimes true, I'll check 
that out
better and
verify that it is not always true on my unit. Thanks for the 
information.
BUT, NO matter, because the max jitter error of around 100ns is the 
same in both
of
the 100Hz and the 1 Hz signal, and the 100Hz error is nonaccumative.
That is when I average 100 points each with an uncertainty of 100ns I 
get at
least the
Square root of 100 better resolution If they where truly random, which 
they are
not,
they have the same basic ramp type phase response as the 1 Hz sawtooth, 
just
much faster
so averaging works much better than if they where random.
What I have found is that the net effect is for the most part that 
averaging 100
100Hz
signals will give about the same error result as averaging 100 One 
second
pulses.
If you want to proof it to yourself use a digital scope with an average 
function
and look
at the results. (there are some rare exceptions, I skip over for now)

For another example, consider what the results would be if you just 
used every
100th 1 second pulse. You'd end up with 100ns uncertainty in 100 
seconds rather
the under 10 ns you get by averaging 100 1 second pulses (most of the 
time).

UR) What is true is that the MEAN frequency of the 100 Hz is locked to 
the GPS
and that is why your fast PLL works as well as James Miller's.
What I tried to state is that the 100Hz is fast enough to make a simple 
analog
PPL,
something that is not very easy to do with the 1 Hz signals.
Thanks for the name, I'll check more on how he is doing his simple GPS 
tracker.
It looks like he is using the 10KHz output of the Jupiter GPS.
Unfortunately my oncore does not have a 10KHz output.

Thanks,
Warren

***************************
James Miller, G3RUH, also uses the 100 Hz signal. So it's neither
specifically new nor the philosopher's stone that you may perhaps
believe to have found. The PPS and the 100 Hz signal come from the SAME
oscillator. The jitter in the PPS comes from the fact that the receiver
logic decides WHICH slope of the oscillator signal comes next close to
the TRUE point of time where the PPS should be generated. The key error
in your idea is the assumption that every 100 positive slopes of your
100 Hz is identical with the start of a new second, which is wrong when
you look at it at a second to second base. What is true is that the MEAN
frequency of the 100 Hz is locked to the GPS and that is why your fast
pll works as well as James Miller's.

Best regards
Ulrich Bangert
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From warrensjmail-one at yahoo.com  Mon Nov 24 13:59:08 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 05:59:08 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <082b01c94e2a$c18e9630$6401a8c0@WSOffice>
	<8CB1C4D8F656B6C-ADC-4AA@WEBMAIL-DC05.sysops.aol.com>
Message-ID: <08e101c94e3c$d264b770$6401a8c0@WSOffice>

Ernie

I do have to agree that the James Miller unit is about as simple as you can get. His BIG advantages is the use of 10KHz to lock on.
If the want to use the Jupiter GPS board, Miller's circuit is the way to go for SIMPLE.
Bob Q has the same basic circuit configuration running off the 100Hz signal. It is listed in  "June 08. "[time-nuts] Simple GPS 10 MHz frequency standard"
Bob's circuit has a lot more bills and whistles than Millers to tell when it is locked etc, but the extra bills he added does not effect the performance, for the most part, once it is locked. All else being equal the 100Hz XOR is not going to be as good as the 10KHz, although with about 100 times more care in the analog circuits to control noise, which Bob's seems to have, and with the right RC's they could be pretty similar performance.

What I am doing is somewhat different in that I wanted mine to work with my 100 Hz Oncore receiver and I do not use a XOR phase detector because of its very low phase low gain at 100 Hz.

Thanks for the response,
Warren

**************
----- Original Message ----- 
From: <ernieperes at aol.com>
To: <time-nuts at febo.com>
Sent: Monday, November 24, 2008 5:13 AM
Subject: Re: [time-nuts] GPSDO using 100Hz


> Hii Warren,
> 
> have a look on this 
> link...http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
> 
> and he is using the 10KHz...rpt 10KHz not the 100Hz......compare with 
> your circuit diagram... / I would like to see / or the other solution 
> just make the same circuit and with your testing method chk both 
> unit.......with the same OCXO....
> the jupiter eng board is still available in the German Ebay....
> 
> Rgds Ernie.
> 
> 
> 
> 
> -----Original Message-----
> From: WarrenS Email <warrensjmail-one at yahoo.com>
> To: Discussion of precise time and frequency measurement 
> <time-nuts at febo.com>
> Sent: Mon, 24 Nov 2008 12:49 pm
> Subject: [time-nuts] GPSDO using 100Hz
> 
> 
> Ulrich Bangert
> 
> Thanks for the great Information.
> 
>>UR) James Miller, G3RUH, also uses the 100 Hz signal
> Thanks, that is what I was asking for, other people that were 
> using the  100Hz.
> Now if I could just figure out how to post a response under an existing
> thread, and not have it start a new one I'd be happy.
> 
> Concerning your other comments:
>>UR) it's neither specifically new nor ...
> I did not mean to imply that the 100Hz was new or its use was 
> discovered by me,
> Mostly I'm wondering why it is so little used, and I'm looking for 
> other people using it.
> Something that I can do with the 100Hz that you probable have not seen 
> before is the ability to make a GPSDO similar to Brooks Shera's processors based 
> unit using just 3 standard off the self 74HC IC's and a pretty crappy Osc.
> 
>>UR) The key error in your idea is the assumption that every 100 
> positive slopes of your
> 100 Hz is identical with the start of a new second, which is wrong when 
> you look at it at
> a second to second base.
> Correct that my assumption was that every 100 pulses gives a one second 
> pulse at the
> same location.You are incorrect that when this is not true, it is a key 
> error in my idea.
> I did see that the 100Hz pulse that comes out at about the time as the 
> 1Hz sawtooth
> correction is updated seems to have the same amount of phase error as 
> reported for
> the 1 Hz, best I could tell. I do know it is sometimes true, I'll check 
> that out better and
> verify that it is not always true on my unit. Thanks for the 
> information.
> BUT, NO matter, because the max jitter error of around 100ns is the 
> same in both of
> the 100Hz and the 1 Hz signal, and the 100Hz error is nonaccumative.
> That is when I average 100 points each with an uncertainty of 100ns I 
> get at least the
> Square root of 100 better resolution If they where truly random, which 
> they are not,
> they have the same basic ramp type phase response as the 1 Hz sawtooth, 
> just much faster
> so averaging works much better than if they where random.
> What I have found is that the net effect is for the most part that 
> averaging 100 100Hz
> signals will give about the same error result as averaging 100 One 
> second pulses.
> If you want to proof it to yourself use a digital scope with an average 
> function and look
> at the results. (there are some rare exceptions, I skip over for now)
> 
> For another example, consider what the results would be if you just 
> used every 100th 1 second pulse. You'd end up with 100ns uncertainty in 100 
> seconds rather the under 10 ns you get by averaging 100 1 second pulses (most of the 
> time).
> 
> UR) What is true is that the MEAN frequency of the 100 Hz is locked to 
> the GPS and that is why your fast PLL works as well as James Miller's.
> What I tried to state is that the 100Hz is fast enough to make a simple 
> analog PPL, something that is not very easy to do with the 1 Hz signals.
> Thanks for the name, I'll check more on how he is doing his simple GPS 
> tracker. It looks like he is using the 10KHz output of the Jupiter GPS.
> Unfortunately my oncore does not have a 10KHz output.
> 
> Thanks,
> Warren
> 
> ***************************
> James Miller, G3RUH, also uses the 100 Hz signal. So it's neither
> specifically new nor the philosopher's stone that you may perhaps
> believe to have found. The PPS and the 100 Hz signal come from the SAME
> oscillator. The jitter in the PPS comes from the fact that the receiver
> logic decides WHICH slope of the oscillator signal comes next close to
> the TRUE point of time where the PPS should be generated. The key error
> in your idea is the assumption that every 100 positive slopes of your
> 100 Hz is identical with the start of a new second, which is wrong when
> you look at it at a second to second base. What is true is that the MEAN
> frequency of the 100 Hz is locked to the GPS and that is why your fast
> pll works as well as James Miller's.
> 
> Best regards
> Ulrich Bangert
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


From eb4apl at cembreros.jazztel.es  Mon Nov 24 14:20:02 2008
From: eb4apl at cembreros.jazztel.es (EB4APL)
Date: Mon, 24 Nov 2008 15:20:02 +0100
Subject: [time-nuts] position determination over short distance
In-Reply-To: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
Message-ID: <492AB812.4050403@cembreros.jazztel.es>

Of course you can use any of the standard photogrammetric tecniques and 
programs.  Even you can do it automatically using image correlation to 
find the paralax and hence the distance.

But I have a simpler and cheaper (and also accurate) solution:

Put a transmiting coil in the object to be measured, about 1-2 cm 
diameter, 0.5 cm high (I don?t remember the frequency now, it is quite 
low but it doesn't matter).
Lay a receiving antenna grid of vertical and horizontal wires, spaced 
about 1 cm, in a surface below the object.
Scan the antennas noting the amplitudes an phases on the 4 or 6 
horizontal and vertical wires surrounding the Tx coil in each moment .
Calculate the position in real time (you obtain a precision of about 0.1 
mm if the antenna surface is calibrated)
Sound complicated? buy a digitizing tablet (used ones are really 
cheap).  This is how these things works.
Regards,
Ignacio Cembreros

Lux, James P wrote:
> There's a fair amount of F/OSS software from JPL available to do this sort of calibration. It's used to calibrate cameras used on Mars rovers, among other things. The target pattern for calibration is a bunch of big circular dots on a background.
>
>
> On 11/23/08 7:56 PM, "Bruce Griffiths" <bruce.griffiths at xtra.co.nz> wrote:
>
> Tom Van Baak wrote:
>   
>>> I need to determine the position of a instrument with a 1mm accuracy or less.
>>> The instrument is not connected to a mechanical device but is separate &
>>> independent.
>>> The surface which the instrument is positioned on is close to the size of a
>>> 11"x11" square.
>>>
>>>       
>> 1 mm or better accuracy on a 300x300 mm surface can be
>> obtained with a cheap webcam mounted above the surface
>> and a little bit a creative software.
>>
>> /tvb
>>
>>     
> Dont forget to calibrate the camera distortion and ensure that this
> doesnt over over time.
>
> i.e. lock the focus and ensure the camera position, tilt etc with
> respect to the reference surface do not vary.
>
> Bruce
>   



From ian.sheffield1 at tesco.net  Mon Nov 24 15:23:12 2008
From: ian.sheffield1 at tesco.net (Ian Sheffield)
Date: Mon, 24 Nov 2008 15:23:12 -0000
Subject: [time-nuts] EZGPIB error
Message-ID: <003201c94e48$91853d90$0201a8c0@cookie>

Thank you to all who replied.

One vital piece of information I omitted was that this is a USB Prologix - not an Ethernet one, so the suggestions of wrong IP address etc. may not apply. - Which makes me wonder why such an error message should appear.

(Both the laptops have WiFi drivers installed, but not the PC ........hmm?)

I will take up the suggestion of using the very latest version of EZGPIB as I am presently using the version before Ulrich's latest download. 

Ulrich - thank you for your contact. I will download your latest version as soon as possible and report back.

I will not be able to test until tomorrow, as tonight I am teaching basic Astronomy to a load of Cubs (Junior Boy Scouts)!

Many thanks,

Ian.

From ik1odo at spin-it.com  Mon Nov 24 15:31:23 2008
From: ik1odo at spin-it.com (Marco IK1ODO -2)
Date: Mon, 24 Nov 2008 16:31:23 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492AB812.4050403@cembreros.jazztel.es>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
	<492AB812.4050403@cembreros.jazztel.es>
Message-ID: <20081124152247.DCDB0E91529@mail.ebirds.it>

Hi all,

I have to carry a 10 MHz standard frequency signal inside an EMC 
screened room via fiber optic cable.

Not willing to re-invent the wheel, do something like an optical 
standard frequency link exist on the market?
I think it is possible to use standard 100MB LAN transceivers, and 
POF. Phase noise requirements
are not very stringent, and the distance is in the order of some tens 
of meters.

Marco IK1ODO / AI4YF



From david.partridge at dsl.pipex.com  Mon Nov 24 15:41:32 2008
From: david.partridge at dsl.pipex.com (David C. Partridge)
Date: Mon, 24 Nov 2008 15:41:32 -0000
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <20081124152247.DCDB0E91529@mail.ebirds.it>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov><492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
Message-ID: <5B6BF8897421469F9266495073434E00@APOLLO>

Why fibre optic?  You'll only need to convert back to copper when you get it
in there (unless the kit that needs the 10Mhz reference has optical 10MHz
in), and if you do that you may as well just take it in there using high
quality coax (say RG-400U) and a bulkhead connector in the wall of the room.

Dave
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Marco IK1ODO -2
Sent: 24 November 2008 15:31
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] 10 MHz over optical fiber?

Hi all,

I have to carry a 10 MHz standard frequency signal inside an EMC screened
room via fiber optic cable.



From rdarlington at gmail.com  Mon Nov 24 15:48:03 2008
From: rdarlington at gmail.com (Robert Darlington)
Date: Mon, 24 Nov 2008 08:48:03 -0700
Subject: [time-nuts] GPS Valid Fix Detector
In-Reply-To: <AE1131EC2B3948E8BAD64AD0766F678B@athlon>
References: <1874045047.20081124062105@ostry.ru>
	<AE1131EC2B3948E8BAD64AD0766F678B@athlon>
Message-ID: <b3bd5fcb0811240748m57bc787t1f380511b2b00020@mail.gmail.com>

I worked wtih a GPS module that would spit out all zeros for lat/long if
there was no fix, and another that would spit out the coordinates for the
manufacturer's office.  It'll probably be hard to weed out every special
case, but with the code, any of us can easily just modify it for our own
needs.  Thank you for taking the time to at least get *me* started :)  You
saved me a lot of trouble.

-Bob

On Mon, Nov 24, 2008 at 3:00 AM, Ulrich Bangert <df6jb at ulrich-bangert.de>wrote:

> Peter,
>
> in general NMEA decoding involves
>
> 1) Message type detection
>
> 2) End of message detection
>
> 4) Checksum test
>
> 5) Looking for what is to be found between comma N and comma N+1, having
> in mind that there may also be NOTHING.
>
> Best regards
> Ulrich Bangert
>
> > -----Ursprungliche Nachricht-----
> > Von: time-nuts-bounces at febo.com
> > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Yuri Ostry
> > Gesendet: Montag, 24. November 2008 04:21
> > An: Peter Putnam; Discussion of precise time and frequency measurement
> > Betreff: Re: [time-nuts] GPS Valid Fix Detector
> >
> >
> > Hello,
> >
> > Monday, November 24, 2008, 1:08:45, Peter Putnam wrote:
> >
> > P> Greetings,
> >
> > P> For those interested in a very simple means of determining if the
> > P> NMEA data stream from a GPS receiver contains valid fix
> > data, I offer
> > P> design details for a "Valid Fix" detector that runs in a Microchip
> > P> 12F629, an 8-pin DIP device.
> >
> > P> No other components are required if the GPS receiver provides CMOS
> > P> output levels:
> >
> > P> http://www.ni6e.com/time/GPS_Valid_Fix.html
> >
> > P> Regards,
> > P> Peter
> >
> >
> > Looks like your firmware will need some correction, as there
> > is a lot of NMEA variations...
> >
> > Below is examples of GPRMC sentences from several different
> > GPS receivers. You'll need to pick character after second
> > comma, not by particular offset, to be compatible.
> >
> >
> > uBlox LEA4A (firmware 4):
> > $GPRMC,214541.00,A,5558.55936,N,03709.54595,E,1.116,104.33,120
> > 107,,,A*6A
> >
> > Trimble Pathfinder Pro XR
> > $GPRMC,050945.00,A,3504.227794,N,13545.810149,E,000.0,57.1,140
> > 302,6.5,W,A*12
> >
> > Garmin GPS III Plus
> > $GPRMC,031655,A,3404.456,N,13531.788,E,000.0,360.0,110101,006.8,W*6D
> >
> > Garmin GPSMAP 76S
> > $GPRMC,040014,A,4242.0410,N,14134.2795,E,1.4,51.0,010802,8.0,W,A*35
> >
> > Blue Logger GPS (Something from Japan)
> > $GPRMC,021803.751,A,3501.5666,N,13546.9457,E,0.00,212.31,110604,,*07
> >
> > uBlox SBR-LS (firmware 3.01)
> > $GPRMC,051250.00,A,5558.55523,N,03709.54211,E,1.177,229.34,080
> > 705,,,A*6E
> >
> > GlobalSat BT-338 (SiRF)
> > $GPRMC,100643.000,A,5522.9036,N,03710.1282,E,0.16,119.11,200507,,*0D
> >
> >
> >
> >
> >
> > --
> > Best regards,
> >  Yuri                          mailto:yuri at ostry.ru
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> > and
> > follow the instructions there.
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From phk at phk.freebsd.dk  Mon Nov 24 15:56:15 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Mon, 24 Nov 2008 15:56:15 +0000
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: Your message of "Mon, 24 Nov 2008 16:31:23 +0100."
	<20081124152247.DCDB0E91529@mail.ebirds.it> 
Message-ID: <9138.1227542175@critter.freebsd.dk>

In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, Marco IK1ODO -2 writes:
>Hi all,
>
>I have to carry a 10 MHz standard frequency signal inside an EMC 
>screened room via fiber optic cable.
>
>Not willing to re-invent the wheel, do something like an optical 
>standard frequency link exist on the market?
>I think it is possible to use standard 100MB LAN transceivers, and 
>POF. Phase noise requirements
>are not very stringent, and the distance is in the order of some tens 
>of meters.

HP used to have kits consisting of transmitter + receiver + plastic
fiber in various lengths.

HParchive.org has a service note that explains how to use that for
reference frequency distribution.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From ik1odo at spin-it.com  Mon Nov 24 15:48:01 2008
From: ik1odo at spin-it.com (Marco IK1ODO -2)
Date: Mon, 24 Nov 2008 16:48:01 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <5B6BF8897421469F9266495073434E00@APOLLO>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
	<5B6BF8897421469F9266495073434E00@APOLLO>
Message-ID: <20081124153925.C2DCDE91A05@mail.ebirds.it>

At 16.41 24/11/2008, you wrote:
>Why fibre optic?  You'll only need to convert back to copper when you get it
>in there (unless the kit that needs the 10Mhz reference has optical 10MHz
>in), and if you do that you may as well just take it in there using high
>quality coax (say RG-400U) and a bulkhead connector in the wall of the room.
>
>Dave

Dave,

the customer wants no bulkheads and asks specifically for an optical 
connection.
The signal will be, of course, be converted back to electrical inside the room.

Marco



From REMartinson at rcn.com  Mon Nov 24 16:03:07 2008
From: REMartinson at rcn.com (Bob Martinson)
Date: Mon, 24 Nov 2008 11:03:07 -0500
Subject: [time-nuts] position determination over short distance
In-Reply-To: <492AB812.4050403@cembreros.jazztel.es>
Message-ID: <AHEFKIADNPMDOPNNPAPDAEPIDEAA.REMartinson@rcn.com>

Her's another approach, see:

http://www.youtube.com/watch?v=FBy_e4yvqhQ

Regards,
Bob Martinson, N1VQR


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of EB4APL
Sent: Monday, November 24, 2008 9:20 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] position determination over short distance


Of course you can use any of the standard photogrammetric tecniques and
programs.  Even you can do it automatically using image correlation to
find the paralax and hence the distance.

But I have a simpler and cheaper (and also accurate) solution:

Put a transmiting coil in the object to be measured, about 1-2 cm
diameter, 0.5 cm high (I don?t remember the frequency now, it is quite
low but it doesn't matter).
Lay a receiving antenna grid of vertical and horizontal wires, spaced
about 1 cm, in a surface below the object.
Scan the antennas noting the amplitudes an phases on the 4 or 6
horizontal and vertical wires surrounding the Tx coil in each moment .
Calculate the position in real time (you obtain a precision of about 0.1
mm if the antenna surface is calibrated)
Sound complicated? buy a digitizing tablet (used ones are really
cheap).  This is how these things works.
Regards,
Ignacio Cembreros

Lux, James P wrote:
> There's a fair amount of F/OSS software from JPL available to do this sort
of calibration. It's used to calibrate cameras used on Mars rovers, among
other things. The target pattern for calibration is a bunch of big circular
dots on a background.
>
>
> On 11/23/08 7:56 PM, "Bruce Griffiths" <bruce.griffiths at xtra.co.nz> wrote:
>
> Tom Van Baak wrote:
>
>>> I need to determine the position of a instrument with a 1mm accuracy or
less.
>>> The instrument is not connected to a mechanical device but is separate &
>>> independent.
>>> The surface which the instrument is positioned on is close to the size
of a
>>> 11"x11" square.
>>>
>>>
>> 1 mm or better accuracy on a 300x300 mm surface can be
>> obtained with a cheap webcam mounted above the surface
>> and a little bit a creative software.
>>
>> /tvb
>>
>>
> Dont forget to calibrate the camera distortion and ensure that this
> doesnt over over time.
>
> i.e. lock the focus and ensure the camera position, tilt etc with
> respect to the reference surface do not vary.
>
> Bruce
>


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From pvince at theiet.org  Mon Nov 24 16:35:15 2008
From: pvince at theiet.org (Peter Vince)
Date: Mon, 24 Nov 2008 16:35:15 +0000
Subject: [time-nuts] 10 MHz over optical fiber?
Message-ID: <1478.1227544515@uk2.net>


>HParchive.org has a service note that explains how to use that for
>reference frequency distribution.

See:
http://www.hparchive.com/Bench_Briefs/HP-Bench-Briefs-1985-06-08.pdf

from page 4

Peter



From smace at intt.net  Mon Nov 24 16:36:38 2008
From: smace at intt.net (Scott Mace)
Date: Mon, 24 Nov 2008 10:36:38 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <20081124152247.DCDB0E91529@mail.ebirds.it>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
Message-ID: <492AD816.1010007@intt.net>

I'm looking for the same thing, but between buildings over singlemode
fiber.  I have not evaluated any of these but I've been looking at:

http://www.terahertztechnologies.com
http://www.highlandtechnology.com/
http://www.luxlink.com/

	Scott

Marco IK1ODO -2 wrote:
> Hi all,
> 
> I have to carry a 10 MHz standard frequency signal inside an EMC 
> screened room via fiber optic cable.
> 
> Not willing to re-invent the wheel, do something like an optical 
> standard frequency link exist on the market?
> I think it is possible to use standard 100MB LAN transceivers, and 
> POF. Phase noise requirements
> are not very stringent, and the distance is in the order of some tens 
> of meters.
> 
> Marco IK1ODO / AI4YF
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From james.p.lux at jpl.nasa.gov  Mon Nov 24 16:55:43 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Mon, 24 Nov 2008 08:55:43 -0800
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492AD816.1010007@intt.net>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it> <492AD816.1010007@intt.net>
Message-ID: <ECE7A93BD093E1439C20020FBE87C47FEB55C309A2@ALTPHYEMBEVSP20.RES.AD.JPL>

We do lots of this sort of thing at JPL. But the high precision does come at a cost..
Here's a paper from Bob Tjoelker and colleagues..
http://ipnpr.jpl.nasa.gov/progress_report/42-167/167C.pdf

There are various off the shelf products too, (you could buy a receiver and transmitter module from Ortel, for instance)

James Lux, P.E.
Task Manager, SOMD Software Defined Radios
Flight Communications Systems Section
Jet Propulsion Laboratory
4800 Oak Grove Drive, Mail Stop 161-213
Pasadena, CA, 91109
+1(818)354-2075 phone
+1(818)393-6875 fax

> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Mace
> Sent: Monday, November 24, 2008 8:37 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10 MHz over optical fiber?
>
> I'm looking for the same thing, but between buildings over
> singlemode fiber.  I have not evaluated any of these but I've
> been looking at:
>
> http://www.terahertztechnologies.com
> http://www.highlandtechnology.com/
> http://www.luxlink.com/
>
>         Scott
>
> Marco IK1ODO -2 wrote:


From XDE-L2G3 at myamail.com  Mon Nov 24 17:02:10 2008
From: XDE-L2G3 at myamail.com (Mike Monett)
Date: Mon, 24 Nov 2008 12:02:10 -0500
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.278.1227541687.2542.time-nuts@febo.com>
Message-ID: <mailman.17.1227546178.2539.time-nuts@febo.com>

Hi,

Sorry, I don't know how to reply to a post using the digest. But my
question is if 100Hz or 10KHz are available from a GPS unit, where do they
come from? Does that mean there is a 10MHz oscillator somewhere on the pcb
that is just divided down?

If so, then adding another PLL loop to control an external 10MHz crystal
will just add additional noise, jitter, variable phase offset, etc.

If there is already a 10MHz oscillator, wouldn't it be simpler to add a
buffer like paralleled sections of a 74AC04 to the source, and drive a 50
ohm coax directly?

Regards,

Mike Monett


From smace at intt.net  Mon Nov 24 17:13:58 2008
From: smace at intt.net (Scott Mace)
Date: Mon, 24 Nov 2008 11:13:58 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <ECE7A93BD093E1439C20020FBE87C47FEB55C309A2@ALTPHYEMBEVSP20.RES.AD.JPL>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es>	<20081124152247.DCDB0E91529@mail.ebirds.it>
	<492AD816.1010007@intt.net>
	<ECE7A93BD093E1439C20020FBE87C47FEB55C309A2@ALTPHYEMBEVSP20.RES.AD.JPL>
Message-ID: <492AE0D6.1030204@intt.net>

I've used the ortel/emcore 5100 series for L-band IF links in places where the
distances and costs of running coax were too high.  Some of the products
launch hot as they were designed for passive/splitter based distribution
so you have to pad the optical rx.

	Scott

Lux, James P wrote:
> We do lots of this sort of thing at JPL. But the high precision does come at a cost..
> Here's a paper from Bob Tjoelker and colleagues..
> http://ipnpr.jpl.nasa.gov/progress_report/42-167/167C.pdf
> 
> There are various off the shelf products too, (you could buy a receiver and transmitter module from Ortel, for instance)
> 
> James Lux, P.E.
> Task Manager, SOMD Software Defined Radios
> Flight Communications Systems Section
> Jet Propulsion Laboratory
> 4800 Oak Grove Drive, Mail Stop 161-213
> Pasadena, CA, 91109
> +1(818)354-2075 phone
> +1(818)393-6875 fax
> 
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Mace
>> Sent: Monday, November 24, 2008 8:37 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] 10 MHz over optical fiber?
>>
>> I'm looking for the same thing, but between buildings over
>> singlemode fiber.  I have not evaluated any of these but I've
>> been looking at:
>>
>> http://www.terahertztechnologies.com
>> http://www.highlandtechnology.com/
>> http://www.luxlink.com/
>>
>>         Scott
>>
>> Marco IK1ODO -2 wrote:
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From SAIDJACK at aol.com  Mon Nov 24 17:19:19 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Mon, 24 Nov 2008 12:19:19 EST
Subject: [time-nuts] Oncore question
Message-ID: <c14.50b53106.365c3c17@aol.com>

Hi Arnold,
 
not sure what voltage the crystal stops at, that is probably different  
unit-to-unit. It happens on the M12+, it may not happen on other Oncores.
 
As someone else mentioned, if you only use the Li battery during power  
outages, it will probably last a very long time, years and years. It's  mostly an 
issue when the unit is un-powered, in storage.
 
bye,
Said
 
 
In a message dated 11/23/2008 13:05:10 Pacific Standard Time,  
Arnold.Tibus at gmx.de writes:

Hi  Said,
thank you very much for the additional clarification, very  interesting 
behaviour. I think this does confirm roughly my assumption.  When only pwr 
fails for a few hours (intermittant) have to be taken into  account, super 
caps 
may be good for safe work during several hours up to  perhaps 24 hours, 
but not beyond, is that right? Do you know at what  voltage the clock does 
resign? 
Perhaps this could be improved with a  software solving the recovery problem 
when repowering the RX. 
You  describe that using LiIon batteries are not yet the ideal way, but why  
cannot higher capacities come into play (space should be not the problem  
for on ground use in fix  stations)?

regards,
Arnold



From kirbybq at bellsouth.net  Mon Nov 24 18:12:42 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Mon, 24 Nov 2008 12:12:42 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492AE0D6.1030204@intt.net>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es>	<20081124152247.DCDB0E91529@mail.ebirds.it>	<492AD816.1010007@intt.net>	<ECE7A93BD093E1439C20020FBE87C47FEB55C309A2@ALTPHYEMBEVSP20.RES.AD.JPL>
	<492AE0D6.1030204@intt.net>
Message-ID: <492AEE9A.9090506@bellsouth.net>



You might look at video fiber optic transmitter/receiver.  I used one 
once to carry a certain telemetry signal for the same reasons your are 
looking for.  The fiber optics were analog in this case and rated from 
30 hz to 10 Mhz at 1 volt P-P.  We had to attenuate the signal going 
into the transmitter and we had to amplify the receiver.  Our run was 
around 400 feet. The signal to noise ratio was somewhere around 55 db.


From warrensjmail-one at yahoo.com  Mon Nov 24 18:27:56 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 10:27:56 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.278.1227541687.2542.time-nuts@febo.com>
	<E1L4epv-0005Xo-6O@meow.febo.com>
Message-ID: <002a01c94e62$6005bc80$6401a8c0@WSOffice>

Mike

Neither do I, know how to reply to a post that is. This may be the blind leading the blind 
and end up in some unknown place.
True it would be simpler to use the High freq Osc directly but it would not be accurate.
The problem with just using the High freq as you suggested is that it is not at any known, exact or even constant  frequency.
The divider  number can change for each low freq cycle. Example if the master freq was say 0.2520 Hz high then 
every forth second the divider would add 1 extra divide count and every 500th second it would divide by an additional extra clock time, 
therefore skipping 11 divides every 500 seconds.  

Regards,
Warren
************
----- Original Message ----- 
From: "Mike Monett" <XDE-L2G3 at myamail.com>
To: <time-nuts at febo.com>
Sent: Monday, November 24, 2008 9:02 AM
Subject: Re: [time-nuts] GPSDO using 100Hz


> Hi,
> 
> Sorry, I don't know how to reply to a post using the digest. But my
> question is if 100Hz or 10KHz are available from a GPS unit, where do they
> come from? Does that mean there is a 10MHz oscillator somewhere on the pcb
> that is just divided down?
> 
> If so, then adding another PLL loop to control an external 10MHz crystal
> will just add additional noise, jitter, variable phase offset, etc.
> 
> If there is already a 10MHz oscillator, wouldn't it be simpler to add a
> buffer like paralleled sections of a 74AC04 to the source, and drive a 50
> ohm coax directly?
> 
> Regards,
> 
> Mike Monett
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


From bruce.griffiths at xtra.co.nz  Mon Nov 24 18:32:59 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 07:32:59 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <E1L4epv-0005Xo-9w@meow.febo.com>
References: <mailman.278.1227541687.2542.time-nuts@febo.com>
	<E1L4epv-0005Xo-9w@meow.febo.com>
Message-ID: <492AF35B.4090002@xtra.co.nz>

Mike Monett wrote:
> Hi,
>
> Sorry, I don't know how to reply to a post using the digest. But my
> question is if 100Hz or 10KHz are available from a GPS unit, where do they
> come from? Does that mean there is a 10MHz oscillator somewhere on the pcb
> that is just divided down?
>
> If so, then adding another PLL loop to control an external 10MHz crystal
> will just add additional noise, jitter, variable phase offset, etc.
>
> If there is already a 10MHz oscillator, wouldn't it be simpler to add a
> buffer like paralleled sections of a 74AC04 to the source, and drive a 50
> ohm coax directly?
>
> Regards,
>
> Mike Monett
>
> _______________________________________________
>   
Few GPS receivers other than Geodetic receivers and the Novatel
Superstar use 10MHz crystal oscillators.
In particular neither the the M12+T nor the Resolution-T uses a 10MHz
crystal

Bruce


From bruce.griffiths at xtra.co.nz  Mon Nov 24 18:47:08 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 07:47:08 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
References: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
Message-ID: <492AF6AC.20606@xtra.co.nz>

WarrenS Email wrote:
> Bruce Griffiths answered:
>
> Its difficult to make much useful comment as you provide few measured
> results.
>
> With an M12+T or equivalent the ADEV of the PPS output (without sawtooth
> correction) goes below 1E-10 at  Tau > 200 sec or so.
> Thus with an optimized GPSDO it wont take an hour or so to achieve 1E-10
> stability.
> However a single shot phase error measurement system resolution of
> around 1ns or so is usually required.
> Take a look at the GPSDO ADEV plots at:
>
> http://www.leapsecond.com/pages/gpsdo/
>
> Where the ADEV for various GPSDO remains below 1E-11 over the Tau range
> of [0.1s, 100,000s]
>
> The achievable performance also depends a great deal on the quality of
> the OCXO used in the GPSDO.
>
> If the "digital" phase error measurement techniques you have been
> comparing your system with have inadequate resolution it will tale
> longer for the measured ADEV to fall below 1E-10.
> If the OCXO used has a relatively high ADEV at low values of tau then it
> may well required averaging over very long time intervals to achieve an
> ADEV below 1E-10.
>
> More detail is required before an analysis of the performance of your
> system is possible.
>
> Bruce
>
> *********************
>
> Bruce, Thanks for the feedback, Good information to know, 
> but you seemed to missed my point and question.
>
> Yes I am comparing to SIMPLE, and home built type, non optimized, 
> trackers like  Brooks Shera's "10 Mhz GPS Frequency Standard". 
> I understand, and even wrote, NIST reports about  a 10ns uncertainty 
> with a 10 minute average, which would give a 1e-8 / 600, or  1.5 parts in 1E-11 
> possible in 600 seconds, 1e-10 in 100 seconds.  Its safe to assume NIST is 
> not using Shera's unit, which I believe adds an additional  24 ns or is 
> it 41.7 ns uncertainty to each 1 second reading. 
> Besides asking if anyone is using the 100Hz output, I would like to ask 
> why don't the generally available GPSDO use the 100Hz, which can give 
> about 1 ns of certainly with a simple PLL and analog RC filter, instead of 
> the using the 1 sec which has more like 100 ns of uncorrected uncertainty 
> in it and must use a processor?
>
> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal results.
> BTW most of what they have plotted is the results of NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation increases in the tracking 
> mode at mid averaging times. The 1 second GPS tracking signal is adding noise, 
> which pretty much makes my point that 1 PPS signal is not so good to use 
> if you want good fast results.
>
> Warren
>   
Warren

The optimum loop time constant depends on the quality of the local
oscillator and the GPS timing receiver timing signals.
A time constant of several hours is only useful with a very high quality
OCXO.

The 100Hz output of an M12+T is phase jerked into alignment with the the
second once every second as is the 10kHz output from Jupiter-T GPS receiver.
The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
to an XOR phase detector, its better to use the leading edges of these
signals.
When one uses a low resolution phase detector with dither as in the
Brooks Shera circuit then making 100 or 10,000 measurements of the phase
error every second can, if the dither is of the right form, improve the
effective resolution. However surely the timing quantisation error of
the leading edges of the 100Hz (or 10kHz) outputs limits the potential
improvement?

One can do much better with an inexpensive processor with little
external hardware other than a high resolution DACX (even that can be
implemented in software and hardware within the processor together with
a couple of opamps).


Bruce


From warrensjmail-one at yahoo.com  Mon Nov 24 18:49:10 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 10:49:10 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.278.1227541687.2542.time-nuts@febo.com><E1L4epv-0005Xo-6O@meow.febo.com>
	<002a01c94e62$6005bc80$6401a8c0@WSOffice>
Message-ID: <00bb01c94e65$572c1520$6401a8c0@WSOffice>

Sorry my example should of said skip 126 cycles every 500 seconds (500/4 +1)
----- Original Message ----- 
From: "WarrenS" <warrensjmail-one at yahoo.com>
To: <time-nuts at febo.com>
Sent: Monday, November 24, 2008 10:27 AM
Subject: Re: [time-nuts] GPSDO using 100Hz


> Mike
> 
> Neither do I, know how to reply to a post that is. This may be the blind leading the blind 
> and end up in some unknown place.
> True it would be simpler to use the High freq Osc directly but it would not be accurate.
> The problem with just using the High freq as you suggested is that it is not at any known, exact or even constant  frequency.
> The divider  number can change for each low freq cycle. Example if the master freq was say 0.2520 Hz high then 
> every forth second the divider would add 1 extra divide count and every 500th second it would divide by an additional extra clock time, 
> therefore skipping 11 divides every 500 seconds.  
> 
> Regards,
> Warren
> ************
> ----- Original Message ----- 
> From: "Mike Monett" <XDE-L2G3 at myamail.com>
> To: <time-nuts at febo.com>
> Sent: Monday, November 24, 2008 9:02 AM
> Subject: Re: [time-nuts] GPSDO using 100Hz
> 
> 
>> Hi,
>> 
>> Sorry, I don't know how to reply to a post using the digest. But my
>> question is if 100Hz or 10KHz are available from a GPS unit, where do they
>> come from? Does that mean there is a 10MHz oscillator somewhere on the pcb
>> that is just divided down?
>> 
>> If so, then adding another PLL loop to control an external 10MHz crystal
>> will just add additional noise, jitter, variable phase offset, etc.
>> 
>> If there is already a 10MHz oscillator, wouldn't it be simpler to add a
>> buffer like paralleled sections of a 74AC04 to the source, and drive a 50
>> ohm coax directly?
>> 
>> Regards,
>> 
>> Mike Monett
>> 
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


From bruce.griffiths at xtra.co.nz  Mon Nov 24 18:53:48 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 07:53:48 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
References: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
Message-ID: <492AF83C.7040207@xtra.co.nz>

WarrenS Email wrote:
>
> Bruce, Thanks for the feedback, Good information to know, 
> but you seemed to missed my point and question.
> in it and must use a processor?
>
> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal results.
> BTW most of what they have plotted is the results of NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation increases in the tracking 
> mode at mid averaging times. The 1 second GPS tracking signal is adding noise, 
> which pretty much makes my point that 1 PPS signal is not so good to use 
> if you want good fast results.
>
> Warren
>   
Analog time constants of several hours are generally considered
impractical due to the lack of suitable low noise components principally
high value resistors and capacitors.
So how do you propose to get around this with an analog control loop?

Bruce


From ernieperes at aol.com  Mon Nov 24 18:54:15 2008
From: ernieperes at aol.com (ernieperes at aol.com)
Date: Mon, 24 Nov 2008 13:54:15 -0500
Subject: [time-nuts] LPRO-101 HELP
In-Reply-To: <c14.50b53106.365c3c17@aol.com>
References: <c14.50b53106.365c3c17@aol.com>
Message-ID: <8CB1C7D2E7BE2FA-F68-853@webmail-md13.sysops.aol.com>

Hi Gents,

Just fired up my LPRO-101, bought a year ago or more on Ebay from 
Switzerland and found unserviceable....

It is a 24V vesion and upon switching ON only 0,47A is the current 
consumption and the 10MHz wondering up/down and
never stops. No lock.
Suspect the Heating part is defective....

Anybody having more info or circuit diagram where to look??????

Thanks in advance.

Rgds Ernie



From steveheidmann at yahoo.com  Mon Nov 24 19:48:25 2008
From: steveheidmann at yahoo.com (steve heidmann)
Date: Mon, 24 Nov 2008 11:48:25 -0800 (PST)
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <20081124152247.DCDB0E91529@mail.ebirds.it>
Message-ID: <561460.12282.qm@web36801.mail.mud.yahoo.com>

Hi Marco ,
?
You might try firecoms if it's not too hot in there.? (plastic)
?
???????????????????? Steve

--- On Mon, 11/24/08, Marco IK1ODO -2 <ik1odo at spin-it.com> wrote:

From: Marco IK1ODO -2 <ik1odo at spin-it.com>
Subject: [time-nuts] 10 MHz over optical fiber?
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Monday, November 24, 2008, 7:31 AM

Hi all,

I have to carry a 10 MHz standard frequency signal inside an EMC 
screened room via fiber optic cable.

Not willing to re-invent the wheel, do something like an optical 
standard frequency link exist on the market?
I think it is possible to use standard 100MB LAN transceivers, and 
POF. Phase noise requirements
are not very stringent, and the distance is in the order of some tens 
of meters.

Marco IK1ODO / AI4YF


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



      

From ik1odo at spin-it.com  Mon Nov 24 17:58:03 2008
From: ik1odo at spin-it.com (Marco IK1ODO -2)
Date: Mon, 24 Nov 2008 18:58:03 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <9138.1227542175@critter.freebsd.dk>
References: <Your message of "Mon, 24 Nov 2008 16:31:23 +0100."
	<20081124152247.DCDB0E91529@mail.ebirds.it>
	<9138.1227542175@critter.freebsd.dk>
Message-ID: <20081124174927.86F5CD7CF26@mail.ebirds.it>

Thanks to all for the quick answers and all the info. As usual, 
time-nuts is a great resource :-)

Marco IK1ODO



From warrensjmail-one at yahoo.com  Mon Nov 24 20:39:43 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 12:39:43 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <012101c94e74$c8fac3e0$6401a8c0@WSOffice>

WarrenS Email wrote:
>
> Bruce, Thanks for the feedback, Good information to know, 
> but you seemed to missed my point and question.
> in it and must use a processor?
>
> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal results.
> BTW most of what they have plotted is the results of NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation increases in the 
> tracking 
> mode at mid averaging times. The 1 second GPS tracking signal is adding 
> noise, 
> which pretty much makes my point that 1 PPS signal is not so good to use 
> if you want good fast results.
>
> Warren
>   
Analog time constants of several hours are generally considered
impractical due to the lack of suitable low noise components principally
high value resistors and capacitors.
So how do you propose to get around this with an analog control loop?

Bruce

*****************
Bruce

In answer to your question of :
"how do you propose to get around this with an analog control loop?"
Short answer is: By using the 100Hz output pulses, instead of the 1 PPS.
What I have found is that it takes about the same number of total pulses for a given accuracy
whether it is 1 Hz or 100 Hz. SO by using the 100Hz signal, the time Constant can go down
by nearly 2 decades. What I have also found is that a 100 seconds RC TC, which is very practical for analog, 
gives pretty good results AND of course this whole discussion only applies to errors caused by the 100 ns 
pulse jitter and not the 10ns GPS jitter, and it does not apply if you are using the 1Hz offset correction to get
each down to 1 ns, etc. This is for the basic GPS tracker that does not use the sawtooth correction.
The reason this works is because it is easy enough to get about a 1ns uncertainty for a 1 sec average 
using the 100 Hz instead of the nearer 100ns uncertainty of the 1 PPS. 
(Note what I am talking about is Typical performance. Worse case, a couple times a day it has some 
other  problems, that I would love to discuses with you, under an advanced topic, if we can ever get that far)

Under another subject, 
You said in one of your other post that the 100hz is not useful for an XOR phase detector because only one 
of its edges are known. 
Sorry, I thought we where above that kind of basic information exchange. I just took it 
that everyone that cares, knows the 100Hz has to be divided by 2 (using the correct edge) 
before it is feed to a simple XOR phase detector. So a 100 Hz XOR phase detector runs 
with 50 Hz square wave inputs and gives out a 100Hz, 50% duty cycle square wave at lock.
(And has a very low gain, which is why I don't use it for low frequencies)

Warren


From iovane at inwind.it  Mon Nov 24 20:51:38 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Mon, 24 Nov 2008 21:51:38 +0100
Subject: [time-nuts] HP 53131A question
Message-ID: <KAUVA2$D029C858AAC1185D3933AEF2446FDD0D@libero.it>

Thanks Magnus and Tom, you clarified more than enough.

73,
Antonio I8IOV




From XDE-L2G3 at myamail.com  Mon Nov 24 21:12:22 2008
From: XDE-L2G3 at myamail.com (Mike Monett)
Date: Mon, 24 Nov 2008 16:12:22 -0500
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.287.1227557685.2542.time-nuts@febo.com>
Message-ID: <mailman.18.1227561157.2539.time-nuts@febo.com>

  > Mike

  > Neither do I, know how to reply to a post that is. This may be the
  > blind leading the blind and end up in some unknown place.

  > True it would be simpler to use the High freq Osc directly  but it
  > would not be accurate.

  > The problem with just using the High freq as you suggested is that
  > it is not at any known, exact or even constant frequency.

  > The divider number can change for each low freq cycle.  Example if
  > the master freq was say 0.2520 Hz high then every forth second the
  > divider would  add 1 extra divide count and every 500th  second it
  > would divide by an additional extra clock time, therefore skipping
  > 11 divides every 500 seconds.

  > Regards,
  > Warren

  Warren, thanks  for the reply. When you say "The divider  number can
  change", what oscillator are you referring to?

  Is this  the cheap crystal oscillator in the GPS unit? If so,  is it
  adjusting the timing of the 100Hz pulses the same way as  it adjusts
  the 1PPS? It doesn't seem it could do it any other way.

  If that's true, how does it do the calculation for each  1Hz message
  from the GPS decode?

  Does it  put out 100 pulses using the same timing  info,  and repeat
  the next cycle with a different timing?

  Then the sawtooth would be a group of 100 pulses, then another group
  shifted slightly  in phase.  Heh - that would be fun  for  a  PLL to
  track:)

  Another alternative  would  be to repeat  the  calculation  for each
  pulse and shift them according to where they are in the  cycle. This
  would be a much nicer signal for a PLL to work with.

  It might  take a lot of calculations, but I suppose  a  lookup table
  would reduce  the  workload on the processor  and  leave  enough cpu
  cycles for other tasks.

  Can you tell if any of the above methods are used in your system?

  Thanks,

  Mike Monett


From vilgotch at bigpond.net.au  Mon Nov 24 21:36:20 2008
From: vilgotch at bigpond.net.au (Morris Odell)
Date: Tue, 25 Nov 2008 08:36:20 +1100
Subject: [time-nuts] Oncore question
Message-ID: <001901c94e7c$b1103370$ad00a8c0@Morris1>

Thanks to all those who replie don this subject. I'm using an old VP Oncore 
purely for timing.

The situation where the RTC stops at low voltage but the memory lingers on 
resulting in the wrong time for the Almanac is a fascinating one of which I 
was not aware. I may do some experiments to see at what voltage the RTC 
stops. In the meantime the discussion prompted a baord redesign to find some 
real estate for a Li cell :-)

Thanks again,

Morris 



From warrensjmail-one at yahoo.com  Mon Nov 24 21:44:43 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 13:44:43 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <01c401c94e7d$dd6608e0$6401a8c0@WSOffice>

> Mike

  > Neither do I, know how to reply to a post that is. This may be the
  > blind leading the blind and end up in some unknown place.

  > True it would be simpler to use the High freq Osc directly  but it
  > would not be accurate.

  > The problem with just using the High freq as you suggested is that
  > it is not at any known, exact or even constant frequency.

  > The divider number can change for each low freq cycle.  Example if
  > the master freq was say 0.2520 Hz high then every forth second the
  > divider would  add 1 extra divide count and every 500th  second it
  > would divide by an additional extra clock time, therefore skipping
  > 11 divides every 500 seconds.

  > Regards,
  > Warren

  Warren, thanks  for the reply. When you say "The divider  number can
  change", what oscillator are you referring to?

  Is this  the cheap crystal oscillator in the GPS unit? If so,  is it
  adjusting the timing of the 100Hz pulses the same way as  it adjusts
  the 1PPS? It doesn't seem it could do it any other way.

  If that's true, how does it do the calculation for each  1Hz message
  from the GPS decode?

  Does it  put out 100 pulses using the same timing  info,  and repeat
  the next cycle with a different timing?

  Then the sawtooth would be a group of 100 pulses, then another group
  shifted slightly  in phase.  Heh - that would be fun  for  a  PLL to
  track:)

  Another alternative  would  be to repeat  the  calculation  for each
  pulse and shift them according to where they are in the  cycle. This
  would be a much nicer signal for a PLL to work with.

  It might  take a lot of calculations, but I suppose  a  lookup table
  would reduce  the  workload on the processor  and  leave  enough cpu
  cycles for other tasks.

  Can you tell if any of the above methods are used in your system?

  Thanks,

  Mike Monett

********************
Mike

Note: I gave you a simple example of why it is not possible to just buffer 
the High Freq osc . The actual working get a bit more complicated.
In short when it is time to give out the next pulse whether it is 1 Hz or 100 Hz 
It sends it outs as close as possible to the correct time, using some 
internal clock. What I have seen on the Oncore is that  this causes a peak of +- 50ns 
of jitter. It works the same with the 100Hz or the 1 Hz, both have the same 
peak to peak rising edge jitter, which is different for each pulse sent.

The 1Hz timing error message it sends out has little to do with the 100 Hz timing.
And is not relevant when using the 100Hz except for a few advanced alising issues.

I hope that answers your questions. Can I ask why the interest?

Warren

From warrensjmail-one at yahoo.com  Mon Nov 24 22:39:30 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 14:39:30 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <020101c94e85$84443810$6401a8c0@WSOffice>

Warren

The optimum loop time constant depends on the quality of the local
oscillator and the GPS timing receiver timing signals.
A time constant of several hours is only useful with a very high quality OCXO.

The 100Hz output of an M12+T is phase jerked into alignment with the the
second once every second as is the 10kHz output from Jupiter-T GPS receiver.
The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
to an XOR phase detector, its better to use the leading edges of these signals.

When one uses a low resolution phase detector with dither as in the
Brooks Shera circuit then making 100 or 10,000 measurements of the phase
error every second can, if the dither is of the right form, improve the
effective resolution. However surely the timing quantisation error of
the leading edges of the 100Hz (or 10kHz) outputs limits the potential
improvement?

One can do much better with an inexpensive processor with little
external hardware other than a high resolution DACX (even that can be
implemented in software and hardware within the processor together with
a couple of opamps).

Bruce

******************
Bruce
It would seem we are now in agreement and on the same track in most areas.

   >B) A time constant of several hours is only useful with a very high quality OCXO.
Agree, a High quality Osc needs a long TC or else it will degrade the noise performance.
On the other hand if using a short time constant (for whatever reason) there is little 
need for a high quality OCXO. A short term stable osc will give about the same results.
AND if you don't care about short term noise such as when you are only averaging the counts   
over say an hour or a day, to compare small phase shifts to get very accurate frequency results, 
then any OSC even the most crappy VCO will do if it is updated fast enough to keep it from skipping counts.

  >B) The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
     to an XOR phase detector, its better to use the leading edges of these signals.
We agree again, That is why they MUST be divided by two first, using the correct edge.

  >B) making 100 or 10,000 measurements of the phase error every second can, 
        if the dither is of the right form, improve the effective resolution. 
        However surely the timing quantisation error of the leading edges of the 100Hz (or 10kHz) 
       outputs limits the potential improvement?  
Yep, there is a limit to how much improvement is available, It can not get better than perfect.
The rule of thumb is the improvement is the square root of the number of samples for random noise.
For the non random noise of the 100 Hz the improvement can be anywhere from Zero to 1/number 
of samples. Typically I'm seeing about a 50 to one improvement, with a worse case of no improvement 
for short periods lasting under a minute (without the addition of a simple processor)

   >B) One can do much better with an inexpensive processor...
I completely agree. One can always do better with something.
But my point is One can do 'good enough' for many applications with a lot less.

 >B)  with little external hardware other than a high resolution DAC
      (even that can be implemented in software and hardware within 
      the processor together with a couple of opamps).
Don't even need that much, most of the time, by providing a seldom 
changed course adjustment along with the fine adjustment. 


Warren


From bruce.griffiths at xtra.co.nz  Mon Nov 24 23:27:57 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 12:27:57 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <020101c94e85$84443810$6401a8c0@WSOffice>
References: <020101c94e85$84443810$6401a8c0@WSOffice>
Message-ID: <492B387D.6060602@xtra.co.nz>

WarrenS wrote:
> Bruce
> It would seem we are now in agreement and on the same track in most areas.
>
>   
We probably always have been, but this certainly wasn't clear from the
original posting.
>    >B) A time constant of several hours is only useful with a very high quality OCXO.
> Agree, a High quality Osc needs a long TC or else it will degrade the noise performance.
> On the other hand if using a short time constant (for whatever reason) there is little 
> need for a high quality OCXO. A short term stable osc will give about the same results.
> AND if you don't care about short term noise such as when you are only averaging the counts   
> over say an hour or a day, to compare small phase shifts to get very accurate frequency results, 
> then any OSC even the most crappy VCO will do if it is updated fast enough to keep it from skipping counts.
>
>   >B) The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
>      to an XOR phase detector, its better to use the leading edges of these signals.
> We agree again, That is why they MUST be divided by two first, using the correct edge.
>   
It is very important to give such detail on this list as the
knowledge/experience of the list members varies so widely.
The last thing one wants to happen is for someone to blindly rush ahead
and use an XOR phase detector without first dividing the the 100Hz or
10kHz by 2 and then wonder why the performance isnt that good. Providing
such detail also engenders more confidence in the soundness of the method.
>   >B) making 100 or 10,000 measurements of the phase error every second can, 
>         if the dither is of the right form, improve the effective resolution. 
>         However surely the timing quantisation error of the leading edges of the 100Hz (or 10kHz) 
>        outputs limits the potential improvement?  
> Yep, there is a limit to how much improvement is available, It can not get better than perfect.
> The rule of thumb is the improvement is the square root of the number of samples for random noise.
> For the non random noise of the 100 Hz the improvement can be anywhere from Zero to 1/number 
> of samples. Typically I'm seeing about a 50 to one improvement, with a worse case of no improvement 
> for short periods lasting under a minute (without the addition of a simple processor)
>
>   
If the phase error counter clock should ever injection lock to the OCXO
or the GPS timing receiver output, then the averaging will fail.
If this clock is sufficiently noisy or is phase dithered sufficiently
with random noise then this wont happen.
>    >B) One can do much better with an inexpensive processor...
> I completely agree. One can always do better with something.
> But my point is One can do 'good enough' for many applications with a lot less.
>
>  >B)  with little external hardware other than a high resolution DAC
>       (even that can be implemented in software and hardware within 
>       the processor together with a couple of opamps).
> Don't even need that much, most of the time, by providing a seldom 
> changed course adjustment along with the fine adjustment. 
>
>
> Warren
>
>   
Bruce


From XDE-L2G3 at myamail.com  Tue Nov 25 00:06:27 2008
From: XDE-L2G3 at myamail.com (Mike Monett)
Date: Mon, 24 Nov 2008 19:06:27 -0500
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.297.1227569283.2542.time-nuts@febo.com>
Message-ID: <mailman.19.1227571601.2539.time-nuts@febo.com>


  Bruce wrote:

  > Analog time  constants of several hours  are  generally considered
  > impractical due  to  the  lack of  suitable  low  noise components
  > principally high value resistors and capacitors.

  > So how do you propose to get around this with an analog control loop?

  > Bruce

  Not that  I'm  recommending  this approach,  but  for  general info,
  Digikey sells a 1 Farad 5.5V cap for about $7.00CAD in singles:

 
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=131084;keywords=1%20farad

  A time constant of 1 hr would need a 3.6k resistor. That's  not bad.
  I have some 5 Farad caps that might be even better.

  The typical leakage spec for electrolytics is

  I = K * C * V

  where

  C = capacitance in Farads
  V = applied voltage
  K = 0.002 for low leakage electrolytic caps, 0.02 for standard

  I have  measured  K values of 7e-7 for double  layer  caps.  This is
  much, much  better  than  any electrolytic I  have  ever  seen. This
  enabled some  advanced silver ion  generators  using differentiation
  that could not be done with electrolytics.

  The typical  frequency  response rolls off above a  few  hundred Hz.
  This is  of  little  consequence  in  timing  circuits  intended for
  several hours duration.

  But I'd go with a digital approach for a low frequency PLL.

  Mike Monett


From pvince at theiet.org  Tue Nov 25 00:14:59 2008
From: pvince at theiet.org (Peter Vince)
Date: Tue, 25 Nov 2008 00:14:59 +0000
Subject: [time-nuts] GPSDO using 100Hz
Message-ID: <1338.1227572099@uk2.net>

> >B) The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
> to an XOR phase detector, its better to use the leading edges of these signals.
> We agree again, That is why they MUST be divided by two first, using the
correct edge.

I'm not convinced that would cure the problem.  Yes, it would correct for pulses
that weren't a perfect 1:1 mark-space ratio, but assuming the shape is constant,
surely that isn't a problem?  However, when a +/- 50ns step was inserted, surely
the effect of that would at best be halved by dividing the 100Hz by two?

Peter Vince



From XDE-L2G3 at myamail.com  Tue Nov 25 00:20:07 2008
From: XDE-L2G3 at myamail.com (Mike Monett)
Date: Mon, 24 Nov 2008 19:20:07 -0500
Subject: [time-nuts] GPSDO using 100Hz
References: <mailman.297.1227569283.2542.time-nuts@febo.com>
Message-ID: <mailman.20.1227572421.2539.time-nuts@febo.com>

  > Mike

  > Note: I  gave  you a simple example of why it is  not  possible to
  > just buffer the High Freq osc . The actual working get a  bit more
  > complicated.

  > In short when it is time to give out the next pulse whether  it is
  > 1 Hz  or  100  Hz It sends it outs as  close  as  possible  to the
  > correct time,  using some internal clock. What I have seen  on the
  > Oncore is  that this causes a peak of +- 50ns of jitter.  It works
  > the same  with the 100Hz or the 1 Hz, both have the  same  peak to
  > peak rising edge jitter, which is different for each pulse sent.

  > The 1Hz  timing error message it sends out has little  to  do with
  > the 100 Hz timing.

  > And is not relevant when using the 100Hz except for a few advanced
  > alising issues.

  > I hope that answers your questions. Can I ask why the interest?

  > Warren

  Ok, it seems they are calculating the best time for each 100Hz pulse
  individually. That makes life a bit easier for a PLL.

  My interest is I have a totally new way of locking to the 1PPS pulse
  that should  improve the performance dramatically.  The  question is
  would it also work with a 100Hz signal.

  The answer is yes. It would also work with a 10KHz signal,  but this
  would require  a  bit  more horsepower. I was  planning  on  using a
  simple inexpensive microprocessor for everything but I don't know if
  it would be fast enough to do 10KHz.

  But there's not many of those around anymore, are there?

  Best Regards,

  Mike Monett


From bruce.griffiths at xtra.co.nz  Tue Nov 25 00:28:05 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 13:28:05 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <E1L4lfB-00047l-9z@meow.febo.com>
References: <mailman.297.1227569283.2542.time-nuts@febo.com>
	<E1L4lfB-00047l-9z@meow.febo.com>
Message-ID: <492B4695.8050703@xtra.co.nz>

Mike Monett wrote:
>  Warren
>
>   Ok, it seems they are calculating the best time for each 100Hz pulse
>   individually. That makes life a bit easier for a PLL.
>
>   
Not according to the datasheets which imply the phase of the 100Hz (or
10kHz) burst is adjusted once per second.
This should be very easy to verify if the leading edges of individual
pulses are time stamped with sufficient resolution.
>   My interest is I have a totally new way of locking to the 1PPS pulse
>   that should  improve the performance dramatically.  The  question is
>   would it also work with a 100Hz signal.
>
>   The answer is yes. It would also work with a 10KHz signal,  but this
>   would require  a  bit  more horsepower. I was  planning  on  using a
>   simple inexpensive microprocessor for everything but I don't know if
>   it would be fast enough to do 10KHz.
>
>   But there's not many of those around anymore, are there?
>
>   Best Regards,
>
>   Mike Monett
>
>
>   
Bruce



From bruce.griffiths at xtra.co.nz  Tue Nov 25 00:42:42 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 13:42:42 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <1338.1227572099@uk2.net>
References: <1338.1227572099@uk2.net>
Message-ID: <492B4A02.5080905@xtra.co.nz>

Peter Vince wrote:
>>> B) The variable pulse width of the 100Hz (and 10kHz) outputs do no favours
>>>       
>> to an XOR phase detector, its better to use the leading edges of these signals.
>> We agree again, That is why they MUST be divided by two first, using the
>>     
> correct edge.
>
> I'm not convinced that would cure the problem.  Yes, it would correct for pulses
> that weren't a perfect 1:1 mark-space ratio, but assuming the shape is constant,
> surely that isn't a problem?  However, when a +/- 50ns step was inserted, surely
> the effect of that would at best be halved by dividing the 100Hz by two?
>
> Peter Vince
>
>
>   
Not so as only the divide by 2 transition that occurs on the second will
have its delay with respect to the previous transition adjusted by 50ns.
The subsequent 99 transitions (or 9999 transitions with 10kHz output)
will occur at intervals of 10ms (or 100uS with 10kHz output).

The pulse duty cycle isn't necessarily constant (datasheet specs for the
pulse width tend to be somewhat ambiguous) and usually the pulse width
of the pulse preceding the second differs.
The spec for the M12+T is:
The 100Hz pulses are high for a period of 2-3ms in duration except for
the pulse that immediately preceding the second which is 6-7 ms in duration.
A 1millisec tolerance in pulse width is comparatively large.

A pulse width variation of 1ms or so should be relatively easy to measure.

Bruce


From warrensjmail-one at yahoo.com  Tue Nov 25 00:48:23 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 16:48:23 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>

Bruce

 My Oncore's phase is definitely different on each 100Hz cycle. A digital storage scope shows it very well.

Some things that come to mine:

1) Not all Oncores are the same, mine is an old 8 channel one. (Don't remember the number, it is the one with the sawtooth capability)
2) The actual error amount is updated each 1 sec and the processors still dithers that to get the 100 Hz to be close to the correct value
3) Other TBD 

Warren
*******************

Mike Monett wrote:
>  Warren
>
>   Ok, it seems they are calculating the best time for each 100Hz pulse
>   individually. That makes life a bit easier for a PLL.
>
>   
Not according to the datasheets which imply the phase of the 100Hz (or
10kHz) burst is adjusted once per second.
This should be very easy to verify if the leading edges of individual
pulses are time stamped with sufficient resolution.
>   My interest is I have a totally new way of locking to the 1PPS pulse
>   that should  improve the performance dramatically.  The  question is
>   would it also work with a 100Hz signal.
>
>   The answer is yes. It would also work with a 10KHz signal,  but this
>   would require  a  bit  more horsepower. I was  planning  on  using a
>   simple inexpensive microprocessor for everything but I don't know if
>   it would be fast enough to do 10KHz.
>
>   But there's not many of those around anymore, are there?
>
>   Best Regards,
>
>   Mike Monett
>
>
>   
Bruce


From tvb at LeapSecond.com  Tue Nov 25 01:16:26 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Mon, 24 Nov 2008 17:16:26 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <07b301c94e19$bb89a9c0$6401a8c0@WSOffice>
Message-ID: <CC68EA4D96984E7E9C4E529E56EB0B01@pc52>

> Besides asking if anyone is using the 100Hz output, I would like to ask 
> why don't the generally available GPSDO use the 100Hz, which can give 
> about 1 ns of certainly with a simple PLL and analog RC filter, instead of 
> the using the 1 sec which has more like 100 ns of uncorrected uncertainty 
> in it and must use a processor?

Where do you get your "1 ns" and "100 ns" figures? Have
you actually measured these values? Also, over what time
average (tau) are you assuming this level of resolution?

> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal results.

For ideal results start with the TC = the tau where the ADEV
of the GPS engine & phase detector crosses the ADEV of the
OCXO. However there are other practical considerations.

> BTW most of what they have plotted is the results of NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation increases in the tracking 
> mode at mid averaging times. The 1 second GPS tracking signal is adding noise, 
> which pretty much makes my point that 1 PPS signal is not so good to use 
> if you want good fast results.
> 
> Warren

At short averaging intervals when there is a phase difference
it is easy for the GPSDO to assume the OCXO is stable and
the GPS engine has noise. So you average more samples.

At long averaging intervals when there is a phase difference
is it easy for the GPSDO to assume the GPS engine is more
correct and the OCXO has drifted. So you steer using EFC.

At the tau of the ideal TC, the GPSDO sees an average phase
difference but can't totally blame either the OCXO or GPS for
the error. By definition at this tau, half the noise is due to each
subsystem. Hence you nearly always see an ADEV hump that
goes above where you'd really like it. Best case sqrt(2).

The ADEV hump itself is not indication of a mistuned TC; it is
an indication that the GPSDO is working correctly.

You can move the hump left and right and distort its shape by
changing the TC.

In practice I suspect most commercial GPSDO have a TC that
appears too low for your liking. I can discuss why if you wish.

/tvb



From bruce.griffiths at xtra.co.nz  Tue Nov 25 01:17:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 14:17:16 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>
References: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>
Message-ID: <492B521C.7040404@xtra.co.nz>

WarrenS wrote:
> Bruce
>
>  My Oncore's phase is definitely different on each 100Hz cycle. A digital storage scope shows it very well.
>
> Some things that come to mine:
>
> 1) Not all Oncores are the same, mine is an old 8 channel one. (Don't remember the number, it is the one with the sawtooth capability)
> 2) The actual error amount is updated each 1 sec and the processors still dithers that to get the 100 Hz to be close to the correct value
> 3) Other TBD 
>
> Warren
> *******************
>
>   
Warren

This raises some questions on the interpreatation of the M12+T and
Jupiter-T receiver specs.

Some measurements are required in order to settle the questions once and
for all.

Can anyone that has either or both of these receivers make the required
measurements?
I have both receivers, but no way of making the required measurements
(timestamping the leading edge transitions of the 100Hz or 10kHz edges
using a digital scope or other means).


Bruce


From magnus at rubidium.dyndns.org  Tue Nov 25 01:29:14 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Tue, 25 Nov 2008 02:29:14 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <20081124152247.DCDB0E91529@mail.ebirds.it>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
Message-ID: <492B54EA.5070301@rubidium.dyndns.org>

Marco IK1ODO -2 skrev:
> Hi all,
> 
> I have to carry a 10 MHz standard frequency signal inside an EMC 
> screened room via fiber optic cable.
> 
> Not willing to re-invent the wheel, do something like an optical 
> standard frequency link exist on the market?

Yes. I know of several commecial systems. If you only need to do a short 
jump, then using fairly basic E/O-O/E equipment should work well 
enought. It all depends if you want/can to roll your own or need to buy 
a finished product (aka "buy this, and you will be fine!").

Stay of plastic "fiber" if you can. Go multimode at least.

> I think it is possible to use standard 100MB LAN transceivers, and 
> POF. Phase noise requirements
> are not very stringent, and the distance is in the order of some tens 
> of meters.

Cheers,
Magnus


From shoppa at trailing-edge.com  Tue Nov 25 01:31:22 2008
From: shoppa at trailing-edge.com (Tim Shoppa)
Date: Mon, 24 Nov 2008 20:31:22 -0500
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <E1L4lRy-0003ZU-C4@meow.febo.com>
References: <mailman.297.1227569283.2542.time-nuts@febo.com>
	<E1L4lRy-0003ZU-C4@meow.febo.com>
Message-ID: <20081125013122.19C26BA4D7C@mini-me.trailing-edge.com>

Bruce wrote:
> Analog time  constants of several hours  are  generally considered
> impractical due  to  the  lack of  suitable  low  noise components
> principally high value resistors and capacitors.
> So how do you propose to get around this with an analog control loop?

Not too many years ago, high-impedance op-amps and teflon capacitors
were the way to do this.

The op-amp companies had application notes discussing "soakage"/dielectric
absorption in these circuits.

Tim.


From tvb at LeapSecond.com  Tue Nov 25 01:33:25 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Mon, 24 Nov 2008 17:33:25 -0800
Subject: [time-nuts] 10 MHz over optical fiber?
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es><20081124152247.DCDB0E91529@mail.ebirds.it>
	<492B54EA.5070301@rubidium.dyndns.org>
Message-ID: <2BFB5AF2EF724F709CC612D2AF20876A@pc52>

> Yes. I know of several commecial systems. If you only need to do a short 
> jump, then using fairly basic E/O-O/E equipment should work well 
> enought. It all depends if you want/can to roll your own or need to buy 
> a finished product (aka "buy this, and you will be fine!").

Magnus, what's the typical noise floor, tempco or drift of cheap
(i.e., non JPL-level) fiber distribution systems like this? Is it less
than regular coax, or phase stabilized heliax? At 100 m lengths?

/tvb



From tvb at LeapSecond.com  Tue Nov 25 01:33:43 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Mon, 24 Nov 2008 17:33:43 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>
	<492B521C.7040404@xtra.co.nz>
Message-ID: <C889ACFE54864AC3A8100ECD7D365294@pc52>

> This raises some questions on the interpreatation of the M12+T and
> Jupiter-T receiver specs.
> 
> Some measurements are required in order to settle the questions once and
> for all.
> 
> Can anyone that has either or both of these receivers make the required
> measurements?

We know the sawtooth correction message only comes once
a second, for both receivers, right? That may be a clue.

/tvb



From didier at cox.net  Tue Nov 25 01:53:44 2008
From: didier at cox.net (Didier Juges)
Date: Mon, 24 Nov 2008 19:53:44 -0600
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>
References: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>
Message-ID: <F34E66D2BDAB4B9AB9B251E7342406F5@d400>

Warren,

This is what I believe, feel free to set me straight :-)

The 100Hz is done by synthesis from the GPS receiver's crystal oscillator,
which is usually not on a harmonic of 100Hz, at least not precisely (cheap
crystal) so the receiver will usually generate each pulse to the best of
it's ability to line up to 100Hz (so these will have somewhat deterministic
jitter due to the difference between 100Hz and the divided crystal), and
only once per second will try to align the average pulse train to GPS. There
is pure jitter 99 times out of a hundred, and actual correction the 1/100
time.  The advantage is that the once-per-second correction is burried under
(spread by would be a better term) a fair amount of 100Hz noise, so it's
probably easier to filter, allowing the use of a faster filter than a 1 PPS
output for the same level of 1 PPS attenuation. You can't use the scope to
determine if the jitter is pure jitter or a GPS correction, but I bet a TIC
feeding a PC would.

The point is that older receivers in particular simply don't have the
horseower to update the timing solutions 100 times/second, or 10,000 times
per second. 

Didier KO4BB

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of WarrenS
Sent: Monday, November 24, 2008 6:48 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] GPSDO using 100Hz

Bruce

 My Oncore's phase is definitely different on each 100Hz cycle. A digital
storage scope shows it very well.

Some things that come to mine:

1) Not all Oncores are the same, mine is an old 8 channel one. (Don't
remember the number, it is the one with the sawtooth capability)
2) The actual error amount is updated each 1 sec and the processors still
dithers that to get the 100 Hz to be close to the correct value
3) Other TBD 

Warren
*******************

Mike Monett wrote:
>  Warren
>
>   Ok, it seems they are calculating the best time for each 100Hz pulse
>   individually. That makes life a bit easier for a PLL.
>
>   
Not according to the datasheets which imply the phase of the 100Hz (or
10kHz) burst is adjusted once per second.
This should be very easy to verify if the leading edges of individual pulses
are time stamped with sufficient resolution.
>   My interest is I have a totally new way of locking to the 1PPS pulse
>   that should  improve the performance dramatically.  The  question is
>   would it also work with a 100Hz signal.
>
>   The answer is yes. It would also work with a 10KHz signal,  but this
>   would require  a  bit  more horsepower. I was  planning  on  using a
>   simple inexpensive microprocessor for everything but I don't know if
>   it would be fast enough to do 10KHz.
>
>   But there's not many of those around anymore, are there?
>
>   Best Regards,
>
>   Mike Monett
>
>
>   
Bruce

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.


--
No virus found in this incoming message.
Checked by AVG. 
Version: 7.5.549 / Virus Database: 270.9.9/1809 - Release Date: 11/24/2008
9:03 AM




From tomknox at nist.gov  Tue Nov 25 01:55:32 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Mon, 24 Nov 2008 20:55:32 -0500
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492B54EA.5070301@rubidium.dyndns.org>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
	<492B54EA.5070301@rubidium.dyndns.org>
Message-ID: <20081124205532.14026fn33loma7mc@webmail.nist.gov>

Hi;
This may fit your needs, Wenzel made a 10MHz reference that was  
disciplined thru fiber. I am currently using one. It could be easily  
modified to use battery power. It had very low phase noise.
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting "Magnus Danielson" <magnus at rubidium.dyndns.org>:

> Marco IK1ODO -2 skrev:
>> Hi all,
>>
>> I have to carry a 10 MHz standard frequency signal inside an EMC
>> screened room via fiber optic cable.
>>
>> Not willing to re-invent the wheel, do something like an optical
>> standard frequency link exist on the market?
>
> Yes. I know of several commecial systems. If you only need to do a short
> jump, then using fairly basic E/O-O/E equipment should work well
> enought. It all depends if you want/can to roll your own or need to buy
> a finished product (aka "buy this, and you will be fine!").
>
> Stay of plastic "fiber" if you can. Go multimode at least.
>
>> I think it is possible to use standard 100MB LAN transceivers, and
>> POF. Phase noise requirements
>> are not very stringent, and the distance is in the order of some tens
>> of meters.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



From warrensjmail-one at yahoo.com  Tue Nov 25 04:18:45 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 20:18:45 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <02cf01c94eb4$a14e68c0$6401a8c0@WSOffice>
Message-ID: <02f401c94eb4$e8fe9cd0$6401a8c0@WSOffice>

Didier

Nicely put.
I'd guess there is a good chance you are mosly correct, In any case correct about the end effect.
(The 100 Hz Phase Jitter is not what would normally be called 'pure' jitter or noise) 
Some day I'll look closer to see what is happening in more detail, but for now at least, 
what I'm doing works for me, and I have taken advantages of what  IT  is doing 
for whatever reason it may have for doing it.

The Jitter is NOT Random Jitter. View a plot of the 1 Hz correction phase sawtooth error signal,  
Mine, as do all I think,  has about a 4 second nominal sawtooth waveform period that slows down to zero Hz, 
then reverses direction and then starts increasing again giving a waveform from near DC  back to a 1 second period.
(note that a sawtooth of DC and one with a period of 1 second is in fact the same thing when sampled at 1 Hz) 
Now the interesting thing is that a plot of the the 100 Hz Phase error jitter signal looks just like the 1 Hz plot, 
except it has a nominal 4 to 10 Hz sawtooth waveform on it, instead of the 1/4 Hz sawtooth.
It also goes thru the same FM cycle, the only difference is that the nominal freq is about 50 times greater.
I also  found interesting that the cause of the 1 Hz sawtooth wave form appears to be totally due to aliasing.
That is there is a nominal say 4 to 5 Hz sawtooth on the 100 Hz that is non synchronous (most of the time) to the 1 Hz 
and when sampled at 1 Hz, only a single sample of the 100 Hz waveform value is output. 
In effecting this causes the 1Hz output to be the product of the beating between the 1 Hz signal and the 4 to 10 Hz 
nominal sawtooth that is on the 100 Hz waveform. 

The net effect to a Phase  filter is that with either the 1 Hz or the 100 Hz output rate, the sawtooth wave form, 
its shape, its peak to peak values are about the same in either mode, the only difference is that one sawtooth is at a 
nominal 1/4 Hz and one is at a nominal 5 Hz.   If you understand and accept that,  It becomes real clear why the 
100 Hz signal is so much easer to filter.
What starts out as about a +- 50 ns peak to peak phase noise, can be averaged down to around 1 ns phase jitter by averaging
 (filtering) from 100 to 200 samples. This works most of the time, i.e as long as there are 10 + cycles of the sawtooth in the sampling period.

Note: this is the results from my old 8 channel Oncore receiver running in fixed mode at 1Hz  and 100Hz. I have little or no experience using other receivers.
  
Warren

*******************
Warren,

This is what I believe, feel free to set me straight :-)

The 100Hz is done by synthesis from the GPS receiver's crystal oscillator,
which is usually not on a harmonic of 100Hz, at least not precisely (cheap
crystal) so the receiver will usually generate each pulse to the best of
it's ability to line up to 100Hz (so these will have somewhat deterministic
jitter due to the difference between 100Hz and the divided crystal), and
only once per second will try to align the average pulse train to GPS. There
is pure jitter 99 times out of a hundred, and actual correction the 1/100
time.  The advantage is that the once-per-second correction is burried under
(spread by would be a better term) a fair amount of 100Hz noise, so it's
probably easier to filter, allowing the use of a faster filter than a 1 PPS
output for the same level of 1 PPS attenuation. You can't use the scope to
determine if the jitter is pure jitter or a GPS correction, but I bet a TIC
feeding a PC would.

The point is that older receivers in particular simply don't have the
horseower to update the timing solutions 100 times/second, or 10,000 times
per second. 

Didier KO4BB

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of WarrenS
Sent: Monday, November 24, 2008 6:48 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] GPSDO using 100Hz

Bruce

My Oncore's phase is definitely different on each 100Hz cycle. A digital
storage scope shows it very well.

Some things that come to mine:

1) Not all Oncores are the same, mine is an old 8 channel one. (Don't
remember the number, it is the one with the sawtooth capability)
2) The actual error amount is updated each 1 sec and the processors still
dithers that to get the 100 Hz to be close to the correct value
3) Other TBD 

Warren
*******************

From bruce.griffiths at xtra.co.nz  Tue Nov 25 04:50:09 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Tue, 25 Nov 2008 17:50:09 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <C889ACFE54864AC3A8100ECD7D365294@pc52>
References: <027c01c94e97$85aaa0b0$6401a8c0@WSOffice>	<492B521C.7040404@xtra.co.nz>
	<C889ACFE54864AC3A8100ECD7D365294@pc52>
Message-ID: <492B8401.6070306@xtra.co.nz>

Tom Van Baak wrote:
>> This raises some questions on the interpreatation of the M12+T and
>> Jupiter-T receiver specs.
>>
>> Some measurements are required in order to settle the questions once and
>> for all.
>>
>> Can anyone that has either or both of these receivers make the required
>> measurements?
>>     
>
> We know the sawtooth correction message only comes once
> a second, for both receivers, right? That may be a clue.
>
> /tvb
>
>
>   
Tom

The picket fence technique can be used to timestamp the leading edges of
the 100Hz (or 10kHz for the Jupiter -T) outputs.
The 100Hz signal being used to start the TIC whilst a 1kHz signal
derived from a low noise OCXO output is used to STOP the TIC.
Sawtooth error should then be able to be derived from the measurements
after removing phase wraps.
ADEV could then be plotted for Tau ranging from 10ms to say 100s.

With a 10KHz signal the STOP input frequency would need to be around
100KHz or so.
Any known frequency >= 2*(Start frequency) will suffice.

Bruce


From warrensjmail-one at yahoo.com  Tue Nov 25 05:07:43 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 21:07:43 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <046c01c94ebb$c01c2290$6401a8c0@WSOffice>

 Warren Answers and comments to /tvb  below in the text.

Besides asking if anyone is using the 100Hz output, I would like to ask 
>> why don't the generally available GPSDO use the 100Hz, which can give 
>> about 1 ns of certainly with a simple PLL and analog RC filter, instead of 
>> the using the 1 sec which has more like 100 ns of uncorrected uncertainty 
>> in it and must use a processor?

>Where do you get your "1 ns" and "100 ns" figures? Have
>you actually measured these values? Also, over what time
>average (tau) are you assuming this level of resolution?

1 ns and 100ns are measured Values of the nominal phase Jitter over a few seconds.
Long enough to let the Phase cycle thru a couple of its sawtooth cycles, 
and short enough so as not to include the added GSP signal errors.
The values are pretty much independent of time, as long as the time is not too long or too short.
The GPS signal errors that I see are around 10 ns over about a 10 + seconds period, 
with short excursions (no more than a few seconds) of up to an additional to 30 ns.  


> Also I should comment that on  LeapSecond.com 
> http://www.leapsecond.com/pages/gpsdo/
> you stated "where the ADEV for various GPSDO remains below 1E-11 
> over the Tau range of [0.1s, 100,000s]. This Tau has NOTHING to do with 
> the tracking time constant that the GPSDO is set to, which is usually 
> recommended to be set for a TC of several hours for optimal results.

>For ideal results start with the TC = the tau where the ADEV
>of the GPS engine & phase detector crosses the ADEV of the
>OCXO. However there are other practical considerations.

Yes we agree on this, and this is somewhere between an hour and a day for good osc.
(and as short as a few seconds for some special applications).

> BTW most of what they have plotted is the results of NOT setting the GPSDO 
> tracking TC slow enough. This is why the Allan Deviation increases in the tracking 
> mode at mid averaging times. The 1 second GPS tracking signal is adding noise, 
> which pretty much makes my point that 1 PPS signal is not so good to use 
> if you want good fast results.
> 
> Warren

At short averaging intervals when there is a phase difference
it is easy for the GPSDO to assume the OCXO is stable and
the GPS engine has noise. So you average more samples.

At long averaging intervals when there is a phase difference
is it easy for the GPSDO to assume the GPS engine is more
correct and the OCXO has drifted. So you steer using EFC.

At the tau of the ideal TC, the GPSDO sees an average phase
difference but can't totally blame either the OCXO or GPS for
the error. By definition at this tau, half the noise is due to each
subsystem. Hence you nearly always see an ADEV hump that
goes above where you'd really like it. Best case sqrt(2).

The ADEV hump itself is not indication of a mistuned TC; it is
an indication that the GPSDO is working correctly.

You can move the hump left and right and distort its shape by
changing the TC.

In practice I suspect most commercial GPSDO have a TC that
appears too low for your liking. I can discuss why if you wish.


/tvb

Thanks, Good information to remember.
Note that in many of the units shown,  the tracking hump is more like 4 to one instead of 1.5 to one.
I would love to know the  'can Discuss more' reasons

Warren

From warrensjmail-one at yahoo.com  Tue Nov 25 05:29:59 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Mon, 24 Nov 2008 21:29:59 -0800
Subject: [time-nuts]  GPSDO using 100Hz
Message-ID: <048401c94ebe$dc8f6e70$6401a8c0@WSOffice>

Tom Van Baak wrote:
>> This raises some questions on the interpreatation of the M12+T and
>> Jupiter-T receiver specs.
>>
>> Some measurements are required in order to settle the questions once and
>> for all.
>>
>> Can anyone that has either or both of these receivers make the required
>> measurements?
>>     
>
> We know the sawtooth correction message only comes once
> a second, for both receivers, right? That may be a clue.
>
> /tvb
>
>
>   
Tom

The picket fence technique can be used to timestamp the leading edges of
the 100Hz (or 10kHz for the Jupiter -T) outputs.
The 100Hz signal being used to start the TIC whilst a 1kHz signal
derived from a low noise OCXO output is used to STOP the TIC.
Sawtooth error should then be able to be derived from the measurements
after removing phase wraps.
ADEV could then be plotted for Tau ranging from 10ms to say 100s.

With a 10KHz signal the STOP input frequency would need to be around
100KHz or so.
Any known frequency >= 2*(Start frequency) will suffice.

Bruce
****************
Bruce

OR on the 100Hz signal, not the 10Khz,  
can I use a digital scope that can log data time values between say the rise time and a marker, for each sweep.
For the most part, the phase jitter on for the Oncore can be seen easily at 100 Hz output by just waiting until the sawtooth jitter frequency is down to below about 5 Hz.
Something else you said, I did not know was that the 100rd pulse is time stamped by extending it length, Something I've always seen, but did not know the extended time was anything more than random. Next time I have it scoped, I'll check and see if the 1 Hz reported error is for that pulse while in the 100 Hz mode.

Warren



From yuri at ostry.ru  Tue Nov 25 11:31:16 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Tue, 25 Nov 2008 14:31:16 +0300
Subject: [time-nuts] Oncore question
In-Reply-To: <001901c94e7c$b1103370$ad00a8c0@Morris1>
References: <001901c94e7c$b1103370$ad00a8c0@Morris1>
Message-ID: <684609330.20081125143116@ostry.ru>

Hello,

Tuesday, November 25, 2008, 0:36:20, Morris Odell wrote:

M> In the meantime the discussion prompted a baord redesign to find some
M> real estate for a Li cell :-)

Not necessarily... You can always get (or make) batery holder with
wires and affix it with piece of adhesive foam or velcro to a
convenient place nearby.



-- 
Best regards,
 Yuri                          mailto:yuri at ostry.ru



From tractorb at ihug.co.nz  Tue Nov 25 11:48:31 2008
From: tractorb at ihug.co.nz (Dave Brown)
Date: Wed, 26 Nov 2008 00:48:31 +1300
Subject: [time-nuts] Wavetek 3010
References: <mailman.238.1227300160.2542.time-nuts@febo.com>
	<22830685-98BB-43BC-A219-04A8679AC723@hughes.net>
Message-ID: <2a3b01c94ef3$bd802080$7900a8c0@athlon1200>

There should still be a 3001 manual around the town somewhere- I sold 
two or three dead 'uns plus a copy of the manual about three years 
back to a local-likely he still has it/them stashed away. Think it was 
Doug, ZL2BCF over at Ch West.

DaveB, CH CH, NZ



----- Original Message ----- 
From: "Richard Moore" <richiem at hughes.net>
To: <time-nuts at febo.com>
Sent: Saturday, November 22, 2008 12:39 PM
Subject: Re: [time-nuts] Wavetek 3010


>
> On Nov 21, 2008, at 12:42 PM, time-nuts-request at febo.com wrote:
>
>> Message: 2
>> Date: Sat, 22 Nov 2008 01:21:16 +1300
>> From: "Steve Rooke" <sar10538 at gmail.com>
>> Subject: [time-nuts] Off-Topic: On Wavetek 3010 lever thumbwheel
>> switches and manual
>> To: "Discussion of precise time and frequency measurement"
>> <time-nuts at febo.com>
>> Message-ID:
>> <1231b6a80811210421x30c58cbt22ea48e2d6906055 at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> snip>>>>
>
>> I've also trawled the Net to find a freely downloadable manual 
>> (user
>> and servicing) but to no avail. If anyone has a copy or could point 
>> me
>> in the right direction, I would be most grateful.
>>
>> 73, Steve
>> --
>> Steve Rooke - ZL3TUV & G8KVD
>> Omnium finis imminet
>>
> Steve, I've got a Wavetek 3001/3002 manual that may get you near to
> where you need to go. Contact me at richiem at hughes.net, and let 
> me
> know if that's something you can use. I'd be happy to loan it to you
> for copying.
>
> Best,
> Dick Moore
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


--------------------------------------------------------------------------------



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Version: 8.0.175 / Virus Database: 270.9.9/1803 - Release Date: 
21/11/2008 09:37



From iovane at inwind.it  Tue Nov 25 14:07:54 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Tue, 25 Nov 2008 15:07:54 +0100
Subject: [time-nuts] Eclipses and atomic clocks
Message-ID: <KAW796$300ACD62328C632CCF95950DBB7AF178@libero.it>

Time-nuts,

I have to admit that I have an interest in gravitational 
anomalies.

If anybody out there has nothing better to do, here is the 
stuff to spend some minutes.
In early 90's a Chinese researcher (Zhou) opened a debate 
claiming to have observed anomalous behaviour on atomic 
clocks during some solar eclipses (Ref 1).

On 1999 a group of German researchers published a report 
claiming to have observed nothing anomalous in the comparison 
of 4 atomic clocks (Nature magazine, Ref 2).
This report seems to have closed the debate among insiders.
The report is also available online at 
http://www.mpq.mpg.de/~haensch/eclipse/full.html 
where they kindly offer the complete data file of their 
records, covering 23 days, for further insights.
I've downloaded the file and plotted their data. The plot is 
uploaded at
http://xoomer.alice.it/iovane/clocks.htm
Each curve is the comparison of two atomic clocks, as 
mentioned in the graph itself.
In the graph the x axis is the time in days centered on the 
day of eclipse, and the y axis is the relative time delay in 
nanoseconds cunulated by each couple of clocks.
You time-nuts don't need any more explanations.

My question is:
Did any of the clocks run unlocked? If any, what of them?

Thanks,
Antonio I8IOV

Ref 1:
[Zhou, S. W.; Huang, B. J., "Abnormalities of the time 
comparisons of atomic clocks during the solar eclipses", 
Nuovo Cimento C, vol. 15 C, no. 2, Mar.-Apr. 1992, p. 133-
137.]

Ref 2:
http://www.nature.com/nature/journal/v402/n6763/abs/402749a0.html




From iovane at inwind.it  Tue Nov 25 15:54:55 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Tue, 25 Nov 2008 16:54:55 +0100
Subject: [time-nuts] Eclipses and atomic clocks
Message-ID: <KAWC7J$8843CE88C7365B1153DBC87218842B41@libero.it>

I got some private answers.
Sorry, I've been concise not to bias your thoughts.
Only, I would precise that for "unlocked" I mean a clock in
which the crystal is free running not locked to Rb or Cs, and not to lock between clocks,
Antonio I8IOV

> Time-nuts,
> 
> I have to admit that I have an interest in gravitational 
> anomalies.
> 
> If anybody out there has nothing better to do, here is the 
> stuff to spend some minutes.
> In early 90's a Chinese researcher (Zhou) opened a debate 
> claiming to have observed anomalous behaviour on atomic 
> clocks during some solar eclipses (Ref 1).
> 
> On 1999 a group of German researchers published a report 
> claiming to have observed nothing anomalous in the comparison 
> of 4 atomic clocks (Nature magazine, Ref 2).
> This report seems to have closed the debate among insiders.
> The report is also available online at 
> http://www.mpq.mpg.de/~haensch/eclipse/full.html 
> where they kindly offer the complete data file of their 
> records, covering 23 days, for further insights.
> I've downloaded the file and plotted their data. The plot is 
> uploaded at
> http://xoomer.alice.it/iovane/clocks.htm
> Each curve is the comparison of two atomic clocks, as 
> mentioned in the graph itself.
> In the graph the x axis is the time in days centered on the 
> day of eclipse, and the y axis is the relative time delay in 
> nanoseconds cunulated by each couple of clocks.
> You time-nuts don't need any more explanations.
> 
> My question is:
> Did any of the clocks run unlocked? If any, what of them?
> 
> Thanks,
> Antonio I8IOV
> 
> Ref 1:
> [Zhou, S. W.; Huang, B. J., "Abnormalities of the time 
> comparisons of atomic clocks during the solar eclipses", 
> Nuovo Cimento C, vol. 15 C, no. 2, Mar.-Apr. 1992, p. 133-
> 137.]
> 
> Ref 2:
> http://www.nature.com/nature/journal/v402/n6763/abs/402749a0.html
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From iovane at inwind.it  Tue Nov 25 16:52:06 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Tue, 25 Nov 2008 17:52:06 +0100
Subject: [time-nuts] Eclipses and atomic clocks
Message-ID: <KAWEUU$7BF3894BDE3AF9A2FD158C5CE4970AD7@libero.it>

Time-nuts,
I was wrong with my interpretation.
The clocks were all working ok.
Thanks.
Antonio I8IOV

> I got some private answers.
> Sorry, I've been concise not to bias your thoughts.
> Only, I would precise that for "unlocked" I mean a clock in
> which the crystal is free running not locked to Rb or Cs, and not to lock between clocks,
> Antonio I8IOV
> 
> > Time-nuts,
> > 
> > I have to admit that I have an interest in gravitational 
> > anomalies.
> > 
> > If anybody out there has nothing better to do, here is the 
> > stuff to spend some minutes.
> > In early 90's a Chinese researcher (Zhou) opened a debate 
> > claiming to have observed anomalous behaviour on atomic 
> > clocks during some solar eclipses (Ref 1).
> > 
> > On 1999 a group of German researchers published a report 
> > claiming to have observed nothing anomalous in the comparison 
> > of 4 atomic clocks (Nature magazine, Ref 2).
> > This report seems to have closed the debate among insiders.
> > The report is also available online at 
> > http://www.mpq.mpg.de/~haensch/eclipse/full.html 
> > where they kindly offer the complete data file of their 
> > records, covering 23 days, for further insights.
> > I've downloaded the file and plotted their data. The plot is 
> > uploaded at
> > http://xoomer.alice.it/iovane/clocks.htm
> > Each curve is the comparison of two atomic clocks, as 
> > mentioned in the graph itself.
> > In the graph the x axis is the time in days centered on the 
> > day of eclipse, and the y axis is the relative time delay in 
> > nanoseconds cunulated by each couple of clocks.
> > You time-nuts don't need any more explanations.
> > 
> > My question is:
> > Did any of the clocks run unlocked? If any, what of them?
> > 
> > Thanks,
> > Antonio I8IOV
> > 
> > Ref 1:
> > [Zhou, S. W.; Huang, B. J., "Abnormalities of the time 
> > comparisons of atomic clocks during the solar eclipses", 
> > Nuovo Cimento C, vol. 15 C, no. 2, Mar.-Apr. 1992, p. 133-
> > 137.]
> > 
> > Ref 2:
> > http://www.nature.com/nature/journal/v402/n6763/abs/402749a0.html
> > 
> > 
> > 
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> > 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From bill at iaxs.net  Tue Nov 25 18:39:41 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Tue, 25 Nov 2008 12:39:41 -0600
Subject: [time-nuts] Eclipses and atomic clocks
In-Reply-To: <KAWEUU$7BF3894BDE3AF9A2FD158C5CE4970AD7@libero.it>
References: <KAWEUU$7BF3894BDE3AF9A2FD158C5CE4970AD7@libero.it>
Message-ID: <342ED13391FC45E9A3E421C5BF4D62D2@cyrus>

There is an article in the Nov 22, 2008, issue of Science News
(www.sciencenews.org) about variations in the decay rate of 
radioactive atoms. The title is "Half-life (More or Less)"
where "more or less" is an idiom for "approximately."

There is no explanation for the observed variation. As you might
expect, not everyone sees the variation, but Brookhaven in the
US and PTB in Germany observed a few parts per 1000 annual
variation. One possibility is the distance from the sun. Another
is the change in seasons.

Peter Cooper, of Fermi Lab, says, "Every experimentalist knows
that the apparatus, or at least your understanding of it, is
always at fault until demonstrated otherwise." He also says,
"Nature is really unmoved by what I, or anyone else, believes."

Bill Hawkins



From p.boven at xs4all.nl  Tue Nov 25 19:15:48 2008
From: p.boven at xs4all.nl (Paul Boven)
Date: Tue, 25 Nov 2008 20:15:48 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
Message-ID: <492C4EE4.3050508@xs4all.nl>

Hi everyone,

In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, Marco IK1ODO -2
writes:
>Hi all,
>
>I have to carry a 10 MHz standard frequency signal inside an EMC 
>screened room via fiber optic cable.
>
>Not willing to re-invent the wheel, do something like an optical 
>standard frequency link exist on the market?
>I think it is possible to use standard 100MB LAN transceivers, and 
>POF. Phase noise requirements
>are not very stringent, and the distance is in the order of some tens 
>of meters.

I'm looking into something similar: transmitting an H-Maser signal
(probably 10MHz) over some 34km using CWDM SFPs. At first glance this
seems fairly uncomplicated: get some SFPs, and SFP connector + cage. Use
a fast opamp/differential driver to drive the transmitting SFP, and use
a similar setup at the other end to transform the received data back to
50 ohm unbalanced. How feasible would such a setup be?
Possible problems might be that a 10MHz squarewave is simply too 'slow'
to be transmitted by an SFP, which expects 1.25Gb/s 8/10 encoded data.
Another interesting question would be how much jitter/noise such a setup
would add?

Regards, Paul Boven.


From smace at intt.net  Tue Nov 25 19:42:07 2008
From: smace at intt.net (Scott Mace)
Date: Tue, 25 Nov 2008 13:42:07 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492C4EE4.3050508@xs4all.nl>
References: <492C4EE4.3050508@xs4all.nl>
Message-ID: <492C550F.3030701@intt.net>

In looking at the off-the-shelf boxes, jitter seemed to vary from ps range
to tens of ns.  Also, how stable is the 34km of fiber...  One of the
manufacturers I looked at had a 1550nm option, so it's probably not a stretch
to get it on a 100GHz ITU grid channel or other CWDM channel.

	Scott

Paul Boven wrote:
> Hi everyone,
> 
> In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, Marco IK1ODO -2
> writes:
>> Hi all,
>>
>> I have to carry a 10 MHz standard frequency signal inside an EMC 
>> screened room via fiber optic cable.
>>
>> Not willing to re-invent the wheel, do something like an optical 
>> standard frequency link exist on the market?
>> I think it is possible to use standard 100MB LAN transceivers, and 
>> POF. Phase noise requirements
>> are not very stringent, and the distance is in the order of some tens 
>> of meters.
> 
> I'm looking into something similar: transmitting an H-Maser signal
> (probably 10MHz) over some 34km using CWDM SFPs. At first glance this
> seems fairly uncomplicated: get some SFPs, and SFP connector + cage. Use
> a fast opamp/differential driver to drive the transmitting SFP, and use
> a similar setup at the other end to transform the received data back to
> 50 ohm unbalanced. How feasible would such a setup be?
> Possible problems might be that a 10MHz squarewave is simply too 'slow'
> to be transmitted by an SFP, which expects 1.25Gb/s 8/10 encoded data.
> Another interesting question would be how much jitter/noise such a setup
> would add?
> 
> Regards, Paul Boven.
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From james.p.lux at jpl.nasa.gov  Tue Nov 25 20:03:15 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Tue, 25 Nov 2008 12:03:15 -0800
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492C550F.3030701@intt.net>
References: <492C4EE4.3050508@xs4all.nl> <492C550F.3030701@intt.net>
Message-ID: <ECE7A93BD093E1439C20020FBE87C47FEB55C30AE9@ALTPHYEMBEVSP20.RES.AD.JPL>

> > I'm looking into something similar: transmitting an H-Maser signal
> > (probably 10MHz) over some 34km using CWDM SFPs. At first
> glance this
> > seems fairly uncomplicated: get some SFPs, and SFP
> connector + cage.
> > Use a fast opamp/differential driver to drive the transmitting SFP,
> > and use a similar setup at the other end to transform the received
> > data back to 50 ohm unbalanced. How feasible would such a setup be?
> > Possible problems might be that a 10MHz squarewave is
> simply too 'slow'
> > to be transmitted by an SFP, which expects 1.25Gb/s 8/10
> encoded data.
> > Another interesting question would be how much jitter/noise such a
> > setup would add?
> >
> > Regards, Paul Boven.
> >



Presumably, you're using a maser because you need good stability over significant time spans (seconds or greater)? Then you probably need some way to compensate for the changes in propagation through the fiber.  That's what the JPL boxes do. They send signals both ways (I don't have it in front of me, but it's possible it's on the same fiber, or at the least, two fibers in close contact, so they're in the same environment) and measure the round trip time.


From gwinn at raytheon.com  Tue Nov 25 20:38:10 2008
From: gwinn at raytheon.com (Joseph M Gwinn)
Date: Tue, 25 Nov 2008 15:38:10 -0500
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <20081125013122.19C26BA4D7C@mini-me.trailing-edge.com>
Message-ID: <OF36B7A696.A548E6A2-ON8525750C.00713611-8525750C.0071504D@mck.us.ray.com>

time-nuts-bounces at febo.com wrote on 11/24/2008 08:31:22 PM:

> Bruce wrote:
> > Analog time  constants of several hours  are  generally considered
> > impractical due  to  the  lack of  suitable  low  noise components
> > principally high value resistors and capacitors.
> > So how do you propose to get around this with an analog control loop?
> 
> Not too many years ago, high-impedance op-amps and teflon capacitors
> were the way to do this.
> 
> The op-amp companies had application notes discussing 
> "soakage"/dielectric
> absorption in these circuits.

One can buy 10 microfarad metallized polypropylene capacitors new for 
about $20 each from Newark et al.  The soakage of polypropylene is very 
small.

Joe Gwinn


From phk at phk.freebsd.dk  Tue Nov 25 22:46:05 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 25 Nov 2008 22:46:05 +0000
Subject: [time-nuts] A loran-C signal movie...
Message-ID: <2007.1227653165@critter.freebsd.dk>


I thought some of you might get a kick out of this too:

I set up a shell-script to snapshot the tek4014 window from my
"AducLoran" receiver every few seconds.

The I managed to get ImageMagick to turn a selection of those images
into an animated gif:

	http://phk.freebsd.dk/AducLoran/animation.gif

The first 100 frames are 4-5 seconds apart, thereafter the rate drops
to 1 frame for each minute.

Here is an initial allan deviation for the receiver, relative to
a free-running FRS-10 Rb:

	http://phk.freebsd.dk/AducLoran/allan_dev.png

The red trace is the averaged off-the-air measurements by the receiver,
the green trace has the linear frequency drift of the Rb removed.

More about the project here:
	http://phk.freebsd.dk/AducLoran/AducLoran-0.2.pdf

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From wittend at wwrinc.com  Tue Nov 25 23:18:53 2008
From: wittend at wwrinc.com (David M. Witten II)
Date: Tue, 25 Nov 2008 17:18:53 -0600
Subject: [time-nuts] A loran-C signal movie...
In-Reply-To: <2007.1227653165@critter.freebsd.dk>
References: <2007.1227653165@critter.freebsd.dk>
Message-ID: <492C87DD.2010705@wwrinc.com>

Very interesting!

I had recently read the information on your website and, having all of 
the necessary pieces, had decided that I wanted to try to duplicate your 
project.  But I was unsure whether it had really worked out to your 
satisfaction and whether you were still using the system.  My questions 
are answered!

Perhaps I will get some time over the holidays to assemble a similar 
system and see if it works here in the remote reaches of the Midwestern US.

Dave Witten


Poul-Henning Kamp wrote:
> I thought some of you might get a kick out of this too:
> 
> I set up a shell-script to snapshot the tek4014 window from my
> "AducLoran" receiver every few seconds.
> 
> The I managed to get ImageMagick to turn a selection of those images
> into an animated gif:
> 
> 	http://phk.freebsd.dk/AducLoran/animation.gif
> 
> The first 100 frames are 4-5 seconds apart, thereafter the rate drops
> to 1 frame for each minute.
> 
> Here is an initial allan deviation for the receiver, relative to
> a free-running FRS-10 Rb:
> 
> 	http://phk.freebsd.dk/AducLoran/allan_dev.png
> 
> The red trace is the averaged off-the-air measurements by the receiver,
> the green trace has the linear frequency drift of the Rb removed.
> 
> More about the project here:
> 	http://phk.freebsd.dk/AducLoran/AducLoran-0.2.pdf
> 
> Poul-Henning
> 


From optomatic at rogers.com  Wed Nov 26 00:39:32 2008
From: optomatic at rogers.com (Patrick)
Date: Tue, 25 Nov 2008 19:39:32 -0500
Subject: [time-nuts] huntron tracker advice & troubleshooting without
	schematic advise
Message-ID: <492C9AC4.3050102@rogers.com>

Hi Everyone

I have consistently had success repairing laboratory instruments(my
small business) when I have a schematic and I have consistently failed
without one, lots of opportunities are slipping threw my fingers.

I want to invest in tools that will help me troubleshoot without a
schematic. I was thinking about getting a Huntron tracker. Has anyone
had any experience with one? Could you feedback?

Are there other tools that have helped you fix circuit boards without a
schematic?

Thanks in advance-Patrick



From brooke at pacific.net  Wed Nov 26 02:20:18 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Tue, 25 Nov 2008 18:20:18 -0800
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
References: <492C9AC4.3050102@rogers.com>
Message-ID: <492CB262.2080502@pacific.net>

Hi Patrick:

I've found in many cases that the problem is related to oxidized electrical 
connections (connectors, switches, printed circuit connectors, etc.) see:
What Goes Wrong
http://www.prc68.com/I/HaT.shtml#Wgw

A Multimeter with Ohms and Diode functions, like the Fluke 87, can check many 
components and has found many things wrong.  In circuit transistor testers are 
faster, see: http://www.prc68.com/I/MTE.shtml#Xistor

I have a Huntron Tracker but haven't used it much, see:
http://www.prc68.com/I/Huntron.shtml
the patents are also linked on that page so you can see how it works.

Have Fun,

Brooke Clarke
http://www.prc68.com

Patrick wrote:
> Hi Everyone
> 
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
> 
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
> 
> Are there other tools that have helped you fix circuit boards without a
> schematic?
> 
> Thanks in advance-Patrick
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From didier at cox.net  Wed Nov 26 02:48:07 2008
From: didier at cox.net (Didier)
Date: Tue, 25 Nov 2008 20:48:07 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492C550F.3030701@intt.net>
References: <492C4EE4.3050508@xs4all.nl> <492C550F.3030701@intt.net>
Message-ID: <1D41E281A3F14FA0B85D3FCDCBC2FD84@didierhp>

By the time you get the signal from the maser through 34 km of fiber optic,
what you get at the end might be not better than a decent GPSDO...

Make sure you go through your drift and jitter budget before commiting.

Didier 

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Mace
> Sent: Tuesday, November 25, 2008 1:42 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10 MHz over optical fiber?
> 
> In looking at the off-the-shelf boxes, jitter seemed to vary 
> from ps range to tens of ns.  Also, how stable is the 34km of 
> fiber...  One of the manufacturers I looked at had a 1550nm 
> option, so it's probably not a stretch to get it on a 100GHz 
> ITU grid channel or other CWDM channel.
> 
> 	Scott
> 
> Paul Boven wrote:
> > Hi everyone,
> > 
> > In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, 
> Marco IK1ODO 
> > -2
> > writes:
> >> Hi all,
> >>
> >> I have to carry a 10 MHz standard frequency signal inside an EMC 
> >> screened room via fiber optic cable.
> >>
> >> Not willing to re-invent the wheel, do something like an optical 
> >> standard frequency link exist on the market?
> >> I think it is possible to use standard 100MB LAN transceivers, and 
> >> POF. Phase noise requirements are not very stringent, and the 
> >> distance is in the order of some tens of meters.
> > 
> > I'm looking into something similar: transmitting an H-Maser signal 
> > (probably 10MHz) over some 34km using CWDM SFPs. At first 
> glance this 
> > seems fairly uncomplicated: get some SFPs, and SFP 
> connector + cage. 
> > Use a fast opamp/differential driver to drive the transmitting SFP, 
> > and use a similar setup at the other end to transform the received 
> > data back to 50 ohm unbalanced. How feasible would such a setup be?
> > Possible problems might be that a 10MHz squarewave is 
> simply too 'slow'
> > to be transmitted by an SFP, which expects 1.25Gb/s 8/10 
> encoded data.
> > Another interesting question would be how much jitter/noise such a 
> > setup would add?
> > 
> > Regards, Paul Boven.
> > 
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> > 
> > 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From wb6bnq at cox.net  Wed Nov 26 04:04:02 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Tue, 25 Nov 2008 20:04:02 -0800
Subject: [time-nuts] huntron tracker advice & troubleshooting
 withoutschematic advise
References: <492C9AC4.3050102@rogers.com>
Message-ID: <492CCAB2.31252283@cox.net>

Patrick,

Please do not take this the wrong way, but having all the test equipment in the
world is not going to help you troubleshoot if you do not have the foundation to
begin with.  The foundation I am referring to is both educational and
experience.  Obviously, experience takes time and is a gradual accumulation of
knowledge from trial and error using tools learned through education.  That said,
one cannot expect to know it all and thus not everything is going to get "fixed"
without some sort of assistance whether it is in the form of schematics or other
people helping with suggestions (i.e., learning from experience).

The more you grasp and understand the general nature of circuits and their
application, the broader your base of knowledge will become.  That ever growing
base of knowledge is the primary tool for attempting repairs when the normal
information is not available.

So before you spend tons of money on what may be ill advised purchases, I would
consider the above in determining the proper course of action.  Obviously having
basic test equipment is important; more importantly is knowing how to properly
apply such equipment.

One last point.  Read, read, and read !  There is a vast wealth of information
available from the IC producers and "some" equipment manufacturers, most notable
Hewlett Packard.  This is in the form of service manuals, component
specifications, application notes and white papers.  Sure, the appnotes and White
papers get quite complicated at times, but you can still grasp some form of
understanding from them.  The spec sheets for various ICs have quite a bit of
educational value, especially from the better companies like Analog Devices,
Maxim and others like them.

Bill....WB6BNQ


Patrick wrote:

> Hi Everyone
>
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
>
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
>
> Are there other tools that have helped you fix circuit boards without a
> schematic?
>
> Thanks in advance-Patrick
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From magnus at rubidium.dyndns.org  Wed Nov 26 08:13:10 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Wed, 26 Nov 2008 09:13:10 +0100
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
References: <492C9AC4.3050102@rogers.com>
Message-ID: <492D0516.7000800@rubidium.dyndns.org>

Patrick wrote:
> Hi Everyone
>
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
>
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
>
> Are there other tools that have helped you fix circuit boards without a
> schematic?
The Huntron tracker does not solve your basic problem of not having the 
schematics, rather it helps you for some of the analysis when you do 
have a schematic. We do alot of analysis at work and the trackers sits 
there idling on a shelf, since we rarely have problems at which we have 
a short on a power-plane or a slightly broken semiconductor. Only a 
handfull of problem would apply. We have alot of other usefull tools 
instead.

For you to buy a Huntron tracker you should do it for the right reason, 
that it applies to your kind of problems and would aid in locating 
problems and measure basic semiconductor behaviour.

Now, Huntron claims that it will aid on undocumented boards. It will to 
a certain extent, since it is agnostic to the design as such, it just 
measures electrical properties. However a Fluke multimeter is similarly 
agnostic and may do similar but not all of the tests the trackers do. 
Also, to some degree a tracker becomes somewhat difficult to use in some 
cases without a functional board alongside for reference.

I don't want to say it is a bad tool, it isn't. I just want to kill your 
overly high expectations. Only then you can buy one and feel happy about 
it in the long run. What the tracker does as a basic measurement tool is 
to do I/V diagrams. You can make your own I/V setup by using an 
(preferably analog) oscilloscope in X/Y setup, a simple diffrential amp 
(4 resistors and an op-amp in a cook-book diffrential amp setup), a 
resistor for current-to-voltage conversion and an audio generator 
producing a sine. This is sufficient to get you started and try the 
principle out. If you learn to use it and find it usefull, getting a 
dedicated instrument might aid your work. If not you have not wasted as 
much money and you only cry over the lost time.

Cheers,
Magnus


From phk at phk.freebsd.dk  Wed Nov 26 08:25:42 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 26 Nov 2008 08:25:42 +0000
Subject: [time-nuts] A loran-C signal movie...
In-Reply-To: Your message of "Tue, 25 Nov 2008 17:18:53 CST."
	<492C87DD.2010705@wwrinc.com> 
Message-ID: <3807.1227687942@critter.freebsd.dk>

In message <492C87DD.2010705 at wwrinc.com>, "David M. Witten II" writes:
>Very interesting!
>
>I had recently read the information on your website and, having all of 
>the necessary pieces, had decided that I wanted to try to duplicate your 
>project.  But I was unsure whether it had really worked out to your 
>satisfaction and whether you were still using the system.  My questions 
>are answered!
>
>Perhaps I will get some time over the holidays to assemble a similar 
>system and see if it works here in the remote reaches of the Midwestern US.

I would be very interested in that myself, I have not been able to
decide if the 4-digit GRI's here in Europe is a big benefit S/N wise
or if it will work just as well on 3-digit GRI's like you have in
USA.

It certainly stands no chance with the 1-digit GRI (8000) of Chayka.
Since the averaging period becomes divisible by 1ms all integer
kHz transmissions survive filtering.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From bruce.griffiths at xtra.co.nz  Wed Nov 26 08:28:23 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Wed, 26 Nov 2008 21:28:23 +1300
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492D0516.7000800@rubidium.dyndns.org>
References: <492C9AC4.3050102@rogers.com>
	<492D0516.7000800@rubidium.dyndns.org>
Message-ID: <492D08A7.80103@xtra.co.nz>

Magnus Danielson wrote:
> Patrick wrote:
>   
>> Hi Everyone
>>
>> I have consistently had success repairing laboratory instruments(my
>> small business) when I have a schematic and I have consistently failed
>> without one, lots of opportunities are slipping threw my fingers.
>>
>> I want to invest in tools that will help me troubleshoot without a
>> schematic. I was thinking about getting a Huntron tracker. Has anyone
>> had any experience with one? Could you feedback?
>>
>> Are there other tools that have helped you fix circuit boards without a
>> schematic?
>>     
> The Huntron tracker does not solve your basic problem of not having the 
> schematics, rather it helps you for some of the analysis when you do 
> have a schematic. We do alot of analysis at work and the trackers sits 
> there idling on a shelf, since we rarely have problems at which we have 
> a short on a power-plane or a slightly broken semiconductor. Only a 
> handfull of problem would apply. We have alot of other usefull tools 
> instead.
>
> For you to buy a Huntron tracker you should do it for the right reason, 
> that it applies to your kind of problems and would aid in locating 
> problems and measure basic semiconductor behaviour.
>
> Now, Huntron claims that it will aid on undocumented boards. It will to 
> a certain extent, since it is agnostic to the design as such, it just 
> measures electrical properties. However a Fluke multimeter is similarly 
> agnostic and may do similar but not all of the tests the trackers do. 
> Also, to some degree a tracker becomes somewhat difficult to use in some 
> cases without a functional board alongside for reference.
>
> I don't want to say it is a bad tool, it isn't. I just want to kill your 
> overly high expectations. Only then you can buy one and feel happy about 
> it in the long run. What the tracker does as a basic measurement tool is 
> to do I/V diagrams. You can make your own I/V setup by using an 
> (preferably analog) oscilloscope in X/Y setup, a simple diffrential amp 
> (4 resistors and an op-amp in a cook-book diffrential amp setup), a 
> resistor for current-to-voltage conversion and an audio generator 
> producing a sine. This is sufficient to get you started and try the 
> principle out. If you learn to use it and find it usefull, getting a 
> dedicated instrument might aid your work. If not you have not wasted as 
> much money and you only cry over the lost time.
>
> Cheers,
> Magnus
>
>   
A link to a page claiming to have the circuit for a build your own version:
http://www.davesplanet.net/tracker/

Bruce


From j.bastemeijer at tudelft.nl  Wed Nov 26 10:01:38 2008
From: j.bastemeijer at tudelft.nl (Jeroen Bastemeijer)
Date: Wed, 26 Nov 2008 11:01:38 +0100
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
References: <492C9AC4.3050102@rogers.com>
Message-ID: <492D1E82.4080005@tudelft.nl>

Hi Patrick,

I saw a lot of replies to your question. Here are my five cents:

The Huntron Tracker is very nice if you have two similar pieces of 
equipment (or circuit boards). From which: one is faulty, the other one 
still okay, or has a different fault. By probing around you can easily 
find the faulty part or component, by looking for differences in the 
Huntrons display. E.g. a faulty transitor will give a different curve, 
even when other circuitry is connected to it.

However, I used to work at an small repair shop. Here we also got lots 
of equipment for which the schematics were not available (usually it was 
classified or obsolete). Although we had access to a Huntron Tracker, we 
didn't use it much. Most of the time, a multimeter and some "common 
sense" did the trick.

One final remark, about the reply from Bruce; There are oscilloscopes 
out there who have the component tester (that is what he reffered to) 
built in. My first oscilloscope I bought, a Handykit, has the 
component-tester built-in. For that reason that scope is still with me ;-)

Good luck, best regards, Jeroen

Patrick wrote:
> Hi Everyone
>
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
>
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
>
> Are there other tools that have helped you fix circuit boards without a
> schematic?
>
> Thanks in advance-Patrick
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>   
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From rk at timing-consultants.com  Wed Nov 26 12:08:42 2008
From: rk at timing-consultants.com (Rob Kimberley)
Date: Wed, 26 Nov 2008 12:08:42 -0000
Subject: [time-nuts] huntron tracker advice & troubleshooting
	withoutschematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
References: <492C9AC4.3050102@rogers.com>
Message-ID: <93265DDCFA574AEDA5CBEB8F8870B19D@Robin>

Huntron Tracker, now there's a blast from the past. Are they still making
them? We had a couple in the service department which I ran at Systron
Donner Ltd. Seem to remember them being on the shelf more times than on the
bench.

;-(

Rob Kimberley 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Patrick
Sent: 26 November 2008 00:40
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] huntron tracker advice & troubleshooting
withoutschematic advise

Hi Everyone

I have consistently had success repairing laboratory instruments(my small
business) when I have a schematic and I have consistently failed without
one, lots of opportunities are slipping threw my fingers.

I want to invest in tools that will help me troubleshoot without a
schematic. I was thinking about getting a Huntron tracker. Has anyone had
any experience with one? Could you feedback?

Are there other tools that have helped you fix circuit boards without a
schematic?

Thanks in advance-Patrick


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



From ian.sheffield1 at tesco.net  Wed Nov 26 16:38:21 2008
From: ian.sheffield1 at tesco.net (Ian Sheffield)
Date: Wed, 26 Nov 2008 16:38:21 -0000
Subject: [time-nuts] EZGPIB Error
Message-ID: <003701c94fe5$6605c8d0$0201a8c0@cookie>

Hello Ulrich and all,

I am pleased to report that the Socket Error # 10065
does not occur with the latest version of EZGPIB and all is fine now.

Many thanks to all who replied.

Ian.

From p.boven at xs4all.nl  Wed Nov 26 17:02:10 2008
From: p.boven at xs4all.nl (Paul Boven)
Date: Wed, 26 Nov 2008 18:02:10 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <1D41E281A3F14FA0B85D3FCDCBC2FD84@didierhp>
References: <492C4EE4.3050508@xs4all.nl> <492C550F.3030701@intt.net>
	<1D41E281A3F14FA0B85D3FCDCBC2FD84@didierhp>
Message-ID: <492D8112.1050103@xs4all.nl>

Hi Didier, everyone,

Didier wrote:
> By the time you get the signal from the maser through 34 km of fiber optic,
> what you get at the end might be not better than a decent GPSDO...

That's exactly what I'm trying to work out before I'll actually start
building something like that. The JPL device (thanks for the hint, James
P. Lux) is very interesting, see:
http://tycho.usno.navy.mil/ptti/1988/Vol%2020_02.pdf

The JPL system aims to achieve better than 1E17 in 1000s, whereas the
H-maser in their publication is quoted as 1E15 in the same averaging
time. They also state that: 'when stabilities higher than 1E15 are
required the link must be actively stabilized'. So, in a nutshell - If I
were to build such a system, the first incarnation would be without such
a compensation system.
If such a compensation does turn out to be necessary I'd probably not
use a 50% mirror but simply loop the received data back to the
trasmitter of the SFP at the receiving end, and use a fiber pair instead
of a single fiber.

Regards, Paul Boven.


From w3kl at w3kl.com  Wed Nov 26 18:59:19 2008
From: w3kl at w3kl.com (w3kl at w3kl.com)
Date: Wed, 26 Nov 2008 10:59:19 -0800 (PST)
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492D8112.1050103@xs4all.nl>
Message-ID: <415366.73414.qm@web35402.mail.mud.yahoo.com>

All:? Sorry for jumping in abruptly on this ongoing thread.? I have been meaning to chime in ever since the discussion got started.
?
I apologize in advance if I am dragging up an issue that has already been discussed and put to rest.
?
That being said, have you given consideration to the effects of chromatic dispersion in the fiber?
?
A good, telcom grade, dispersion shifted (designed for the 1550nm wavelength band, where absorption of the light by water is small), single mode fiber has a chromatic dispersion of approximately 1 to 10 ps/nm/km.? The concern therefore is changes in timing induced by changing wavelength content of the laser or LED used to drive the fiber - for example, due to temperature changes, etc.
?
If you've already considered this, then please ignore this.? Otherwise, it would be interesting to work through a "what if"?
?
jeff

Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402

--- On Wed, 11/26/08, Paul Boven <p.boven at xs4all.nl> wrote:

From: Paul Boven <p.boven at xs4all.nl>
Subject: Re: [time-nuts] 10 MHz over optical fiber?
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Wednesday, November 26, 2008, 12:02 PM

Hi Didier, everyone,

Didier wrote:
> By the time you get the signal from the maser through 34 km of fiber
optic,
> what you get at the end might be not better than a decent GPSDO...

That's exactly what I'm trying to work out before I'll actually
start
building something like that. The JPL device (thanks for the hint, James
P. Lux) is very interesting, see:
http://tycho.usno.navy.mil/ptti/1988/Vol%2020_02.pdf

The JPL system aims to achieve better than 1E17 in 1000s, whereas the
H-maser in their publication is quoted as 1E15 in the same averaging
time. They also state that: 'when stabilities higher than 1E15 are
required the link must be actively stabilized'. So, in a nutshell - If I
were to build such a system, the first incarnation would be without such
a compensation system.
If such a compensation does turn out to be necessary I'd probably not
use a 50% mirror but simply loop the received data back to the
trasmitter of the SFP at the receiving end, and use a fiber pair instead
of a single fiber.

Regards, Paul Boven.

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From bruce.griffiths at xtra.co.nz  Wed Nov 26 19:13:10 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 08:13:10 +1300
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <415366.73414.qm@web35402.mail.mud.yahoo.com>
References: <415366.73414.qm@web35402.mail.mud.yahoo.com>
Message-ID: <492D9FC6.5040903@xtra.co.nz>

w3kl at w3kl.com wrote:
> All:  Sorry for jumping in abruptly on this ongoing thread.  I have been meaning to chime in ever since the discussion got started.
>  
> I apologize in advance if I am dragging up an issue that has already been discussed and put to rest.
>  
> That being said, have you given consideration to the effects of chromatic dispersion in the fiber?
>  
> A good, telcom grade, dispersion shifted (designed for the 1550nm wavelength band, where absorption of the light by water is small), single mode fiber has a chromatic dispersion of approximately 1 to 10 ps/nm/km.  The concern therefore is changes in timing induced by changing wavelength content of the laser or LED used to drive the fiber - for example, due to temperature changes, etc.
>  
> If you've already considered this, then please ignore this.  Otherwise, it would be interesting to work through a "what if"?
>  
> jeff
>
> Jeffrey K. Okamitsu, PhD, MBA
> +1-609-638-5402
>
>   
Without compensation, the delay tempco of 34 km of fiber will be
somewhat more problematic unless the temperature of the entire run is
constant and/or expensive low delay tempco fiber is used.

Bruce


From w3kl at w3kl.com  Wed Nov 26 19:49:35 2008
From: w3kl at w3kl.com (w3kl at w3kl.com)
Date: Wed, 26 Nov 2008 11:49:35 -0800 (PST)
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492D9FC6.5040903@xtra.co.nz>
Message-ID: <710912.13858.qm@web35402.mail.mud.yahoo.com>

The biggest concern with temperature effects in the fiber would be thermal expansion.? Potentially, as well, changes in waveguide shape, which could add more waveguide dispersion as well as potential polarization mode dispersion.
?
Jeff

Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402

--- On Wed, 11/26/08, Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:

From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] 10 MHz over optical fiber?
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Wednesday, November 26, 2008, 2:13 PM

w3kl at w3kl.com wrote:
> All:  Sorry for jumping in abruptly on this ongoing thread.  I have been
meaning to chime in ever since the discussion got started.
>  
> I apologize in advance if I am dragging up an issue that has already been
discussed and put to rest.
>  
> That being said, have you given consideration to the effects of chromatic
dispersion in the fiber?
>  
> A good, telcom grade, dispersion shifted (designed for the 1550nm
wavelength band, where absorption of the light by water is small), single mode
fiber has a chromatic dispersion of approximately 1 to 10 ps/nm/km.  The concern
therefore is changes in timing induced by changing wavelength content of the
laser or LED used to drive the fiber - for example, due to temperature changes,
etc.
>  
> If you've already considered this, then please ignore this. 
Otherwise, it would be interesting to work through a "what if"?
>  
> jeff
>
> Jeffrey K. Okamitsu, PhD, MBA
> +1-609-638-5402
>
>   
Without compensation, the delay tempco of 34 km of fiber will be
somewhat more problematic unless the temperature of the entire run is
constant and/or expensive low delay tempco fiber is used.

Bruce

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

From warrensjmail-one at yahoo.com  Wed Nov 26 19:53:59 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Wed, 26 Nov 2008 11:53:59 -0800
Subject: [time-nuts] GPSDO using 100Hz
Message-ID: <077a01c95000$ba1a07e0$6401a8c0@WSOffice>


I am having trouble keeping my responses from starting new threads, 
If anyone could shed some light on what I'm doing wrong it would be a 
great help to me. It will be interesting to see what thread this post ends up in.

(Now back to the original subject; I've cleaned up things and added my responses in the text below)


Re: [time-nuts] GPSDO using 100Hz
from Tom Van Baak
Mon, 24 Nov 2008 17:17:34 -0800


by WarrenS
>> Besides asking if anyone is using the 100Hz output, 
>> I would like to know why it is that the generally available 
>> GPSDO don't use the 100Hz. I have found that this can 
>> give about 1 ns of certainly with a simple PLL and analog 
>> RC filter, whereas the 1 PPS  has more like 100 ns of uncorrected 
>> uncertainty in it, and for the most part the 1PPS needs a processor 
>> to use it instead of simple Phase Lock Loops that I am able to 
>> be used on the 100 PPS

by /tvb
>Where do you get your "1 ns" and "100 ns" figures? 
> Have you actually measured these values? Also, 
> over what time average (tau) are you assuming 
> this level of resolution?


by WarrenS
The 1ns and 100ns are measured peak values of the 
nominal phase Jitter over a few seconds time as 
displayed on a scope and averaged from a time interval meter.
The averaged time has to be long enough to let the GPS Phase 
noise cycle thru a few of the Oncore's sawtooth cycles, 
and short enough so as not to include the added received GSP 
signal errors.
The GPS signal errors that I see are around 10 ns over a 10 plus 
seconds period, with short excursions of an additional 30 ns 
every few minutes generally lasting no longer more than a few seconds. 
These Phase noise values I see are pretty much independent of time, 
as long as the viewed average time is not too long or too short. 

There is also another nominal 50 ns phase error that comes along maybe 
every hour on the 1 PPS and once or twice a day on the 100 PPS both 
lasting from 1 to 10 minutes or so. This happens when the various 
different frequencies involved sync up for a while.


by WarrenS
>> On the  LeapSecond.com site
>> http://www.leapsecond.com/pages/gpsdo/
>> It would seem that much of the noise what they have 
>> plotted is the results of  NOT setting the GPSDO  tracking 
>> TC slow enough.  The GPS is adding noise, to the low noise 
>> oscillator.
>> This is why the Allan Deviation increases by more than 3 db in 
>> the tracking  mode at mid averaging times below a 1
>> 1000 seconds, (15 minutes)
>> For a low noise Rubidium Oscillator like the SRS PRS10 

>> Bruce early said, "where the ADEV for various GPSDO remains 
>> below 1E-11 over the Tau range of [0.1s, 100,000s]. 
>> I said: That Tau has nothing to do with the tracking time 
>> constant that the GPSDO has been is set to, which is usually 
>> recommended to be set for a TC of several hours for optimal results.
     ( for low noise Rubidium Oscillators)

from /tvb
> For ideal results start with the TC = the tau where the ADEV
> of the GPS engine & phase detector crosses the ADEV of the
> OCXO. However there are other practical considerations.

>At short averaging intervals when there is a phase difference
>it is easy for the GPSDO to assume the OCXO is stable and
>the GPS engine has noise. So you average more samples.

>At long averaging intervals when there is a phase difference
>is it easy for the GPSDO to assume the GPS engine is more
>correct and the OCXO has drifted. So you steer using EFC.

>At the tau of the ideal TC, the GPSDO sees an average phase
>difference but can't totally blame either the OCXO or GPS for
>the error. By definition at this tau, half the noise is due to each
>subsystem. Hence you nearly always see an ADEV hump that
>goes above where you'd really like it. Best case sqrt(2).

>The ADEV hump itself is not indication of a mistuned TC; it is
>an indication that the GPSDO is working correctly.

>You can move the hump left and right and distort its shape by
>changing the TC.

>In practice I suspect most commercial GPSDO have a TC that
>appears too low for your liking. I can discuss why if you wish.
>/tvb

from WarrenS
Thanks, Very Good information to know and remember, and It 
gives me a much better understanding of what is happing.
I see that in many of the graphs shown on the Leap Second plots,  
the tracking hump is more like 4 to one instead of 1.5 to one.
Is this because the tracking TC is too fast for best noise?
I would love to hear more about it, Please 'Discuss why'.

Also if you would, I'd like to have a better understand of
what seems like an over obsessions with Low Noise GPSDO.
I do understand the need (or at least the desire) 
to have low noise oscillators when using them directly for high 
frequency and/or short time scale data taking applications, 
and the need for a good stable oscillator where it must maintain 
frequency if the GPS signal is lost, 
BUT it sounds like this is not what a large percentage of the 
second hand GPS trackers discussed here are used for. 
It does not seem like it would matter what the noise of the internal 
OSC is, if the unit is only being used for averaging things over longer 
periods such as looking at phase drift over time when doing freq checks. 
Any data taken at a period of say 1000 second to several days is 
pretty much limited by the noise of the GPS and not the Oscillator, 
so why is there the desire for the low noise oscillators in these cases?

Warren
*****************

From tvb at LeapSecond.com  Wed Nov 26 20:28:12 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Wed, 26 Nov 2008 12:28:12 -0800
Subject: [time-nuts] Thunderbolt time-nuts/TAPR Group Buy - status
Message-ID: <F1337CC966C34ADEAE7C594F69299FE1@pc52>

Hi all,

Last month's lot of 100 Thunderbolts sold out in a day or two.
The status is that more than half have been shipped so far;
the rest within a few weeks. Thank you all for your patience.

That was the 4th large batch of Thunderbolts that I was able
to obtain, test, and send to TAPR to distribute as kits. I know
a number of you wanted one but missed out on each of the
previous group buys.

Please let me know, off-list, if you are one of those time-nuts
who have been passed over. I'm at tvb at LeapSecond.com.

I think we'll do one more group buy next month and then I'm
done with this project. At that time I'll also announce the plans
for all the TBolts that dropped out of the testing process over
the past year.

If you have questions or suggestions please contact me off-list.

Thanks,
/tvb
http://www.leapsecond.com/time-nuts.htm







From bruce.griffiths at xtra.co.nz  Wed Nov 26 20:33:18 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 09:33:18 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <077a01c95000$ba1a07e0$6401a8c0@WSOffice>
References: <077a01c95000$ba1a07e0$6401a8c0@WSOffice>
Message-ID: <492DB28E.5060404@xtra.co.nz>

WarrenS wrote:
> I am having trouble keeping my responses from starting new threads, 
> If anyone could shed some light on what I'm doing wrong it would be a 
> great help to me. It will be interesting to see what thread this post ends up in.
>
> (Now back to the original subject; I've cleaned up things and added my responses in the text below)
>
>
> Re: [time-nuts] GPSDO using 100Hz
> from Tom Van Baak
> Mon, 24 Nov 2008 17:17:34 -0800
>
>
> by WarrenS
>   
>>> Besides asking if anyone is using the 100Hz output, 
>>> I would like to know why it is that the generally available 
>>> GPSDO don't use the 100Hz. I have found that this can 
>>> give about 1 ns of certainly with a simple PLL and analog 
>>> RC filter, whereas the 1 PPS  has more like 100 ns of uncorrected 
>>> uncertainty in it, and for the most part the 1PPS needs a processor 
>>> to use it instead of simple Phase Lock Loops that I am able to 
>>> be used on the 100 PPS
>>>       
>
> by /tvb
>   
>> Where do you get your "1 ns" and "100 ns" figures? 
>> Have you actually measured these values? Also, 
>> over what time average (tau) are you assuming 
>> this level of resolution?
>>     
>
>
> by WarrenS
> The 1ns and 100ns are measured peak values of the 
> nominal phase Jitter over a few seconds time as 
> displayed on a scope and averaged from a time interval meter.
> The averaged time has to be long enough to let the GPS Phase 
> noise cycle thru a few of the Oncore's sawtooth cycles, 
> and short enough so as not to include the added received GSP 
> signal errors.
> The GPS signal errors that I see are around 10 ns over a 10 plus 
> seconds period, with short excursions of an additional 30 ns 
> every few minutes generally lasting no longer more than a few seconds. 
> These Phase noise values I see are pretty much independent of time, 
> as long as the viewed average time is not too long or too short. 
>
> There is also another nominal 50 ns phase error that comes along maybe 
> every hour on the 1 PPS and once or twice a day on the 100 PPS both 
> lasting from 1 to 10 minutes or so. This happens when the various 
> different frequencies involved sync up for a while.
>
>
> by WarrenS
>   
>>> On the  LeapSecond.com site
>>> http://www.leapsecond.com/pages/gpsdo/
>>> It would seem that much of the noise what they have 
>>> plotted is the results of  NOT setting the GPSDO  tracking 
>>> TC slow enough.  The GPS is adding noise, to the low noise 
>>> oscillator.
>>> This is why the Allan Deviation increases by more than 3 db in 
>>> the tracking  mode at mid averaging times below a 1
>>> 1000 seconds, (15 minutes)
>>> For a low noise Rubidium Oscillator like the SRS PRS10 
>>>       
>
>   
>>> Bruce early said, "where the ADEV for various GPSDO remains 
>>> below 1E-11 over the Tau range of [0.1s, 100,000s]. 
>>> I said: That Tau has nothing to do with the tracking time 
>>> constant that the GPSDO has been is set to, which is usually 
>>> recommended to be set for a TC of several hours for optimal results.
>>>       
>      ( for low noise Rubidium Oscillators)
>
> from /tvb
>   
>> For ideal results start with the TC = the tau where the ADEV
>> of the GPS engine & phase detector crosses the ADEV of the
>> OCXO. However there are other practical considerations.
>>     
>
>   
>> At short averaging intervals when there is a phase difference
>> it is easy for the GPSDO to assume the OCXO is stable and
>> the GPS engine has noise. So you average more samples.
>>     
>
>   
>> At long averaging intervals when there is a phase difference
>> is it easy for the GPSDO to assume the GPS engine is more
>> correct and the OCXO has drifted. So you steer using EFC.
>>     
>
>   
>> At the tau of the ideal TC, the GPSDO sees an average phase
>> difference but can't totally blame either the OCXO or GPS for
>> the error. By definition at this tau, half the noise is due to each
>> subsystem. Hence you nearly always see an ADEV hump that
>> goes above where you'd really like it. Best case sqrt(2).
>>     
>
>   
>> The ADEV hump itself is not indication of a mistuned TC; it is
>> an indication that the GPSDO is working correctly.
>>     
>
>   
>> You can move the hump left and right and distort its shape by
>> changing the TC.
>>     
>
>   
>> In practice I suspect most commercial GPSDO have a TC that
>> appears too low for your liking. I can discuss why if you wish.
>> /tvb
>>     
>
> from WarrenS
> Thanks, Very Good information to know and remember, and It 
> gives me a much better understanding of what is happing.
> I see that in many of the graphs shown on the Leap Second plots,  
> the tracking hump is more like 4 to one instead of 1.5 to one.
> Is this because the tracking TC is too fast for best noise?
> I would love to hear more about it, Please 'Discuss why'.
>
> Also if you would, I'd like to have a better understand of
> what seems like an over obsessions with Low Noise GPSDO.
> I do understand the need (or at least the desire) 
> to have low noise oscillators when using them directly for high 
> frequency and/or short time scale data taking applications, 
> and the need for a good stable oscillator where it must maintain 
> frequency if the GPS signal is lost, 
> BUT it sounds like this is not what a large percentage of the 
> second hand GPS trackers discussed here are used for. 
> It does not seem like it would matter what the noise of the internal 
> OSC is, if the unit is only being used for averaging things over longer 
> periods such as looking at phase drift over time when doing freq checks. 
> Any data taken at a period of say 1000 second to several days is 
> pretty much limited by the noise of the GPS and not the Oscillator, 
> so why is there the desire for the low noise oscillators in these cases?
>
> Warren
> *****************
>   
Often the use of a low noise OCXO is mandated by unstated applications
such as:

1) The OCXO output is used to drive the external frequency standard
input of a counter.

2) The OCXO output is used calibrate other oscillators to 1E-9 or
perhaps a little better and averaging over 1000 seconds or so during
adjustments isnt a sensible option.

3) The OCXO output may be used to control the frequency of a microwave
transmitter and/or the LO of a receiver which requires low drift and
phase noise.

4) Obsession

Bruce


From wb6bnq at cox.net  Wed Nov 26 20:40:41 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Wed, 26 Nov 2008 12:40:41 -0800
Subject: [time-nuts] GPSDO using 100Hz
References: <077a01c95000$ba1a07e0$6401a8c0@WSOffice>
	<492DB28E.5060404@xtra.co.nz>
Message-ID: <492DB449.77A1C7F2@cox.net>

Bruce Griffiths wrote:

> 4) Obsession
>
> Bruce

Bruce,

I think you are confused.  #4 is the name of a perfume !

Bill....WB6BNQ




From tomknox at nist.gov  Wed Nov 26 20:49:48 2008
From: tomknox at nist.gov (tomknox at nist.gov)
Date: Wed, 26 Nov 2008 15:49:48 -0500
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492C4EE4.3050508@xs4all.nl>
References: <492C4EE4.3050508@xs4all.nl>
Message-ID: <20081126154948.810446610oz5itf0@webmail.nist.gov>

Hi Group;
It seems to me that the increase in noise introduced with an  
optoelectronic device would not matter in most applications if a  
cleanup oscillator is added.

Best Wishes;
Thomas Knox
NIST
4475 Whitney Place
Boulder Colorado 80305
1-303-554-0307
tomknox at nist.gov



Quoting "Paul Boven" <p.boven at xs4all.nl>:

> Hi everyone,
>
> In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, Marco IK1ODO -2
> writes:
>> Hi all,
>>
>> I have to carry a 10 MHz standard frequency signal inside an EMC
>> screened room via fiber optic cable.
>>
>> Not willing to re-invent the wheel, do something like an optical
>> standard frequency link exist on the market?
>> I think it is possible to use standard 100MB LAN transceivers, and
>> POF. Phase noise requirements
>> are not very stringent, and the distance is in the order of some tens
>> of meters.
>
> I'm looking into something similar: transmitting an H-Maser signal
> (probably 10MHz) over some 34km using CWDM SFPs. At first glance this
> seems fairly uncomplicated: get some SFPs, and SFP connector + cage. Use
> a fast opamp/differential driver to drive the transmitting SFP, and use
> a similar setup at the other end to transform the received data back to
> 50 ohm unbalanced. How feasible would such a setup be?
> Possible problems might be that a 10MHz squarewave is simply too 'slow'
> to be transmitted by an SFP, which expects 1.25Gb/s 8/10 encoded data.
> Another interesting question would be how much jitter/noise such a setup
> would add?
>
> Regards, Paul Boven.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



From warrensjmail-one at yahoo.com  Wed Nov 26 21:09:09 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Wed, 26 Nov 2008 13:09:09 -0800
Subject: [time-nuts] GPSDO using 100Hz
Message-ID: <07b501c9500b$39b75bb0$6401a8c0@WSOffice>

...

> Also if you would, I'd like to have a better understand of
> what seems like an over obsessions with Low Noise GPSDO.
> I do understand the need (or at least the desire) 
> to have low noise oscillators when using them directly for high 
> frequency and/or short time scale data taking applications, 
> and the need for a good stable oscillator where it must maintain 
> frequency if the GPS signal is lost, 
> BUT it sounds like this is not what a large percentage of the 
> second hand GPS trackers discussed here are used for. 
> It does not seem like it would matter what the noise of the internal 
> OSC is, if the unit is only being used for averaging things over longer 
> periods such as looking at phase drift over time when doing freq checks. 
> Any data taken at a period of say 1000 second to several days is 
> pretty much limited by the noise of the GPS and not the Oscillator, 
> so why is there the desire for the low noise oscillators in these cases?
>
> Warren
> *****************
>   
Often the use of a low noise OCXO is mandated by unstated applications
such as:

1) The OCXO output is used to drive the external frequency standard
input of a counter.

2) The OCXO output is used calibrate other oscillators to 1E-9 or
perhaps a little better and averaging over 1000 seconds or so during
adjustments isnt a sensible option.

3) The OCXO output may be used to control the frequency of a microwave
transmitter and/or the LO of a receiver which requires low drift and
phase noise.

4) Obsession

Bruce

****************
Bruce

Thanks, I'd  forgotten about really good counters with resolution better than a1 ns,
 because I don't have one, Wish I did. 

and I understand the microwave and Obsession needs,

But  as far as #2, calibrating to 1E-9 or better, am I forgetting something else?
I think even the poorest Osc's, that would ever be put in a GPSDO,  
have phase noise and drift of under 1 ns, so in 1 sec it could  do 
1E-9 or in 10 sec 1E-10.  Are you saying that 1 to 10 seconds may 
be too long of time to average over?

Warren

From rdarlington at gmail.com  Wed Nov 26 21:56:33 2008
From: rdarlington at gmail.com (Robert Darlington)
Date: Wed, 26 Nov 2008 14:56:33 -0700
Subject: [time-nuts] NIST tours
Message-ID: <b3bd5fcb0811261356s6c14d0aq55a89ee672556880@mail.gmail.com>

Hi all,

I see NIST has no official tours currently, but am wondering if they do this
for weirdos that are into this sort of thing as compared to the general
public.  I'm finding myself in Boulder more often due to work and would love
to eyeball the latest and greatest gadgetry.  Also, as a ham operator, I
lust after the transmitter equipment up in Fort Collins.

Thanks,
Bob D

From robert8rpi at yahoo.co.uk  Wed Nov 26 22:13:21 2008
From: robert8rpi at yahoo.co.uk (Robert Atkinson)
Date: Wed, 26 Nov 2008 22:13:21 +0000 (GMT)
Subject: [time-nuts] huntron tracker advice & troubleshooting without
	schematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
Message-ID: <937212.21839.qm@web27105.mail.ukl.yahoo.com>

Hi Patrick,
The Tracker is great but needs experience and skill to use. One of the best investments you can make is an in-circuit capacitor ESR (equivilent series resistance) meter. Many faults on modern equipment are due to faulty elecrolytic capacitors. in many instances these will test OK for capacitance value but have a high impedance. An ESR mater will tell you the impedance, not the capacitance of the capacitor. This is very important in high speed circuits and switch mode power supplies. 
?
Robert G8RPI.

--- On Wed, 26/11/08, Patrick <optomatic at rogers.com> wrote:

From: Patrick <optomatic at rogers.com>
Subject: [time-nuts] huntron tracker advice & troubleshooting without schematic advise
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Wednesday, 26 November, 2008, 12:39 AM

Hi Everyone

I have consistently had success repairing laboratory instruments(my
small business) when I have a schematic and I have consistently failed
without one, lots of opportunities are slipping threw my fingers.

I want to invest in tools that will help me troubleshoot without a
schematic. I was thinking about getting a Huntron tracker. Has anyone
had any experience with one? Could you feedback?

Are there other tools that have helped you fix circuit boards without a
schematic?

Thanks in advance-Patrick


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



      

From imp at bsdimp.com  Wed Nov 26 22:11:53 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Wed, 26 Nov 2008 15:11:53 -0700 (MST)
Subject: [time-nuts] NIST tours
In-Reply-To: <b3bd5fcb0811261356s6c14d0aq55a89ee672556880@mail.gmail.com>
References: <b3bd5fcb0811261356s6c14d0aq55a89ee672556880@mail.gmail.com>
Message-ID: <20081126.151153.1306325523.imp@bsdimp.com>

In message: <b3bd5fcb0811261356s6c14d0aq55a89ee672556880 at mail.gmail.com>
            "Robert Darlington" <rdarlington at gmail.com> writes:
: I see NIST has no official tours currently, but am wondering if they do this
: for weirdos that are into this sort of thing as compared to the general
: public.  I'm finding myself in Boulder more often due to work and would love
: to eyeball the latest and greatest gadgetry.  Also, as a ham operator, I
: lust after the transmitter equipment up in Fort Collins.

If you have the right connections, you can get a tour still...  I was
there for a time and frequency symposium a year ago and got a tour
then...  Also, got a briefer tour of the atomic clocks a year or two
before that when I went to check up on some gear that my old company
had there measuring the atomic clocks...

Warner


From KFIam640 at aol.com  Wed Nov 26 23:18:23 2008
From: KFIam640 at aol.com (KFIam640 at aol.com)
Date: Wed, 26 Nov 2008 18:18:23 EST
Subject: [time-nuts] NIST tours
Message-ID: <c0c.4d2973a1.365f333f@aol.com>

Bob, maybe things are better now but I was in Fort Collins, CO not too long  
after 9/11 and even though I talked to one of the WWV/WWVB staff members on 
the  telephone there was no way I could get a tour at that time.
 
Marvin, W6OQI
 
 
In a message dated 11/26/2008 1:57:11 P.M. Pacific Standard Time,  
rdarlington at gmail.com writes:

Hi  all,

I see NIST has no official tours currently, but am wondering if  they do this
for weirdos that are into this sort of thing as compared to  the general
public.  I'm finding myself in Boulder more often due to  work and would love
to eyeball the latest and greatest gadgetry.   Also, as a ham operator, I
lust after the transmitter equipment up in Fort  Collins.

Thanks,
Bob  D
_______________________________________________
time-nuts mailing list  -- time-nuts at febo.com
To unsubscribe, go to  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.


**************Life should be easier. So should your homepage. Try the NEW 
AOL.com. 
(http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000002)

From Brucekareen at aol.com  Wed Nov 26 23:28:43 2008
From: Brucekareen at aol.com (Brucekareen at aol.com)
Date: Wed, 26 Nov 2008 18:28:43 EST
Subject: [time-nuts] time-nuts Digest, Vol 52, Issue 74
Message-ID: <be1.49dce24f.365f35ab@aol.com>

 
In a message dated 11/26/2008 12:29:32 P.M. Pacific Standard Time,  
time-nuts-request at febo.com writes:

tvb at LeapSecond.com


Tom,
 
I would be interested in one of the Thunderbolt units  if you are able  to do 
another group buy.
 
Best regards,
 
Bruce, KG6OJI
**************Finally, one site has it all: your friends, your email, your 
favorite sites. Try the NEW AOL.com. 
(http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000006)

From bpowell at intrex.net  Wed Nov 26 23:45:47 2008
From: bpowell at intrex.net (bpowell )
Date: Wed, 26 Nov 2008 18:45:47 -0500
Subject: [time-nuts] NIST tours
Message-ID: <200811261845.AA2045051012@intrex.net>

Bob, Marvin,
If you happen to have an interest in Telecom-related synchronization presentations, there is an annual synchronization workshop that has been held yearly in the Boulder area called WSTS-xx (Workshop for Synchronization Telecommunications Standards), jointly sponsored by NIST, ATIS (Alliance for Telecommunications Industry Solutions), and the IEEE.  The next workshop is WSTS-09, and will be held from March 10-12, 2009 in Broomfield Hills, CO (a few miles south of Boulder).  After the workshop, there is a tour of the NIST/Boulder time and frequency facilities on morning of Friday, March 11, 2009.  See the following link for registration info:

http://tf.nist.gov/timefreq/seminars/WSTS/WSTS.html

Click on the WSTS'08 link to see the agenda/papers from last year.

This workshop presents a great overview of legacy as well as emerging Telecom synchronization issues, including wireless, cable, and sync over packet networks (including IEEE1588v2, NTP, and Synchronous Ethernet standards).

Regards,
Bill Powell


---------- Original Message ----------------------------------
From: KFIam640 at aol.com
Reply-To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Date:  Wed, 26 Nov 2008 18:18:23 EST

>Bob, maybe things are better now but I was in Fort Collins, CO not too long  
>after 9/11 and even though I talked to one of the WWV/WWVB staff members on 
>the  telephone there was no way I could get a tour at that time.
> 
>Marvin, W6OQI
> 
> 
>In a message dated 11/26/2008 1:57:11 P.M. Pacific Standard Time,  
>rdarlington at gmail.com writes:
>
>Hi  all,
>
>I see NIST has no official tours currently, but am wondering if  they do this
>for weirdos that are into this sort of thing as compared to  the general
>public.  I'm finding myself in Boulder more often due to  work and would love
>to eyeball the latest and greatest gadgetry.   Also, as a ham operator, I
>lust after the transmitter equipment up in Fort  Collins.
>
>Thanks,
>Bob  D
>_______________________________________________
>time-nuts mailing list  -- time-nuts at febo.com
>To unsubscribe, go to  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the  instructions there.
>
>
>**************Life should be easier. So should your homepage. Try the NEW 
>AOL.com. 
>(http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000002)
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
>


From bruce.griffiths at xtra.co.nz  Thu Nov 27 00:23:42 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 13:23:42 +1300
Subject: [time-nuts] GPSDO using 100Hz
In-Reply-To: <07b501c9500b$39b75bb0$6401a8c0@WSOffice>
References: <07b501c9500b$39b75bb0$6401a8c0@WSOffice>
Message-ID: <492DE88E.2000409@xtra.co.nz>

WarrenS wrote:
> ...
>
>   
>> Also if you would, I'd like to have a better understand of
>> what seems like an over obsessions with Low Noise GPSDO.
>> I do understand the need (or at least the desire) 
>> to have low noise oscillators when using them directly for high 
>> frequency and/or short time scale data taking applications, 
>> and the need for a good stable oscillator where it must maintain 
>> frequency if the GPS signal is lost, 
>> BUT it sounds like this is not what a large percentage of the 
>> second hand GPS trackers discussed here are used for. 
>> It does not seem like it would matter what the noise of the internal 
>> OSC is, if the unit is only being used for averaging things over longer 
>> periods such as looking at phase drift over time when doing freq checks. 
>> Any data taken at a period of say 1000 second to several days is 
>> pretty much limited by the noise of the GPS and not the Oscillator, 
>> so why is there the desire for the low noise oscillators in these cases?
>>
>> Warren
>> *****************
>>   
>>     
> Often the use of a low noise OCXO is mandated by unstated applications
> such as:
>
> 1) The OCXO output is used to drive the external frequency standard
> input of a counter.
>
> 2) The OCXO output is used calibrate other oscillators to 1E-9 or
> perhaps a little better and averaging over 1000 seconds or so during
> adjustments isnt a sensible option.
>
> 3) The OCXO output may be used to control the frequency of a microwave
> transmitter and/or the LO of a receiver which requires low drift and
> phase noise.
>
> 4) Obsession
>
> Bruce
>
> ****************
> Bruce
>
> Thanks, I'd  forgotten about really good counters with resolution better than a1 ns,
>  because I don't have one, Wish I did. 
>
> and I understand the microwave and Obsession needs,
>
> But  as far as #2, calibrating to 1E-9 or better, am I forgetting something else?
> I think even the poorest Osc's, that would ever be put in a GPSDO,  
> have phase noise and drift of under 1 ns, so in 1 sec it could  do 
> 1E-9 or in 10 sec 1E-10.  Are you saying that 1 to 10 seconds may 
> be too long of time to average over?
>
> Warren
>   
No, but one likes to have a local standard at least 10 x better than the
device being calibrated.

Bruce


From didier at cox.net  Thu Nov 27 00:38:22 2008
From: didier at cox.net (Didier)
Date: Wed, 26 Nov 2008 18:38:22 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <20081126154948.810446610oz5itf0@webmail.nist.gov>
References: <492C4EE4.3050508@xs4all.nl>
	<20081126154948.810446610oz5itf0@webmail.nist.gov>
Message-ID: <BDA63C014A764F06B39F103C53B7B568@didierhp>

If your concern is simply a stable frequency reference, that's true, even
though I am not sure what kind of cleanup oscillator would match the short
term stability of a maser. But also if you want to use it as a time
standard, the phase shift in the fiber has to be compensated, and it's
variations over temperature/humidity/gravity and whatnot must be accounted
for.

This is time-nuts, we don't simply want to make things work, we want to make
them work good :-)

Didier

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of tomknox at nist.gov
> Sent: Wednesday, November 26, 2008 2:50 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10 MHz over optical fiber?
> 
> Hi Group;
> It seems to me that the increase in noise introduced with an 
> optoelectronic device would not matter in most applications 
> if a cleanup oscillator is added.
> 
> Best Wishes;
> Thomas Knox
> NIST
> 4475 Whitney Place
> Boulder Colorado 80305
> 1-303-554-0307
> tomknox at nist.gov
> 
> 
> 
> Quoting "Paul Boven" <p.boven at xs4all.nl>:
> 
> > Hi everyone,
> >
> > In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, 
> Marco IK1ODO 
> > -2
> > writes:
> >> Hi all,
> >>
> >> I have to carry a 10 MHz standard frequency signal inside an EMC 
> >> screened room via fiber optic cable.
> >>
> >> Not willing to re-invent the wheel, do something like an optical 
> >> standard frequency link exist on the market?
> >> I think it is possible to use standard 100MB LAN transceivers, and 
> >> POF. Phase noise requirements are not very stringent, and the 
> >> distance is in the order of some tens of meters.
> >
> > I'm looking into something similar: transmitting an H-Maser signal 
> > (probably 10MHz) over some 34km using CWDM SFPs. At first 
> glance this 
> > seems fairly uncomplicated: get some SFPs, and SFP 
> connector + cage. 
> > Use a fast opamp/differential driver to drive the transmitting SFP, 
> > and use a similar setup at the other end to transform the received 
> > data back to 50 ohm unbalanced. How feasible would such a setup be?
> > Possible problems might be that a 10MHz squarewave is 
> simply too 'slow'
> > to be transmitted by an SFP, which expects 1.25Gb/s 8/10 
> encoded data.
> > Another interesting question would be how much jitter/noise such a 
> > setup would add?
> >
> > Regards, Paul Boven.
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From optomatic at rogers.com  Thu Nov 27 00:42:18 2008
From: optomatic at rogers.com (Patrick)
Date: Wed, 26 Nov 2008 19:42:18 -0500
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise-Thanks
In-Reply-To: <937212.21839.qm@web27105.mail.ukl.yahoo.com>
References: <937212.21839.qm@web27105.mail.ukl.yahoo.com>
Message-ID: <492DECEA.3030400@rogers.com>

Although I have sent  "personal thank yous" I would like to thank
everyone for their posts and re-iterate my love for this list.

Big thanks to John Ackermann for it-Patrick


From bruce.griffiths at xtra.co.nz  Thu Nov 27 00:55:41 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 13:55:41 +1300
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <BDA63C014A764F06B39F103C53B7B568@didierhp>
References: <492C4EE4.3050508@xs4all.nl>	<20081126154948.810446610oz5itf0@webmail.nist.gov>
	<BDA63C014A764F06B39F103C53B7B568@didierhp>
Message-ID: <492DF00D.4050402@xtra.co.nz>

Didier wrote:
> If your concern is simply a stable frequency reference, that's true, even
> though I am not sure what kind of cleanup oscillator would match the short
> term stability of a maser. But also if you want to use it as a time
> standard, the phase shift in the fiber has to be compensated, and it's
> variations over temperature/humidity/gravity and whatnot must be accounted
> for.
>
> This is time-nuts, we don't simply want to make things work, we want to make
> them work good :-)
>
> Didier
>
>   
Didier

A linear temperature ramp will create a linear ramp (equivalent to a
frequency shift) in the fiber delay.
Such temperature ramps may be expected at least twice a day. In other
words the the rate of change of temperature needs to be low to preserve
the frequency accuracy at the receive end of the fiber.

Bruce


From smace at intt.net  Thu Nov 27 02:04:09 2008
From: smace at intt.net (Scott Mace)
Date: Wed, 26 Nov 2008 20:04:09 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492DF00D.4050402@xtra.co.nz>
References: <492C4EE4.3050508@xs4all.nl>	<20081126154948.810446610oz5itf0@webmail.nist.gov>	<BDA63C014A764F06B39F103C53B7B568@didierhp>
	<492DF00D.4050402@xtra.co.nz>
Message-ID: <492E0019.2040908@intt.net>

I think for singlemode LEAF fiber you see something around 100ps/km per degree C.
Hopefully the fiber is buried and the temperature changes are more gradual.

	Scott




Bruce Griffiths wrote:
> Didier wrote:
>> If your concern is simply a stable frequency reference, that's true, even
>> though I am not sure what kind of cleanup oscillator would match the short
>> term stability of a maser. But also if you want to use it as a time
>> standard, the phase shift in the fiber has to be compensated, and it's
>> variations over temperature/humidity/gravity and whatnot must be accounted
>> for.
>>
>> This is time-nuts, we don't simply want to make things work, we want to make
>> them work good :-)
>>
>> Didier
>>
>>   
> Didier
> 
> A linear temperature ramp will create a linear ramp (equivalent to a
> frequency shift) in the fiber delay.
> Such temperature ramps may be expected at least twice a day. In other
> words the the rate of change of temperature needs to be low to preserve
> the frequency accuracy at the receive end of the fiber.
> 
> Bruce
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From bruce.griffiths at xtra.co.nz  Thu Nov 27 02:39:20 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 15:39:20 +1300
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492E0019.2040908@intt.net>
References: <492C4EE4.3050508@xs4all.nl>	<20081126154948.810446610oz5itf0@webmail.nist.gov>	<BDA63C014A764F06B39F103C53B7B568@didierhp>	<492DF00D.4050402@xtra.co.nz>
	<492E0019.2040908@intt.net>
Message-ID: <492E0858.3070904@xtra.co.nz>

Scott Mace wrote:
> I think for singlemode LEAF fiber you see something around 100ps/km per degree C.
> Hopefully the fiber is buried and the temperature changes are more gradual.
>
> 	Scott
>   
Most of it may be buried, however the ends of the fiber run may not be.
There are expensive fibers available with much smaller tempcos, at least
over limited temperature ranges.
The thermal expansion tempco of fused silica fibers is relatively low
(0.5ppm/C or so depending on exact composition) so most of the
propagation delay tempco is due to the refractive index tempco.

Bruce


From smace at intt.net  Thu Nov 27 03:44:12 2008
From: smace at intt.net (Scott Mace)
Date: Wed, 26 Nov 2008 21:44:12 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492E0858.3070904@xtra.co.nz>
References: <492C4EE4.3050508@xs4all.nl>	<20081126154948.810446610oz5itf0@webmail.nist.gov>	<BDA63C014A764F06B39F103C53B7B568@didierhp>	<492DF00D.4050402@xtra.co.nz>	<492E0019.2040908@intt.net>
	<492E0858.3070904@xtra.co.nz>
Message-ID: <492E178C.2040109@intt.net>

 From the corning leaf spec:

Environmental Test Induced Attenuation
Condition (dB/km)
1550 nm /1625 nm
Temperature Dependence
-60?C to +85?C* ? 0.05
Temperature ? Humidity Cycling
-10?C to +85?C* and up to
98% RH ? 0.05
Water Immersion, +23?C ? 0.05
Heat Aging, +85?C* ? 0.05
*Reference Temperature = +23?C
Operating Temperature Range: -60?C to +85?

I just checked the daily variation of optical loss, and it seems to be about +-0.15dB
over a 90km DWDM system that operates in the NY,NJ metro area.  It's slightly larger
from summer to winter.  Clearly measuring delay through a loop would be a more accurate
metric, but this should give you a ballpark of real-world environmental influence.  All
of the electronics are in cooled rooms (typical CO or datacenter), all the fiber was
buried and in building risers.

And don't forget about back-hoe induced phase shifts.

	Scott


Bruce Griffiths wrote:
> Scott Mace wrote:
>> I think for singlemode LEAF fiber you see something around 100ps/km per degree C.
>> Hopefully the fiber is buried and the temperature changes are more gradual.
>>
>> 	Scott
>>   
> Most of it may be buried, however the ends of the fiber run may not be.
> There are expensive fibers available with much smaller tempcos, at least
> over limited temperature ranges.
> The thermal expansion tempco of fused silica fibers is relatively low
> (0.5ppm/C or so depending on exact composition) so most of the
> propagation delay tempco is due to the refractive index tempco.
> 
> Bruce
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 


From didier at cox.net  Thu Nov 27 04:23:28 2008
From: didier at cox.net (Didier)
Date: Wed, 26 Nov 2008 22:23:28 -0600
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492DF00D.4050402@xtra.co.nz>
References: <492C4EE4.3050508@xs4all.nl>	<20081126154948.810446610oz5itf0@webmail.nist.gov><BDA63C014A764F06B39F103C53B7B568@didierhp>
	<492DF00D.4050402@xtra.co.nz>
Message-ID: <C461F9FD60F14B68ABBDFECCB4E6EAA9@didierhp>

 

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths
> Sent: Wednesday, November 26, 2008 6:56 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10 MHz over optical fiber?
> 
> Didier wrote:
> > If your concern is simply a stable frequency reference, 
> that's true, 
> > even though I am not sure what kind of cleanup oscillator 
> would match 
> > the short term stability of a maser. But also if you want 
> to use it as 
> > a time standard, the phase shift in the fiber has to be 
> compensated, 
> > and it's variations over temperature/humidity/gravity and 
> whatnot must 
> > be accounted for.
> >
> > This is time-nuts, we don't simply want to make things 
> work, we want 
> > to make them work good :-)
> >
> > Didier
> >
> >   
> Didier
> 
> A linear temperature ramp will create a linear ramp 
> (equivalent to a frequency shift) in the fiber delay.
> Such temperature ramps may be expected at least twice a day. 
> In other words the the rate of change of temperature needs to 
> be low to preserve the frequency accuracy at the receive end 
> of the fiber.
> 
> Bruce
> 

Bruce,

Over a 34 km path, one should expect temperature variations not to be
uniform (unless the fiber is buried, but over 34 km, that would be
expensive), so simple open loop pre-programmed compensation would probably
not work well, some form of active, dynamic compensation should probably be
used.

Didier



From bruce.griffiths at xtra.co.nz  Thu Nov 27 05:37:48 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Thu, 27 Nov 2008 18:37:48 +1300
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <2BFB5AF2EF724F709CC612D2AF20876A@pc52>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es><20081124152247.DCDB0E91529@mail.ebirds.it>	<492B54EA.5070301@rubidium.dyndns.org>
	<2BFB5AF2EF724F709CC612D2AF20876A@pc52>
Message-ID: <492E322C.4000002@xtra.co.nz>

Tom Van Baak wrote:
>> Yes. I know of several commecial systems. If you only need to do a short 
>> jump, then using fairly basic E/O-O/E equipment should work well 
>> enought. It all depends if you want/can to roll your own or need to buy 
>> a finished product (aka "buy this, and you will be fine!").
>>     
>
> Magnus, what's the typical noise floor, tempco or drift of cheap
> (i.e., non JPL-level) fiber distribution systems like this? Is it less
> than regular coax, or phase stabilized heliax? At 100 m lengths?
>
> /tvb
>   
Tom

At 1550nm:
Tight buffered fiber has a delay tempco of around 57 ppm/K
Bare SMF28 has a delay tempco of about  7.9ppm/K
Loose fibers in gel filled tube have a delay tempco of about 6.6ppm/K
Bare Spectran fiber has a delay temcpco of about 5.1ppm/K
Sumitomo phase stabilised fiber has a delay tempco of about 0.4ppm/K at
293K.


Bruce


From fortime at bellsouth.net  Thu Nov 27 07:04:01 2008
From: fortime at bellsouth.net (phil)
Date: Thu, 27 Nov 2008 02:04:01 -0500
Subject: [time-nuts] huntron tracker advice & troubleshooting
	withoutschematic advise
References: <492C9AC4.3050102@rogers.com>
Message-ID: <001001c9505e$545a1ef0$a101a8c0@officemail>


----- Original Message ----- 
From: "Patrick" <optomatic at rogers.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, November 25, 2008 7:39 PM
Subject: [time-nuts] huntron tracker advice & troubleshooting 
withoutschematic advise


> Hi Everyone
>
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
>
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
>
> Are there other tools that have helped you fix circuit boards without a
> schematic?
>
> Thanks in advance-Patrick

Patrick,
We have used that technique of quick troubleshooting some components off an 
on for forty years, long before the "Huntron tracker came about.

I first saw an article about that method in a service bulletin from Sylvania 
back in the mid 60's.
If you have an x-y scope or a scope that has and external horizontal input 
with variable gain, a small external circuit in addition to the scope will 
do the same thing as the Huntron tracker. This would give you the ability to 
play with it without spending any money.

The circuit consists of a transformer with 3 to 6 volts out, a few 
resistors, diode or two and a switch. If needed I could find the original 
schematic, but doing a google on it turned up a couple of links, noted 
below.

Inexpensive Curve Tracer
http://www.fisica.ucn.cl/sochifi/actas/pdf/A039.pdf
http://groups.google.com/group/rec.audio.tubes/browse_thread/thread/384a37553565e87b

As others have noted in this thread, it doesn't fix anything but can be 
useful in "some" applications. It will quickly identify a short or open and 
with experience, identify most defective "discreet" semiconductors. In the 
case of complex IC's, I doubt it would be much use. If you research the 
Huntron tracker display results, you will see the patterns displayed in 
various semiconductor situations.

As a general rule, servicing electronics, or about anything is simply a 
logic and deduction process. Basic knowledge of the components, theory of 
operation, and of the circuit under test is still necessary.

Phil



From rdarlington at gmail.com  Thu Nov 27 07:16:31 2008
From: rdarlington at gmail.com (Robert Darlington)
Date: Thu, 27 Nov 2008 00:16:31 -0700
Subject: [time-nuts] huntron tracker advice & troubleshooting without
	schematic advise
In-Reply-To: <492C9AC4.3050102@rogers.com>
References: <492C9AC4.3050102@rogers.com>
Message-ID: <b3bd5fcb0811262316o17b6f998j6a79bda500ddc98d@mail.gmail.com>

I picked up a Tektronix 7000 series mainframe scope and a curve tracer
plugin for under $200, and I bet you can too if you look around on eBay.   I
have a Tek 7854 digital storage analog scope (400MHz analog with digital
sampling capabilities, GPIB port, and 4 mainframe slots).   The cart was
another $40 though!

-Bob

On Tue, Nov 25, 2008 at 5:39 PM, Patrick <optomatic at rogers.com> wrote:

> Hi Everyone
>
> I have consistently had success repairing laboratory instruments(my
> small business) when I have a schematic and I have consistently failed
> without one, lots of opportunities are slipping threw my fingers.
>
> I want to invest in tools that will help me troubleshoot without a
> schematic. I was thinking about getting a Huntron tracker. Has anyone
> had any experience with one? Could you feedback?
>
> Are there other tools that have helped you fix circuit boards without a
> schematic?
>
> Thanks in advance-Patrick
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From david.partridge at dsl.pipex.com  Thu Nov 27 07:40:54 2008
From: david.partridge at dsl.pipex.com (David C. Partridge)
Date: Thu, 27 Nov 2008 07:40:54 -0000
Subject: [time-nuts] huntron tracker advice & troubleshooting
	withoutschematic advise
In-Reply-To: <b3bd5fcb0811262316o17b6f998j6a79bda500ddc98d@mail.gmail.com>
References: <492C9AC4.3050102@rogers.com>
	<b3bd5fcb0811262316o17b6f998j6a79bda500ddc98d@mail.gmail.com>
Message-ID: <E9CFE2C3DF5A49ABA66EB738CAE0C2D2@APOLLO>

 I envy you guys over in the US - test gear on the 2nd hand market seems so
much cheaper than here in the UK.   Current shipping costs from USA seem to
wipe out the difference most of the time - I wish they'd bring back the USPS
Surface Mail service.

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Robert Darlington
Sent: 27 November 2008 07:17
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
withoutschematic advise

I picked up a Tektronix 7000 series mainframe scope and a curve tracer
plugin for under $200, and I bet you can too if you look around on eBay.   I
have a Tek 7854 digital storage analog scope (400MHz analog with digital
sampling capabilities, GPIB port, and 4 mainframe slots).   The cart was
another $40 though!

-Bob



From sar10538 at gmail.com  Thu Nov 27 08:21:02 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Thu, 27 Nov 2008 21:21:02 +1300
Subject: [time-nuts] huntron tracker advice & troubleshooting
	withoutschematic advise
In-Reply-To: <E9CFE2C3DF5A49ABA66EB738CAE0C2D2@APOLLO>
References: <492C9AC4.3050102@rogers.com>
	<b3bd5fcb0811262316o17b6f998j6a79bda500ddc98d@mail.gmail.com>
	<E9CFE2C3DF5A49ABA66EB738CAE0C2D2@APOLLO>
Message-ID: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>

And I envy you guys in the UK and the US as over here in New Zealand
there is little to be had and anything that comes up costs an arm and
a leg. My Mother is just emigrating over here and so I bought a few
items (all I could afford) and had them sent to her so they can come
over in the container with her furniture etc as there is no way I
could afford the shipping otherwise. At least shipping via surface was
a workable option with heavy items like scopes, even with the 3 month
wait, but that is now gone :(

The other thing that really gets my goat is the habit of a lot of US
eBay sellers who won't ship outside of the country. What really rubs
is that it's usually the really hard to locate items or the ones that
are going really cheap that will not ship. They always say that you
can bid if you have a US address to ship to but that is hopeless for
me.

Still, I have a great lifestyle over here and wouldn't swap it for the
US or going back home to Blighty anytime soon.

73
Steve

2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>  I envy you guys over in the US - test gear on the 2nd hand market seems so
> much cheaper than here in the UK.   Current shipping costs from USA seem to
> wipe out the difference most of the time - I wish they'd bring back the USPS
> Surface Mail service.
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Robert Darlington
> Sent: 27 November 2008 07:17
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
> withoutschematic advise
>
> I picked up a Tektronix 7000 series mainframe scope and a curve tracer
> plugin for under $200, and I bet you can too if you look around on eBay.   I
> have a Tek 7854 digital storage analog scope (400MHz analog with digital
> sampling capabilities, GPIB port, and 4 mainframe slots).   The cart was
> another $40 though!
>
> -Bob
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From robert8rpi at yahoo.co.uk  Thu Nov 27 08:42:13 2008
From: robert8rpi at yahoo.co.uk (Robert Atkinson)
Date: Thu, 27 Nov 2008 08:42:13 +0000 (GMT)
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>
Message-ID: <693057.30597.qm@web27103.mail.ukl.yahoo.com>

One reasion why many US dealers will not ship otside the USA is the ITAR export regulations (Google it!). These are very hard to follow and the penalties are heavy. I know a couple of dealers have been warned and have just decided not to export anything rather than take the risk. 
Robert G8RPI.

--- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:

From: Steve Rooke <sar10538 at gmail.com>
Subject: Re: [time-nuts] huntron tracker advice & troubleshooting withoutschematic advise
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Thursday, 27 November, 2008, 8:21 AM

And I envy you guys in the UK and the US as over here in New Zealand
there is little to be had and anything that comes up costs an arm and
a leg. My Mother is just emigrating over here and so I bought a few
items (all I could afford) and had them sent to her so they can come
over in the container with her furniture etc as there is no way I
could afford the shipping otherwise. At least shipping via surface was
a workable option with heavy items like scopes, even with the 3 month
wait, but that is now gone :(

The other thing that really gets my goat is the habit of a lot of US
eBay sellers who won't ship outside of the country. What really rubs
is that it's usually the really hard to locate items or the ones that
are going really cheap that will not ship. They always say that you
can bid if you have a US address to ship to but that is hopeless for
me.

Still, I have a great lifestyle over here and wouldn't swap it for the
US or going back home to Blighty anytime soon.

73
Steve

2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>  I envy you guys over in the US - test gear on the 2nd hand market seems
so
> much cheaper than here in the UK.   Current shipping costs from USA seem
to
> wipe out the difference most of the time - I wish they'd bring back
the USPS
> Surface Mail service.
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Robert Darlington
> Sent: 27 November 2008 07:17
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
> withoutschematic advise
>
> I picked up a Tektronix 7000 series mainframe scope and a curve tracer
> plugin for under $200, and I bet you can too if you look around on eBay.  
I
> have a Tek 7854 digital storage analog scope (400MHz analog with digital
> sampling capabilities, GPIB port, and 4 mainframe slots).   The cart was
> another $40 though!
>
> -Bob
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.



      

From sar10538 at gmail.com  Thu Nov 27 08:55:26 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Thu, 27 Nov 2008 21:55:26 +1300
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <693057.30597.qm@web27103.mail.ukl.yahoo.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>
	<693057.30597.qm@web27103.mail.ukl.yahoo.com>
Message-ID: <1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>

Hmmm... International Traffic in Arms Regulations, well I don't like
to poke holes in that excuse but unless the US customs are REALLY
paranoid, I can't see how most of the items I have tried to purchase
would be covered under this. But, I suppose you could poke someone in
the eye with a ball-point pen therefore it could be labled an an arm
but I'm sure there are other reasons for most of refusals to ship
outside the 48 States. It's not just a couple of dealers who take this
position, it seems to be the case with a number of sellers sadly.

What I need is a magic wormhole that runs from a US address and ends
up in my home. Anyone got a design for one of these, sort of like a
stargate :-)

73, Steve - ZL3TUV

2008/11/27 Robert Atkinson <robert8rpi at yahoo.co.uk>:
> One reasion why many US dealers will not ship otside the USA is the ITAR export regulations (Google it!). These are very hard to follow and the penalties are heavy. I know a couple of dealers have been warned and have just decided not to export anything rather than take the risk.
> Robert G8RPI.
>
> --- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
>
> From: Steve Rooke <sar10538 at gmail.com>
> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting withoutschematic advise
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> Date: Thursday, 27 November, 2008, 8:21 AM
>
> And I envy you guys in the UK and the US as over here in New Zealand
> there is little to be had and anything that comes up costs an arm and
> a leg. My Mother is just emigrating over here and so I bought a few
> items (all I could afford) and had them sent to her so they can come
> over in the container with her furniture etc as there is no way I
> could afford the shipping otherwise. At least shipping via surface was
> a workable option with heavy items like scopes, even with the 3 month
> wait, but that is now gone :(
>
> The other thing that really gets my goat is the habit of a lot of US
> eBay sellers who won't ship outside of the country. What really rubs
> is that it's usually the really hard to locate items or the ones that
> are going really cheap that will not ship. They always say that you
> can bid if you have a US address to ship to but that is hopeless for
> me.
>
> Still, I have a great lifestyle over here and wouldn't swap it for the
> US or going back home to Blighty anytime soon.
>
> 73
> Steve
>
> 2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>>  I envy you guys over in the US - test gear on the 2nd hand market seems
> so
>> much cheaper than here in the UK.   Current shipping costs from USA seem
> to
>> wipe out the difference most of the time - I wish they'd bring back
> the USPS
>> Surface Mail service.
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Robert Darlington
>> Sent: 27 November 2008 07:17
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
>> withoutschematic advise
>>
>> I picked up a Tektronix 7000 series mainframe scope and a curve tracer
>> plugin for under $200, and I bet you can too if you look around on eBay.
> I
>> have a Tek 7854 digital storage analog scope (400MHz analog with digital
>> sampling capabilities, GPIB port, and 4 mainframe slots).   The cart was
>> another $40 though!
>>
>> -Bob
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
>
> --
> Steve Rooke - ZL3TUV & G8KVD
> Omnium finis imminet
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From grant at ghengineering.co.uk  Thu Nov 27 09:38:37 2008
From: grant at ghengineering.co.uk (Grant Hodgson)
Date: Thu, 27 Nov 2008 09:38:37 +0000
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <mailman.374.1227776131.2542.time-nuts@febo.com>
References: <mailman.374.1227776131.2542.time-nuts@febo.com>
Message-ID: <492E6A9D.9000203@ghengineering.co.uk>

There are companies that provide a 'real' USA mail address and then 
forward the items on, overseas.

Google 'US address' and 'USA address'.

regards

Grant


From namichie at gmail.com  Thu Nov 27 09:46:58 2008
From: namichie at gmail.com (Neville Michie)
Date: Thu, 27 Nov 2008 20:46:58 +1100
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>
	<693057.30597.qm@web27103.mail.ukl.yahoo.com>
	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
Message-ID: <1A362720-7682-4EAC-AEB8-E8DEF8EB96C6@gmail.com>

Many US or UK sellers will sell out of their country if you email  
them and ask them,
even if they list as home country only.
I bought an HP 54501A oscilloscope from US, and it was sent to  
Australia.
Cost 30% more with the freight, but it was still only a few hundred  
dollars,
and I would not have found anything as useful in Australia at the price.
cheers, Neville Michie

On 27/11/2008, at 7:55 PM, Steve Rooke wrote:

> Hmmm... International Traffic in Arms Regulations, well I don't like
> to poke holes in that excuse but unless the US customs are REALLY
> paranoid, I can't see how most of the items I have tried to purchase
> would be covered under this. But, I suppose you could poke someone in
> the eye with a ball-point pen therefore it could be labled an an arm
> but I'm sure there are other reasons for most of refusals to ship
> outside the 48 States. It's not just a couple of dealers who take this
> position, it seems to be the case with a number of sellers sadly.
>
> What I need is a magic wormhole that runs from a US address and ends
> up in my home. Anyone got a design for one of these, sort of like a
> stargate :-)
>
> 73, Steve - ZL3TUV
>
> 2008/11/27 Robert Atkinson <robert8rpi at yahoo.co.uk>:
>> One reasion why many US dealers will not ship otside the USA is  
>> the ITAR export regulations (Google it!). These are very hard to  
>> follow and the penalties are heavy. I know a couple of dealers  
>> have been warned and have just decided not to export anything  
>> rather than take the risk.
>> Robert G8RPI.
>>
>> --- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
>>
>> From: Steve Rooke <sar10538 at gmail.com>
>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting  
>> withoutschematic advise
>> To: "Discussion of precise time and frequency measurement" <time- 
>> nuts at febo.com>
>> Date: Thursday, 27 November, 2008, 8:21 AM
>>
>> And I envy you guys in the UK and the US as over here in New Zealand
>> there is little to be had and anything that comes up costs an arm and
>> a leg. My Mother is just emigrating over here and so I bought a few
>> items (all I could afford) and had them sent to her so they can come
>> over in the container with her furniture etc as there is no way I
>> could afford the shipping otherwise. At least shipping via surface  
>> was
>> a workable option with heavy items like scopes, even with the 3 month
>> wait, but that is now gone :(
>>
>> The other thing that really gets my goat is the habit of a lot of US
>> eBay sellers who won't ship outside of the country. What really rubs
>> is that it's usually the really hard to locate items or the ones that
>> are going really cheap that will not ship. They always say that you
>> can bid if you have a US address to ship to but that is hopeless for
>> me.
>>
>> Still, I have a great lifestyle over here and wouldn't swap it for  
>> the
>> US or going back home to Blighty anytime soon.
>>
>> 73
>> Steve
>>
>> 2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>>>  I envy you guys over in the US - test gear on the 2nd hand  
>>> market seems
>> so
>>> much cheaper than here in the UK.   Current shipping costs from  
>>> USA seem
>> to
>>> wipe out the difference most of the time - I wish they'd bring back
>> the USPS
>>> Surface Mail service.
>>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
>>> bounces at febo.com] On
>>> Behalf Of Robert Darlington
>>> Sent: 27 November 2008 07:17
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
>>> withoutschematic advise
>>>
>>> I picked up a Tektronix 7000 series mainframe scope and a curve  
>>> tracer
>>> plugin for under $200, and I bet you can too if you look around  
>>> on eBay.
>> I
>>> have a Tek 7854 digital storage analog scope (400MHz analog with  
>>> digital
>>> sampling capabilities, GPIB port, and 4 mainframe slots).   The  
>>> cart was
>>> another $40 though!
>>>
>>> -Bob
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>
>>
>>
>> --
>> Steve Rooke - ZL3TUV & G8KVD
>> Omnium finis imminet
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>> listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>> listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
>
> -- 
> Steve Rooke - ZL3TUV & G8KVD
> Omnium finis imminet
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.



From magnus at rubidium.dyndns.org  Thu Nov 27 11:16:37 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Thu, 27 Nov 2008 12:16:37 +0100
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492D1E82.4080005@tudelft.nl>
References: <492C9AC4.3050102@rogers.com> <492D1E82.4080005@tudelft.nl>
Message-ID: <492E8195.2000802@rubidium.dyndns.org>

Jeroen Bastemeijer skrev:
> Hi Patrick,
> 
> I saw a lot of replies to your question. Here are my five cents:
> 
> The Huntron Tracker is very nice if you have two similar pieces of 
> equipment (or circuit boards). From which: one is faulty, the other one 
> still okay, or has a different fault. By probing around you can easily 
> find the faulty part or component, by looking for differences in the 
> Huntrons display. E.g. a faulty transitor will give a different curve, 
> even when other circuitry is connected to it.

You can do that, but you need to know what is expected. The easiest way 
to know that is to probe the same point on a working board. Otherwise 
you would need to think for yourself and here a factor of confusion 
comes in. Add the factor of unknown when you don't have a schematic.

With two boards and no schematic you have a chance. There are a class of 
errors the Huntron can't find, errors internal to a chip or module. They 
do not need to show up at all. Consider for instance a bit error in an 
EPROM. One or a few bit errors may be exactly what is needed for a total 
failure.

> However, I used to work at an small repair shop. Here we also got lots 
> of equipment for which the schematics were not available (usually it was 
> classified or obsolete). Although we had access to a Huntron Tracker, we 
> didn't use it much. Most of the time, a multimeter and some "common 
> sense" did the trick.

Indeed. But you do develop your strategies based on the tools you have. 
You could have chosen a tracker based strategy.

> One final remark, about the reply from Bruce; There are oscilloscopes 
> out there who have the component tester (that is what he reffered to) 
> built in. My first oscilloscope I bought, a Handykit, has the 
> component-tester built-in. For that reason that scope is still with me ;-)

If nothing else, it is a very good educational tool.

Cheers,
Magnus


From optomatic at rogers.com  Thu Nov 27 12:02:06 2008
From: optomatic at rogers.com (Patrick)
Date: Thu, 27 Nov 2008 07:02:06 -0500
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <1A362720-7682-4EAC-AEB8-E8DEF8EB96C6@gmail.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>	<693057.30597.qm@web27103.mail.ukl.yahoo.com>	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
	<1A362720-7682-4EAC-AEB8-E8DEF8EB96C6@gmail.com>
Message-ID: <492E8C3E.5090608@rogers.com>

I am on the lower end(maybe dumbest) of the intelligence spectrum on
this list when it comes to pure electronics. However I have plenty to
offer in logistics. I ship all over the world, this week it was Nigeria
and Lebanon from my home based business in Canada.

Virtually all of my parts come from the U.S.

I have a P.O box at a UPS store in New Hampshire. I had one in N.Y state
before but I ended up paying state taxes for certain items. It is
hopeless to claim these taxes back as a foreign entity. N.H has 0% state
taxes, taxes are due in the state that you take possession in. However
if you arrange for shipping via a third party some states, such as
Michigan, will have deemed you to already have taken possession even
though you never entered the country.

With the dark spectra of a severe recession looming on most of us I find
myself in a peculiar situation. I have little money but the cliente`le I
service are dying for the products I sell. I could easily sell >20X what
I do now. I have been trying to slow my business down for months in the
hope of re-organizing myself but to no avail. I can't hire anyone, as I
work from home due to some health issues with my Wife and Son.

I can't promise anything at this time but if someone would like help
shipping items out of the U.S(or Canada) I would love to help. The
logistics of servicing unknown equipment from a far is likely impossible
to overcome but I have plenty of work that needs to get done. If
something could be worked out I would gladly pay for shipping or
shipping & labor for help with my business.

-Patrick


Neville Michie wrote:
> Many US or UK sellers will sell out of their country if you email  
> them and ask them,
> even if they list as home country only.
> I bought an HP 54501A oscilloscope from US, and it was sent to  
> Australia.
> Cost 30% more with the freight, but it was still only a few hundred  
> dollars,
> and I would not have found anything as useful in Australia at the price.
> cheers, Neville Michie
>
> On 27/11/2008, at 7:55 PM, Steve Rooke wrote:
>
>   
>> Hmmm... International Traffic in Arms Regulations, well I don't like
>> to poke holes in that excuse but unless the US customs are REALLY
>> paranoid, I can't see how most of the items I have tried to purchase
>> would be covered under this. But, I suppose you could poke someone in
>> the eye with a ball-point pen therefore it could be labled an an arm
>> but I'm sure there are other reasons for most of refusals to ship
>> outside the 48 States. It's not just a couple of dealers who take this
>> position, it seems to be the case with a number of sellers sadly.
>>
>> What I need is a magic wormhole that runs from a US address and ends
>> up in my home. Anyone got a design for one of these, sort of like a
>> stargate :-)
>>
>> 73, Steve - ZL3TUV
>>
>> 2008/11/27 Robert Atkinson <robert8rpi at yahoo.co.uk>:
>>     
>>> One reasion why many US dealers will not ship otside the USA is  
>>> the ITAR export regulations (Google it!). These are very hard to  
>>> follow and the penalties are heavy. I know a couple of dealers  
>>> have been warned and have just decided not to export anything  
>>> rather than take the risk.
>>> Robert G8RPI.
>>>
>>> --- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
>>>
>>> From: Steve Rooke <sar10538 at gmail.com>
>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting  
>>> withoutschematic advise
>>> To: "Discussion of precise time and frequency measurement" <time- 
>>> nuts at febo.com>
>>> Date: Thursday, 27 November, 2008, 8:21 AM
>>>
>>> And I envy you guys in the UK and the US as over here in New Zealand
>>> there is little to be had and anything that comes up costs an arm and
>>> a leg. My Mother is just emigrating over here and so I bought a few
>>> items (all I could afford) and had them sent to her so they can come
>>> over in the container with her furniture etc as there is no way I
>>> could afford the shipping otherwise. At least shipping via surface  
>>> was
>>> a workable option with heavy items like scopes, even with the 3 month
>>> wait, but that is now gone :(
>>>
>>> The other thing that really gets my goat is the habit of a lot of US
>>> eBay sellers who won't ship outside of the country. What really rubs
>>> is that it's usually the really hard to locate items or the ones that
>>> are going really cheap that will not ship. They always say that you
>>> can bid if you have a US address to ship to but that is hopeless for
>>> me.
>>>
>>> Still, I have a great lifestyle over here and wouldn't swap it for  
>>> the
>>> US or going back home to Blighty anytime soon.
>>>
>>> 73
>>> Steve
>>>
>>> 2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>>>       
>>>>  I envy you guys over in the US - test gear on the 2nd hand  
>>>> market seems
>>>>         
>>> so
>>>       
>>>> much cheaper than here in the UK.   Current shipping costs from  
>>>> USA seem
>>>>         
>>> to
>>>       
>>>> wipe out the difference most of the time - I wish they'd bring back
>>>>         
>>> the USPS
>>>       
>>>> Surface Mail service.
>>>>
>>>> -----Original Message-----
>>>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
>>>> bounces at febo.com] On
>>>> Behalf Of Robert Darlington
>>>> Sent: 27 November 2008 07:17
>>>> To: Discussion of precise time and frequency measurement
>>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
>>>> withoutschematic advise
>>>>
>>>> I picked up a Tektronix 7000 series mainframe scope and a curve  
>>>> tracer
>>>> plugin for under $200, and I bet you can too if you look around  
>>>> on eBay.
>>>>         
>>> I
>>>       
>>>> have a Tek 7854 digital storage analog scope (400MHz analog with  
>>>> digital
>>>> sampling capabilities, GPIB port, and 4 mainframe slots).   The  
>>>> cart was
>>>> another $40 though!
>>>>
>>>> -Bob
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com
>>>> To unsubscribe, go to
>>>>         
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>       
>>>> and follow the instructions there.
>>>>
>>>>         
>>>
>>> --
>>> Steve Rooke - ZL3TUV & G8KVD
>>> Omnium finis imminet
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>>> listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>>> listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>       
>>
>> -- 
>> Steve Rooke - ZL3TUV & G8KVD
>> Omnium finis imminet
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
>> time-nuts
>> and follow the instructions there.
>>     
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>   



From j.bastemeijer at tudelft.nl  Thu Nov 27 12:15:22 2008
From: j.bastemeijer at tudelft.nl (Jeroen Bastemeijer)
Date: Thu, 27 Nov 2008 13:15:22 +0100
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492E8195.2000802@rubidium.dyndns.org>
References: <492C9AC4.3050102@rogers.com> <492D1E82.4080005@tudelft.nl>
	<492E8195.2000802@rubidium.dyndns.org>
Message-ID: <492E8F5A.6070002@tudelft.nl>

Hi Magnus,

I totally agree with you. But doing a quick repair is more an art than a 
science ;-) By having some feeling for common faults it is easier to 
locate them.

The Huntron tracker was of use for equipment which was almost impossible 
to service when under power. For example power-electronics with high 
voltages and nice little radios which consisted of a stack of boards, 
here it was impossible to probe around. The only solution was soldeing a 
wire to a component, assemble the whole thing, switch on measure... for 
testing another point, the whole procedure had to be repeated. Ok, for 
some equipment we used extension cables, but it was not always possible 
to use them.

Some failures are very difficult to track: Firmware related problems. 
The only solution to that, was finding a working unit and copy the 
firmware to the faulty machine (e.g. EEPROM copying)....

But as I indicated in the beginning: Repairing is more like an art than 
a science. Over the years a whole bunch of tricks and strategies was 
developed to locate the faults and fix them. Repairing needs a solid 
background in electronics and a lot of experience.

But: When you manage to repair something, it usually gives a lot of 
satisfaction! ;-)

Best regards, Jeroen
Magnus Danielson wrote:
> Jeroen Bastemeijer skrev:
>   
>> Hi Patrick,
>>
>> I saw a lot of replies to your question. Here are my five cents:
>>
>> The Huntron Tracker is very nice if you have two similar pieces of 
>> equipment (or circuit boards). From which: one is faulty, the other one 
>> still okay, or has a different fault. By probing around you can easily 
>> find the faulty part or component, by looking for differences in the 
>> Huntrons display. E.g. a faulty transitor will give a different curve, 
>> even when other circuitry is connected to it.
>>     
>
> You can do that, but you need to know what is expected. The easiest way 
> to know that is to probe the same point on a working board. Otherwise 
> you would need to think for yourself and here a factor of confusion 
> comes in. Add the factor of unknown when you don't have a schematic.
>
> With two boards and no schematic you have a chance. There are a class of 
> errors the Huntron can't find, errors internal to a chip or module. They 
> do not need to show up at all. Consider for instance a bit error in an 
> EPROM. One or a few bit errors may be exactly what is needed for a total 
> failure.
>
>   
>> However, I used to work at an small repair shop. Here we also got lots 
>> of equipment for which the schematics were not available (usually it was 
>> classified or obsolete). Although we had access to a Huntron Tracker, we 
>> didn't use it much. Most of the time, a multimeter and some "common 
>> sense" did the trick.
>>     
>
> Indeed. But you do develop your strategies based on the tools you have. 
> You could have chosen a tracker based strategy.
>
>   
>> One final remark, about the reply from Bruce; There are oscilloscopes 
>> out there who have the component tester (that is what he reffered to) 
>> built in. My first oscilloscope I bought, a Handykit, has the 
>> component-tester built-in. For that reason that scope is still with me ;-)
>>     
>
> If nothing else, it is a very good educational tool.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>   
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From optomatic at rogers.com  Thu Nov 27 12:21:55 2008
From: optomatic at rogers.com (Patrick)
Date: Thu, 27 Nov 2008 07:21:55 -0500
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <492E8C3E.5090608@rogers.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>	<693057.30597.qm@web27103.mail.ukl.yahoo.com>	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>	<1A362720-7682-4EAC-AEB8-E8DEF8EB96C6@gmail.com>
	<492E8C3E.5090608@rogers.com>
Message-ID: <492E90E3.5080403@rogers.com>

BTW since we are talking about Ebay, they are not the only game in town.
I buy lots of laboratory instruments of Dovebid. Dovebid has been
purchased my Go-industry and their site is a mess. They are also
incredibly cruel bastards. When you purchase something from them you buy
it as-is, where-is. You need to hire someone from a UPS store to come to
the auction site, pick it up, pack it and ship it to you. They charge
you the state taxes and they will rarely refund them to you. Despite the
fact that they are so evil, much of the equipment is cheaper and of much
higher quality then that found on Ebay, you just need to find out why it
is being liquidated to begin with. Companies that are shutting down are
usually safer then those still standing. They always have scopes and
other equipment such as x-ray inspection units etc...

Equipnet and Bidspotter are two other sites that may be of use from time
to time-Patrick

Patrick wrote:
> I am on the lower end(maybe dumbest) of the intelligence spectrum on
> this list when it comes to pure electronics. However I have plenty to
> offer in logistics. I ship all over the world, this week it was Nigeria
> and Lebanon from my home based business in Canada.
>
> Virtually all of my parts come from the U.S.
>
> I have a P.O box at a UPS store in New Hampshire. I had one in N.Y state
> before but I ended up paying state taxes for certain items. It is
> hopeless to claim these taxes back as a foreign entity. N.H has 0% state
> taxes, taxes are due in the state that you take possession in. However
> if you arrange for shipping via a third party some states, such as
> Michigan, will have deemed you to already have taken possession even
> though you never entered the country.
>
> With the dark spectra of a severe recession looming on most of us I find
> myself in a peculiar situation. I have little money but the cliente`le I
> service are dying for the products I sell. I could easily sell >20X what
> I do now. I have been trying to slow my business down for months in the
> hope of re-organizing myself but to no avail. I can't hire anyone, as I
> work from home due to some health issues with my Wife and Son.
>
> I can't promise anything at this time but if someone would like help
> shipping items out of the U.S(or Canada) I would love to help. The
> logistics of servicing unknown equipment from a far is likely impossible
> to overcome but I have plenty of work that needs to get done. If
> something could be worked out I would gladly pay for shipping or
> shipping & labor for help with my business.
>
> -Patrick
>
>
> Neville Michie wrote:
>   
>> Many US or UK sellers will sell out of their country if you email  
>> them and ask them,
>> even if they list as home country only.
>> I bought an HP 54501A oscilloscope from US, and it was sent to  
>> Australia.
>> Cost 30% more with the freight, but it was still only a few hundred  
>> dollars,
>> and I would not have found anything as useful in Australia at the price.
>> cheers, Neville Michie
>>
>> On 27/11/2008, at 7:55 PM, Steve Rooke wrote:
>>
>>   
>>     
>>> Hmmm... International Traffic in Arms Regulations, well I don't like
>>> to poke holes in that excuse but unless the US customs are REALLY
>>> paranoid, I can't see how most of the items I have tried to purchase
>>> would be covered under this. But, I suppose you could poke someone in
>>> the eye with a ball-point pen therefore it could be labled an an arm
>>> but I'm sure there are other reasons for most of refusals to ship
>>> outside the 48 States. It's not just a couple of dealers who take this
>>> position, it seems to be the case with a number of sellers sadly.
>>>
>>> What I need is a magic wormhole that runs from a US address and ends
>>> up in my home. Anyone got a design for one of these, sort of like a
>>> stargate :-)
>>>
>>> 73, Steve - ZL3TUV
>>>
>>> 2008/11/27 Robert Atkinson <robert8rpi at yahoo.co.uk>:
>>>     
>>>       
>>>> One reasion why many US dealers will not ship otside the USA is  
>>>> the ITAR export regulations (Google it!). These are very hard to  
>>>> follow and the penalties are heavy. I know a couple of dealers  
>>>> have been warned and have just decided not to export anything  
>>>> rather than take the risk.
>>>> Robert G8RPI.
>>>>
>>>> --- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
>>>>
>>>> From: Steve Rooke <sar10538 at gmail.com>
>>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting  
>>>> withoutschematic advise
>>>> To: "Discussion of precise time and frequency measurement" <time- 
>>>> nuts at febo.com>
>>>> Date: Thursday, 27 November, 2008, 8:21 AM
>>>>
>>>> And I envy you guys in the UK and the US as over here in New Zealand
>>>> there is little to be had and anything that comes up costs an arm and
>>>> a leg. My Mother is just emigrating over here and so I bought a few
>>>> items (all I could afford) and had them sent to her so they can come
>>>> over in the container with her furniture etc as there is no way I
>>>> could afford the shipping otherwise. At least shipping via surface  
>>>> was
>>>> a workable option with heavy items like scopes, even with the 3 month
>>>> wait, but that is now gone :(
>>>>
>>>> The other thing that really gets my goat is the habit of a lot of US
>>>> eBay sellers who won't ship outside of the country. What really rubs
>>>> is that it's usually the really hard to locate items or the ones that
>>>> are going really cheap that will not ship. They always say that you
>>>> can bid if you have a US address to ship to but that is hopeless for
>>>> me.
>>>>
>>>> Still, I have a great lifestyle over here and wouldn't swap it for  
>>>> the
>>>> US or going back home to Blighty anytime soon.
>>>>
>>>> 73
>>>> Steve
>>>>
>>>> 2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
>>>>       
>>>>         
>>>>>  I envy you guys over in the US - test gear on the 2nd hand  
>>>>> market seems
>>>>>         
>>>>>           
>>>> so
>>>>       
>>>>         
>>>>> much cheaper than here in the UK.   Current shipping costs from  
>>>>> USA seem
>>>>>         
>>>>>           
>>>> to
>>>>       
>>>>         
>>>>> wipe out the difference most of the time - I wish they'd bring back
>>>>>         
>>>>>           
>>>> the USPS
>>>>       
>>>>         
>>>>> Surface Mail service.
>>>>>
>>>>> -----Original Message-----
>>>>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
>>>>> bounces at febo.com] On
>>>>> Behalf Of Robert Darlington
>>>>> Sent: 27 November 2008 07:17
>>>>> To: Discussion of precise time and frequency measurement
>>>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
>>>>> withoutschematic advise
>>>>>
>>>>> I picked up a Tektronix 7000 series mainframe scope and a curve  
>>>>> tracer
>>>>> plugin for under $200, and I bet you can too if you look around  
>>>>> on eBay.
>>>>>         
>>>>>           
>>>> I
>>>>       
>>>>         
>>>>> have a Tek 7854 digital storage analog scope (400MHz analog with  
>>>>> digital
>>>>> sampling capabilities, GPIB port, and 4 mainframe slots).   The  
>>>>> cart was
>>>>> another $40 though!
>>>>>
>>>>> -Bob
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>> To unsubscribe, go to
>>>>>         
>>>>>           
>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>       
>>>>         
>>>>> and follow the instructions there.
>>>>>
>>>>>         
>>>>>           
>>>> --
>>>> Steve Rooke - ZL3TUV & G8KVD
>>>> Omnium finis imminet
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com
>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>>>> listinfo/time-nuts
>>>> and follow the instructions there.
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com
>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
>>>> listinfo/time-nuts
>>>> and follow the instructions there.
>>>>
>>>>       
>>>>         
>>> -- 
>>> Steve Rooke - ZL3TUV & G8KVD
>>> Omnium finis imminet
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
>>> time-nuts
>>> and follow the instructions there.
>>>     
>>>       
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>   
>>     
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>   



From james.p.lux at jpl.nasa.gov  Thu Nov 27 13:54:51 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Thu, 27 Nov 2008 05:54:51 -0800
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <693057.30597.qm@web27103.mail.ukl.yahoo.com>
Message-ID: <C553E6AB.2F0A%James.P.Lux@jpl.nasa.gov>




On 11/27/08 12:42 AM, "Robert Atkinson" <robert8rpi at yahoo.co.uk> wrote:

> One reasion why many US dealers will not ship otside the USA is the ITAR
> export regulations (Google it!). These are very hard to follow and the
> penalties are heavy. I know a couple of dealers have been warned and have just
> decided not to export anything rather than take the risk.
> Robert G8RPI.
>

Too bad "I ship only to US addresses" isn't a safe harbor for ITAR.  What if
"foreign person" Bob Smith lives in Podunk, Iowa...  You'll still go to jail
if Bob Smith happens to be a representative for a evil-doer, even if ol' Bob
was born, lived, and makes his home in Podunk and takes care of his mother,
eats apple pie, and plays baseball every week.

I think the ebay "CONUS only" phenomenon is more laziness... You could have
a single shipping fee.

There's also the purported difficulty of getting paid from a foreign country
(hmm.. Services like PayPal, might have fixed that)



From cfharris at erols.com  Thu Nov 27 15:12:13 2008
From: cfharris at erols.com (Chuck Harris)
Date: Thu, 27 Nov 2008 10:12:13 -0500
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>	<693057.30597.qm@web27103.mail.ukl.yahoo.com>
	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
Message-ID: <492EB8CD.2090608@erols.com>

Steve Rooke wrote:
> Hmmm... International Traffic in Arms Regulations, well I don't like
> to poke holes in that excuse but unless the US customs are REALLY
> paranoid, I can't see how most of the items I have tried to purchase

Fortunately, the determination of what is ITAR is not left up to you to
see, but rather is determined by the DOD and the State Department... where
they use the most highly placed morons to scientifically assess the risk
and make the classifications.

They are from the government, and they are here to help you.

> would be covered under this. But, I suppose you could poke someone in
> the eye with a ball-point pen therefore it could be labled an an arm
> but I'm sure there are other reasons for most of refusals to ship
> outside the 48 States. It's not just a couple of dealers who take this
> position, it seems to be the case with a number of sellers sadly.

If you have ever been on the other side of an ITAR investigation, you
would rightly conclude that it isn't safe to do anything other than scrap
and destroy US surplus materials... which is precisely what they want you
to do.

-Chuck Harris


From stanley_reynolds at yahoo.com  Thu Nov 27 16:28:41 2008
From: stanley_reynolds at yahoo.com (Stanley Reynolds)
Date: Thu, 27 Nov 2008 08:28:41 -0800 (PST)
Subject: [time-nuts] US Shipping Was huntron tracker advice
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>
	<693057.30597.qm@web27103.mail.ukl.yahoo.com>
	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
	<492EB8CD.2090608@erols.com>
Message-ID: <706199.30125.qm@web30308.mail.mud.yahoo.com>





________________________________

From: Chuck Harris <cfharris at erols.com>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Thursday, November 27, 2008 9:12:13 AM
Subject: Re: [time-nuts] US Shipping Was huntron tracker advice


The sad part is there is no incentive to reverse the process, once deemed sensitive/restricted it may stay that way forever. I'm sure many items that a End Use Certificate is required for are marked that way just in case. The EUC process is so clumsy and time consuming I could only imagine the de-restricting process would be. Like toxic waste my basement is full of 1950s to 1970s equipment that I must legally dispose?of as long as I'm?compos mentis which is in question just because I agreed to this contract.

Stanley


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Steve Rooke wrote:
> Hmmm... International Traffic in Arms Regulations, well I don't like
> to poke holes in that excuse but unless the US customs are REALLY
> paranoid, I can't see how most of the items I have tried to purchase

Fortunately, the determination of what is ITAR is not left up to you to
see, but rather is determined by the DOD and the State Department... where
they use the most highly placed morons to scientifically assess the risk
and make the classifications.

They are from the government, and they are here to help you.

> would be covered under this. But, I suppose you could poke someone in
> the eye with a ball-point pen therefore it could be labled an an arm
> but I'm sure there are other reasons for most of refusals to ship
> outside the 48 States. It's not just a couple of dealers who take this
> position, it seems to be the case with a number of sellers sadly.

If you have ever been on the other side of an ITAR investigation, you
would rightly conclude that it isn't safe to do anything other than scrap
and destroy US surplus materials... which is precisely what they want you
to do.

-Chuck Harris

From brooke at pacific.net  Thu Nov 27 17:13:24 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Thu, 27 Nov 2008 09:13:24 -0800
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <693057.30597.qm@web27103.mail.ukl.yahoo.com>
References: <693057.30597.qm@web27103.mail.ukl.yahoo.com>
Message-ID: <492ED534.5040204@pacific.net>

Hi David:

I got a couple of Austron 2000 LORAN-C timing receivers from Government 
Liquidation and they required an End Use Certification.  One was sold to 
someone on this list.  Later a couple of investigators showed up at my house 
(that required a long trip from Sacramento and an overnight stay at a hotel, 
two agents = two rooms, food, etc.).  They wanted to see the two receivers or 
get the name and address where they were.  The cost to make this audit far 
exceeded what I paid for the two receivers.  Note these are commercial items, 
not military specific, but I suspect they were purchased for use on a military 
program and so have been tagged with that program's restraints.  Not the 
brightest thing to do, but something that does not require anyone in the 
government to think.

EUC items can be shipped internationally and that's a provision of the terms of 
the EUC.  The problem is that to do it requires getting an export license. 
That's something that I haven't done and probably requires a steep learning 
curve or hiring someone to do it.  Not economical for items that sell for under 
maybe $10k or $100k.

I have a small home business and ship world wide.  But that requires a customs 
form be filled out and attached to the package and most of the time also a trip 
to the Post Office.  So there's an added cost both in terms of dollars and time.

Have Fun,

Brooke Clarke
http://www.prc68.com


From rdarlington at gmail.com  Thu Nov 27 17:41:34 2008
From: rdarlington at gmail.com (Robert Darlington)
Date: Thu, 27 Nov 2008 10:41:34 -0700
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <492ED534.5040204@pacific.net>
References: <693057.30597.qm@web27103.mail.ukl.yahoo.com>
	<492ED534.5040204@pacific.net>
Message-ID: <b3bd5fcb0811270941p64ae72d6gda5ec67db95688b9@mail.gmail.com>

It's much easier to buy our technology back from China after they get it on
the surplus market anyway!

On Thu, Nov 27, 2008 at 10:13 AM, Brooke Clarke <brooke at pacific.net> wrote:

> Hi David:
>
> I got a couple of Austron 2000 LORAN-C timing receivers from Government
> Liquidation and they required an End Use Certification.  One was sold to
> someone on this list.  Later a couple of investigators showed up at my
> house
> (that required a long trip from Sacramento and an overnight stay at a
> hotel,
> two agents = two rooms, food, etc.).  They wanted to see the two receivers
> or
> get the name and address where they were.  The cost to make this audit far
> exceeded what I paid for the two receivers.  Note these are commercial
> items,
> not military specific, but I suspect they were purchased for use on a
> military
> program and so have been tagged with that program's restraints.  Not the
> brightest thing to do, but something that does not require anyone in the
> government to think.
>
> EUC items can be shipped internationally and that's a provision of the
> terms of
> the EUC.  The problem is that to do it requires getting an export license.
> That's something that I haven't done and probably requires a steep learning
> curve or hiring someone to do it.  Not economical for items that sell for
> under
> maybe $10k or $100k.
>
> I have a small home business and ship world wide.  But that requires a
> customs
> form be filled out and attached to the package and most of the time also a
> trip
> to the Post Office.  So there's an added cost both in terms of dollars and
> time.
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

From hmurray at megapathdsl.net  Thu Nov 27 19:32:14 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Thu, 27 Nov 2008 11:32:14 -0800
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: Message from "Steve Rooke" <sar10538@gmail.com> of "Thu,
	27 Nov 2008 21:55:26 +1300."
	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com> 
Message-ID: <20081127193215.F2A69BCD5@ip-64-139-1-69.sjc.megapath.net>


> Hmmm... International Traffic in Arms Regulations, well I don't like
> to poke holes in that excuse but unless the US customs are REALLY
> paranoid, I can't see how most of the items I have tried to purchase
> would be covered under this. But, I suppose you could poke someone in
> the eye with a ball-point pen therefore it could be labled an an arm
> but I'm sure there are other reasons for most of refusals to ship
> outside the 48 States. It's not just a couple of dealers who take this
> position, it seems to be the case with a number of sellers sadly. 

I'm far from an expert on this area, but I can easily sympathize with anybody 
trying to avoid that layer of paperwork.

I used to work for a small company that occasionally shipped equipment to our 
office in OZ.  The paperwork was a pain in the ass.  I like to think that I 
have a reasonable IQ, but I had troubles finding one of their code numbers 
that matched the gear we were shipping.

I suspect anything a time-nut would be interested is likely to be suspicious.


> I got a couple of Austron 2000 LORAN-C timing receivers from
> Government  Liquidation and they required an End Use Certification.
> One was sold to  someone on this list.  Later a couple of
> investigators showed up at my house  (that required a long trip from
> Sacramento and an overnight stay at a hotel,  two agents = two rooms,
> food, etc.).  They wanted to see the two receivers or  get the name
> and address where they were.  The cost to make this audit far
> exceeded what I paid for the two receivers.  Note these are commercial
> items,  not military specific, but I suspect they were purchased for
> use on a military  program and so have been tagged with that program's
> restraints.  Not the  brightest thing to do, but something that does
> not require anyone in the  government to think.

It may be like classified information.  An individual piece of equipment 
isn't critical, but a collection of them is useful for something nasty.

I could also imagine that they were checking you out to see if it was worth 
keeping an eye on you.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From warrensjmail-one at yahoo.com  Thu Nov 27 20:32:46 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Thu, 27 Nov 2008 12:32:46 -0800
Subject: [time-nuts] James Miller Stabilized 10 MHz Oscillator
Message-ID: <00c401c950cf$4f1c5900$6401a8c0@WSOffice>

Ernie

Concerning the James Miller,  "Simple GPS Stabilized 10 MHz Oscillator" 
using 10KHz from the Jupiter-T GPS, schematic posted at
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm

Although the circuit is definitely made very simple by using the 10KHz. 
I feel it has gone just a bit too far, and may be contributing to the poor 
reputation of analog trackers.
The schematic posted has a very basic, easy to fix, 
shortcoming in its Phase detector that limits the performance as a GPSDO.

The basic problem is that circuit as shown does not insure that the 
phase detectors inputs stay at a constant 90 degrees.
This is generally done by providing an integrator at its output, 
and insuring that the XOR's input are truly square.

I'd bet the unit James sales has fixed that issue.

It would be very interesting to see what kind of performance this 
circuit is capable of with the detector's shortcoming removed.


Warren

**************
----- Original Message ----- 
From: <ernieperes at aol.com>
To: <time-nuts at febo.com>
Sent: Monday, November 24, 2008 5:13 AM
Subject: Re: [time-nuts] GPSDO using 100Hz


> Hii Warren,
> 
> have a look on this 
> link...http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
> 
> and he is using the 10KHz...rpt 10KHz not the 100Hz......compare with 
> your circuit diagram... / I would like to see / or the other solution 
> just make the same circuit and with your testing method chk both 
> unit.......with the same OCXO....
> the jupiter eng board is still available in the German Ebay....
> 
> Rgds Ernie.
> 
> 

From magnus at rubidium.dyndns.org  Fri Nov 28 00:52:26 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 28 Nov 2008 01:52:26 +0100
Subject: [time-nuts] huntron tracker advice & troubleshooting without
 schematic advise
In-Reply-To: <492E8F5A.6070002@tudelft.nl>
References: <492C9AC4.3050102@rogers.com>
	<492D1E82.4080005@tudelft.nl>	<492E8195.2000802@rubidium.dyndns.org>
	<492E8F5A.6070002@tudelft.nl>
Message-ID: <492F40CA.1040409@rubidium.dyndns.org>

Hi Jeroen,

Jeroen Bastemeijer skrev:
> Hi Magnus,
> 
> I totally agree with you. But doing a quick repair is more an art than a 
> science ;-) By having some feeling for common faults it is easier to 
> locate them.

Certainly, and I totally agree. Repairing electronics requires 
experience, and you need to gain experience in many diverse fields.
Experience include typical error behaviour of components, designs and 
also knowing typical design types helps. Also learning to "cheat" in a 
safe way can also be rewarding.

> The Huntron tracker was of use for equipment which was almost impossible 
> to service when under power. For example power-electronics with high 
> voltages and nice little radios which consisted of a stack of boards, 
> here it was impossible to probe around. The only solution was soldeing a 
> wire to a component, assemble the whole thing, switch on measure... for 
> testing another point, the whole procedure had to be repeated. Ok, for 
> some equipment we used extension cables, but it was not always possible 
> to use them.

These days the 3,3 V is becoming more and more a high voltage power rail 
from which you can switch down to suitable voltages. 5 V is becoming 
scary high and 12 V or +/- 15 V is just unheard of. Sigh.

> Some failures are very difficult to track: Firmware related problems. 
> The only solution to that, was finding a working unit and copy the 
> firmware to the faulty machine (e.g. EEPROM copying)....

Making backup images of EPROMs etc. is a good thing. While the actual 
EPROM may not be faulty, even single bit errors may be the cause of much 
greif.

> But as I indicated in the beginning: Repairing is more like an art than 
> a science. Over the years a whole bunch of tricks and strategies was 
> developed to locate the faults and fix them. Repairing needs a solid 
> background in electronics and a lot of experience.

Certainly. I find myself being pulled into the lab every now and then to 
aid a debug-hunt. It seems that I am looking a little more out of the 
box than they do... pulling a spec in and point on the error or just 
turn the timebase knob to zoom in on the spurious signal...

> But: When you manage to repair something, it usually gives a lot of 
> satisfaction! ;-)

Certainly. Also, the rarer or more expensive it is, the greater 
satisfaction. Also beating someone to it can be gratifying.

A common mistake is to invent too complex fault causes and try to proove 
those. It is usually a much simpler cause, but the engineer keep 
inventing complex causes.

Cheers,
Magnus


From bob.paddock at gmail.com  Fri Nov 28 01:12:55 2008
From: bob.paddock at gmail.com (Bob Paddock)
Date: Thu, 27 Nov 2008 20:12:55 -0500
Subject: [time-nuts] US Shipping Was huntron tracker advice
In-Reply-To: <492EB8CD.2090608@erols.com>
References: <1231b6a80811270021n405461cfy9b8d437a2978a13b@mail.gmail.com>
	<693057.30597.qm@web27103.mail.ukl.yahoo.com>
	<1231b6a80811270055x2bbd2b0bhf610c39e0f67edb0@mail.gmail.com>
	<492EB8CD.2090608@erols.com>
Message-ID: <bf689bbe0811271712i3437f99gee576f91117a590e@mail.gmail.com>

>
>
> If you have ever been on the other side of an ITAR investigation, you
> would rightly conclude that it isn't safe to do anything other than scrap
> and destroy US surplus materials... which is precisely what they want you
> to do.


In a past life I designed Coal Mining Equipment, back when the 68000
was a new part to the world.  China bought some of our equipment using
the 68K.  We had to jump through hopes to prove that this embedded
system could not launch a missile etc. to the State Department.

The interesting wrinkle was that the delivery truck wrecked on the
way to the mine in China, in China.  Some of our equipment was damaged
and so was the *Cray-1* that we discovered was on the truck too.
We never could find out what it was on that truck for.

An obscure site if you do what to see what is going on in Missile tech
is http://www.mdatechnology.net/ and
http://www.mda.mil/mdalink/html/mdalink.html .

-- 
http://www.wearablesmartsensors.com/
http://www.softwaresafety.net/
http://www.designer-iii.com/
http://www.unusualresearch.com/

From magnus at rubidium.dyndns.org  Fri Nov 28 01:50:30 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 28 Nov 2008 02:50:30 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <2BFB5AF2EF724F709CC612D2AF20876A@pc52>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>	<492AB812.4050403@cembreros.jazztel.es><20081124152247.DCDB0E91529@mail.ebirds.it>	<492B54EA.5070301@rubidium.dyndns.org>
	<2BFB5AF2EF724F709CC612D2AF20876A@pc52>
Message-ID: <492F4E66.7050708@rubidium.dyndns.org>

Tom Van Baak skrev:
>> Yes. I know of several commecial systems. If you only need to do a short 
>> jump, then using fairly basic E/O-O/E equipment should work well 
>> enought. It all depends if you want/can to roll your own or need to buy 
>> a finished product (aka "buy this, and you will be fine!").
> 
> Magnus, what's the typical noise floor, tempco or drift of cheap
> (i.e., non JPL-level) fiber distribution systems like this? Is it less
> than regular coax, or phase stabilized heliax? At 100 m lengths?

The temperature stability is fairly good, but what Bruce posting didn't 
expose is the temperature stability of the laser. The problem is that 
the laser changes frequency (not wavelength as the optics people say, as 
that depends on the refraction index of the material) with temperature. 
This is a fairly dramatic effect over distances. The fiber delay changes 
by three factors: thermal expansion of fiber (lengthwise), change of 
wave-solution as dielectric and physical expansion occurs, and 
wavelength of light. The lasers for WDM networks typically has a peltier 
cooler for stabilizing temperature.

Choice of fiber and laser is also important. Multi-mode fiber is not 
good at all since the dispersion provided by the many different 
wavepaths in the fiber will shift in a not so forgiving fashion. For 
shorter runs like 100 m and with not too high requirements it will be 
fine, but tune up your requirements and you want to go single-mode.

The laser-type is also important. Cheap lasers exhibit a huge number of 
frequencies and when looking at an optical spectrum analyzer it can be 
hard to decide which has most energy... there is typcially a shape but 
the spikes are so many and close that you can't say point out with 
certaintly which will be the strongest peak... it will shift. Also, the 
dispersion that is gained from the aggregate of those peaks is not nice. 
  WDM lasers like those for 1550 nm has a much cleaner spectrum which 
will gain you alot in the dispersion field.

Long distance communication is very dispersion-sensitive and both 
chromatic and non-chromatic dispersion is being considered. While 
inter-symbol interference as such is not that important to a pure sine 
distribution, the stability aspect of dispersion is.

If you want optimum performance for longer taus, there is really no 
option but to do two-way time transfer compensation. Typically the 
process is fairly slow on properly laid fiber. For a pure frequency 
transport, just looping the signal back to the source and do phase 
measure and phase-adjust so that the sent phase compensate the phase 
error will work. This way you can continuously compensate the variations 
out. Such systems is used for instance in DSN and similar systems with 
multiple arrays of antennas at microwave frequencies.

Anyway, I beleive I had the sum of errors become about 85 ps/nm/K/km. 
Could be wrong, it's just a number stuck in my head.

Does this effect occur in real life? Well, naturally I have an anecdote 
to share on that. In Sweden the national power company had put fibers on 
their high voltage cables running through the country. They needed it 
for their internal use, but could of course provide service to others, 
which they do. They have a SDH network on top of that and can then 
provide SDH based services, alongside WDM channels. However, about 7 in 
the Monday mornings in February their SDH network failed as the sync 
went totally bananas. They called in a synchronisation expert which I 
happend to know. He measured the wander and picked up a very nice 
deviation with a huge swing right there in the morning hours. What 
happend? Well, what happens 7 in the Monday mornings which is 
exceptional? That's when they start up all the heavy machinery in the 
industry, they increase heating since it is cold, people wake up and 
turn TVs on etc. etc. etc. Many of the things which have been off or 
turned down during the weekend is starter up. This makes the current go 
up, this makes the power cables go warmer (they will expand quite 
noticably!) and the fiber being pulled on the cable will change 
temperature. As the heater and fiber run over a considerable length 
together, many 100s of km, and the shift in temperature is several C 
then it is not strange that they experienced a huge shift in delay. 
Having heard my comments on this, the synchronisation expert pointed 
this out. They ended up to move the fibers to the relatively unloaded 
ground wire at the top, and have a much more quieter system.

This shows that uncompensated delay even in a good fiber system can eat 
you for lunch.

The depth by which you have buried your fibers is another issue. Deeper 
means higher stability in temperature, as mother wander (the sun) will 
contribute alot at tau = 43,2 ks.

For shorter runs, one way transfer can work well. The requirements on 
stability may be an issue if you have high requirements. If you do a 10 
m run, few would have a problem on an uncompensated system. Off the 
shelf components could probably satisfy most needs even for 100 m or so.

Interestingly enought, there is a Siemens patent for a fiber based 
oscillator. The short term stability of silica fiber is actually quite 
good. It is the long term aspects which can eat you out if you do not 
deal with it.

Consider also things like laser gyroscopes. The stability of the fiber 
is sufficient to detect even small shifts frequency due to Sagnac effect.

Cheers,
Magnus


From magnus at rubidium.dyndns.org  Fri Nov 28 02:07:22 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 28 Nov 2008 03:07:22 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492C4EE4.3050508@xs4all.nl>
References: <492C4EE4.3050508@xs4all.nl>
Message-ID: <492F525A.6010202@rubidium.dyndns.org>

Paul Boven skrev:
> Hi everyone,
> 
> In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, Marco IK1ODO -2
> writes:
>> Hi all,
>>
>> I have to carry a 10 MHz standard frequency signal inside an EMC 
>> screened room via fiber optic cable.
>>
>> Not willing to re-invent the wheel, do something like an optical 
>> standard frequency link exist on the market?
>> I think it is possible to use standard 100MB LAN transceivers, and 
>> POF. Phase noise requirements
>> are not very stringent, and the distance is in the order of some tens 
>> of meters.
> 
> I'm looking into something similar: transmitting an H-Maser signal
> (probably 10MHz) over some 34km using CWDM SFPs. At first glance this
> seems fairly uncomplicated: get some SFPs, and SFP connector + cage. Use
> a fast opamp/differential driver to drive the transmitting SFP, and use
> a similar setup at the other end to transform the received data back to
> 50 ohm unbalanced. How feasible would such a setup be?
> Possible problems might be that a 10MHz squarewave is simply too 'slow'
> to be transmitted by an SFP, which expects 1.25Gb/s 8/10 encoded data.

Not if you choose STM-1 SFPs. STM-1 has a baudrate of 155,52 MBd so a 
cycle will be 15,552 symbols, which is certainly not a problem as a 
STM-1 must be able to handle runs as long as 72 symbols of 0 or 1, and 
then the problem is really in the clock recovery PLL. The AGC will 
certainly work well. These SFPs are of the shelf components. You would 
like to drive them diffrentially and all that, but it is not too hard. 
There are nifty test boards with SMA connectors which would make it easy 
to hook up to form a nice rig.

> Another interesting question would be how much jitter/noise such a setup
> would add?

Consider that for SDH links as such, the jitter must be less than 0,07 
UI, where a UI is the length of a symbol. This turns out to be 450 ps 
for a STM-1. However, that includes ISI which would be essentially 
canceled out for a 10 MHz signal, so you should expect less than that.

It's off the shelf stuff. 34 km is not a big problem. You could pick up 
a pair of 70 km SFPs for better specs, but be sure to not overload the 
input, you might need to insert a damping pad in that case.

STM-4, GE or STM-16 SFPs can also be used, with increased requirements 
on jitter... GE SFPs will probably work very well even if they expect 
8B10B data according to standard, but they are not significantly 
different to the SDH SFPs these days. The expected jitter on STM-16 
would be about 28 ps, but can again be expected to be less...

So, jitter-wise it is a valid solution and off the shelf components will 
probably work well for you. I recommend you to use SFPs with monitoring 
functions, so you can monitor levels, temperatures etc. It's fairly 
simple I2C stuff so it is not big magic there.

Cheers,
Magnus


From magnus at rubidium.dyndns.org  Fri Nov 28 02:14:55 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 28 Nov 2008 03:14:55 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492D8112.1050103@xs4all.nl>
References: <492C4EE4.3050508@xs4all.nl>
	<492C550F.3030701@intt.net>	<1D41E281A3F14FA0B85D3FCDCBC2FD84@didierhp>
	<492D8112.1050103@xs4all.nl>
Message-ID: <492F541F.4010109@rubidium.dyndns.org>

Paul Boven skrev:
> Hi Didier, everyone,
> 
> Didier wrote:
>> By the time you get the signal from the maser through 34 km of fiber optic,
>> what you get at the end might be not better than a decent GPSDO...
> 
> That's exactly what I'm trying to work out before I'll actually start
> building something like that. The JPL device (thanks for the hint, James
> P. Lux) is very interesting, see:
> http://tycho.usno.navy.mil/ptti/1988/Vol%2020_02.pdf
> 
> The JPL system aims to achieve better than 1E17 in 1000s, whereas the
> H-maser in their publication is quoted as 1E15 in the same averaging
> time. They also state that: 'when stabilities higher than 1E15 are
> required the link must be actively stabilized'. So, in a nutshell - If I
> were to build such a system, the first incarnation would be without such
> a compensation system.
> If such a compensation does turn out to be necessary I'd probably not
> use a 50% mirror but simply loop the received data back to the
> trasmitter of the SFP at the receiving end, and use a fiber pair instead
> of a single fiber.

You'd get a fiber-pair anyway, and the SFP provides both transmitter and 
receiver, so use them!

Infact, you should loop back the signal to the original site and monitor 
the signal there. If you use standard SFP testboards, you can take one 
of the signals from the SFP and loop it back to the SFP using a short 
semi-rigid SMA cable and put a 50 Ohm terminator on the other input 
signal. That's all the loopback you would need. Then at the transmitter 
end you use the output and send it to a counter and measure 10 MHz phase 
against the H-maser.

Logg against time and log outdoor temperature as well as lab temperature 
in both ends. Preferably SFP temperature in addition.

Cheers,
Magnus


From bg at lysator.liu.se  Fri Nov 28 03:23:56 2008
From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson)
Date: Fri, 28 Nov 2008 04:23:56 +0100
Subject: [time-nuts] 10 MHz over optical fiber?
In-Reply-To: <492F4E66.7050708@rubidium.dyndns.org>
References: <C54F6D0D.2CED%James.P.Lux@jpl.nasa.gov>
	<492AB812.4050403@cembreros.jazztel.es>
	<20081124152247.DCDB0E91529@mail.ebirds.it>
	<492B54EA.5070301@rubidium.dyndns.org>
	<2BFB5AF2EF724F709CC612D2AF20876A@pc52>
	<492F4E66.7050708@rubidium.dyndns.org>
Message-ID: <1227842636.15718.16.camel@bg-desktop>


On Fri, 2008-11-28 at 02:50 +0100, Magnus Danielson wrote:

> Consider also things like laser gyroscopes. The stability of the fiber 
> is sufficient to detect even small shifts frequency due to Sagnac effect.

Usually called FOGs (Fiber Optic Gyroscope), where the other "laser"
type, no fibers here, is called RLG (Ring Laser Gyroscope).

--

    Bj?rn



From slburris at gmail.com  Fri Nov 28 05:17:40 2008
From: slburris at gmail.com (Scott Burris)
Date: Thu, 27 Nov 2008 21:17:40 -0800
Subject: [time-nuts] any way to bootstrap a frequency standard into a
 voltage or resistance standard?
Message-ID: <492F7EF4.8080909@gmail.com>

Now that many of us have a nice 10Mhz reference courtesy of TAPR,
I was wondering if there was any way to use that to build a precise
voltage or resistance standard?

I've got once of those high precision standard resistors with a sticker
on it noting the actual measured resistance.  Is it still accurate?  Who 
knows?

As well, I have a +5v reference that uses an Analog Devices precision
reference chip as its source.  I have more faith that this reference is
correct within the tolerances specified in the datasheet.

Now if I could somehow take that frequency reference and derive a 
voltage standard or the like, I'd be in business.  But I can't think
of a way that wouldn't require calibration of some sort, and if I had
the means to calibrate, I wouldn't need the standard in the first place.

Any voltage-nuts or resistance-nuts out there?

Scott


From cfharris at erols.com  Fri Nov 28 05:42:27 2008
From: cfharris at erols.com (Chuck Harris)
Date: Fri, 28 Nov 2008 00:42:27 -0500
Subject: [time-nuts] any way to bootstrap a frequency standard into a
 voltage or resistance standard?
In-Reply-To: <492F7EF4.8080909@gmail.com>
References: <492F7EF4.8080909@gmail.com>
Message-ID: <492F84C3.2010108@erols.com>

If I recall correctly, a Josephson Junction is the critter
you are looking for.  Put one at liquid nitrogen temperatures,
feed it with a precise microwave frequency, and it will produce
a known voltage.  Typically, JJ's are strung together to produce
1, or 10 volts.  The US standard volt is defined in terms of a
JJ excited by a particular frequency.

Now what we need is a TAPR priced JJ array.

-Chuck Harris

Scott Burris wrote:
> Now that many of us have a nice 10Mhz reference courtesy of TAPR,
> I was wondering if there was any way to use that to build a precise
> voltage or resistance standard?
> 
> I've got once of those high precision standard resistors with a sticker
> on it noting the actual measured resistance.  Is it still accurate?  Who 
> knows?
> 
> As well, I have a +5v reference that uses an Analog Devices precision
> reference chip as its source.  I have more faith that this reference is
> correct within the tolerances specified in the datasheet.
> 
> Now if I could somehow take that frequency reference and derive a 
> voltage standard or the like, I'd be in business.  But I can't think
> of a way that wouldn't require calibration of some sort, and if I had
> the means to calibrate, I wouldn't need the standard in the first place.
> 
> Any voltage-nuts or resistance-nuts out there?
> 
> Scott
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From bruce.griffiths at xtra.co.nz  Fri Nov 28 05:44:12 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Fri, 28 Nov 2008 18:44:12 +1300
Subject: [time-nuts] any way to bootstrap a frequency standard into a
 voltage or resistance standard?
In-Reply-To: <492F7EF4.8080909@gmail.com>
References: <492F7EF4.8080909@gmail.com>
Message-ID: <492F852C.2060707@xtra.co.nz>

Scott Burris wrote:
> Now that many of us have a nice 10Mhz reference courtesy of TAPR,
> I was wondering if there was any way to use that to build a precise
> voltage or resistance standard?
>
> I've got once of those high precision standard resistors with a sticker
> on it noting the actual measured resistance.  Is it still accurate?  Who 
> knows?
>
> As well, I have a +5v reference that uses an Analog Devices precision
> reference chip as its source.  I have more faith that this reference is
> correct within the tolerances specified in the datasheet.
>
> Now if I could somehow take that frequency reference and derive a 
> voltage standard or the like, I'd be in business.  But I can't think
> of a way that wouldn't require calibration of some sort, and if I had
> the means to calibrate, I wouldn't need the standard in the first place.
>
> Any voltage-nuts or resistance-nuts out there?
>
> Scott
>
>   
Scott

1) Frequency to voltage via the Josephson effect.

2) Resistance standard via the quantised Hall effect

3) Resistance caibration via a calculable capacitor (Thompson Lampard
theorem) and an AC bridge (excitation frequency has to be accurately known).

The Josephson voltage standard requires an array of Josephson junctions
immersed in Liquid helium and excitation by a stable microwave source.

The quantised hall effect also requires a cryostat.

The calculable capacitor requires accurate length measurements
(frequency stabilised laser or equivalent).


Bruce


From ed_palmer at sasktel.net  Fri Nov 28 07:49:50 2008
From: ed_palmer at sasktel.net (Ed Palmer)
Date: Fri, 28 Nov 2008 01:49:50 -0600
Subject: [time-nuts]  any way to bootstrap a frequency standard into a,
	voltage or resistance standard?
In-Reply-To: <mailman.400.1227851057.2542.time-nuts@febo.com>
References: <mailman.400.1227851057.2542.time-nuts@febo.com>
Message-ID: <492FA29E.6080801@sasktel.net>

It's nowhere near the idea of a Josephson array, but if a NIST-traceable 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you can buy it from www.gellerlabs.com for $35.

I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be interested in calibrating, but I can't seem to come up with a practical way of doing it.

Frustrating, isn't it? :-)

Ed

Scott Burris wrote:

> Now that many of us have a nice 10Mhz reference courtesy of TAPR,
> I was wondering if there was any way to use that to build a precise
> voltage or resistance standard?
>
> I've got once of those high precision standard resistors with a sticker
> on it noting the actual measured resistance.  Is it still accurate?  Who 
> knows?
>
> As well, I have a +5v reference that uses an Analog Devices precision
> reference chip as its source.  I have more faith that this reference is
> correct within the tolerances specified in the datasheet.
>
> Now if I could somehow take that frequency reference and derive a 
> voltage standard or the like, I'd be in business.  But I can't think
> of a way that wouldn't require calibration of some sort, and if I had
> the means to calibrate, I wouldn't need the standard in the first place.
>
> Any voltage-nuts or resistance-nuts out there?
>
> Scott
>   



From kirbybq at bellsouth.net  Fri Nov 28 09:03:26 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Fri, 28 Nov 2008 03:03:26 -0600
Subject: [time-nuts] any way to bootstrap a frequency standard into a,
 voltage or resistance standard?
In-Reply-To: <492FA29E.6080801@sasktel.net>
References: <mailman.400.1227851057.2542.time-nuts@febo.com>
	<492FA29E.6080801@sasktel.net>
Message-ID: <492FB3DE.8050609@bellsouth.net>

Geller's specs are not is good as you have quoted.  The 10 volts +/-10uv 
is very, very short term.

BUT, it really depends what you are looking to do with the voltage 
references.....it may meet your requirements.

 From his site:
SVR Specifications:

     Temperature Coefficient "L" grade: 5 ppm / ?C

     Short term transfer accuracy: better than +/- .0005% absolute (+/- 
5 ppm).

     Short term transfer accuracy applies in the short term at the 
reported temperature and at the specified power supply voltage (15.0V 
for 10V SVR references) after of warm up period of 30 to 60 minutes, <10 
ppm within 5 minutes.

     All reference boards and boxes are calibrated to within +/- 10 uV 
absolute and guaranteed to remain longer term (6 months) within +/- 500 
uV (+/- .005%) of absolute as rated.

     Extra trim resistors are added to narrow the trim range for easier 
calibration. Calibration data is reported to 10 uV resolution (.0001%).

The AD587 series reference chips are rated at 15 ppm / 1,000 hours of 
operation. Very close inspection of most monolithic reference chip 
family specification sheets reveals a 1,000 hour rating generally 
ranging from 10 to 60 ppm / 1,000 hours.

end of his quotes =======

if you really need a good voltage reference, consider the LM199 series 
which is affordable.  But you will have to burn it in and have it 
calibrated.  These are heated buried zeners and were used in the HP3456A 
  (2ppm) and HP3457A (5ppm) multimeters, and others.  The LM399A is 
rated at 1 ppm/C and has a time stability of 8-20 ppm a year.

if you have a little more money to spend, consider the LTZ1000, which is 
used in the HP3458A multimeter, and the national Instruments PXI-4071 
DMM.  The LTZ1000 is rated at 0.3ppm/C and has a time stability of 8 PPM 
a year.

You will also find, that maintaining voltage references are a little 
more difficult then time/frequency - we all have GPS or LORAN to verify 
our time standards, etc.  You either have to have the equipment to 
monitor the voltage references, or send them out for calibration.  I 
prefer to leave standards/references where they are for stability 
reasons, and send the test equipment out for regular calibration.  You 
have the same environmental problems, you name a stable temperature 
environment to operate them in.

Linear, the IC manufacturer, has many applications notes on the 
LM199/399 and LTZ1000 series - and they can show you how to build a good 
reference and they can save you a lot of common pitfalls.  When you get 
into measuring microvolts at 6 to 10 volt levels you have to account 
Kelvin/Seebeck thermal and galvanic effects.

If your requirements are less than what I have mentioned here, check on 
the Xicor X60008 (Intersil has bought them).  They make a reference 
thats good to a half a millivolt level at 5V, and it has some promising 
specs.  I have 5 units they sent me for evaluation that have been 
burning in for 2 years.

If you have the instrumentation, you can also pick up a standard cell 
off of fleabay - but make sure the voltage is good - I've seen too many 
of these units sold and they are below specifications for using as a 
transfer standard.  If they can not tell you the voltage of the cell, 
don't buy it.  Any body with a decent DVM can check one quickly to see 
if its OK.  Nominal is 1.0183 volts - and there are differences between 
saturated and unsaturated cells that you need to read up on.

You may consider purchasing a HP3456 or 3457A off of fleabay and put it 
in a calibration program.  I have picked these meters up for around 
$150, and the local cal lab here calibrates the 3456A for $200 and the 
3457A for $160.  They give me before and after data and I cal them every 
2 years.  You can also pick up Fluke voltage calibrators or differential 
voltmeters, too from fleabay...

These multimeters can also measure your "calibrated resistors" with 
extremely good accuracy - they can use what is called 4 wire 
measurements - where they compensate for voltage drop in the measuring 
leads.

In "the good old days" Mallory (Duracell) use to sell a mercury battery 
voltage reference that was the workhorse of many labs.  It was like 10 
cells in series and they brought out each tap.  But since mecury is bad 
news now...they are a part of history.

Brian KD4FM





Ed Palmer wrote:
> It's nowhere near the idea of a Josephson array, but if a NIST-traceable 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you can buy it from www.gellerlabs.com for $35.
> 
> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be interested in calibrating, but I can't seem to come up with a practical way of doing it.
> 
> Frustrating, isn't it? :-)
> 
> Ed
> 
> Scott Burris wrote:
> 
>> Now that many of us have a nice 10Mhz reference courtesy of TAPR,
>> I was wondering if there was any way to use that to build a precise
>> voltage or resistance standard?
>>
>> I've got once of those high precision standard resistors with a sticker
>> on it noting the actual measured resistance.  Is it still accurate?  Who 
>> knows?
>>
>> As well, I have a +5v reference that uses an Analog Devices precision
>> reference chip as its source.  I have more faith that this reference is
>> correct within the tolerances specified in the datasheet.
>>
>> Now if I could somehow take that frequency reference and derive a 
>> voltage standard or the like, I'd be in business.  But I can't think
>> of a way that wouldn't require calibration of some sort, and if I had
>> the means to calibrate, I wouldn't need the standard in the first place.
>>
>> Any voltage-nuts or resistance-nuts out there?
>>
>> Scott
>>   
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From wb6bnq at cox.net  Fri Nov 28 10:27:36 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Fri, 28 Nov 2008 02:27:36 -0800
Subject: [time-nuts] any way to bootstrap a frequency standard into  a,
 voltage or resistance standard?
References: <mailman.400.1227851057.2542.time-nuts@febo.com>
	<492FA29E.6080801@sasktel.net>
Message-ID: <492FC798.EBA5149@cox.net>

Ed,

No way in hell does that thing qualify as a voltage standard.  It barely qualifies as a VERY short term transfer device assuming the temperature does not change.

If you want a real voltage reference then buy, from eBay, a Fluke 731B voltage standard.  You will still need to get it calibrated, but then it will hold under 10ppm for well over a year or
more.  Actually, if they are adjusted correctly, you can get less than 5ppm and it will hold it at a given temperature.  These items are serious devices and their latest versions (very expensive)
are better than a properly maintained and operated group of standard cells.

I completely disagree with Brian about buying any standard cells.  Whatever voltage value they had is lost upon shipment.  Shaking the cells changes the value and it will not return to the
original value.  If you did have a set of cells, you would want at least 4 of them.  Then study statistical math all over again because you will need it to use the cells.

As Brian does suggest, you would be much better off picking up a hp3456A, 3457A, 3458A or getting one of Fluke 8500 series if it has the Ohms and AC options included.  The basic Fluke 8500 series
is DC only mainframe.

Measuring your resistors, using one of the above DVMs, in the 4-wire mode is about the best you could possibly do.  To do any better would require some very serious effort.

By the way you could buy several of the latest and greatest Fluke super DVMs for the cost of what it would take to do a Josephson array and still have money left over to fund that divorce.

Bill....WB6BNQ


Ed Palmer wrote:

> It's nowhere near the idea of a Josephson array, but if a NIST-traceable 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you can buy it from www.gellerlabs.com for $35.
>
> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be interested in calibrating, but I can't seem to come up with a practical way of doing it.
>
> Frustrating, isn't it? :-)
>
> Ed



From didier at cox.net  Fri Nov 28 14:57:55 2008
From: didier at cox.net (Didier)
Date: Fri, 28 Nov 2008 08:57:55 -0600
Subject: [time-nuts] any way to bootstrap a frequency standard into a
	voltage or resistance standard?
In-Reply-To: <492F7EF4.8080909@gmail.com>
References: <492F7EF4.8080909@gmail.com>
Message-ID: <5836C7931C404285A0AD08436277B859@didierhp>

Scott,

A relatively inexpensive voltage reference is to actually buy an HP 3456A
DVM. It is rated as a transfer standard, that means you send it to NIST to
have it calibrated, and then you can use it to calibrate other instruments.
I have two here and together they cost me $130.

It is also a 6 1/2 digit DVM with GPIB interface. The reference voltage is
not provided externally, but you would use the meter to check and correct an
external reference or stable voltage source.

The service manual is on my web site http://www.ko4bb.com/cgi-bin/manuals.pl

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Burris
> Sent: Thursday, November 27, 2008 11:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] any way to bootstrap a frequency 
> standard into a voltage or resistance standard?
> 
> Now that many of us have a nice 10Mhz reference courtesy of 
> TAPR, I was wondering if there was any way to use that to 
> build a precise voltage or resistance standard?
> 
> I've got once of those high precision standard resistors with 
> a sticker on it noting the actual measured resistance.  Is it 
> still accurate?  Who knows?
> 
> As well, I have a +5v reference that uses an Analog Devices 
> precision reference chip as its source.  I have more faith 
> that this reference is correct within the tolerances 
> specified in the datasheet.
> 
> Now if I could somehow take that frequency reference and 
> derive a voltage standard or the like, I'd be in business.  
> But I can't think of a way that wouldn't require calibration 
> of some sort, and if I had the means to calibrate, I wouldn't 
> need the standard in the first place.
> 
> Any voltage-nuts or resistance-nuts out there?
> 
> Scott
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From johneburgar at cox.net  Fri Nov 28 15:55:09 2008
From: johneburgar at cox.net (John E Burgar)
Date: Fri, 28 Nov 2008 07:55:09 -0800
Subject: [time-nuts] Make your own functional equivalent to a Huntron Tracker
Message-ID: <9D3530116FC246428207DEF6AD7994DD@john>

These troubleshooting aids have also been known as an "octopus" and as a V/I
curve tracer.  Below are some links for schematics and details on their use.

1.  http://octopus.freeyellow.com/octopus.html

 

2.  http://www.armory.com/~rstevew/Public/TestEquip/CurveTracer.pdf

 

3.  http://www.ionpool.net/arcade/tech/octopus.pdf

 

4.  http://www.tpub.com/content/neets/14191/css/14191_142.htm

 

5.  http://www.electronics-lab.com/projects/test/018/

 

6.  A portion of chapter 5 of this Navy document describes the features and
the use of the Huntron Tracker 2000.
http://www.tpub.com/content/neets/14188/index.htm

 

Regards, John Burgar


From j.bastemeijer at tudelft.nl  Fri Nov 28 16:23:51 2008
From: j.bastemeijer at tudelft.nl (Jeroen Bastemeijer)
Date: Fri, 28 Nov 2008 17:23:51 +0100
Subject: [time-nuts] Make your own functional equivalent to a Huntron
 Tracker
In-Reply-To: <9D3530116FC246428207DEF6AD7994DD@john>
References: <9D3530116FC246428207DEF6AD7994DD@john>
Message-ID: <49301B17.6060105@tudelft.nl>

Hi John, and others,

That is a nice compilation!

There is one thing all the testers have in common: They use a mains 
transformer to generate the AC-voltage (signal source). To make a more 
versatile unit I would suggest to use a small audio-transformer and use 
a lab-sinewave generator as signal source.

This makes it possible to perform measurements at different frequencies. 
This could be handy when measuring circuits with coils and/or small 
capacitors.

Good luck to all the builders and experimenters.

Best regards, Jeroen

John E Burgar wrote:
> These troubleshooting aids have also been known as an "octopus" and as a V/I
> curve tracer.  Below are some links for schematics and details on their use.
>
> 1.  http://octopus.freeyellow.com/octopus.html
>
>  
>
> 2.  http://www.armory.com/~rstevew/Public/TestEquip/CurveTracer.pdf
>
>  
>
> 3.  http://www.ionpool.net/arcade/tech/octopus.pdf
>
>  
>
> 4.  http://www.tpub.com/content/neets/14191/css/14191_142.htm
>
>  
>
> 5.  http://www.electronics-lab.com/projects/test/018/
>
>  
>
> 6.  A portion of chapter 5 of this Navy document describes the features and
> the use of the Huntron Tracker 2000.
> http://www.tpub.com/content/neets/14188/index.htm
>
>  
>
> Regards, John Burgar
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>   
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From bill at iaxs.net  Fri Nov 28 19:27:45 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Fri, 28 Nov 2008 13:27:45 -0600
Subject: [time-nuts] Calibration and temperature
In-Reply-To: <492FB3DE.8050609@bellsouth.net>
References: <mailman.400.1227851057.2542.time-nuts@febo.com><492FA29E.6080801@sasktel.net>
	<492FB3DE.8050609@bellsouth.net>
Message-ID: <6D3AC52128424986A16AB823763F4AEE@cyrus>

Re: [time-nuts] any way to bootstrap a frequency standard into a voltage
or resistance standard?
Brian Kirby said, in part,

"You will also find, that maintaining voltage references are a little
more difficult then time/frequency - we all have GPS or LORAN to verify
our time standards, etc.  You either have to have the equipment to
monitor the voltage references, or send them out for calibration.  I
prefer to leave standards/references where they are for stability
reasons, and send the test equipment out for regular calibration.  You
have the same environmental problems, you name a stable temperature
environment to operate them in."

Seems to me that all physical quantities have to be calibrated against
standards, because they're all defined by humans, starting with the
length of the king's arm. Timenuts have the great advantage of being
able to do calibration with radio waves. Don't think you can do that
with any of the other physical properties, and perhaps time is not a
physical property.

Temperature does affect everything made of atoms. PV=NRT and all that.
Timenuts strive for constant temperature inside small ovens. Industrial
sensors, which have to operate over a wide range of temperature daily
and seasonally, now rely on microprocessors with local temperature
sensors for temperature compensation. Some interesting designs have been
used to compensate the length of time-keeping pendulum oscillators.

Has any work been done on temperature compensation of quartz or other
oscillators to avoid the expense, space, and power of ovens? The
oscillating material must have a repeatable temperature curve, of
course.

Bill Hawkins



From phk at phk.freebsd.dk  Fri Nov 28 19:38:39 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Fri, 28 Nov 2008 19:38:39 +0000
Subject: [time-nuts] Calibration and temperature
In-Reply-To: Your message of "Fri, 28 Nov 2008 13:27:45 CST."
	<6D3AC52128424986A16AB823763F4AEE@cyrus> 
Message-ID: <32119.1227901119@critter.freebsd.dk>

In message <6D3AC52128424986A16AB823763F4AEE at cyrus>, "Bill Hawkins" writes:

>Seems to me that all physical quantities have to be calibrated against
>standards, because they're all defined by humans, starting with the
>length of the king's arm.

For several decades now, the metrological community has been on a steady
march away from "artifact based" standards to "physical phenomena"
standards.

For instance the measure of length is no longer a piece of metal in Paris
but a given number of wavelengths of a particular spectral line under
certain conditions.

The biggest missing piece is the kilogram, where the two best contenders
are both too unmanageable still:

One contender is a perfect sphere of silicon-28 is so state of the
art that it takes russia to separate the isotopes, germany to make
a crystal and australia to polish it into sphere.
	http://www.csiro.au/science/ps35k.html
The point is that if the crystal is perfect and the spherical form
is prefect, you can calculate how many atoms there are.

The other contender is the "Watt-balance", where in essense you link
energy spent in an electro magnet to force, and from force to
mass using newtons 2nd law:
	http://en.wikipedia.org/wiki/Watt_balance

So overall, the strategy is to find physical phenomena which are locally
reproducible, exactly like the second is derived from Cs-133 atoms,
instead of comparing to "random artifacts".

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


From yuri at ostry.ru  Fri Nov 28 20:23:51 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Fri, 28 Nov 2008 23:23:51 +0300
Subject: [time-nuts] Eclipses and atomic clocks
In-Reply-To: <342ED13391FC45E9A3E421C5BF4D62D2@cyrus>
References: <KAWEUU$7BF3894BDE3AF9A2FD158C5CE4970AD7@libero.it>
	<342ED13391FC45E9A3E421C5BF4D62D2@cyrus>
Message-ID: <17910239896.20081128232351@ostry.ru>

Hello,

Tuesday, November 25, 2008, 21:39:41, Bill Hawkins wrote:

B> There is an article in the Nov 22, 2008, issue of Science News
B> (www.sciencenews.org) about variations in the decay rate of 
B> radioactive atoms. The title is "Half-life (More or Less)"
B> where "more or less" is an idiom for "approximately."

B> There is no explanation for the observed variation. As you might
B> expect, not everyone sees the variation, but Brookhaven in the
B> US and PTB in Germany observed a few parts per 1000 annual
B> variation. One possibility is the distance from the sun. Another
B> is the change in seasons.

B> Peter Cooper, of Fermi Lab, says, "Every experimentalist knows
B> that the apparatus, or at least your understanding of it, is
B> always at fault until demonstrated otherwise." He also says,
B> "Nature is really unmoved by what I, or anyone else, believes."

B> Bill Hawkins

http://www.amendez.com/Noahs%20Ark%20Articles/NAS%20Radioactive%20Accleration.pdf , page 4...

===
* 163 Dysprosium under ionized plasma like conditions was found to
decay into 163Holmium with a t1/2 of 47 days (6). Normally 163Dy is a
stable atom, which does not radioactively decay!

* In the 187Rhenuim?187Osmium system ?b decay was found to occur. In
this experiment, fully ionized 187Re was found to decay in an amazing
measurable rate of 33 years (7, 8)! The conventional half-life of
rhenium is 43 billion years. The 187Re?187Os system is one of the
commonly used radioactive processes used to date rocks (9).

* The Lutetium-Hafnium system (176Lu?176Hf) is a newer system used by
scientists to date rocks. In this system at very high temperatures
(200-600 MK) part of the lutetium goes into a fast decay mode and
shows a t1/2 of between 3.68 hours and 8 days (10, 11). The normal
t1/2 of lutetium is about 40 billion years!    
===

So, sometimes it so much less, so it is hard to compare. ;)

I hope 87Rb isn't decay so fast in ionized state... ;)


-- 
Best regards,
 Yuri                          mailto:yuri at ostry.ru



From jmiles at pop.net  Fri Nov 28 21:16:28 2008
From: jmiles at pop.net (John Miles)
Date: Fri, 28 Nov 2008 13:16:28 -0800
Subject: [time-nuts] Eclipses and atomic clocks
In-Reply-To: <17910239896.20081128232351@ostry.ru>
Message-ID: <PKEGJHPHLLBACEOICCBJAEHOPGAB.jmiles@pop.net>


> http://www.amendez.com/Noahs%20Ark...

I'm sure there's a more appropriate list for this bogosity.  

-- john, KE5FX



From bruce.griffiths at xtra.co.nz  Fri Nov 28 21:38:53 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sat, 29 Nov 2008 10:38:53 +1300
Subject: [time-nuts] any way to bootstrap a frequency standard into  a,
 voltage or resistance standard?
In-Reply-To: <492FC798.EBA5149@cox.net>
References: <mailman.400.1227851057.2542.time-nuts@febo.com>	<492FA29E.6080801@sasktel.net>
	<492FC798.EBA5149@cox.net>
Message-ID: <493064ED.1030501@xtra.co.nz>

WB6BNQ wrote:
> Ed,
>
> No way in hell does that thing qualify as a voltage standard.  It barely qualifies as a VERY short term transfer device assuming the temperature does not change.
>
> If you want a real voltage reference then buy, from eBay, a Fluke 731B voltage standard.  You will still need to get it calibrated, but then it will hold under 10ppm for well over a year or
> more.  Actually, if they are adjusted correctly, you can get less than 5ppm and it will hold it at a given temperature.  These items are serious devices and their latest versions (very expensive)
> are better than a properly maintained and operated group of standard cells.
>
>   
The latest Fluke voltage standards use a selected LTZ1000 plus a
precision resistor array.
The earlier versions used selected Motorola zener diode references.
The latest versions allow the LTZ1000 chip temperature to be cycled to
largely eliminate hysteresis which may occur when they lose power during
shipment.
> Bill....WB6BNQ
>
>
>   

Bruce


From yuri at ostry.ru  Fri Nov 28 22:13:42 2008
From: yuri at ostry.ru (Yuri Ostry)
Date: Sat, 29 Nov 2008 01:13:42 +0300
Subject: [time-nuts] Eclipses and atomic clocks
In-Reply-To: <PKEGJHPHLLBACEOICCBJAEHOPGAB.jmiles@pop.net>
References: <17910239896.20081128232351@ostry.ru>
	<PKEGJHPHLLBACEOICCBJAEHOPGAB.jmiles@pop.net>
Message-ID: <1426385254.20081129011342@ostry.ru>

Hello,

Saturday, November 29, 2008, 0:16:28, John Miles wrote:

J> I'm sure there's a more appropriate list for this bogosity.

There is list of facts on page 4 and related references that saved me
some time searching them all... ;) The rest... I do not pretend that
the rest it is somewhat related to this list (and maybe to common
sense as well), but I hate to omit source of information.

-- 
Best regards,
 Yuri                          mailto:yuri at ostry.ru



From iovane at inwind.it  Fri Nov 28 22:34:13 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Fri, 28 Nov 2008 23:34:13 +0100
Subject: [time-nuts] Cesium vs H Maser clocks
Message-ID: <KB2EP1$C697B386F8A205299061A4449624B569@libero.it>

What is the reference used to measure stability and accuracy
of H Masers?

Do Caesium clocks have something like a C field adjustment 
(as Rb clocks have), and in the case, what it acts upon?

Thanks in advance,

Antonio I8IOV



From tvb at LeapSecond.com  Fri Nov 28 23:53:49 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 28 Nov 2008 15:53:49 -0800
Subject: [time-nuts] Cesium vs H Maser clocks
References: <KB2EP1$C697B386F8A205299061A4449624B569@libero.it>
Message-ID: <BE525E3CADE24CAC9278845919B1A9AB@pc52>

> What is the reference used to measure stability and accuracy
> of H Masers?

Antonio,

Good question.

You compare against other H-maser(s), or an ensemble of Cs
clocks, or high-precision coax, fiber, or two-way satellite links to
other timing laboratories that happen to have much better clocks.

In general, when you have a really good clock in your lab, the
obvious way to measure its performance is to find a clock that
is 10x more accurate and compare your clock against it.

But if you can't find a better reference, or can't afford a better
reference, or if a better reference doesn't even exist, then you
use a different trick -- you make two or three clocks of the same
design and compare them amongst themselves.

> Do Caesium clocks have something like a C-field adjustment 
> (as Rb clocks have), and in the case, what it acts upon?

Yes, all commercial Cs clocks do have a C-field adjustment or
an internal phase micro-stepper (frequency offset generator).
This is useful since they are generally more stable (parts in 1e-13
to 1e-15) than they are accurate (parts in 1e-12 to 1e-13). So
the C-field is the traditional way to fine-tune the frequency of the
clock. Modern Cs clocks find it easier (and perhaps more reliable)
to adjust by synthesizer than by magnetic field.

On the other hand, laboratory Cs standards correct for all these
systematic effects and are thus about as accurate as they are
stable. If you'd like more details, let me know.

> Thanks in advance,
> 
> Antonio I8IOV

/tvb



From d.seiter at comcast.net  Sat Nov 29 00:49:45 2008
From: d.seiter at comcast.net (d.seiter at comcast.net)
Date: Sat, 29 Nov 2008 00:49:45 +0000
Subject: [time-nuts] US Shipping Was huntron tracker advice
Message-ID: <112920080049.3731.493091A9000C700C00000E9322007374789D0A9B070A9CD20B@comcast.net>

My local Dovebid people (Hayward, CA) have always been great to work with, and have bent over backwards to help me, but I haven't purchased anything from them lately because the bids have been higher than they used to be. Of course, there is no shipping involved because I pick up the items. The gear is usually in better condition than epay.  It's the govliquidation folks that I hate to deal with...

-Dave
 -------------- Original message ----------------------
From: Patrick <optomatic at rogers.com>
> BTW since we are talking about Ebay, they are not the only game in town.
> I buy lots of laboratory instruments of Dovebid. Dovebid has been
> purchased my Go-industry and their site is a mess. They are also
> incredibly cruel bastards. When you purchase something from them you buy
> it as-is, where-is. You need to hire someone from a UPS store to come to
> the auction site, pick it up, pack it and ship it to you. They charge
> you the state taxes and they will rarely refund them to you. Despite the
> fact that they are so evil, much of the equipment is cheaper and of much
> higher quality then that found on Ebay, you just need to find out why it
> is being liquidated to begin with. Companies that are shutting down are
> usually safer then those still standing. They always have scopes and
> other equipment such as x-ray inspection units etc...
> 
> Equipnet and Bidspotter are two other sites that may be of use from time
> to time-Patrick
> 
> Patrick wrote:
> > I am on the lower end(maybe dumbest) of the intelligence spectrum on
> > this list when it comes to pure electronics. However I have plenty to
> > offer in logistics. I ship all over the world, this week it was Nigeria
> > and Lebanon from my home based business in Canada.
> >
> > Virtually all of my parts come from the U.S.
> >
> > I have a P.O box at a UPS store in New Hampshire. I had one in N.Y state
> > before but I ended up paying state taxes for certain items. It is
> > hopeless to claim these taxes back as a foreign entity. N.H has 0% state
> > taxes, taxes are due in the state that you take possession in. However
> > if you arrange for shipping via a third party some states, such as
> > Michigan, will have deemed you to already have taken possession even
> > though you never entered the country.
> >
> > With the dark spectra of a severe recession looming on most of us I find
> > myself in a peculiar situation. I have little money but the cliente`le I
> > service are dying for the products I sell. I could easily sell >20X what
> > I do now. I have been trying to slow my business down for months in the
> > hope of re-organizing myself but to no avail. I can't hire anyone, as I
> > work from home due to some health issues with my Wife and Son.
> >
> > I can't promise anything at this time but if someone would like help
> > shipping items out of the U.S(or Canada) I would love to help. The
> > logistics of servicing unknown equipment from a far is likely impossible
> > to overcome but I have plenty of work that needs to get done. If
> > something could be worked out I would gladly pay for shipping or
> > shipping & labor for help with my business.
> >
> > -Patrick
> >
> >
> > Neville Michie wrote:
> >   
> >> Many US or UK sellers will sell out of their country if you email  
> >> them and ask them,
> >> even if they list as home country only.
> >> I bought an HP 54501A oscilloscope from US, and it was sent to  
> >> Australia.
> >> Cost 30% more with the freight, but it was still only a few hundred  
> >> dollars,
> >> and I would not have found anything as useful in Australia at the price.
> >> cheers, Neville Michie
> >>
> >> On 27/11/2008, at 7:55 PM, Steve Rooke wrote:
> >>
> >>   
> >>     
> >>> Hmmm... International Traffic in Arms Regulations, well I don't like
> >>> to poke holes in that excuse but unless the US customs are REALLY
> >>> paranoid, I can't see how most of the items I have tried to purchase
> >>> would be covered under this. But, I suppose you could poke someone in
> >>> the eye with a ball-point pen therefore it could be labled an an arm
> >>> but I'm sure there are other reasons for most of refusals to ship
> >>> outside the 48 States. It's not just a couple of dealers who take this
> >>> position, it seems to be the case with a number of sellers sadly.
> >>>
> >>> What I need is a magic wormhole that runs from a US address and ends
> >>> up in my home. Anyone got a design for one of these, sort of like a
> >>> stargate :-)
> >>>
> >>> 73, Steve - ZL3TUV
> >>>
> >>> 2008/11/27 Robert Atkinson <robert8rpi at yahoo.co.uk>:
> >>>     
> >>>       
> >>>> One reasion why many US dealers will not ship otside the USA is  
> >>>> the ITAR export regulations (Google it!). These are very hard to  
> >>>> follow and the penalties are heavy. I know a couple of dealers  
> >>>> have been warned and have just decided not to export anything  
> >>>> rather than take the risk.
> >>>> Robert G8RPI.
> >>>>
> >>>> --- On Thu, 27/11/08, Steve Rooke <sar10538 at gmail.com> wrote:
> >>>>
> >>>> From: Steve Rooke <sar10538 at gmail.com>
> >>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting  
> >>>> withoutschematic advise
> >>>> To: "Discussion of precise time and frequency measurement" <time- 
> >>>> nuts at febo.com>
> >>>> Date: Thursday, 27 November, 2008, 8:21 AM
> >>>>
> >>>> And I envy you guys in the UK and the US as over here in New Zealand
> >>>> there is little to be had and anything that comes up costs an arm and
> >>>> a leg. My Mother is just emigrating over here and so I bought a few
> >>>> items (all I could afford) and had them sent to her so they can come
> >>>> over in the container with her furniture etc as there is no way I
> >>>> could afford the shipping otherwise. At least shipping via surface  
> >>>> was
> >>>> a workable option with heavy items like scopes, even with the 3 month
> >>>> wait, but that is now gone :(
> >>>>
> >>>> The other thing that really gets my goat is the habit of a lot of US
> >>>> eBay sellers who won't ship outside of the country. What really rubs
> >>>> is that it's usually the really hard to locate items or the ones that
> >>>> are going really cheap that will not ship. They always say that you
> >>>> can bid if you have a US address to ship to but that is hopeless for
> >>>> me.
> >>>>
> >>>> Still, I have a great lifestyle over here and wouldn't swap it for  
> >>>> the
> >>>> US or going back home to Blighty anytime soon.
> >>>>
> >>>> 73
> >>>> Steve
> >>>>
> >>>> 2008/11/27 David C. Partridge <david.partridge at dsl.pipex.com>:
> >>>>       
> >>>>         
> >>>>>  I envy you guys over in the US - test gear on the 2nd hand  
> >>>>> market seems
> >>>>>         
> >>>>>           
> >>>> so
> >>>>       
> >>>>         
> >>>>> much cheaper than here in the UK.   Current shipping costs from  
> >>>>> USA seem
> >>>>>         
> >>>>>           
> >>>> to
> >>>>       
> >>>>         
> >>>>> wipe out the difference most of the time - I wish they'd bring back
> >>>>>         
> >>>>>           
> >>>> the USPS
> >>>>       
> >>>>         
> >>>>> Surface Mail service.
> >>>>>
> >>>>> -----Original Message-----
> >>>>> From: time-nuts-bounces at febo.com [mailto:time-nuts- 
> >>>>> bounces at febo.com] On
> >>>>> Behalf Of Robert Darlington
> >>>>> Sent: 27 November 2008 07:17
> >>>>> To: Discussion of precise time and frequency measurement
> >>>>> Subject: Re: [time-nuts] huntron tracker advice & troubleshooting
> >>>>> withoutschematic advise
> >>>>>
> >>>>> I picked up a Tektronix 7000 series mainframe scope and a curve  
> >>>>> tracer
> >>>>> plugin for under $200, and I bet you can too if you look around  
> >>>>> on eBay.
> >>>>>         
> >>>>>           
> >>>> I
> >>>>       
> >>>>         
> >>>>> have a Tek 7854 digital storage analog scope (400MHz analog with  
> >>>>> digital
> >>>>> sampling capabilities, GPIB port, and 4 mainframe slots).   The  
> >>>>> cart was
> >>>>> another $40 though!
> >>>>>
> >>>>> -Bob
> >>>>>
> >>>>>
> >>>>> _______________________________________________
> >>>>> time-nuts mailing list -- time-nuts at febo.com
> >>>>> To unsubscribe, go to
> >>>>>         
> >>>>>           
> >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>>>       
> >>>>         
> >>>>> and follow the instructions there.
> >>>>>
> >>>>>         
> >>>>>           
> >>>> --
> >>>> Steve Rooke - ZL3TUV & G8KVD
> >>>> Omnium finis imminet
> >>>>
> >>>> _______________________________________________
> >>>> time-nuts mailing list -- time-nuts at febo.com
> >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
> >>>> listinfo/time-nuts
> >>>> and follow the instructions there.
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> time-nuts mailing list -- time-nuts at febo.com
> >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ 
> >>>> listinfo/time-nuts
> >>>> and follow the instructions there.
> >>>>
> >>>>       
> >>>>         
> >>> -- 
> >>> Steve Rooke - ZL3TUV & G8KVD
> >>> Omnium finis imminet
> >>>
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts at febo.com
> >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> >>> time-nuts
> >>> and follow the instructions there.
> >>>     
> >>>       
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at febo.com
> >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >>
> >>   
> >>     
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> >   
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From iovane at inwind.it  Sat Nov 29 00:56:09 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Sat, 29 Nov 2008 01:56:09 +0100
Subject: [time-nuts] Cesium vs H Maser clocks
Message-ID: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>

Tom,

The conceptual deadlock that I would overcome is whether adjusting the C-field the Cs resonance varies, as this would impact the defition of the "second".

Thanks,
Antonio I8IOV

> > What is the reference used to measure stability and accuracy
> > of H Masers?
> 
> Antonio,
> 
> Good question.
> 
> You compare against other H-maser(s), or an ensemble of Cs
> clocks, or high-precision coax, fiber, or two-way satellite links to
> other timing laboratories that happen to have much better clocks.
> 
> In general, when you have a really good clock in your lab, the
> obvious way to measure its performance is to find a clock that
> is 10x more accurate and compare your clock against it.
> 
> But if you can't find a better reference, or can't afford a better
> reference, or if a better reference doesn't even exist, then you
> use a different trick -- you make two or three clocks of the same
> design and compare them amongst themselves.
> 
> > Do Caesium clocks have something like a C-field adjustment 
> > (as Rb clocks have), and in the case, what it acts upon?
> 
> Yes, all commercial Cs clocks do have a C-field adjustment or
> an internal phase micro-stepper (frequency offset generator).
> This is useful since they are generally more stable (parts in 1e-13
> to 1e-15) than they are accurate (parts in 1e-12 to 1e-13). So
> the C-field is the traditional way to fine-tune the frequency of the
> clock. Modern Cs clocks find it easier (and perhaps more reliable)
> to adjust by synthesizer than by magnetic field.
> 
> On the other hand, laboratory Cs standards correct for all these
> systematic effects and are thus about as accurate as they are
> stable. If you'd like more details, let me know.
> 
> > Thanks in advance,
> > 
> > Antonio I8IOV
> 
> /tvb
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 



From tvb at LeapSecond.com  Sat Nov 29 01:20:18 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 28 Nov 2008 17:20:18 -0800
Subject: [time-nuts] Cesium vs H Maser clocks
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>
Message-ID: <DA795DE5C8AF4A17A671A30171BACAE3@pc52>

> Tom,
> 
> The conceptual deadlock that I would overcome is whether
> adjusting the C-field the Cs resonance varies, as this would
> impact the defition of the "second".
> 
> Thanks,
> Antonio I8IOV

Correct, the C-field can vary and it has a slight impact on the
accuracy of the seconds that your Cs clock is generating. So
that's why it's very important for the best of primary standards
to get the C-field right. And they do. Half the work is making a
stable clock; the other half is understanding what apparatus you
have made and turning it into an accurate clock, with a detailed
series of experiments.

If you really get into the details of the physics, remember that no
commercial or laboratory Cs clock actually resonates at precisely
9 192 631 770.000 Hz. There are corrections for magnetic fields,
velocity of atoms, temperature, cavity design, even for gravity; a
whole bunch of interesting effects.

For a great example of the level of care that goes into the design
and calibration of a primary cesium standard read papers like:

< Accuracy evaluation of NIST-7>
http://tf.nist.gov/timefreq/general/pdf/1497.pdf

<Accuracy evaluation of NIST-F1>
http://tf.nist.gov/timefreq/general/pdf/1823.pdf

Or, for an informal description of C-field and Cs standards see:

<HP 5062C Theory of Operation>
http://www.leapsecond.com/museum/hp5062c/theory.htm

/tvb



From mikes at flatsurface.com  Sat Nov 29 01:41:23 2008
From: mikes at flatsurface.com (Mike S)
Date: Fri, 28 Nov 2008 20:41:23 -0500
Subject: [time-nuts] Cesium vs H Maser clocks
In-Reply-To: <DA795DE5C8AF4A17A671A30171BACAE3@pc52>
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>
	<DA795DE5C8AF4A17A671A30171BACAE3@pc52>
Message-ID: <20081129014129.181471165C3@hamburg.alientech.net>

At 08:20 PM 11/28/2008, Tom Van Baak wrote...
>If you really get into the details of the physics, remember that no
>commercial or laboratory Cs clock actually resonates at precisely
>9 192 631 770.000 Hz. There are corrections for magnetic fields,
>velocity of atoms, temperature, cavity design, even for gravity; a
>whole bunch of interesting effects.

Isn't the temperature the _only_ thing to correct for?

The definition of the second is "...the duration of 9 192 631 770 
periods of the radiation corresponding to the transition between the 
two hyperfine levels of the ground state of the cesium 133 atom." (and 
affirmed by the CIPM in 1997 that this definition refers to a cesium 
atom in its ground state at a temperature of 0 K)

That other factors can change the relative frequency of different Cs 
clocks is a problem with the definition, not an indication that any 
particular one is better than another. If a magnetic field changes the 
relative frequency, but that isn't reflected in the definition, is it 
not the definition which is faulty, and not the timepiece? The second 
is imprecise in this regard. 



From richiem at hughes.net  Sat Nov 29 03:50:37 2008
From: richiem at hughes.net (Richard Moore)
Date: Fri, 28 Nov 2008 19:50:37 -0800
Subject: [time-nuts] Voltage standards
In-Reply-To: <mailman.417.1227910425.2542.time-nuts@febo.com>
References: <mailman.417.1227910425.2542.time-nuts@febo.com>
Message-ID: <B022E133-EDAD-4914-A1AA-B756AF69A6CF@hughes.net>

RE  Message 8 and a couple of earlier posts on standards

> Date: Sat, 29 Nov 2008 10:38:53 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] any way to bootstrap a frequency standard
> 	into  a, voltage or resistance standard?
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <493064ED.1030501 at xtra.co.nz>
> Content-Type: text/plain; charset=ISO-8859-1
>
> WB6BNQ wrote:
>> Ed,
>>
>> No way in hell does that thing qualify as a voltage standard.  It  
>> barely qualifies as a VERY short term transfer device assuming the  
>> temperature does not change.
>>
>> If you want a real voltage reference then buy, from eBay, a Fluke  
>> 731B voltage standard.  You will still need to get it calibrated,  
>> but then it will hold under 10ppm for well over a year or
>> more.  Actually, if they are adjusted correctly, you can get less  
>> than 5ppm and it will hold it at a given temperature.  These items  
>> are serious devices and their latest versions (very expensive)
>> are better than a properly maintained and operated group of  
>> standard cells.
>>
> The latest Fluke voltage standards use a selected LTZ1000 plus a
> precision resistor array.
> The earlier versions used selected Motorola zener diode references.
> The latest versions allow the LTZ1000 chip temperature to be cycled to
> largely eliminate hysteresis which may occur when they lose power  
> during
> shipment.
>> Bill....WB6BNQ
>
> Bruce

Since we've kinda strayed from the original topic, I'll throw in a  
couple of cents. The V references in these 6-1/2 and 7-1/2 digit DMMs  
(that I currently own at least one each of):  Keithley 196, HP 3456,  
3457, and 34401, use selected -- some more than others -- National  
LM199/299/399 series references, which have their own heaters. The  
Datron 1080 series (that I own two of), as well as the 1070 series  
and 1060 series, use selected pairs of zeners connected in parallel,  
but not housed in ovens. The Fluke 8502/05/06 (and my Fluke 510A ACV  
std) use the aforementioned Motorola transistor+buried zener  
reference, also not in ovens.

The HP 3458, as mentioned before, uses the Linear LTZ1000/1000A,  
which has its own heater. As to others, the old Fluke 895A, 887A, and  
885A 6-digit analog Differential Meters (with K-V bridges for  
comparing the reference to the unknown in various ways), all use a  
pair of zeners in series, in an oven. A Fluke engineer told me years  
ago that those zeners were selected to have slightly different TC  
peaks so when one was falling in V the other was rising, so that they  
would spread the peak over a larger temperature range. They had a  
very elaborate automated system for testing the temp, voltage, and  
current values to do the pairing.

My Fluke 732A DC reference standard, which uses the Motorola  
transistor+buried zener reference, housed in an oven together with  
all of the various fixed and variable resistors and the other active  
devices, has an extremely low drift rate -- unmeasurable over a month  
in any definitive way -- as measured with a rented HP 3458A. I have  
disabled the batteries because I discovered, thanks to the 3458A,  
that when turned off, cooled off, and turned back on, within a day,  
the output returned within 0.05ppm to it's cal'd value -- I know  
there can be hysteresis, I just couldn't see it.

I have one of the little Geller 10V refs built around the AD587  
reference chips, and if you keep it enclosed and away from air  
currents, it's pretty stable, but would need to be in an oven to  
approach the performance of the LM199 series.

All this is to say that if you can get a working HP 3458A or a Datron  
1280 series (which is also the Fluke 8805), or a Datron 1270 series  
meter, all of which are self-calibrating in various ingenious ways,  
it will serve you well as a secondary standard for measurement on  
everything that  it can measure. I can't, or more properly, won't at  
the moment, spend the current freight of around $4,000 USD for a  
known good working 3458 or 1281.

What to do? Seems like a possible stable, yet low-cost source would  
be to buy 10 or so LM399s and hook them up to a power supply to age  
for 6 to 12 months, then use two or four in parallel (with suitable  
resistor buffering) driving a chopper amp like the LT1050 to give  
gain. Powered by a good, stiff regulated supply, and kept away from  
stray air currents, this arrangement wouldn't cost as much as a  
single LTZ1000A (which in singles is over $100 USD) and -- dang it,  
there's always a catch -- after lab calibration, could be a source  
that might need adjustment only once every few years to stay within 5  
or 10ppm or so. Paralleling more LM399s would be better, and with an  
initial purchase of 10, you could throw away the stinkers and  
parallel all the rest. So, short of having a Fluke 732A or those  
8-1/2 digit meters, that's my recommendation for a low-cost V  
standard. Unless you know someone, it'll cost less to build than to  
calibrate...

Dick Moore


From james.p.lux at jpl.nasa.gov  Sat Nov 29 03:52:35 2008
From: james.p.lux at jpl.nasa.gov (Lux, James P)
Date: Fri, 28 Nov 2008 19:52:35 -0800
Subject: [time-nuts] Calibration and temperature
In-Reply-To: <6D3AC52128424986A16AB823763F4AEE@cyrus>
Message-ID: <C555FC83.2F5E%James.P.Lux@jpl.nasa.gov>




On 11/28/08 11:27 AM, "Bill Hawkins" <bill at iaxs.net> wrote:
>
> Has any work been done on temperature compensation of quartz or other
> oscillators to avoid the expense, space, and power of ovens? The
> oscillating material must have a repeatable temperature curve, of
> course.
Look at MCXOs, a very clever technique using the different between third
overtone and fundamental to measure the temperature of the rock.


Jim Lux



From bruce.griffiths at xtra.co.nz  Sat Nov 29 04:12:40 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sat, 29 Nov 2008 17:12:40 +1300
Subject: [time-nuts] Voltage standards
In-Reply-To: <B022E133-EDAD-4914-A1AA-B756AF69A6CF@hughes.net>
References: <mailman.417.1227910425.2542.time-nuts@febo.com>
	<B022E133-EDAD-4914-A1AA-B756AF69A6CF@hughes.net>
Message-ID: <4930C138.3020105@xtra.co.nz>

Richard Moore wrote:
> What to do? Seems like a possible stable, yet low-cost source would  
> be to buy 10 or so LM399s and hook them up to a power supply to age  
> for 6 to 12 months, then use two or four in parallel (with suitable  
> resistor buffering) driving a chopper amp like the LT1050 to give  
> gain. Powered by a good, stiff regulated supply, and kept away from  
> stray air currents, this arrangement wouldn't cost as much as a  
> single LTZ1000A (which in singles is over $100 USD)
LTZ1000A list price is about $54 (excluding freight and taxes) when
ordering from Linear Technology.
The LTC1050 is a bit marginal unless you bootstrap its power supply the
LTC1151 is a better fit.
>  and -- dang it,  
> there's always a catch -- after lab calibration, could be a source  
> that might need adjustment only once every few years to stay within 5  
> or 10ppm or so. Paralleling more LM399s would be better, and with an  
> initial purchase of 10, you could throw away the stinkers and  
> parallel all the rest. So, short of having a Fluke 732A or those  
> 8-1/2 digit meters, that's my recommendation for a low-cost V  
> standard. Unless you know someone, it'll cost less to build than to  
> calibrate...
>
> Dick Moore
>
>
>   
Bruce



From warrensjmail-one at yahoo.com  Sat Nov 29 04:51:12 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Fri, 28 Nov 2008 20:51:12 -0800
Subject: [time-nuts] Voltage standards
Message-ID: <029701c951de$1adadb70$6401a8c0@WSOffice>


Just to add my experiences and throw in another two cents worth.
I live in California,  and a few years back I did some experiments 
with Geller on the East coast shipping back and forth some of his 10V 
References in the regular mail that I had added a simple 1 transistor 
1st order Temperature compensation circuit to some of his selected aged 
units and proved to my satisfaction that better than 2PPM transfer 
accuracy was obtained across the country. In house I can consistently  
get better than 1 PPM transfer with the same units. Of course there 
are more accurate ways, but for us cheap guys It sure beats the $500 
I heard Fluke charges to do their underlying Fluke 732B calibration.

WarrenS
*********************

RE  Message 8 and a couple of earlier posts on standards

> Date: Sat, 29 Nov 2008 10:38:53 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] any way to bootstrap a frequency standard
>  into  a, voltage or resistance standard?
> To: Discussion of precise time and frequency measurement
>  <time-nuts at febo.com>
> Message-ID: <493064ED.1030501 at xtra.co.nz>
> Content-Type: text/plain; charset=ISO-8859-1
>
> WB6BNQ wrote:
>> Ed,
>>
>> No way in hell does that thing qualify as a voltage standard.  It  
>> barely qualifies as a VERY short term transfer device assuming the  
>> temperature does not change.
>>
>> If you want a real voltage reference then buy, from eBay, a Fluke  
>> 731B voltage standard.  You will still need to get it calibrated,  
>> but then it will hold under 10ppm for well over a year or
>> more.  Actually, if they are adjusted correctly, you can get less  
>> than 5ppm and it will hold it at a given temperature.  These items  
>> are serious devices and their latest versions (very expensive)
>> are better than a properly maintained and operated group of  
>> standard cells.
>>
> The latest Fluke voltage standards use a selected LTZ1000 plus a
> precision resistor array.
> The earlier versions used selected Motorola zener diode references.
> The latest versions allow the LTZ1000 chip temperature to be cycled to
> largely eliminate hysteresis which may occur when they lose power  
> during
> shipment.
>> Bill....WB6BNQ
>
> Bruce

Since we've kinda strayed from the original topic, I'll throw in a  
couple of cents. The V references in these 6-1/2 and 7-1/2 digit DMMs  
(that I currently own at least one each of):  Keithley 196, HP 3456,  
3457, and 34401, use selected -- some more than others -- National  
LM199/299/399 series references, which have their own heaters. The  
Datron 1080 series (that I own two of), as well as the 1070 series  
and 1060 series, use selected pairs of zeners connected in parallel,  
but not housed in ovens. The Fluke 8502/05/06 (and my Fluke 510A ACV  
std) use the aforementioned Motorola transistor+buried zener  
reference, also not in ovens.

The HP 3458, as mentioned before, uses the Linear LTZ1000/1000A,  
which has its own heater. As to others, the old Fluke 895A, 887A, and  
885A 6-digit analog Differential Meters (with K-V bridges for  
comparing the reference to the unknown in various ways), all use a  
pair of zeners in series, in an oven. A Fluke engineer told me years  
ago that those zeners were selected to have slightly different TC  
peaks so when one was falling in V the other was rising, so that they  
would spread the peak over a larger temperature range. They had a  
very elaborate automated system for testing the temp, voltage, and  
current values to do the pairing.

My Fluke 732A DC reference standard, which uses the Motorola  
transistor+buried zener reference, housed in an oven together with  
all of the various fixed and variable resistors and the other active  
devices, has an extremely low drift rate -- unmeasurable over a month  
in any definitive way -- as measured with a rented HP 3458A. I have  
disabled the batteries because I discovered, thanks to the 3458A,  
that when turned off, cooled off, and turned back on, within a day,  
the output returned within 0.05ppm to it's cal'd value -- I know  
there can be hysteresis, I just couldn't see it.

I have one of the little Geller 10V refs built around the AD587  
reference chips, and if you keep it enclosed and away from air  
currents, it's pretty stable, but would need to be in an oven to  
approach the performance of the LM199 series.

All this is to say that if you can get a working HP 3458A or a Datron  
1280 series (which is also the Fluke 8805), or a Datron 1270 series  
meter, all of which are self-calibrating in various ingenious ways,  
it will serve you well as a secondary standard for measurement on  
everything that  it can measure. I can't, or more properly, won't at  
the moment, spend the current freight of around $4,000 USD for a  
known good working 3458 or 1281.

What to do? Seems like a possible stable, yet low-cost source would  
be to buy 10 or so LM399s and hook them up to a power supply to age  
for 6 to 12 months, then use two or four in parallel (with suitable  
resistor buffering) driving a chopper amp like the LT1050 to give  
gain. Powered by a good, stiff regulated supply, and kept away from  
stray air currents, this arrangement wouldn't cost as much as a  
single LTZ1000A (which in singles is over $100 USD) and -- dang it,  
there's always a catch -- after lab calibration, could be a source  
that might need adjustment only once every few years to stay within 5  
or 10ppm or so. Paralleling more LM399s would be better, and with an  
initial purchase of 10, you could throw away the stinkers and  
parallel all the rest. So, short of having a Fluke 732A or those  
8-1/2 digit meters, that's my recommendation for a low-cost V  
standard. Unless you know someone, it'll cost less to build than to  
calibrate...

Dick Moore


From ed_palmer at sasktel.net  Sat Nov 29 05:18:39 2008
From: ed_palmer at sasktel.net (Ed Palmer)
Date: Fri, 28 Nov 2008 23:18:39 -0600
Subject: [time-nuts] any way to bootstrap a frequency standard, into a,
 voltage or resistance standard?
In-Reply-To: <mailman.1.1227873601.25018.time-nuts@febo.com>
References: <mailman.1.1227873601.25018.time-nuts@febo.com>
Message-ID: <4930D0AF.9050708@sasktel.net>

Bill,

I agree with the comments made by you and everyone else.  That's why I said "..if it's good enough..".  But there's one thing that kind of slid by everyone.  All the other suggestions conclude with some variation of "..needs to be calibrated..".  Is there any other way to get a NIST-traceable voltage into your shop for $35?  (I'm not challenging you, I'd really like to know if there is another alternative)  Granted, it's only at the 10 uv level, but for many applications that *is* good enough.

Let's be honest, as time-nuts we're spoiled rotten.  Almost all of us have got rubidium standards at 10E-11 per day or better and at a ridiculously low price.  Many have got cesium standards and a few have got hydrogen masers.  We can calibrate them against GPS or Loran-C to obsessive-compulsive levels.  So far, none of the other physical standards allow that level of independence for hobbyists.  So when dealing with other measurement units (e.g. volts, ohms, etc) we either have to ease the requirements by orders of magnitude or increase the budget by orders of magnitude!

If you're doing this as part of your job and can justify the need and the expense - great!  I'm a hobbyist and I won't be spending $1843 any time soon to have NIST calibrate a DC solid-state voltage reference.  For my needs Geller Labs provides good value for the very nominal cost.

And just to be clear, I have no relationship with Geller Labs.

Ed

WB6BNQ wrote:

> No way in hell does that thing qualify as a voltage standard.  It barely qualifies as a VERY short term transfer device assuming the temperature does not change.
>
> If you want a real voltage reference then buy, from eBay, a Fluke 731B voltage standard.  You will still need to get it calibrated, but then it will hold under 10ppm for well over a year or
> more.  Actually, if they are adjusted correctly, you can get less than 5ppm and it will hold it at a given temperature.  These items are serious devices and their latest versions (very expensive)
> are better than a properly maintained and operated group of standard cells.
>
> I completely disagree with Brian about buying any standard cells.  Whatever voltage value they had is lost upon shipment.  Shaking the cells changes the value and it will not return to the
> original value.  If you did have a set of cells, you would want at least 4 of them.  Then study statistical math all over again because you will need it to use the cells.
>
> As Brian does suggest, you would be much better off picking up a hp3456A, 3457A, 3458A or getting one of Fluke 8500 series if it has the Ohms and AC options included.  The basic Fluke 8500 series
> is DC only mainframe.
>
> Measuring your resistors, using one of the above DVMs, in the 4-wire mode is about the best you could possibly do.  To do any better would require some very serious effort.
>
> By the way you could buy several of the latest and greatest Fluke super DVMs for the cost of what it would take to do a Josephson array and still have money left over to fund that divorce.
>
> Bill....WB6BNQ
>
>
> Ed Palmer wrote:
>
>   
>> It's nowhere near the idea of a Josephson array, but if a NIST-traceable 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you can buy it from www.gellerlabs.com for $35.
>>
>> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be interested in calibrating, but I can't seem to come up with a practical way of doing it.
>>
>> Frustrating, isn't it? :-)
>>
>> Ed
>>     

From tvb at LeapSecond.com  Sat Nov 29 06:30:33 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Fri, 28 Nov 2008 22:30:33 -0800
Subject: [time-nuts] Cesium vs H Maser clocks
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>
	<DA795DE5C8AF4A17A671A30171BACAE3@pc52>
	<20081129014129.181471165C3@hamburg.alientech.net>
Message-ID: <9FB14428535B4E0EAE3C34C33EE617F6@pc52>

> Isn't the temperature the _only_ thing to correct for?

No, not at all. Read the links that I provided to see that a real
cesium standard is not quite so simple, at least when you get
down to the ten to the -13, -14, -15 levels. At that level there
are all sorts of cool things that push or pull the frequency and
need to be corrected for.

> The definition of the second is "...the duration of 9 192 631 770 
> periods of the radiation corresponding to the transition between the 
> two hyperfine levels of the ground state of the cesium 133 atom." (and 
> affirmed by the CIPM in 1997 that this definition refers to a cesium 
> atom in its ground state at a temperature of 0 K)

Right. But realize that most of the cesium standards that we use
are not running at 0 Kelvin. So there is a correction for that.

In order for cesium beam standards to even work, one must apply
a slight magnetic field, the so-called C-field, which rather strongly
distorts the shape of the resonance peak. The definition assumes
zero magnetic field, so this too must be modeled and corrected for.
That's why, for example, the hp 5062c runs at 9,192,631,774.3133 Hz,
not the textbook 9,192,631,770 Hz. An internal synthesizer takes
care of this correction.

The NIST papers list a dozen or so of these corrections, each of
which is a nice lesson in atomic physics by itself.

Note also that clocks at NIST run about 1.8e-13 fast due to the high
elevation of Boulder, CO (general relativity), which is yet another
factor that has to be corrected for compared to the official sea-level
definition of the second.

> That other factors can change the relative frequency of different Cs 
> clocks is a problem with the definition, not an indication that any 
> particular one is better than another. If a magnetic field changes the 
> relative frequency, but that isn't reflected in the definition, is it 
> not the definition which is faulty, and not the timepiece? The second 
> is imprecise in this regard. 

The definition is fine -- it applies to the ideal conditions. But if you
decide to build an apparatus to implement the definition, and if for
whatever reason the ideal conditions can't be met in your apparatus,
then is it up to you, the clock builder, to anticipate this and make
corrections for it so that your clock still counts SI seconds at the
output BNC connector.

The other thing to note is that most cesium standards come with a
specification, based on design. I don't have the exact numbers but
a 5061A might be accurate out-of-the-box to 1e-11 while a 5071A
might be accurate to 1e-13. This reflects the difference in design,
manufacturing tolerances, and the number of internal frequency
offsets that are controlled or compensated for in hardware or in
firmware. So the definition of the SI second is fine; it's just that
some clocks can get closer to realizing the definition than others.

/tvb



From kirbybq at bellsouth.net  Sat Nov 29 07:25:39 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Sat, 29 Nov 2008 01:25:39 -0600
Subject: [time-nuts] Cesium vs H Maser clocks
In-Reply-To: <9FB14428535B4E0EAE3C34C33EE617F6@pc52>
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>	<DA795DE5C8AF4A17A671A30171BACAE3@pc52>	<20081129014129.181471165C3@hamburg.alientech.net>
	<9FB14428535B4E0EAE3C34C33EE617F6@pc52>
Message-ID: <4930EE73.5080903@bellsouth.net>

The clocks (rubidium and cesium) in the GPS satellites are also run at a 
different frequency because of their altitudes....

Also magnetic field are different on the earth and they sometimes adjust 
the "C" fields to correct for these differences.

>> Isn't the temperature the _only_ thing to correct for?
> 
> No, not at all. Read the links that I provided to see that a real
> cesium standard is not quite so simple, at least when you get
> down to the ten to the -13, -14, -15 levels. At that level there
> are all sorts of cool things that push or pull the frequency and
> need to be corrected for.
> 
>> The definition of the second is "...the duration of 9 192 631 770 
>> periods of the radiation corresponding to the transition between the 
>> two hyperfine levels of the ground state of the cesium 133 atom." (and 
>> affirmed by the CIPM in 1997 that this definition refers to a cesium 
>> atom in its ground state at a temperature of 0 K)


From richiem at hughes.net  Sat Nov 29 08:14:04 2008
From: richiem at hughes.net (Richard Moore)
Date: Sat, 29 Nov 2008 00:14:04 -0800
Subject: [time-nuts] TBolt TC recs wanted
Message-ID: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>

Dear nuts -- What TBolt time constant setting have you found to work  
best for best frequency accuracy and-or stability?

Dick Moore


From richiem at hughes.net  Sat Nov 29 08:32:18 2008
From: richiem at hughes.net (Richard Moore)
Date: Sat, 29 Nov 2008 00:32:18 -0800
Subject: [time-nuts] Geller V std
In-Reply-To: <mailman.431.1227946459.2542.time-nuts@febo.com>
References: <mailman.431.1227946459.2542.time-nuts@febo.com>
Message-ID: <B86B4C2D-B97D-43DB-91D8-D578629C0AD4@hughes.net>

> Message: 3
> Date: Fri, 28 Nov 2008 20:51:12 -0800
> From: "WarrenS" <warrensjmail-one at yahoo.com>
> Subject: Re: [time-nuts] Voltage standards
> To: "Discussion of precise time and frequency measurement"
> 	<time-nuts at febo.com>
> Message-ID: <029701c951de$1adadb70$6401a8c0 at WSOffice>
> Content-Type: text/plain;	charset="iso-8859-1"
>
> Just to add my experiences and throw in another two cents worth.
> I live in California,  and a few years back I did some experiments
> with Geller on the East coast shipping back and forth some of his 10V
> References in the regular mail that I had added a simple 1 transistor
> 1st order Temperature compensation circuit to some of his selected  
> aged
> units and proved to my satisfaction that better than 2PPM transfer
> accuracy was obtained across the country. In house I can consistently
> get better than 1 PPM transfer with the same units. Of course there
> are more accurate ways, but for us cheap guys It sure beats the $500
> I heard Fluke charges to do their underlying Fluke 732B calibration.
>
> WarrenS
> *********************

Warren, could you or would  you share that little mod with us?

Dick Moore


From wb6bnq at cox.net  Sat Nov 29 08:54:40 2008
From: wb6bnq at cox.net (WB6BNQ)
Date: Sat, 29 Nov 2008 00:54:40 -0800
Subject: [time-nuts] any way to bootstrap a frequency standard, into  a,
 voltage or resistance standard?
References: <mailman.1.1227873601.25018.time-nuts@febo.com>
	<4930D0AF.9050708@sasktel.net>
Message-ID: <4931034F.C4574B6D@cox.net>

Ed,

Your are right, it is quite expensive and difficult to send something to NIST.  BUT all is not lost as other alternatives do exist.

Besides NIST, other cal labs referred to as type 1 and type 2 exist with more than enough capability to handle fairly strenuous requirements of most of the modern test equipment.  A type 1 lab is one step below a ?primary? lab and, obviously, a type 2 lab is under the type 1 with lessor capability.  These designations are used with the military labs, but there is a relationship to the commercial labs.  For instance, Fluke and Hp have (had?) both a primary capability in their respective fields and type 1 level.  Most of the really  major manufacturers supporting military
contracts have at least a type 1 lab and some of them have primary capability in some fields.

Except for Fluke and Hp, the others, above, would not take work from outside sources like you or me.  There are plenty of commercial enterprises that have so called ?cal labs? that are at least at the type 2 level.  Unfortunately, also a number of them do not qualify either because they do not have the properly maintained standards or they fail due to quality of their personnel.

A really decent commercial lab would be cheaper than NIST and can easily handle top of the line DVMs referred to elsewhere.  It would not hurt to see what Fluke would charge to calibrate their 731 or 732 voltage reference or one of their very good DVMs.

The best item for an individual to own is a truly top of the line DVM.  It provides a reasonable reference for DC, AC, and Ohms that far surpasses what most hobbyist and for that matter most companies would ever need.

As for the Geller unit, I have a problem with people who advertise such stuff to unsuspecting buyers with such fanfare. Too many people have no clue and develop a false sense of security relative to what they thought they purchased.

Here is a good app-note from the Linear Technology that discusses the various issues about voltage references:

http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1021,P1567,D4171

Although it is well worth reading, it does not cover off board issues like thermals in the hook leads or external guard circuits and 4 wire connections besides other things.

One last issue, that of NIST traceability.  For the largest part this statement really means that a measurement method was followed.  It does not necessarily mean a direct comparison was made with NIST.  Many people I have talked to have a misconception wrapped around this phrase.

Bill....WB6BNQ


Ed Palmer wrote:

> Bill,
>
> I agree with the comments made by you and everyone else.  That's why I said "..if it's good enough..".  But there's one thing that kind of slid by everyone.  All the other suggestions conclude with some variation of "..needs to be calibrated..".  Is there any other way to get a NIST-traceable voltage into your shop for $35?  (I'm not challenging you, I'd really like to know if there is another alternative)  Granted, it's only at the 10 uv level, but for many applications that *is* good enough.
>
> Let's be honest, as time-nuts we're spoiled rotten.  Almost all of us have got rubidium standards at 10E-11 per day or better and at a ridiculously low price.  Many have got cesium standards and a few have got hydrogen masers.  We can calibrate them against GPS or Loran-C to obsessive-compulsive levels.  So far, none of the other physical standards allow that level of independence for hobbyists.  So when dealing with other measurement units (e.g. volts, ohms, etc) we either have to ease the requirements by orders of magnitude or increase the budget by orders of magnitude!
>
> If you're doing this as part of your job and can justify the need and the expense - great!  I'm a hobbyist and I won't be spending $1843 any time soon to have NIST calibrate a DC solid-state voltage reference.  For my needs Geller Labs provides good value for the very nominal cost.
>
> And just to be clear, I have no relationship with Geller Labs.
>
> Ed
>
> WB6BNQ wrote:
>
> > No way in hell does that thing qualify as a voltage standard.  It barely qualifies as a VERY short term transfer device assuming the temperature does not change.
> >
> > If you want a real voltage reference then buy, from eBay, a Fluke 731B voltage standard.  You will still need to get it calibrated, but then it will hold under 10ppm for well over a year or
> > more.  Actually, if they are adjusted correctly, you can get less than 5ppm and it will hold it at a given temperature.  These items are serious devices and their latest versions (very expensive)
> > are better than a properly maintained and operated group of standard cells.
> >
> > I completely disagree with Brian about buying any standard cells.  Whatever voltage value they had is lost upon shipment.  Shaking the cells changes the value and it will not return to the
> > original value.  If you did have a set of cells, you would want at least 4 of them.  Then study statistical math all over again because you will need it to use the cells.
> >
> > As Brian does suggest, you would be much better off picking up a hp3456A, 3457A, 3458A or getting one of Fluke 8500 series if it has the Ohms and AC options included.  The basic Fluke 8500 series
> > is DC only mainframe.
> >
> > Measuring your resistors, using one of the above DVMs, in the 4-wire mode is about the best you could possibly do.  To do any better would require some very serious effort.
> >
> > By the way you could buy several of the latest and greatest Fluke super DVMs for the cost of what it would take to do a Josephson array and still have money left over to fund that divorce.
> >
> > Bill....WB6BNQ
> >
> >
> > Ed Palmer wrote:
> >
> >
> >> It's nowhere near the idea of a Josephson array, but if a NIST-traceable 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you can buy it from www.gellerlabs.com for $35.
> >>
> >> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be interested in calibrating, but I can't seem to come up with a practical way of doing it.
> >>
> >> Frustrating, isn't it? :-)
> >>
> >> Ed
> >>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From kirbybq at bellsouth.net  Sat Nov 29 09:32:23 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Sat, 29 Nov 2008 03:32:23 -0600
Subject: [time-nuts] Voltage Standards
In-Reply-To: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>
References: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>
Message-ID: <49310C27.2000902@bellsouth.net>


We'll, I did not mean to hijack the previous thread on the subject.

In my case, I own one LM199AH/883 based voltage reference that I bought 
several years ago.  I have traceability on the unit from when it was 
made and all the factory test data when they qualified it.  It cost me 
around $60 to get it because of the certifications.

It uses a constant current generator to set to 2 ma.  That feeds two 
LM399s in series that draw 1 ma, and then I feed a set of precision 
resistors off of it to the LM199AH/883, which draws the other 1ma.  The 
constant current generator is a LT1000, with a buffer transistor.  The 
heaters are regulated by a LM317 regulator, that is referenced to 
another LM399 regulator.  The system runs off of a Lamba 24 volt linear 
power supply, I have a set of power diodes "or'ed" where I can hook up a 
couple of gell cells for backup power and so I can transport them to the 
cal lab.  This system holds 6.862429 volts and with no filtering on the 
output it will wander around +/- 3 to 4 uV.  When filtered, we have 
watched this unit give around 0.3 PPM over 30 minutes to an hour.  When 
I built this unit, I burned it in for 6 months and then I carried it to 
work where we had a HP3458A.  I was able to use the voltmeter for about 
2 weeks and we let it run and recorded 1 second data to characterize it. 
  This unit is my primary reference.  I have since left that place of 
employment and now I carry it to the cal lab once a year and they 
measure it for me.

I also have another unit using a selected LM399.  I bought 10 LM399s and 
burned them in for a year and then we characterized them for noise.  In 
the end you keep the quietest one which has the lowest drift over time. 
  This one used OP07s for the constant current generators, and it 
appears to perform around 2 PPM during the day.  On this circuit, I also 
bring out several points, so it has a 10V output, and a divider to bring 
out 1.0183 volts (it was used for standard cell comparison), the 6V 
reference point and 16V out of the current generator.  I use this one to 
checks voltmeters for quick test. I also hook it up to an external 
bridge and use the bridge as a divider to generate precision voltage steps.

I built another super power supply, its based on several LM399s and its 
basically a variable unit and you can set the output from 1 volt to 10.5 
volts.  It uses 2 each ten turn pots and you can set it down to the 10 
microvolt level.  I used it for working with synthesizers to set VCO's, 
etc, and some precision temp sensor work, etc.

I had mention standard cells - Now that I think about it, its probably 
not very useful for folks nowadays - they require extreme care and 
handling and can be very easily ruined.  I still use one in the 
precision variable power supply in the above paragraph.  I swap it in 
place of the reference, because they are very quiet and its a quick 
problem solver in my case.  I have several standard cells.  What I used 
to do, was when the arrived, I measured them the next day and recorded 
their values.  Then I did not disturbs them for a month and checked 
again.  After 90 days, if they looked good, then I hand carried them to 
the cal lab and I let them keep them for a week and they would watch 
them and give me back the results.

Some folks mention the Motorola zener diodes and I believe that would 
also make a good source for a project.  I bought a differential 
voltmeter at a hamfest one time and it did not work correctly.  WHile 
troubleshooting, I noticed that Fluke had wrote down the zener diodes 
voltages along with the zeners current.  I pulled these units and used a 
constant current generator set for the values it needed and the voltage 
on the zeners where what Fluke had called for.  I have set them aside 
for a future project.  Also, I was able to salvage a lot of excellent 
precision resistors from the differential voltmeter - and I picked it up 
for $15.  So thats another source of good parts to look at , at your 
next hamfest.

The LTZ1000 use to be able to be purchased from DigiKey for $75-80 each. 
  I noticed they do not have any current stock and they ask you to call 
if you want a single unit.

This is the problem with our hobby, it becomes serious...next thing you 
know, we all end up owning part of a calibration lab...the best part is 
there is a lot of excellent surplus test equipment out there that can be 
picked up cheap.  My method is I decide what I want, and I watch 
auctions that are not too high priced to start with.  I try to go into a 
dialog with the seller and I have found that most who know what the 
device is can tell you about the shape and condition of the unit.  I buy 
cheap and then I attempt to check it out.  It it appears OK, then I 
spend the money to get the unit calibrated.  If the units fail, I hang 
onto them a while, and then I will find another someday.  If you find 
another unit cheap, you may be able to mix and match parts and get a 
unit that will play - and then I carry it off to be calibrated.

The cal lab I use, gives me a price break.  They know I am not a 
business, I let them know I am a ham who just likes to use good 
equipment that gives repeatable performance. In my case they usually 
give me before data, they cal it, and then give me after data, on my 
precision multimeters.  They take their time calibrating it, they 
usually perform when their business is slow and that helps keeps the 
cost down.  I call before I go, just to see how there schedule is.  On 
other devices, I only have it cal to make sure its meeting specs, and I 
do not ask for before/after data.  All I want to know is it passed - and 
that saves lots of money.  And it will surprise you, some items do not 
cost much for calibration - there are a lot of equipment that is closed 
case calibration - they hook up to the calibrator and a controller and 
it puts it thru the paces without much human intervention.

Maybe we should consider coming up with a standard voltage reference as 
a TAPR project.  We have a lot of good brainpower out here and it seems 
a lot of experience available.

Brian - KD4FM











From kyndbo at gmail.com  Sat Nov 29 09:46:36 2008
From: kyndbo at gmail.com (Helge Kyndbo)
Date: Sat, 29 Nov 2008 10:46:36 +0100
Subject: [time-nuts] time-nuts Geller 10 volt ref. modification.
Message-ID: <33899fa20811290146v72d90cedk753fd63c2c4631f0@mail.gmail.com>

Geller 10 volt ref.

Hello WarrenS,
Is it possible to have some details of your 1 transistor 1st order
temperature modification,
on the Geller 10 volt ref. ?

Helge



2008/11/29 <time-nuts-request at febo.com>

> Send time-nuts mailing list submissions to
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> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of time-nuts digest..."
>
>
> Today's Topics:
>
>   1. Re: Calibration and temperature (Lux, James P)
>   2. Re: Voltage standards (Bruce Griffiths)
>   3. Re: Voltage standards (WarrenS)
>   4. Re: any way to bootstrap a frequency standard, into a,
>      voltage or resistance standard? (Ed Palmer)
>   5. Re: Cesium vs H Maser clocks (Tom Van Baak)
>   6. Re: Cesium vs H Maser clocks (Brian Kirby)
>   7. TBolt TC recs wanted (Richard Moore)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 28 Nov 2008 19:52:35 -0800
> From: "Lux, James P" <james.p.lux at jpl.nasa.gov>
> Subject: Re: [time-nuts] Calibration and temperature
> To: Discussion of precise time and frequency measurement
>        <time-nuts at febo.com>
> Message-ID: <C555FC83.2F5E%James.P.Lux at jpl.nasa.gov<C555FC83.2F5E%25James.P.Lux at jpl.nasa.gov>
> >
> Content-Type: text/plain; charset="iso-8859-1"
>
>
>
>
> On 11/28/08 11:27 AM, "Bill Hawkins" <bill at iaxs.net> wrote:
> >
> > Has any work been done on temperature compensation of quartz or other
> > oscillators to avoid the expense, space, and power of ovens? The
> > oscillating material must have a repeatable temperature curve, of
> > course.
> Look at MCXOs, a very clever technique using the different between third
> overtone and fundamental to measure the temperature of the rock.
>
>
> Jim Lux
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 29 Nov 2008 17:12:40 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] Voltage standards
> To: Discussion of precise time and frequency measurement
>        <time-nuts at febo.com>
> Message-ID: <4930C138.3020105 at xtra.co.nz>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Richard Moore wrote:
> > What to do? Seems like a possible stable, yet low-cost source would
> > be to buy 10 or so LM399s and hook them up to a power supply to age
> > for 6 to 12 months, then use two or four in parallel (with suitable
> > resistor buffering) driving a chopper amp like the LT1050 to give
> > gain. Powered by a good, stiff regulated supply, and kept away from
> > stray air currents, this arrangement wouldn't cost as much as a
> > single LTZ1000A (which in singles is over $100 USD)
> LTZ1000A list price is about $54 (excluding freight and taxes) when
> ordering from Linear Technology.
> The LTC1050 is a bit marginal unless you bootstrap its power supply the
> LTC1151 is a better fit.
> >  and -- dang it,
> > there's always a catch -- after lab calibration, could be a source
> > that might need adjustment only once every few years to stay within 5
> > or 10ppm or so. Paralleling more LM399s would be better, and with an
> > initial purchase of 10, you could throw away the stinkers and
> > parallel all the rest. So, short of having a Fluke 732A or those
> > 8-1/2 digit meters, that's my recommendation for a low-cost V
> > standard. Unless you know someone, it'll cost less to build than to
> > calibrate...
> >
> > Dick Moore
> >
> >
> >
> Bruce
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 28 Nov 2008 20:51:12 -0800
> From: "WarrenS" <warrensjmail-one at yahoo.com>
> Subject: Re: [time-nuts] Voltage standards
> To: "Discussion of precise time and frequency measurement"
>        <time-nuts at febo.com>
> Message-ID: <029701c951de$1adadb70$6401a8c0 at WSOffice>
> Content-Type: text/plain;       charset="iso-8859-1"
>
>
> Just to add my experiences and throw in another two cents worth.
> I live in California,  and a few years back I did some experiments
> with Geller on the East coast shipping back and forth some of his 10V
> References in the regular mail that I had added a simple 1 transistor
> 1st order Temperature compensation circuit to some of his selected aged
> units and proved to my satisfaction that better than 2PPM transfer
> accuracy was obtained across the country. In house I can consistently
> get better than 1 PPM transfer with the same units. Of course there
> are more accurate ways, but for us cheap guys It sure beats the $500
> I heard Fluke charges to do their underlying Fluke 732B calibration.
>
> WarrenS
> *********************
>
> RE  Message 8 and a couple of earlier posts on standards
>
> > Date: Sat, 29 Nov 2008 10:38:53 +1300
> > From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> > Subject: Re: [time-nuts] any way to bootstrap a frequency standard
> >  into  a, voltage or resistance standard?
> > To: Discussion of precise time and frequency measurement
> >  <time-nuts at febo.com>
> > Message-ID: <493064ED.1030501 at xtra.co.nz>
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > WB6BNQ wrote:
> >> Ed,
> >>
> >> No way in hell does that thing qualify as a voltage standard.  It
> >> barely qualifies as a VERY short term transfer device assuming the
> >> temperature does not change.
> >>
> >> If you want a real voltage reference then buy, from eBay, a Fluke
> >> 731B voltage standard.  You will still need to get it calibrated,
> >> but then it will hold under 10ppm for well over a year or
> >> more.  Actually, if they are adjusted correctly, you can get less
> >> than 5ppm and it will hold it at a given temperature.  These items
> >> are serious devices and their latest versions (very expensive)
> >> are better than a properly maintained and operated group of
> >> standard cells.
> >>
> > The latest Fluke voltage standards use a selected LTZ1000 plus a
> > precision resistor array.
> > The earlier versions used selected Motorola zener diode references.
> > The latest versions allow the LTZ1000 chip temperature to be cycled to
> > largely eliminate hysteresis which may occur when they lose power
> > during
> > shipment.
> >> Bill....WB6BNQ
> >
> > Bruce
>
> Since we've kinda strayed from the original topic, I'll throw in a
> couple of cents. The V references in these 6-1/2 and 7-1/2 digit DMMs
> (that I currently own at least one each of):  Keithley 196, HP 3456,
> 3457, and 34401, use selected -- some more than others -- National
> LM199/299/399 series references, which have their own heaters. The
> Datron 1080 series (that I own two of), as well as the 1070 series
> and 1060 series, use selected pairs of zeners connected in parallel,
> but not housed in ovens. The Fluke 8502/05/06 (and my Fluke 510A ACV
> std) use the aforementioned Motorola transistor+buried zener
> reference, also not in ovens.
>
> The HP 3458, as mentioned before, uses the Linear LTZ1000/1000A,
> which has its own heater. As to others, the old Fluke 895A, 887A, and
> 885A 6-digit analog Differential Meters (with K-V bridges for
> comparing the reference to the unknown in various ways), all use a
> pair of zeners in series, in an oven. A Fluke engineer told me years
> ago that those zeners were selected to have slightly different TC
> peaks so when one was falling in V the other was rising, so that they
> would spread the peak over a larger temperature range. They had a
> very elaborate automated system for testing the temp, voltage, and
> current values to do the pairing.
>
> My Fluke 732A DC reference standard, which uses the Motorola
> transistor+buried zener reference, housed in an oven together with
> all of the various fixed and variable resistors and the other active
> devices, has an extremely low drift rate -- unmeasurable over a month
> in any definitive way -- as measured with a rented HP 3458A. I have
> disabled the batteries because I discovered, thanks to the 3458A,
> that when turned off, cooled off, and turned back on, within a day,
> the output returned within 0.05ppm to it's cal'd value -- I know
> there can be hysteresis, I just couldn't see it.
>
> I have one of the little Geller 10V refs built around the AD587
> reference chips, and if you keep it enclosed and away from air
> currents, it's pretty stable, but would need to be in an oven to
> approach the performance of the LM199 series.
>
> All this is to say that if you can get a working HP 3458A or a Datron
> 1280 series (which is also the Fluke 8805), or a Datron 1270 series
> meter, all of which are self-calibrating in various ingenious ways,
> it will serve you well as a secondary standard for measurement on
> everything that  it can measure. I can't, or more properly, won't at
> the moment, spend the current freight of around $4,000 USD for a
> known good working 3458 or 1281.
>
> What to do? Seems like a possible stable, yet low-cost source would
> be to buy 10 or so LM399s and hook them up to a power supply to age
> for 6 to 12 months, then use two or four in parallel (with suitable
> resistor buffering) driving a chopper amp like the LT1050 to give
> gain. Powered by a good, stiff regulated supply, and kept away from
> stray air currents, this arrangement wouldn't cost as much as a
> single LTZ1000A (which in singles is over $100 USD) and -- dang it,
> there's always a catch -- after lab calibration, could be a source
> that might need adjustment only once every few years to stay within 5
> or 10ppm or so. Paralleling more LM399s would be better, and with an
> initial purchase of 10, you could throw away the stinkers and
> parallel all the rest. So, short of having a Fluke 732A or those
> 8-1/2 digit meters, that's my recommendation for a low-cost V
> standard. Unless you know someone, it'll cost less to build than to
> calibrate...
>
> Dick Moore
>
>
>
> ------------------------------
>
> Message: 4
> Date: Fri, 28 Nov 2008 23:18:39 -0600
> From: Ed Palmer <ed_palmer at sasktel.net>
> Subject: Re: [time-nuts] any way to bootstrap a frequency standard,
>        into a, voltage or resistance standard?
> To: time-nuts at febo.com
> Message-ID: <4930D0AF.9050708 at sasktel.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Bill,
>
> I agree with the comments made by you and everyone else.  That's why I said
> "..if it's good enough..".  But there's one thing that kind of slid by
> everyone.  All the other suggestions conclude with some variation of
> "..needs to be calibrated..".  Is there any other way to get a
> NIST-traceable voltage into your shop for $35?  (I'm not challenging you,
> I'd really like to know if there is another alternative)  Granted, it's only
> at the 10 uv level, but for many applications that *is* good enough.
>
> Let's be honest, as time-nuts we're spoiled rotten.  Almost all of us have
> got rubidium standards at 10E-11 per day or better and at a ridiculously low
> price.  Many have got cesium standards and a few have got hydrogen masers.
>  We can calibrate them against GPS or Loran-C to obsessive-compulsive
> levels.  So far, none of the other physical standards allow that level of
> independence for hobbyists.  So when dealing with other measurement units
> (e.g. volts, ohms, etc) we either have to ease the requirements by orders of
> magnitude or increase the budget by orders of magnitude!
>
> If you're doing this as part of your job and can justify the need and the
> expense - great!  I'm a hobbyist and I won't be spending $1843 any time soon
> to have NIST calibrate a DC solid-state voltage reference.  For my needs
> Geller Labs provides good value for the very nominal cost.
>
> And just to be clear, I have no relationship with Geller Labs.
>
> Ed
>
> WB6BNQ wrote:
>
> > No way in hell does that thing qualify as a voltage standard.  It barely
> qualifies as a VERY short term transfer device assuming the temperature does
> not change.
> >
> > If you want a real voltage reference then buy, from eBay, a Fluke 731B
> voltage standard.  You will still need to get it calibrated, but then it
> will hold under 10ppm for well over a year or
> > more.  Actually, if they are adjusted correctly, you can get less than
> 5ppm and it will hold it at a given temperature.  These items are serious
> devices and their latest versions (very expensive)
> > are better than a properly maintained and operated group of standard
> cells.
> >
> > I completely disagree with Brian about buying any standard cells.
>  Whatever voltage value they had is lost upon shipment.  Shaking the cells
> changes the value and it will not return to the
> > original value.  If you did have a set of cells, you would want at least
> 4 of them.  Then study statistical math all over again because you will need
> it to use the cells.
> >
> > As Brian does suggest, you would be much better off picking up a hp3456A,
> 3457A, 3458A or getting one of Fluke 8500 series if it has the Ohms and AC
> options included.  The basic Fluke 8500 series
> > is DC only mainframe.
> >
> > Measuring your resistors, using one of the above DVMs, in the 4-wire mode
> is about the best you could possibly do.  To do any better would require
> some very serious effort.
> >
> > By the way you could buy several of the latest and greatest Fluke super
> DVMs for the cost of what it would take to do a Josephson array and still
> have money left over to fund that divorce.
> >
> > Bill....WB6BNQ
> >
> >
> > Ed Palmer wrote:
> >
> >
> >> It's nowhere near the idea of a Josephson array, but if a NIST-traceable
> 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you
> can buy it from www.gellerlabs.com for $35.
> >>
> >> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be
> interested in calibrating, but I can't seem to come up with a practical way
> of doing it.
> >>
> >> Frustrating, isn't it? :-)
> >>
> >> Ed
> >>
>
>
> ------------------------------
>
> Message: 5
> Date: Fri, 28 Nov 2008 22:30:33 -0800
> From: "Tom Van Baak" <tvb at LeapSecond.com>
> Subject: Re: [time-nuts] Cesium vs H Maser clocks
> To: "Discussion of precise time and frequency measurement"
>        <time-nuts at febo.com>
> Message-ID: <9FB14428535B4E0EAE3C34C33EE617F6 at pc52>
> Content-Type: text/plain; format=flowed; charset="Windows-1252";
>        reply-type=original
>
> > Isn't the temperature the _only_ thing to correct for?
>
> No, not at all. Read the links that I provided to see that a real
> cesium standard is not quite so simple, at least when you get
> down to the ten to the -13, -14, -15 levels. At that level there
> are all sorts of cool things that push or pull the frequency and
> need to be corrected for.
>
> > The definition of the second is "...the duration of 9 192 631 770
> > periods of the radiation corresponding to the transition between the
> > two hyperfine levels of the ground state of the cesium 133 atom." (and
> > affirmed by the CIPM in 1997 that this definition refers to a cesium
> > atom in its ground state at a temperature of 0 K)
>
> Right. But realize that most of the cesium standards that we use
> are not running at 0 Kelvin. So there is a correction for that.
>
> In order for cesium beam standards to even work, one must apply
> a slight magnetic field, the so-called C-field, which rather strongly
> distorts the shape of the resonance peak. The definition assumes
> zero magnetic field, so this too must be modeled and corrected for.
> That's why, for example, the hp 5062c runs at 9,192,631,774.3133 Hz,
> not the textbook 9,192,631,770 Hz. An internal synthesizer takes
> care of this correction.
>
> The NIST papers list a dozen or so of these corrections, each of
> which is a nice lesson in atomic physics by itself.
>
> Note also that clocks at NIST run about 1.8e-13 fast due to the high
> elevation of Boulder, CO (general relativity), which is yet another
> factor that has to be corrected for compared to the official sea-level
> definition of the second.
>
> > That other factors can change the relative frequency of different Cs
> > clocks is a problem with the definition, not an indication that any
> > particular one is better than another. If a magnetic field changes the
> > relative frequency, but that isn't reflected in the definition, is it
> > not the definition which is faulty, and not the timepiece? The second
> > is imprecise in this regard.
>
> The definition is fine -- it applies to the ideal conditions. But if you
> decide to build an apparatus to implement the definition, and if for
> whatever reason the ideal conditions can't be met in your apparatus,
> then is it up to you, the clock builder, to anticipate this and make
> corrections for it so that your clock still counts SI seconds at the
> output BNC connector.
>
> The other thing to note is that most cesium standards come with a
> specification, based on design. I don't have the exact numbers but
> a 5061A might be accurate out-of-the-box to 1e-11 while a 5071A
> might be accurate to 1e-13. This reflects the difference in design,
> manufacturing tolerances, and the number of internal frequency
> offsets that are controlled or compensated for in hardware or in
> firmware. So the definition of the SI second is fine; it's just that
> some clocks can get closer to realizing the definition than others.
>
> /tvb
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sat, 29 Nov 2008 01:25:39 -0600
> From: Brian Kirby <kirbybq at bellsouth.net>
> Subject: Re: [time-nuts] Cesium vs H Maser clocks
> To: Tom Van Baak <tvb at leapsecond.com>,  Discussion of precise time and
>        frequency measurement <time-nuts at febo.com>
> Message-ID: <4930EE73.5080903 at bellsouth.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> The clocks (rubidium and cesium) in the GPS satellites are also run at a
> different frequency because of their altitudes....
>
> Also magnetic field are different on the earth and they sometimes adjust
> the "C" fields to correct for these differences.
>
> >> Isn't the temperature the _only_ thing to correct for?
> >
> > No, not at all. Read the links that I provided to see that a real
> > cesium standard is not quite so simple, at least when you get
> > down to the ten to the -13, -14, -15 levels. At that level there
> > are all sorts of cool things that push or pull the frequency and
> > need to be corrected for.
> >
> >> The definition of the second is "...the duration of 9 192 631 770
> >> periods of the radiation corresponding to the transition between the
> >> two hyperfine levels of the ground state of the cesium 133 atom." (and
> >> affirmed by the CIPM in 1997 that this definition refers to a cesium
> >> atom in its ground state at a temperature of 0 K)
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sat, 29 Nov 2008 00:14:04 -0800
> From: Richard Moore <richiem at hughes.net>
> Subject: [time-nuts] TBolt TC recs wanted
> To: time-nuts at febo.com
> Message-ID: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58 at hughes.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> Dear nuts -- What TBolt time constant setting have you found to work
> best for best frequency accuracy and-or stability?
>
> Dick Moore
>
>
>
> ------------------------------
>
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
> End of time-nuts Digest, Vol 52, Issue 85
> *****************************************
>

From kirbybq at bellsouth.net  Sat Nov 29 09:53:39 2008
From: kirbybq at bellsouth.net (Brian Kirby)
Date: Sat, 29 Nov 2008 03:53:39 -0600
Subject: [time-nuts] App Notes Voltage References
Message-ID: <49311123.9030503@bellsouth.net>

App Notes for good reading

Linear Technology - LTZ1000
AN86 Standards Lab Grade 20 Bit DAC with 0.1 PPM drift
AN82 Understanding and Applying Voltage References
AN42 Voltage Reference Collection
DN229 ABout long term testing

National Semiconductor LM399
AN-161 1 PPM voltage reference
AN-173 IC Zener eases reference design
AN-184 References for A/D COnvertors

Xicor X60008A-50
AN177


From magnus at rubidium.dyndns.org  Sat Nov 29 12:08:00 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sat, 29 Nov 2008 13:08:00 +0100
Subject: [time-nuts] Cesium vs H Maser clocks
In-Reply-To: <20081129014129.181471165C3@hamburg.alientech.net>
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>	<DA795DE5C8AF4A17A671A30171BACAE3@pc52>
	<20081129014129.181471165C3@hamburg.alientech.net>
Message-ID: <493130A0.9030800@rubidium.dyndns.org>

Mike S skrev:
> At 08:20 PM 11/28/2008, Tom Van Baak wrote...
>> If you really get into the details of the physics, remember that no
>> commercial or laboratory Cs clock actually resonates at precisely
>> 9 192 631 770.000 Hz. There are corrections for magnetic fields,
>> velocity of atoms, temperature, cavity design, even for gravity; a
>> whole bunch of interesting effects.
> 
> Isn't the temperature the _only_ thing to correct for?
> 
> The definition of the second is "...the duration of 9 192 631 770 
> periods of the radiation corresponding to the transition between the 
> two hyperfine levels of the ground state of the cesium 133 atom." (and 
> affirmed by the CIPM in 1997 that this definition refers to a cesium 
> atom in its ground state at a temperature of 0 K)
> 
> That other factors can change the relative frequency of different Cs 
> clocks is a problem with the definition, not an indication that any 
> particular one is better than another. If a magnetic field changes the 
> relative frequency, but that isn't reflected in the definition, is it 
> not the definition which is faulty, and not the timepiece? The second 
> is imprecise in this regard. 

Far from. What all Cesium clocks do is to de-tune with the C-field. This 
is not a bad thing since you may hit a numerically more suitable number 
that way such that the generated 5 MHz or 10 MHz has a neat relationship 
to the de-tune frequency. Modern CPU controlled cesiums contains a loop 
in which the nearby peaks is also monitored, as they spread out from the 
central peak very rapidly (square of C-field). This spreading you want 
anyway, since then you can observe the stable transition free from the 
more sensitive transitions. By monitoring the side-bands distance the C 
field can be locked up and remain at the stable value throughout the 
clocks life. This avoids a classic long term drift component and is part 
of a battery of improvements to achieve better frequency error. It also 
actively cancels whatever magnetic field that did get through the 
magnetic shielding.

Temperature and gravitational potential are among those that needs 
compensation.

The temperature of the gas stream will provide a continous set of 
doppler frequencies.

Shifts in phase of the microwave interrigation also cause problems, and 
it can be off to start with and shift with temperature of assembly.

There are many error sources. The simple story is that nobody get it 
"right". We have a common goal to approximate towards.

Cheers,
Magnus


From mikes at flatsurface.com  Sat Nov 29 11:59:33 2008
From: mikes at flatsurface.com (Mike S)
Date: Sat, 29 Nov 2008 06:59:33 -0500
Subject: [time-nuts] Cesium vs H Maser clocks
In-Reply-To: <9FB14428535B4E0EAE3C34C33EE617F6@pc52>
References: <KB2L9L$F725B2677CC405A0E8CF71C9A05A75B2@libero.it>
	<DA795DE5C8AF4A17A671A30171BACAE3@pc52>
	<20081129014129.181471165C3@hamburg.alientech.net>
	<9FB14428535B4E0EAE3C34C33EE617F6@pc52>
Message-ID: <20081129121239.C74691165C3@hamburg.alientech.net>

At 01:30 AM 11/29/2008, Tom Van Baak wrote...
>Note also that clocks at NIST run about 1.8e-13 fast due to the high
>elevation of Boulder, CO (general relativity), which is yet another
>factor that has to be corrected for compared to the official sea-level
>definition of the second.

Do they really adjust to sea level on earth? That isn't part of the 
definition. Within that convention, as the mean sea level rises (~20 cm 
in the last 100 years), does the length of the second change 
(relatively)?

Relativity tells us that time can be different in different reference 
frames, and that no frame of reference is unique. The NIST Cs clocks 
may differ from others, but they run perfectly (after adjustment for 
radiation effects), by definition. I understand that some practical 
uses of time (e.g. GPS) require that clocks in different reference 
frames be synchronized, but then a paradox is created, since even 
though different, both are correct.

"The second is the duration of 9 192 631 770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the 

ground state of the caesium 133 atom." "This definition refers to a 
caesium atom at rest at a temperature of 0 K." - 
http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf

What does "at rest" mean, other than that the definition applies to 
only the local frame of reference (i.e. observers to whom the atom 
appears at rest)? There is no absolute rest, which is what special 
relativity addressed.

Finally, at "0 K," "at rest," (is there a difference?) how is 
_anything_ happening with that atom? Doesn't time actually stop? You 
can't reach 0 K anymore than you can accelerate a mass to C.



From magnus at rubidium.dyndns.org  Sat Nov 29 12:40:40 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sat, 29 Nov 2008 13:40:40 +0100
Subject: [time-nuts] Calibration and temperature
In-Reply-To: <C555FC83.2F5E%James.P.Lux@jpl.nasa.gov>
References: <C555FC83.2F5E%James.P.Lux@jpl.nasa.gov>
Message-ID: <49313848.4030000@rubidium.dyndns.org>

Lux, James P skrev:
> 
> 
> On 11/28/08 11:27 AM, "Bill Hawkins" <bill at iaxs.net> wrote:
>> Has any work been done on temperature compensation of quartz or other
>> oscillators to avoid the expense, space, and power of ovens? The
>> oscillating material must have a repeatable temperature curve, of
>> course.
> Look at MCXOs, a very clever technique using the different between third
> overtone and fundamental to measure the temperature of the rock.

The fundamental and third overtones have different temperature 
dependencies. The difference is essentially linear, so by dividing the 
third overtone down by three or tripping the base frequency and then 
compare them in a mixer to get the beat frequency and count that, 
adjustment to the frequency can be performed, often through a DDS 
clocked at the third overtone.

The traditional suppression of major resonances becomes slightly 
different in the oscillator core, since now both the fundamental and 
third overtones is wanted. It is however not a big mystery.

You could use this temperature sensing technique to with an OCXO 
solution to let the inner oven be sensed in the crystal. A combined 
solution would both feed forward and feed backwards.

The MCXO and many others is very well presented in the big presentation 
that John Vig has 
(http://www.ieee-uffc.org/freqcontrol/tutorials/vig3/vig3.ppt). In 
general, there is plentifull of good information to read at:
http://www.ieee-uffc.org/fcmain.asp?view=review#tutor

Reading through that and parts of the NIST T&F archive should elivate 
your knowledge pretty fast and it is all for free. Just costs you the 
time to read.

Cheers,
Magnus


From iovane at inwind.it  Sat Nov 29 13:22:38 2008
From: iovane at inwind.it (iovane at inwind.it)
Date: Sat, 29 Nov 2008 14:22:38 +0100
Subject: [time-nuts] Cesium vs H Maser clocks
Message-ID: <KB3JTQ$69087F01F6FBA8B2A27CB0176F2499BA@libero.it>

> In order for cesium beam standards to even work, one must apply
> a slight magnetic field, the so-called C-field, which rather strongly
> distorts the shape of the resonance peak. 

Tom (and all),

do you think that a Cs clock, having a not-well-adjusted 
C field, might have a shape of the resonant peak distorted 
such that the clock might show metastability?

Antonio I8IOV





From bruce.griffiths at xtra.co.nz  Sat Nov 29 13:23:41 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 02:23:41 +1300
Subject: [time-nuts] Voltage Standards
In-Reply-To: <49310C27.2000902@bellsouth.net>
References: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>
	<49310C27.2000902@bellsouth.net>
Message-ID: <4931425D.8020407@xtra.co.nz>

Brian Kirby wrote:
> We'll, I did not mean to hijack the previous thread on the subject.
>
>
>
> The LTZ1000 use to be able to be purchased from DigiKey for $75-80 each. 
>   I noticed they do not have any current stock and they ask you to call 
> if you want a single unit.
>   
They can still be ordered on line direct from Linear Technology for
somewhat less.
>
> Maybe we should consider coming up with a standard voltage reference as 
> a TAPR project.  We have a lot of good brainpower out here and it seems 
> a lot of experience available.
>
> Brian - KD4FM
>
>   

Bruce


From brooke at pacific.net  Sat Nov 29 16:24:43 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 29 Nov 2008 08:24:43 -0800
Subject: [time-nuts] Voltage Standards
In-Reply-To: <4931425D.8020407@xtra.co.nz>
References: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>	<49310C27.2000902@bellsouth.net>
	<4931425D.8020407@xtra.co.nz>
Message-ID: <49316CCB.4030203@pacific.net>

Hi:

Geller's patent 7382179 Voltage reference with enhanced stability explains how 
he combines the AD587 voltage reference with the LM399 voltage reference to 
obtain improved temperature stability.  The method can be used with the LT1000.
http://www.google.com/patents?id=v0GqAAAAEBAJ&dq=7382179

7380471 Micro gust thermal anemometer is a similar circuit by Geller where the 
LM399 is installed on the PCB using the untrimmed leads so that it's up in the 
air.  Any wind changes it's temperature which is seen as an output.
http://www.google.com/patents?id=GDuqAAAAEBAJ&dq=7380471

I found a drawing on the National Semi web site for a Valox plastic shield for 
the LM199, but there's not any other info about it or the specified material.
http://www.national.com/packaging/mkt/h04d.pdf

Brooke Clarke
http://www.prc68.com


From tvb at LeapSecond.com  Sat Nov 29 18:03:36 2008
From: tvb at LeapSecond.com (Tom Van Baak)
Date: Sat, 29 Nov 2008 10:03:36 -0800
Subject: [time-nuts] Cesium vs H Maser clocks
References: <KB3JTQ$69087F01F6FBA8B2A27CB0176F2499BA@libero.it>
Message-ID: <8F73C2CB9C4344DBA55894CAE17460D8@pc52>

>> In order for cesium beam standards to even work, one must apply
>> a slight magnetic field, the so-called C-field, which rather strongly
>> distorts the shape of the resonance peak. 
> 
> Tom (and all),
> 
> do you think that a Cs clock, having a not-well-adjusted 
> C field, might have a shape of the resonant peak distorted 
> such that the clock might show metastability?
> 
> Antonio I8IOV

Hi Antonio,

Perhaps I shouldn't have used the word "strongly". Here are
real numbers instead -- a typical Cs beam tube has a 53 kHz
splitting (compare with the 9 192 631 kHz center peak) when
the C-field is 76 milligauss.

Here's an old time nuts thread about Zeeman frequencies:
http://www.mail-archive.com/time-nuts at febo.com/msg00233.html

If you want to see the peaks for yourself, see this experiment:
http://www.leapsecond.com/pages/cspeak/

And my favorite, a large color plot of peak splitting vs. C-field:
http://www.leapsecond.com/images/cfield.gif

/tvb



From gbusg at comcast.net  Sat Nov 29 18:24:33 2008
From: gbusg at comcast.net (Greg Burnett)
Date: Sat, 29 Nov 2008 11:24:33 -0700
Subject: [time-nuts] Voltage standards
References: <mailman.417.1227910425.2542.time-nuts@febo.com>
	<B022E133-EDAD-4914-A1AA-B756AF69A6CF@hughes.net>
Message-ID: <003001c9524f$ba923d90$6501a8c0@gb02>

The Linear LTZ1000 is a pretty wonderful voltage reference, but they're not 
all created equal. It would be nice to pick the "cream of the crop" from a 
sample of 100 of them, but that would get expensive (and time consuming) in 
a hurry.

For use in their 3458A DMM, Agilent burns-in the LTZ1000 references and 
hand-selects the ones deemed good enough. The few, "cream of the crop" are 
set aside for use as high stability references in Option 02 3458A DMMs (spec 
= 4ppm/year) and the references not quite that good are set aside for the 
standard version 3458A DMMs (spec = 8ppm/year).

I've found that, after a few years use, the vast majority of standard 3458As 
easily meet the option 02's tighter 4ppm/year spec. In fact, I've seen a lot 
of 3458As drifting less than 2ppm/year, which is really good.

I'm guessing that the LTZ1000 can exhibit, perhaps, as much as 0.5 to 0.7 
ppm hysteresis when powered down and back up again, because I've 
occasionally observed shifts that large after power down/up and 
restabilization.

Greg



From warrensjmail-one at yahoo.com  Sat Nov 29 20:05:43 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Sat, 29 Nov 2008 12:05:43 -0800
Subject: [time-nuts] Voltage standards
Message-ID: <050701c9525d$dd015ce0$6401a8c0@WSOffice>

A Time-nut group may not be the best place top discuss Voltage references. 
Where is the Volt-Nuts site?

First thing to be aware of if you are planning to build your own reference is:
Good voltage reference parts are "SELECTED" which is just another word 
for cherry-picked. My better modified AD587LN Geller Lab voltage 
reference's are good to 0.1 PPM transfer accuracy over a 5 degree F 
temperature change and a 1 Hr time range, They also stay with in about 1PPM long term. 
I  think that  will 'qualify as a voltage standard'  to some.

The TC correction circuit I use is just two standard parts. 
A100K pot is placed between an added transistor's collector 
and ground with the pot's wiper going to the transitor's base.
What that does when current is applied to the transistor is to make  
the collector voltage vary with temperature by an adjustable amount. 
This temperature sensitive voltage is then added with the trim voltage 
to the reference's trim input to cancel the 1st order temperature drift.
The results I got was a settable 4 degF wide ZERO TC, 
turnover point at any desired room temperature.
The added parts fit on the small Geller's PCB.

The other suggestions that I have heard so far on this post take more skill 
and additional precision parts that quite frankly the average home builder 
is not going to have.

I do not mind posting my mod and results on line, if soneone will tell me a place to do it.

Some notes from my own  'make a state of the art voltage reference' efforts.
I.ve tested everything I could get my hands on, looking for simple solutions.

1) All AD587 are NOT created equal, but the 'noise' of the better ones is in 
the same general range as the 732B &/or the 3458A.
The best AD587 parts show that calibration and measurement is settable 
short term to better than 1uv (0.1 PPM).  
The poorer parts  show approx 4 uv step pulses every so often, 
but even then, If using a strip chart recorder, it is no problem to see 
their non stepped value to 1uv on most of the ones I tested.

2) The existing best references need to be kept ON to insure their calibration, 
A better low cost solution for long term stability seems to be to keep it OFF most 
of the time (using the right kind of selected zero warm up no hysteresis part).

3) My conclusion on 399's after months of long term test is,. they are great for having  a 
wide temp range low TC, but not so good for noise and long turn stability at the sub PPM levels
Holding a part at 90 degC is how you burn them in to age them 64 times faster, 
not how to hold good long term stability.

4) I personal didn't like LTZ1000's because their accuracy is very dependent on 
the stability of the external 2 terminal 100 ohm resistor that sets its zener current. 
If I remember right, it has only 10 to1 rejection so you still need a 1 PPM 
resistor to get sub PPM performance, and that's an absolute value on 
two terminals, not a tracking resistance.

BTW, I have no connection with Geller Labs other than buying some of this parts.
I must add that he was very helpful in my past quest for a good stable voltage source. 

WarrenS
**************
Re [time-nuts] time-nuts Geller 10 volt ref. modification.

Hello WarrenS,
Is it possible to have some details of your 1 transistor 1st order
temperature modification,
on the Geller 10 volt ref. ?

Helge
*****************
RE: Geller 10 volt ref.

Warren, could you or would  you share that little mod with us?

Dick Moore
*****************
RE: [time-nuts] Voltage standards

> Just to add my experiences and throw in another two cents worth.
> I live in California, and a few years back I did some experiments
> with Geller Labs which is located on the East coast by shipping back 
> and forth some of his 10V References in the regular mail.  I built  the 
> units myself on his PCBs so that I could added a simple 1 transistor 
> 1st order  Temperature compensation circuit. Using selected aged 
> AD587LN units that I also bought from him, I proved to my satisfaction 
> that better than 2PPM transfer accuracy was obtained thru the mail 
> across the country.  
> In house I can consistently get better than 1 PPM transfer with the 
> same units. Of course there are more accurate ways, but for us cheap 
> guys It sure beats the $500 I heard Fluke charges to do their underlying 
> Fluke 732B calibration.
>
> WarrenS
> *********************


From bruce.griffiths at xtra.co.nz  Sat Nov 29 20:48:06 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 09:48:06 +1300
Subject: [time-nuts] Voltage standards
In-Reply-To: <050701c9525d$dd015ce0$6401a8c0@WSOffice>
References: <050701c9525d$dd015ce0$6401a8c0@WSOffice>
Message-ID: <4931AA86.4090804@xtra.co.nz>

WarrenS wrote:
> A Time-nut group may not be the best place top discuss Voltage references. 
> Where is the Volt-Nuts site?
>
> First thing to be aware of if you are planning to build your own reference is:
> Good voltage reference parts are "SELECTED" which is just another word 
> for cherry-picked. My better modified AD587LN Geller Lab voltage 
> reference's are good to 0.1 PPM transfer accuracy over a 5 degree F 
> temperature change and a 1 Hr time range, They also stay with in about 1PPM long term. 
> I  think that  will 'qualify as a voltage standard'  to some.
>
> The TC correction circuit I use is just two standard parts. 
> A100K pot is placed between an added transistor's collector 
> and ground with the pot's wiper going to the transitor's base.
> What that does when current is applied to the transistor is to make  
> the collector voltage vary with temperature by an adjustable amount. 
> This temperature sensitive voltage is then added with the trim voltage 
> to the reference's trim input to cancel the 1st order temperature drift.
> The results I got was a settable 4 degF wide ZERO TC, 
> turnover point at any desired room temperature.
> The added parts fit on the small Geller's PCB.
>
>   
In other words an adjustable VBE multiplier??
> The other suggestions that I have heard so far on this post take more skill 
> and additional precision parts that quite frankly the average home builder 
> is not going to have.
>
> I do not mind posting my mod and results on line, if soneone will tell me a place to do it.
>
> Some notes from my own  'make a state of the art voltage reference' efforts.
> I.ve tested everything I could get my hands on, looking for simple solutions.
>
> 1) All AD587 are NOT created equal, but the 'noise' of the better ones is in 
> the same general range as the 732B &/or the 3458A.
> The best AD587 parts show that calibration and measurement is settable 
> short term to better than 1uv (0.1 PPM).  
> The poorer parts  show approx 4 uv step pulses every so often, 
> but even then, If using a strip chart recorder, it is no problem to see 
> their non stepped value to 1uv on most of the ones I tested.
>
> 2) The existing best references need to be kept ON to insure their calibration, 
> A better low cost solution for long term stability seems to be to keep it OFF most 
> of the time (using the right kind of selected zero warm up no hysteresis part).
>
>   
With a thermal conditioning cycle, before use, the LTZ1000 stability has
good stability (according to Fluke) even when powered off.
Implementing such a conditioning cycle would probably require using a
microprocessor to implement the conditioning cycle algorithm.
> 3) My conclusion on 399's after months of long term test is,. they are great for having  a 
> wide temp range low TC, but not so good for noise and long turn stability at the sub PPM levels
> Holding a part at 90 degC is how you burn them in to age them 64 times faster, 
> not how to hold good long term stability.
>
> 4) I personal didn't like LTZ1000's because their accuracy is very dependent on 
> the stability of the external 2 terminal 100 ohm resistor that sets its zener current. 
> If I remember right, it has only 10 to1 rejection so you still need a 1 PPM 
> resistor to get sub PPM performance, and that's an absolute value on 
> two terminals, not a tracking resistance.
>
>   
The LTZ1000 datasheet states that 100ppm change in this resistor
produces a 1ppm shift in the LTZ1000 reference voltage.
It is possible to use a 4 terminal resistor for this part to improve
accuracy somewhat as the base current of th compensation resistor is
around 1uA and its emitter current is 100uA.
This isn't ideal but the emitter current is about 40x lower than the
zener current.
If the LTZ1000 output is scaled to 10V any humidity sensitivity of the
scaling resistors will probably contribute more error than the 120 ohm
resistor.
> BTW, I have no connection with Geller Labs other than buying some of this parts.
> I must add that he was very helpful in my past quest for a good stable voltage source. 
>
> WarrenS
> **************
>
>   
>

Bruce


From bruce.griffiths at xtra.co.nz  Sat Nov 29 20:48:52 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 09:48:52 +1300
Subject: [time-nuts] Voltage standards
In-Reply-To: <003001c9524f$ba923d90$6501a8c0@gb02>
References: <mailman.417.1227910425.2542.time-nuts@febo.com>	<B022E133-EDAD-4914-A1AA-B756AF69A6CF@hughes.net>
	<003001c9524f$ba923d90$6501a8c0@gb02>
Message-ID: <4931AAB4.80606@xtra.co.nz>

Greg Burnett wrote:
> The Linear LTZ1000 is a pretty wonderful voltage reference, but they're not 
> all created equal. It would be nice to pick the "cream of the crop" from a 
> sample of 100 of them, but that would get expensive (and time consuming) in 
> a hurry.
>
> For use in their 3458A DMM, Agilent burns-in the LTZ1000 references and 
> hand-selects the ones deemed good enough. The few, "cream of the crop" are 
> set aside for use as high stability references in Option 02 3458A DMMs (spec 
> = 4ppm/year) and the references not quite that good are set aside for the 
> standard version 3458A DMMs (spec = 8ppm/year).
>
> I've found that, after a few years use, the vast majority of standard 3458As 
> easily meet the option 02's tighter 4ppm/year spec. In fact, I've seen a lot 
> of 3458As drifting less than 2ppm/year, which is really good.
>
> I'm guessing that the LTZ1000 can exhibit, perhaps, as much as 0.5 to 0.7 
> ppm hysteresis when powered down and back up again, because I've 
> occasionally observed shifts that large after power down/up and 
> restabilization.
>
> Greg
>
>
>   
Greg

Fluke largely overcome the hysteresis due to temperature cycling by a
thermal conditioning process.
The LTZ1000 temperature is varied cyclically with a decreasing amplitude
(probably requires a microprocessor to do this).
Of course, the dwell times, initial temperature excursion, and the
number of cycles are not stated in the publicly available literature.
They also operate the LTZ1000 with a junction temperature somewhat lower
than that used in the datasheet circuits.
There is an error in the datasheet, the negative regulator as drawn will
probably destroy the chip.
The heater connections should be reversed.
The latest datasheet shows the internal connection of the various
substrate and other parasitic diodes earlier datasheets do not.


Bruce


From richiem at hughes.net  Sat Nov 29 20:58:53 2008
From: richiem at hughes.net (Richard Moore)
Date: Sat, 29 Nov 2008 12:58:53 -0800
Subject: [time-nuts] V standards
In-Reply-To: <mailman.452.1227989112.2542.time-nuts@febo.com>
References: <mailman.452.1227989112.2542.time-nuts@febo.com>
Message-ID: <7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>

RE Brooke Clarke and Warren S posts:

> Message: 6
> Date: Sat, 29 Nov 2008 08:24:43 -0800
> From: Brooke Clarke <brooke at pacific.net>
> Subject: Re: [time-nuts] Voltage Standards
>
> Hi:
> Geller's patent 7382179 Voltage reference with enhanced stability  
> explains how
> he combines the AD587 voltage reference with the LM399 voltage  
> reference to
> obtain improved temperature stability.  The method can be used with  
> the LT1000.
> http://www.google.com/patents?id=v0GqAAAAEBAJ&dq=7382179
>
> Brooke Clarke
> http://www.prc68.com
> ------------------------------

Brooke, I read the patent with interest, and I cannot see how using  
the LM399 and AD587 together represents an improvement over just  
using a 399 and a chopper amp for the needed gain to get 10V (or  
whatever) out. Geller's external adjustment R chain will suffer  
tempco problems similar to a set of Rs used to gain-set the chopper,  
and making the chopper an integrator with a long TC should help with  
the 399's noise. Can anyone see where a further tempco improvement  
from using the AD587might come from?

> Message: 9
> Date: Sat, 29 Nov 2008 12:05:43 -0800
> From: "WarrenS" <warrensjmail-one at yahoo.com>
> Subject: Re: [time-nuts] Voltage standards
> .....clip
> The TC correction circuit I use is just two standard parts.
> A100K pot is placed between an added transistor's collector
> and ground with the pot's wiper going to the transitor's base.
> What that does when current is applied to the transistor is to make
> the collector voltage vary with temperature by an adjustable amount.
> This temperature sensitive voltage is then added with the trim voltage
> to the reference's trim input to cancel the 1st order temperature  
> drift.
> The results I got was a settable 4 degF wide ZERO TC,
> turnover point at any desired room temperature.
> The added parts fit on the small Geller's PCB.
> ...../clip
> WarrenS
> **************

Thanks for the input Warren -- I think your mod explanation is pretty  
clear -- and nice.

Dick Moore


From bruce.griffiths at xtra.co.nz  Sat Nov 29 21:03:46 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 10:03:46 +1300
Subject: [time-nuts] Voltage Standards
In-Reply-To: <49316CCB.4030203@pacific.net>
References: <604DA6FE-2511-4CBB-8D1B-2758A3FA5C58@hughes.net>	<49310C27.2000902@bellsouth.net>	<4931425D.8020407@xtra.co.nz>
	<49316CCB.4030203@pacific.net>
Message-ID: <4931AE32.7060403@xtra.co.nz>

Brooke Clarke wrote:
> Hi:
>
> Geller's patent 7382179 Voltage reference with enhanced stability explains how 
> he combines the AD587 voltage reference with the LM399 voltage reference to 
> obtain improved temperature stability.  The method can be used with the LT1000.
> http://www.google.com/patents?id=v0GqAAAAEBAJ&dq=7382179
>
>   
However the instability of the AD587 internal resistor network and
buffer amplifier would significantly degrade the LTZ1000 performance.
> 7380471 Micro gust thermal anemometer is a similar circuit by Geller where the 
> LM399 is installed on the PCB using the untrimmed leads so that it's up in the 
> air.  Any wind changes it's temperature which is seen as an output.
> http://www.google.com/patents?id=GDuqAAAAEBAJ&dq=7380471
>
>   
There has to be a better sensor than an LM399 surely.
A sensor that isnt nominally temperature compensated should be better.
> I found a drawing on the National Semi web site for a Valox plastic shield for 
> the LM199, but there's not any other info about it or the specified material.
> http://www.national.com/packaging/mkt/h04d.pdf
>
>   
The original ones were polysulphone.
> Brooke Clarke
> http://www.prc68.com
>
>   
Bruce



From brooke at pacific.net  Sat Nov 29 21:06:55 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 29 Nov 2008 13:06:55 -0800
Subject: [time-nuts] V standards
In-Reply-To: <7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>
References: <mailman.452.1227989112.2542.time-nuts@febo.com>
	<7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>
Message-ID: <4931AEEF.5050009@pacific.net>

Hi Dick:

I got the impression that the tempcos of the two parts were different and by 
blending them the resultant was lower than either (zero for the set point).

Have Fun,

Brooke Clarke
http://www.prc68.com

Richard Moore wrote:
> RE Brooke Clarke and Warren S posts:
> 
>> Message: 6
>> Date: Sat, 29 Nov 2008 08:24:43 -0800
>> From: Brooke Clarke <brooke at pacific.net>
>> Subject: Re: [time-nuts] Voltage Standards
>>
>> Hi:
>> Geller's patent 7382179 Voltage reference with enhanced stability  
>> explains how
>> he combines the AD587 voltage reference with the LM399 voltage  
>> reference to
>> obtain improved temperature stability.  The method can be used with  
>> the LT1000.
>> http://www.google.com/patents?id=v0GqAAAAEBAJ&dq=7382179
>>
>> Brooke Clarke
>> http://www.prc68.com
>> ------------------------------
> 
> Brooke, I read the patent with interest, and I cannot see how using  
> the LM399 and AD587 together represents an improvement over just  
> using a 399 and a chopper amp for the needed gain to get 10V (or  
> whatever) out. Geller's external adjustment R chain will suffer  
> tempco problems similar to a set of Rs used to gain-set the chopper,  
> and making the chopper an integrator with a long TC should help with  
> the 399's noise. Can anyone see where a further tempco improvement  
> from using the AD587might come from?
> 
>> Message: 9
>> Date: Sat, 29 Nov 2008 12:05:43 -0800
>> From: "WarrenS" <warrensjmail-one at yahoo.com>
>> Subject: Re: [time-nuts] Voltage standards
>> .....clip
>> The TC correction circuit I use is just two standard parts.
>> A100K pot is placed between an added transistor's collector
>> and ground with the pot's wiper going to the transitor's base.
>> What that does when current is applied to the transistor is to make
>> the collector voltage vary with temperature by an adjustable amount.
>> This temperature sensitive voltage is then added with the trim voltage
>> to the reference's trim input to cancel the 1st order temperature  
>> drift.
>> The results I got was a settable 4 degF wide ZERO TC,
>> turnover point at any desired room temperature.
>> The added parts fit on the small Geller's PCB.
>> ...../clip
>> WarrenS
>> **************
> 
> Thanks for the input Warren -- I think your mod explanation is pretty  
> clear -- and nice.
> 
> Dick Moore
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 


From bruce.griffiths at xtra.co.nz  Sat Nov 29 21:28:48 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 10:28:48 +1300
Subject: [time-nuts] V standards
In-Reply-To: <4931AEEF.5050009@pacific.net>
References: <mailman.452.1227989112.2542.time-nuts@febo.com>	<7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>
	<4931AEEF.5050009@pacific.net>
Message-ID: <4931B410.7000706@xtra.co.nz>

Brooke Clarke wrote:
> Hi Dick:
>
> I got the impression that the tempcos of the two parts were different and by 
> blending them the resultant was lower than either (zero for the set point).
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
>   
Brooke

Its actually a crude attempt to avoid using a pair of precision ratio
tracking resistors.
This works best when the external reference voltage is close to that of
the AD587 internal zener voltage.
With an LTZ1000 the degradation of the the LTZ1000 performance is
significant.
You still need 3 precision resistors to set the LTZ1000 zener current
and chip temperature.

Bruce


From warrensjmail-one at yahoo.com  Sat Nov 29 21:33:35 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Sat, 29 Nov 2008 13:33:35 -0800
Subject: [time-nuts]  V standards
Message-ID: <055401c9526a$22bde0d0$6401a8c0@WSOffice>


First off, it is good to remember we are mixing what can be done 
on the cheap at home with what can be done at Fluke with their resources.

Most of what that Geller's patent does is just provides a 
 source for some slightly less than near perfect parts 
all in one neat little package for a couple of dollars to 
those of us that don't already have them setting around.
It does NOT give better performance than a 
Perfect amp and perfect match resistors,

Second off you are not going to filter random "flicker noise with a 
RC, which is what limits the short term accuracy of most references.


WarrenS
*****************
RE Brooke Clarke and Warren SO posts:

> Message: 6
> Date: Sat, 29 Nov 2008 08:24:43 -0800
> From: Brooke Clarke <brooke at pacific.net>
> Subject: Re: [time-nuts] Voltage Standards
>
> Hi:
> Geller's patent 7382179 Voltage reference with enhanced stability  
> explains how
> he combines the AD587 voltage reference with the LM399 voltage  
> reference to
> obtain improved temperature stability.  The method can be used with  
> the LT1000.
> http://www.google.com/patents?id=v0GqAAAAEBAJ&dq=7382179
>
> Brooke Clarke
> http://www.prc68.com
> ------------------------------

Brooke, I read the patent with interest, and I cannot see how using  
the LM399 and AD587 together represents an improvement over just  
using a 399 and a chopper amp for the needed gain to get 10V (or  
whatever) out. Geller's external adjustment R chain will suffer  
tempco problems similar to a set of Rs used to gain-set the chopper,  
and making the chopper an integrator with a long TC should help with  
the 399's noise. Can anyone see where a further tempco improvement  
from using the AD587might come from?

> Message: 9
> Date: Sat, 29 Nov 2008 12:05:43 -0800
> From: "WarrenS" <warrensjmail-one at yahoo.com>
> Subject: Re: [time-nuts] Voltage standards
> .....clip
> The TC correction circuit I use is just two standard parts.
> A100K pot is placed between an added transistor's collector
> and ground with the pot's wiper going to the transitor's base.
> What that does when current is applied to the transistor is to make
> the collector voltage vary with temperature by an adjustable amount.
> This temperature sensitive voltage is then added with the trim voltage
> to the reference's trim input to cancel the 1st order temperature  
> drift.
> The results I got was a settable 4 degF wide ZERO TC,
> turnover point at any desired room temperature.
> The added parts fit on the small Geller's PCB.
> ...../clip
> WarrenS
> **************

Thanks for the input Warren -- I think your mod explanation is pretty  
clear -- and nice.

Dick Moore


From bruce.griffiths at xtra.co.nz  Sat Nov 29 21:33:36 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 10:33:36 +1300
Subject: [time-nuts] V standards
In-Reply-To: <7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>
References: <mailman.452.1227989112.2542.time-nuts@febo.com>
	<7B99840E-E972-4AB3-9711-63A06BB3D9E4@hughes.net>
Message-ID: <4931B530.3060304@xtra.co.nz>

Richard Moore wrote:
> Brooke, I read the patent with interest, and I cannot see how using  
> the LM399 and AD587 together represents an improvement over just  
> using a 399 and a chopper amp for the needed gain to get 10V (or  
> whatever) out. Geller's external adjustment R chain will suffer  
> tempco problems similar to a set of Rs used to gain-set the chopper,  
> and making the chopper an integrator with a long TC should help with  
> the 399's noise. 
You need a low pass filter with a well defined dc gain not an integrator.
You can also average the outputs of several 399s to reduce the noise.
However this requires a lot of 399s if one wants to reduce the noise by
a large factor.
The LTZ1000 is significantly quieter than an LM399.
Its significantly cheaper to use a single LTZ1000 than an array of 399s
with the same noise (using the same low pas filter).
> Can anyone see where a further tempco improvement  
> from using the AD587might come from?
>
> Dick Moore
>
>   
Bruce


From bruce.griffiths at xtra.co.nz  Sat Nov 29 22:17:58 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 11:17:58 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <49311123.9030503@bellsouth.net>
References: <49311123.9030503@bellsouth.net>
Message-ID: <4931BF96.5030608@xtra.co.nz>

Brian Kirby wrote:
> App Notes for good reading
>
> Linear Technology - LTZ1000
> AN86 Standards Lab Grade 20 Bit DAC with 0.1 PPM drift
> AN82 Understanding and Applying Voltage References
> AN42 Voltage Reference Collection
> DN229 ABout long term testing
>
> National Semiconductor LM399
> AN-161 1 PPM voltage reference
> AN-173 IC Zener eases reference design
> AN-184 References for A/D COnvertors
>
> Xicor X60008A-50
> AN177
>
>   
The Xicor references are very noisy and their relatively large flicker
noise probably precludes them from use in high precision applications.

Bruce


From SAIDJACK at aol.com  Sun Nov 30 00:07:08 2008
From: SAIDJACK at aol.com (SAIDJACK at aol.com)
Date: Sat, 29 Nov 2008 19:07:08 EST
Subject: [time-nuts] Voltage Standards
Message-ID: <c18.456deca4.3663332c@aol.com>

Hi Brian, guys,
 
I think the original thread stated something like "how to use a GPSDO as a  
voltage reference".
 
To this I have a couple of suggestions for tinkering (not sure if this has  
been suggested before):
 
  1) Most OCXO's have an internal Zener reference voltage that is  located 
inside the oven, and thus extremely stable. This voltage is usually on  the 
center pin on a Eurocan OCXO, and it is meant to drive a pot that can be  used to 
trim the crystal frequency. Thus your GPSDO may just give you a  free ovenized 
Zener reference already.
 
The better the OCXO, the better the reference typically. Absolute voltage  
will be different from unit to unit though. High-end double oven units can be  
expected to have the best performance.
_____________________
 
   2) If we have a well aged GPSDO OCXO with extremely small  aging (such as 
the Jackson Labs Fury GPSDO unit in Mexico: 
_http://resco.ucol.mx/Fury/gpsstat.htm_ (http://resco.ucol.mx/Fury/gpsstat.htm) ,  and it does not jump (this 
one does from time to time), then the control voltage  of this OCXO can be used 
as a reference voltage with very high stability.
 
Number 2) would be generating a voltage directly from locking to a  frequency 
(UTC), so it would fulfill the premise of generating a voltage from a  
frequency :) This method only works if the OCXO has extremely small aging, the  
GPSDO has a very high resolution DAC (the Fury has 330nV lsb DAC resolution for  
example) and the OCXO does not jump. Some SC-cut OCXO's have close to zero 
aging  after months of operation, so maybe you are lucky to have one of these. 
 
You can see that the unit in Mexico typically has a DAC variation of  +/-20uV 
over the period of a day at 2.80055V, this includes the DAC/Reference  
stability errors of course, so the actual voltage variation may be less than  this.
 
Note that by locking to GPS, the method in 2) corrects for the temperature  
sensitivity of the external DAC and DAC reference!
 
The absolute OCXO EFC voltage is somewhat arbitrary of course, but the  
stability could be excellent depending on your OCXO aging.
 
Due to the OCXO aging affecting the measurement this may not be a perfect  
solution, but it does generate a voltage from a frequency, and many folks may  
have access to old OCXO's that do not age much at all anymore.
 
bye,
Said
 
 
In a message dated 11/29/2008 01:33:02 Pacific Standard Time,  
kirbybq at bellsouth.net writes:

Maybe we  should consider coming up with a standard voltage reference as 
a TAPR  project.  We have a lot of good brainpower out here and it seems 
a  lot of experience available.

Brian -  KD4FM


From brooke at pacific.net  Sun Nov 30 00:22:57 2008
From: brooke at pacific.net (Brooke Clarke)
Date: Sat, 29 Nov 2008 16:22:57 -0800
Subject: [time-nuts] Voltage Standards
In-Reply-To: <c18.456deca4.3663332c@aol.com>
References: <c18.456deca4.3663332c@aol.com>
Message-ID: <4931DCE1.9030602@pacific.net>

Hi Bruce:

Do you know how the Agilent 4352 VCO tester generates the very clean 
programmable control voltage for the VCO?

Also why polysulphone for the thermal can for the LM399?  Would Delrin or Nylon 
work?

Have Fun,

Brooke Clarke
http://www.prc68.com


From holrum at hotmail.com  Sun Nov 30 00:27:31 2008
From: holrum at hotmail.com (Mark Sims)
Date: Sun, 30 Nov 2008 00:27:31 +0000
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <mailman.456.1227994381.2542.time-nuts@febo.com>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
Message-ID: <BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>


If you want to play with the Xicor references,  I can recommend the device sold by Ebay zildjianboy7 (Doug Malone)  See current auction item 280289828315.   For $30 shipped,  it makes for a very handy meter checker / portable voltage reference.  Not as stable as the Geller Labs board,  but it runs on a 9V battery.
_________________________________________________________________
Get more done, have more fun, and stay more connected with Windows Mobile?. 
http://clk.atdmt.com/MRT/go/119642556/direct/01/

From XDE-L2G3 at myamail.com  Sun Nov 30 00:27:34 2008
From: XDE-L2G3 at myamail.com (Mike Monett)
Date: Sat, 29 Nov 2008 19:27:34 -0500
Subject: [time-nuts] V standards
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
Message-ID: <mailman.21.1228004888.2539.time-nuts@febo.com>

This discussion of voltage standards is very informative and useful, and my
thanks to all who are contributing. 

It is clear why precise frequency standards are needed - there are
innumerable applications such as GPS, VLBI, secure spread spectrum radio,
deep space navigation using doppler, and so on.

But I wonder why extreme accuracy is needed in measuring voltage? Don't get
me wrong - I have a HP 3456A, and I would love to have a 3458. But the
prices on eBay can reach $6k, and I can't see spending that much money for
two more digits. As Bill would say, six digits should be enough for
everyone:)

As well as the HP, I have a number of other DMM's. But the one I use the
most is a simple 3 1/2 digit Walmart special. You have to switch ranges
manually, but it provides a reading much faster than the other units which
are all autoranging. Most of the time, I am concerned with the supply
voltages. If they are correct, then CMOS and ECL logic pretty much have to
have the correct swing, and you have to use a scope to see the pulses
anyway.

So my question to the group is what kind of things do you do that require
high precision in voltage measurements?

Regards,

Mike Monett


From sar10538 at gmail.com  Sun Nov 30 00:33:44 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 30 Nov 2008 13:33:44 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
Message-ID: <1231b6a80811291633r3a3f6c37o5c79c8181aa52b95@mail.gmail.com>

2008/11/30 Mark Sims <holrum at hotmail.com>:
>
> If you want to play with the Xicor references,  I can recommend the device sold by Ebay zildjianboy7 (Doug Malone)  See current auction item 280289828315.   For $30 shipped,  it makes for a very handy meter checker / portable voltage reference.  Not as stable as the Geller Labs board,  but it runs on a 9V battery.

I looks handy for that purpose given its output is traceable to a
calibrated standard. The only problem is that the seller is not
interested in shipping outside the country as the paperwork is to
tedious for the price.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From bruce.griffiths at xtra.co.nz  Sun Nov 30 01:12:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 14:12:16 +1300
Subject: [time-nuts] Voltage Standards
In-Reply-To: <4931DCE1.9030602@pacific.net>
References: <c18.456deca4.3663332c@aol.com> <4931DCE1.9030602@pacific.net>
Message-ID: <4931E870.1090502@xtra.co.nz>

Brooke Clarke wrote:
> Hi Bruce:
>
> Do you know how the Agilent 4352 VCO tester generates the very clean 
> programmable control voltage for the VCO?
>
> Also why polysulphone for the thermal can for the LM399?  Would Delrin or Nylon 
> work?
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
>   
Brooke

Polysulfone foam is better since the case temperature can approach the
90C junction temperature.
Delrin has inferior high temperature mechanical and electrical properties.
Leakage (from the heater to the zener) between pins via the insulator
may be problematic.
AFAIK nylon/delrin is a poor insulator at high temperatures.

Bruce


From bruce.griffiths at xtra.co.nz  Sun Nov 30 01:15:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 14:15:16 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
Message-ID: <4931E924.1090900@xtra.co.nz>

Mark Sims wrote:
> If you want to play with the Xicor references,  I can recommend the device sold by Ebay zildjianboy7 (Doug Malone)  See current auction item 280289828315.   For $30 shipped,  it makes for a very handy meter checker / portable voltage reference.  Not as stable as the Geller Labs board,  but it runs on a 9V battery.
>   
Beware of their large flicker and wideband noise.
Because of the relatively high flicker noise, they wont, in practice be
anywhere near as stable as a good zener based reference
However they may be useful for checking lower resolution devices such as
a handheld DMM.

bruce


From bruce.griffiths at xtra.co.nz  Sun Nov 30 01:27:16 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 14:27:16 +1300
Subject: [time-nuts] Voltage standards
In-Reply-To: <4931AA86.4090804@xtra.co.nz>
References: <050701c9525d$dd015ce0$6401a8c0@WSOffice>
	<4931AA86.4090804@xtra.co.nz>
Message-ID: <4931EBF4.7030700@xtra.co.nz>

Bruce Griffiths wrote:
>>   
>>     
> The LTZ1000 datasheet states that 100ppm change in this resistor
> produces a 1ppm shift in the LTZ1000 reference voltage.
> It is possible to use a 4 terminal resistor for this part to improve
> accuracy somewhat as the base current of th compensation resistor is
> around 1uA and its emitter current is 100uA.
> This isn't ideal but the emitter current is about 40x lower than the
> zener current.
>   
On reflection this resistor operates in quasi 3 terminal mode  with
about 200uA current flowing in one of the sense leads.

> Bruce
>
>   
If this resistor is replaced by a modified Howland current source
(reference voltage derived from the temperature compensation transistor
Vbe) then the 120 ohm resistor can be employed in 4 terminal mode within
the Howland circuit. Depending on the degree of elaboration the
sensitivity to lead resistance of the 120 ohm resistor can be reduced by
a factor of 10-100 or more.
Other possibilities include sinking a 4mA current from the zener
transistor base node using a current source (with diode clamp to protect
the transistor base emitter junction against reverse breakdown) whose
value is determined by the 7V reference output of the LTZ1000. However
this requires a precision current mirror and a startup circuit.


Bruce


From sar10538 at gmail.com  Sun Nov 30 01:30:14 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 30 Nov 2008 14:30:14 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <4931E924.1090900@xtra.co.nz>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
	<4931E924.1090900@xtra.co.nz>
Message-ID: <1231b6a80811291730u7b077dbal9e245a2d3e529081@mail.gmail.com>

2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
> Mark Sims wrote:
>> If you want to play with the Xicor references,  I can recommend the device sold by Ebay zildjianboy7 (Doug Malone)  See current auction item 280289828315.   For $30 shipped,  it makes for a very handy meter checker / portable voltage reference.  Not as stable as the Geller Labs board,  but it runs on a 9V battery.
>>
> Beware of their large flicker and wideband noise.
> Because of the relatively high flicker noise, they wont, in practice be
> anywhere near as stable as a good zener based reference
> However they may be useful for checking lower resolution devices such as
> a handheld DMM.

Thanks, that's exactly the use I had intended one for.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From bruce.griffiths at xtra.co.nz  Sun Nov 30 01:39:29 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 14:39:29 +1300
Subject: [time-nuts] V standards
In-Reply-To: <E1L6aAS-0001gZ-0V@meow.febo.com>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<E1L6aAS-0001gZ-0V@meow.febo.com>
Message-ID: <4931EED1.8040207@xtra.co.nz>

Mike Monett wrote:
> This discussion of voltage standards is very informative and useful, and my
> thanks to all who are contributing. 
>
> It is clear why precise frequency standards are needed - there are
> innumerable applications such as GPS, VLBI, secure spread spectrum radio,
> deep space navigation using doppler, and so on.
>
> But I wonder why extreme accuracy is needed in measuring voltage? Don't get
> me wrong - I have a HP 3456A, and I would love to have a 3458. But the
> prices on eBay can reach $6k, and I can't see spending that much money for
> two more digits. As Bill would say, six digits should be enough for
> everyone:)
>
> As well as the HP, I have a number of other DMM's. But the one I use the
> most is a simple 3 1/2 digit Walmart special. You have to switch ranges
> manually, but it provides a reading much faster than the other units which
> are all autoranging. Most of the time, I am concerned with the supply
> voltages. If they are correct, then CMOS and ECL logic pretty much have to
> have the correct swing, and you have to use a scope to see the pulses
> anyway.
>
> So my question to the group is what kind of things do you do that require
> high precision in voltage measurements?
>
> Regards,
>
> Mike Monett
>
>   
Mike

In testing high resolution DACs (20+ bits) used in GPSDOs etc a high
resolution DVM (or equivalent) with low noise and good short term
stability is useful if not essential.
Monotonicity and perhaps linearity together with good short term
stability are generally more important than absolute accuracy.
Higher resolution is usually accompanied with higher accuracy.
DVMs like the 3457A. 3456A etc dont have sufficiently low noise or good
enough short term stability for testing DACs with 24 bit resolution.

Bruce


From bruce.griffiths at xtra.co.nz  Sun Nov 30 01:47:00 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 14:47:00 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <1231b6a80811291730u7b077dbal9e245a2d3e529081@mail.gmail.com>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>	<4931E924.1090900@xtra.co.nz>
	<1231b6a80811291730u7b077dbal9e245a2d3e529081@mail.gmail.com>
Message-ID: <4931F094.1050509@xtra.co.nz>

Steve Rooke wrote:
> 2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
>   
>> Mark Sims wrote:
>>     
>>> If you want to play with the Xicor references,  I can recommend the device sold by Ebay zildjianboy7 (Doug Malone)  See current auction item 280289828315.   For $30 shipped,  it makes for a very handy meter checker / portable voltage reference.  Not as stable as the Geller Labs board,  but it runs on a 9V battery.
>>>
>>>       
>> Beware of their large flicker and wideband noise.
>> Because of the relatively high flicker noise, they wont, in practice be
>> anywhere near as stable as a good zener based reference
>> However they may be useful for checking lower resolution devices such as
>> a handheld DMM.
>>     
>
> Thanks, that's exactly the use I had intended one for.
>
> 73, Steve
>   
Steve

Since these devices actually store the reference voltage on an internal
capacitor, it would be interesting/informative to plot the output as a
function of time over several years/decades.
They haven't yet been available for long enough to establish their long
term stability in actual use.
I wonder if one can recharge the internal capacitor should this prove
necessary or if one wanted to adjust the output?
This probably requires access to an internal node.
During manufacture, a servo loop adjusts the output by changing the
voltage on the internal capacitor until the output reaches the voltage
of the external precision reference.
The servo loop is then opened trapping the required charge on the capacitor.

Bruce


From sar10538 at gmail.com  Sun Nov 30 01:47:04 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 30 Nov 2008 14:47:04 +1300
Subject: [time-nuts] V standards
In-Reply-To: <4931EED1.8040207@xtra.co.nz>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<E1L6aAS-0001gZ-0V@meow.febo.com> <4931EED1.8040207@xtra.co.nz>
Message-ID: <1231b6a80811291747g1bfd6976y6660111f5b6c506e@mail.gmail.com>

2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:

> In testing high resolution DACs (20+ bits) used in GPSDOs etc a high
> resolution DVM (or equivalent) with low noise and good short term
> stability is useful if not essential.
> Monotonicity and perhaps linearity together with good short term
> stability are generally more important than absolute accuracy.
> Higher resolution is usually accompanied with higher accuracy.
> DVMs like the 3457A. 3456A etc dont have sufficiently low noise or good
> enough short term stability for testing DACs with 24 bit resolution.

Blast! So that's why I can't get good results with my AVO 8 :)

-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From sar10538 at gmail.com  Sun Nov 30 01:51:16 2008
From: sar10538 at gmail.com (Steve Rooke)
Date: Sun, 30 Nov 2008 14:51:16 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <4931F094.1050509@xtra.co.nz>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>
	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>
	<4931E924.1090900@xtra.co.nz>
	<1231b6a80811291730u7b077dbal9e245a2d3e529081@mail.gmail.com>
	<4931F094.1050509@xtra.co.nz>
Message-ID: <1231b6a80811291751w3524eda5yff5566f575228b32@mail.gmail.com>

2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:

> Since these devices actually store the reference voltage on an internal
> capacitor, it would be interesting/informative to plot the output as a
> function of time over several years/decades.
> They haven't yet been available for long enough to establish their long
> term stability in actual use.
> I wonder if one can recharge the internal capacitor should this prove
> necessary or if one wanted to adjust the output?
> This probably requires access to an internal node.
> During manufacture, a servo loop adjusts the output by changing the
> voltage on the internal capacitor until the output reaches the voltage
> of the external precision reference.
> The servo loop is then opened trapping the required charge on the capacitor.

I guess that would require having a suitably accurate measuring
instrument with an accurate reference voltage in the first place.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet


From bruce.griffiths at xtra.co.nz  Sun Nov 30 02:01:03 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 15:01:03 +1300
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <1231b6a80811291751w3524eda5yff5566f575228b32@mail.gmail.com>
References: <mailman.456.1227994381.2542.time-nuts@febo.com>	<BLU125-W47BD4E5AE3C24F266928DCE060@phx.gbl>	<4931E924.1090900@xtra.co.nz>	<1231b6a80811291730u7b077dbal9e245a2d3e529081@mail.gmail.com>	<4931F094.1050509@xtra.co.nz>
	<1231b6a80811291751w3524eda5yff5566f575228b32@mail.gmail.com>
Message-ID: <4931F3DF.5000908@xtra.co.nz>

Steve Rooke wrote:
> 2008/11/30 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
>
>   
>> Since these devices actually store the reference voltage on an internal
>> capacitor, it would be interesting/informative to plot the output as a
>> function of time over several years/decades.
>> They haven't yet been available for long enough to establish their long
>> term stability in actual use.
>> I wonder if one can recharge the internal capacitor should this prove
>> necessary or if one wanted to adjust the output?
>> This probably requires access to an internal node.
>> During manufacture, a servo loop adjusts the output by changing the
>> voltage on the internal capacitor until the output reaches the voltage
>> of the external precision reference.
>> The servo loop is then opened trapping the required charge on the capacitor.
>>     
>
> I guess that would require having a suitably accurate measuring
> instrument with an accurate reference voltage in the first place.
>
> 73, Steve
>   
Steve

Not necessarily, a stable (not necessarily having a known absolute
error) standard is required.
If the drift is high enough it could be detected by comparison with a
fresh standard of the same type every few years.
Assuming the manufacurer's specifications can be relied upon.

Bruce


From warrensjmail-one at yahoo.com  Sun Nov 30 03:23:14 2008
From: warrensjmail-one at yahoo.com (WarrenS)
Date: Sat, 29 Nov 2008 19:23:14 -0800
Subject: [time-nuts] V standards
Message-ID: <062201c9529a$fb6521c0$6401a8c0@WSOffice>

Mike

> So my questions to the group are
>1) what kind of things do you do that require high precision in voltage measurements?
>2)  I wonder why extreme accuracy is needed in measuring voltage?

That is two different questions.
Bruce already answered the precision question
I'll make attempt at answering the accuracy question.

Voltmeters with the ability to measure extremely accuracy voltages are 
needed all the time and everywhere to measure the voltages of extremely accurate
things  that are used as voltage standards. These standard are used to calibrate 
and test less extremely accurate voltmeters.
Everything else, including  dace's, bridges, resister testers etc depend on extreme precision 
or accurate voltage ratios not extreme absolute voltage accuracy.
The only other time I know of that you would need any true absolute voltage accuracy is 
to measure a Joseph voltage standard. If you had one of those you wanted to check, 
I guess you'd need a extremely accurate absolute voltmeter,  AND if you saw that your 
extreme accurate voltmeter read something different than expected, you would know 
it was time to have the voltmeter recalibrate, which you could do right then and there.

So to answer your second question, the only things that really requires high accuracy in 
voltage measurements are all the things that are used to calibrate accurate voltmeters. 
Everything else is it would seem is actually done with precisions voltage ratios.

WarrenS
******************


----- Original Message ----- 
From: "Mike Monett" <XDE-L2G3 at myamail.com>
To: <time-nuts at febo.com>
Sent: Saturday, November 29, 2008 4:27 PM
Subject: Re: [time-nuts] V standards


> This discussion of voltage standards is very informative and useful, and my
> thanks to all who are contributing. 
> 
> It is clear why precise frequency standards are needed - there are
> innumerable applications such as GPS, VLBI, secure spread spectrum radio,
> deep space navigation using doppler, and so on.
> 
> But I wonder why extreme accuracy is needed in measuring voltage? Don't get
> me wrong - I have a HP 3456A, and I would love to have a 3458. But the
> prices on eBay can reach $6k, and I can't see spending that much money for
> two more digits. As Bill would say, six digits should be enough for
> everyone:)
> 
> As well as the HP, I have a number of other DMM's. But the one I use the
> most is a simple 3 1/2 digit Walmart special. You have to switch ranges
> manually, but it provides a reading much faster than the other units which
> are all autoranging. Most of the time, I am concerned with the supply
> voltages. If they are correct, then CMOS and ECL logic pretty much have to
> have the correct swing, and you have to use a scope to see the pulses
> anyway.
> 
> So my question to the group is what kind of things do you do that require
> high precision in voltage measurements?
> 
> Regards,
> 
> Mike Monett
> 
Mike

In testing high resolution DACs (20+ bits) used in GPSDOs etc a high
resolution DVM (or equivalent) with low noise and good short term
stability is useful if not essential.
Monotonicity and perhaps linearity together with good short term
stability are generally more important than absolute accuracy.
Higher resolution is usually accompanied with higher accuracy.
DVMs like the 3457A. 3456A etc dont have sufficiently low noise or good
enough short term stability for testing DACs with 24 bit resolution.

Bruce




From richiem at hughes.net  Sun Nov 30 03:58:43 2008
From: richiem at hughes.net (Richard Moore)
Date: Sat, 29 Nov 2008 19:58:43 -0800
Subject: [time-nuts] V refs
In-Reply-To: <mailman.462.1228008441.2542.time-nuts@febo.com>
References: <mailman.462.1228008441.2542.time-nuts@febo.com>
Message-ID: <989828E5-97BE-47F5-9404-5A7DD0D18E89@hughes.net>

RE comments from Bruce --

> Message: 1
> Date: Sun, 30 Nov 2008 10:33:36 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] V standards
>
> Richard Moore wrote:
>> Brooke, I read the patent with interest, and I cannot see how using
>> the LM399 and AD587 together represents an improvement over just
>> using a 399 and a chopper amp for the needed gain to get 10V (or
>> whatever) out. Geller's external adjustment R chain will suffer
>> tempco problems similar to a set of Rs used to gain-set the chopper,
>> and making the chopper an integrator with a long TC should help with
>> the 399's noise.
> You need a low pass filter with a well defined dc gain not an  
> integrator.
> You can also average the outputs of several 399s to reduce the noise.
> However this requires a lot of 399s if one wants to reduce the  
> noise by
> a large factor.
> The LTZ1000 is significantly quieter than an LM399.
> Its significantly cheaper to use a single LTZ1000 than an array of  
> 399s
> with the same noise (using the same low pas filter).
>>
> Bruce
> ------------------------------

Bruce, thanks for the clarification, and also for your earlier  
suggestion on the chopper amp. I think I've got a couple of LT1150 or  
1151s in a drawer. If I remember correctly, noise should improve  
roughly 3dB for every doubling of devices, which means that 8 399s  
should yield a 9dB improvement, which is nothing to sneeze at, and is  
still pretty cost-effective. Seems like using a chopper on each one  
and then paralleling those outputs into a chopper gain stage would  
make effective LP filtering relatively easy and would further average  
out noise and drift contributions from the various discrete parts,  
which means that using 1% MF resistors, for example, might be  
practical for sub-ppm results.

I'm beginning to like this, and I can see replacing the dual zeners  
in one of my 7-1/2 digit Datron 1082s  might be a lot of fun (the one  
with the bad VF display that's going to get 7-seg LEDs instead,  
'cause I HATE LCD displays that aren't backlit -- no wonder HP went  
to VF in the 3458 -- they sure must have got tired of the complaints  
about the 3457). That 1082 shifts its reading of my Fluke 732A's 10V  
output about 8-10 ppm/year or a bit more, when I can get everything  
at the same temp for repeating the measuremement...

Nevertheless, if I can get LTZ1000s for $60 a pop, that's a much  
simpler way to go mechanically and electrically. Are you sure that  
the price you stated is for singles? I wouldn't be averse to having a  
couple of them around.

I appreciate very much the depth of both your theoretical and  
practical experience and the insight you bring to everything you  
comment on here.

Dick Moore


From bruce.griffiths at xtra.co.nz  Sun Nov 30 04:26:28 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 17:26:28 +1300
Subject: [time-nuts] V refs
In-Reply-To: <989828E5-97BE-47F5-9404-5A7DD0D18E89@hughes.net>
References: <mailman.462.1228008441.2542.time-nuts@febo.com>
	<989828E5-97BE-47F5-9404-5A7DD0D18E89@hughes.net>
Message-ID: <493215F4.9050307@xtra.co.nz>

Richard Moore wrote:
> RE comments from Bruce --
>   
> Bruce, thanks for the clarification, and also for your earlier  
> suggestion on the chopper amp. I think I've got a couple of LT1150 or  
> 1151s in a drawer. If I remember correctly, noise should improve  
> roughly 3dB for every doubling of devices, which means that 8 399s  
> should yield a 9dB improvement, which is nothing to sneeze at, and is  
> still pretty cost-effective. Seems like using a chopper on each one  
> and then paralleling those outputs into a chopper gain stage would  
> make effective LP filtering relatively easy and would further average  
> out noise and drift contributions from the various discrete parts,  
> which means that using 1% MF resistors, for example, might be  
> practical for sub-ppm results.
>
> I'm beginning to like this, and I can see replacing the dual zeners  
> in one of my 7-1/2 digit Datron 1082s  might be a lot of fun (the one  
> with the bad VF display that's going to get 7-seg LEDs instead,  
> 'cause I HATE LCD displays that aren't backlit -- no wonder HP went  
> to VF in the 3458 -- they sure must have got tired of the complaints  
> about the 3457). That 1082 shifts its reading of my Fluke 732A's 10V  
> output about 8-10 ppm/year or a bit more, when I can get everything  
> at the same temp for repeating the measuremement...
>
> Nevertheless, if I can get LTZ1000s for $60 a pop, that's a much  
> simpler way to go mechanically and electrically. Are you sure that  
> the price you stated is for singles? I wouldn't be averse to having a  
> couple of them around.
>
> I appreciate very much the depth of both your theoretical and  
> practical experience and the insight you bring to everything you  
> comment on here.
>
> Dick Moore
>
>   

Dick

The prices are taken from the Linear Technology website but do not
include shipping.
They ship via UPS (at least thats what they used when I ordered an
LTC1407A demo board).
They can be ordered on line and charged to a credit card.
However you may need to register with them (a quick and fairly trivial
process - at least when I did it).
Note you will need to use a few high stability (wire wound or Vishay
bulk film or equivalent performance) resistors with the LTZ1000 to get
the best out of it.
One thing to watch is thermoelectric emfs at resistor junctions (solder
joints and lead to resistance element). careful thermal matching of the
thermal capacitance and resistance of connections to resistors is
required. Resistors should have equal lead lengths and the resistor body
should be parallel to the PCB.

Usually the zener flicker noise far exceeds the noise of any associated
amplifier so there's probably not too much point in using chopper
stabilised opamps just to bias each LM399.
However a chopper stabilised opamp buffering the resistively averaged
output is worthwhile.

The LTC1151 is probably more straight forward to use.
The LTC1150 has a noise peak that the LTC1151 lacks, it also has a
smoother gain rolloff.

Does the Datron use a series stack of zeners or does it use the once
popular ring of 2 reference circuit?

Bruce


From holrum at hotmail.com  Sun Nov 30 04:55:55 2008
From: holrum at hotmail.com (Mark Sims)
Date: Sun, 30 Nov 2008 04:55:55 +0000
Subject: [time-nuts] App Notes Voltage References
In-Reply-To: <mailman.466.1228017535.2542.time-nuts@febo.com>
References: <mailman.466.1228017535.2542.time-nuts@febo.com>
Message-ID: <BLU125-W50110ED99043D4705575E2CE060@phx.gbl>


I have several Tektronix DM5120 6 1/2 digit DVMs (actually a repackaged Keithley design) that I have been checking against the Malone Xicor voltage standard.  Over the last year or so,  it has proven to be rather stable (either that or it and the four meters are drifting in sync)...  much better than the specs would suggest.  The Tek meters ARE in need of a real calibration (along with a dozen or so DM501A's)...  I need to sweet talk my way into a cal lab or see if I can borrow/rent a Fluke 5700 and spend a weekend calibrating anything that moves.Most accurate DVMs have a rather long integration time.  I think that masks much of the noise of the Xicor chip.  It is certainly good for 4.5 digit meters and gives meaningful/repeatable data on 6.5 digit meters.
_________________________________________________________________
Color coding for safety: Windows Live Hotmail alerts you to suspicious email.
http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_safety_112008 

From jmiles at pop.net  Sun Nov 30 09:28:37 2008
From: jmiles at pop.net (John Miles)
Date: Sun, 30 Nov 2008 01:28:37 -0800
Subject: [time-nuts] Thoughts on Cs tube failure modes
Message-ID: <PKEGJHPHLLBACEOICCBJGEPDPGAB.jmiles@pop.net>

I recently found a tube from a 5062C on eBay in unknown condition for not
*too* much money, and thought it would be interesting to power it up on the
bench.  Once I got it and saw the 19xx-prefix serial number, I wasn't too
optimistic, since it could potentially be 25 years old or more.  Things went
well for the first few steps of the process, but then the experiment failed
big-time.

1) I first applied +2600V to the ion pump with nothing else connected.  Spec
is < 10 uA.  There was a brief spike to ~100 uA, but within a few seconds,
the current began to drop rapidly, ending up at about 1 uA after a few
minutes.  So far, so good.

2) I then brought the Cs oven up to temperature slowly with a variable
supply.  The 5062C runs its oven in a thermostatic loop, but it was easy
enough to warm the oven up slowly over 10 minutes or so, watching the
thermistor resistance to achieve the 200-ohm reading indicated on the tube
label.  The ion pump current rose to about 2.5 uA during the Cs oven warmup
process.

3) I then attempted to bring up the hot-wire ionizer, which takes 1 volt at
about 1.6 amps (when hot).  Simultaneously, the 22-mA C-field current and
13.9-volt mass-spec supply was applied.  As with the Cs oven, I brought the
ionizer voltage up slowly.

4) At that point the ion pump supply went into full current limiting at
circa 300 uA.

I killed the power quickly, removed the oven and hot-wire ionizer supplies,
and tried powering the ion pump up by itself once again.  Although a DMM
check indicated infinite resistance across the ion pump, the HV supply still
went into current limiting.

I'm guessing that the hot-wire ionizer element had enough crud on it to kill
the vacuum when it vaporized.  The tube envelope is probably OK, because the
ionizer wire itself didn't burn out.  Unfortunately I was watching only the
hot-wire ionizer current during that part of the process, so I don't know if
there was a point where I could have observed a rise in ion pump current and
backed off in time to avoid permanent damage.

The last step would have been to connect the -1900V electron multiplier
supply, feed in a 9.192632 GHz signal from an HP 8672A which would be
frequency-modulated with a slow sawtooth, and watch for an output signal on
a scope with a high-Z opamp buffer.  Unless there is some kind of sequencing
taboo that says "bring up the electron multiplier before the ionizer", I
don't immediately see what I might have done wrong.  Anyone see any obvious
newbie mistakes in the account above?  Or was it just a matter of expecting
too much from a Cs tube that might have been 20 years old?

For what it's worth, the electron multiplier also shorts out its (negative)
supply now.  I don't know if that would've happened earlier, since I never
tried to energize it during the pre-test checkout.

-- john, KE5FX



From bruce.griffiths at xtra.co.nz  Sun Nov 30 09:49:27 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Sun, 30 Nov 2008 22:49:27 +1300
Subject: [time-nuts] Thoughts on Cs tube failure modes
In-Reply-To: <PKEGJHPHLLBACEOICCBJGEPDPGAB.jmiles@pop.net>
References: <PKEGJHPHLLBACEOICCBJGEPDPGAB.jmiles@pop.net>
Message-ID: <493261A7.1070308@xtra.co.nz>

John Miles wrote:
> I recently found a tube from a 5062C on eBay in unknown condition for not
> *too* much money, and thought it would be interesting to power it up on the
> bench.  Once I got it and saw the 19xx-prefix serial number, I wasn't too
> optimistic, since it could potentially be 25 years old or more.  Things went
> well for the first few steps of the process, but then the experiment failed
> big-time.
>
> 1) I first applied +2600V to the ion pump with nothing else connected.  Spec
> is < 10 uA.  There was a brief spike to ~100 uA, but within a few seconds,
> the current began to drop rapidly, ending up at about 1 uA after a few
> minutes.  So far, so good.
>
> 2) I then brought the Cs oven up to temperature slowly with a variable
> supply.  The 5062C runs its oven in a thermostatic loop, but it was easy
> enough to warm the oven up slowly over 10 minutes or so, watching the
> thermistor resistance to achieve the 200-ohm reading indicated on the tube
> label.  The ion pump current rose to about 2.5 uA during the Cs oven warmup
> process.
>
> 3) I then attempted to bring up the hot-wire ionizer, which takes 1 volt at
> about 1.6 amps (when hot).  Simultaneously, the 22-mA C-field current and
> 13.9-volt mass-spec supply was applied.  As with the Cs oven, I brought the
> ionizer voltage up slowly.
>
> 4) At that point the ion pump supply went into full current limiting at
> circa 300 uA.
>
> I killed the power quickly, removed the oven and hot-wire ionizer supplies,
> and tried powering the ion pump up by itself once again.  Although a DMM
> check indicated infinite resistance across the ion pump, the HV supply still
> went into current limiting.
>
> I'm guessing that the hot-wire ionizer element had enough crud on it to kill
> the vacuum when it vaporized.  The tube envelope is probably OK, because the
> ionizer wire itself didn't burn out.  Unfortunately I was watching only the
> hot-wire ionizer current during that part of the process, so I don't know if
> there was a point where I could have observed a rise in ion pump current and
> backed off in time to avoid permanent damage.
>
> The last step would have been to connect the -1900V electron multiplier
> supply, feed in a 9.192632 GHz signal from an HP 8672A which would be
> frequency-modulated with a slow sawtooth, and watch for an output signal on
> a scope with a high-Z opamp buffer.  Unless there is some kind of sequencing
> taboo that says "bring up the electron multiplier before the ionizer", I
> don't immediately see what I might have done wrong.  Anyone see any obvious
> newbie mistakes in the account above?  Or was it just a matter of expecting
> too much from a Cs tube that might have been 20 years old?
>
> For what it's worth, the electron multiplier also shorts out its (negative)
> supply now.  I don't know if that would've happened earlier, since I never
> tried to energize it during the pre-test checkout.
>
> -- john, KE5FX
>   
John

Perhaps everything is now coated in Caesium, especially the electon
multiplier input dynode insulation??

Bruce


From robert8rpi at yahoo.co.uk  Sun Nov 30 12:04:49 2008
From: robert8rpi at yahoo.co.uk (Robert Atkinson)
Date: Sun, 30 Nov 2008 12:04:49 +0000 (GMT)
Subject: [time-nuts] Blatent plug Sidereal frequency standard
Message-ID: <737860.2804.qm@web27108.mail.ukl.yahoo.com>

Hi all, Pardon the blatent plug, I just put an HCD research OCXO sidereal (5.0136895 MHz xtal) frequency reference on ebay. See item 260323643052.
Robert G8RPI.


      

From drfrank.stellmach at freenet.de  Sun Nov 30 15:18:14 2008
From: drfrank.stellmach at freenet.de (Dr. Frank Stellmach)
Date: Sun, 30 Nov 2008 16:18:14 +0100
Subject: [time-nuts] VRefs - I'm a bigger Voltnut than a timenut..
Message-ID: <4932AEB6.30905@freenet.de>

Hello,

there's currently no easy way to convert a frequency into Volt, i.e. 
other than by cryo Josephson junction array or realizing Ohm by a 
Klitzing quantum hall effect device. Otherwise, FLUKE would have 
implemented that already in their Calibrators/Standards. They still rely 
on Artefact Calibration, i.e. ovenized longterm stable Zener References 
and Reference Resistors.

The 5720A uses a stacked double Zener reference on a proprietary hybrid 
circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the 
LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the 
Motorola device (Zener below BE junction), and the elder 332D and 335D 
use similar, but less longterm stable references.
The LM199, AD587 and I think also the Geller device may only be used as 
transfer standards, having poor longterm stabilities of 20ppm/yr. or more.

Therefore, the LTZ1000 only may serve as a really affordable standard, 
i.e. below 8ppm longterm stability, for private use.

I was lucky to get some LTZ1000 samples, and used the standard circuit 
from the LT datasheet for creating a small PCB. I purchased commercially 
available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary 
reference resistors and two OP07. Those resistors should give less than 
TK 1 and 1ppm/yr additional drifts.
 
Compared to my HP34401A, the circuitry showed quite good short term 
stability below 1ppm, but shielding still has to be improved, as the 
LTZ1000 circuit is susceptible to external EMC disturbances. This Volt 
reference then costs less than 100 Euros/Dollars in total.

I designed further circuitry (with TK 0.3 and TK 0.1 precision metal 
foil resistors from Alpha and Vishay, chopper amp, precision switches 
and Teflon insulated wires) to have the possibility for precision 
transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V 
level.
Only then, a Volt Standard is complete.

All this stuff will emulate or replace the commonly needed 732A (ref), 
720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).

Got no time yet to finish and improve the system, and to do the repair 
on an old 332B standard, but would like to share my knowledge, if 
anyone's interested.

Frank Stellmach


From wje at quackers.net  Sun Nov 30 15:35:47 2008
From: wje at quackers.net (wje)
Date: Sun, 30 Nov 2008 10:35:47 -0500
Subject: [time-nuts] VRefs - I'm a bigger Voltnut than a timenut..
In-Reply-To: <4932AEB6.30905@freenet.de>
References: <4932AEB6.30905@freenet.de>
Message-ID: <4932B2D3.2000006@quackers.net>

Another (sometimes) relatively inexpensive outstanding reference is 
either a Datron 4910 or 4912. These are also LTZ1000 based. The 10 has 
one reference, the 12 has four that can be averaged or used 
independently. You can on rare occasions pick one up for a few hundred. 
I have a pair, and yes, I paid Fluke $600 for traceable certification 
for one.

These use a rather clever way of generating 1V and 1.18 volts without 
significant division error. The 10V reference is sampled by a 
pulse-width modulator whose duty cycle is crystal-controlled and 
programmable. The result is then LP filtered using an active filter and 
tracks the primary reference to better than 1ppm.

My primary one was hot-shipped from Fluke after certification (it has 
battery backup) and hasn't ever been turned off. I have turned the 
secondary one on and off a few times, and the resultant error is less 
than 0.3 ppm. Both of these units had thousands of hours of burn-in 
before I got them, and I've added another 30 thousand or so.

I also have a Solartron 7081 8.5 digit meter, which is a marvelous unit. 
It uses a selected ultra-low TC Zener with a transistor for temp 
compensation, a sort-of discrete implementation of the LTZ1000. The 
Zener current is programmable, and is used to set the zero point for the 
particular zener/transistor pair. I can turn mine off for months at a 
time, turn it back on, and after a 24 h warmup, usually have it within 
1ppm(!) of my primary ref. These are somewhat rare, but can be picked up 
for a few hundreds. I paid $300 for mine.

As for why, I'm surprised that no one has stated the obvious reason - 
because you can. It's the same reason time-nuts collect 10e-13 frequency 
standards. I was into precision voltage and resistance metrology well 
before I got into precision frequency. I find it fascinating to be able 
to determine various values to precisions that not all that long ago 
were limited to national standards labs.

Bill Ezell
----------
They said 'Windows or better'
so I used Linux.



Dr. Frank Stellmach wrote:
> Hello,
>
> there's currently no easy way to convert a frequency into Volt, i.e. 
> other than by cryo Josephson junction array or realizing Ohm by a 
> Klitzing quantum hall effect device. Otherwise, FLUKE would have 
> implemented that already in their Calibrators/Standards. They still rely 
> on Artefact Calibration, i.e. ovenized longterm stable Zener References 
> and Reference Resistors.
>
> The 5720A uses a stacked double Zener reference on a proprietary hybrid 
> circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the 
> LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the 
> Motorola device (Zener below BE junction), and the elder 332D and 335D 
> use similar, but less longterm stable references.
> The LM199, AD587 and I think also the Geller device may only be used as 
> transfer standards, having poor longterm stabilities of 20ppm/yr. or more.
>
> Therefore, the LTZ1000 only may serve as a really affordable standard, 
> i.e. below 8ppm longterm stability, for private use.
>
> I was lucky to get some LTZ1000 samples, and used the standard circuit 
> from the LT datasheet for creating a small PCB. I purchased commercially 
> available wire wound resistors (TK 3, 25ppm/yr) for the 5 necessary 
> reference resistors and two OP07. Those resistors should give less than 
> TK 1 and 1ppm/yr additional drifts.
>  
> Compared to my HP34401A, the circuitry showed quite good short term 
> stability below 1ppm, but shielding still has to be improved, as the 
> LTZ1000 circuit is susceptible to external EMC disturbances. This Volt 
> reference then costs less than 100 Euros/Dollars in total.
>
> I designed further circuitry (with TK 0.3 and TK 0.1 precision metal 
> foil resistors from Alpha and Vishay, chopper amp, precision switches 
> and Teflon insulated wires) to have the possibility for precision 
> transfers of the 7,2V reference voltage to 100mV, 1V, 10V, 100V, 1000V 
> level.
> Only then, a Volt Standard is complete.
>
> All this stuff will emulate or replace the commonly needed 732A (ref), 
> 720A (Kelvin Varley), 752A (Reference Divider) and 834B (Null Detector).
>
> Got no time yet to finish and improve the system, and to do the repair 
> on an old 332B standard, but would like to share my knowledge, if 
> anyone's interested.
>
> Frank Stellmach
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>   


From drfrank.stellmach at freenet.de  Sun Nov 30 17:29:05 2008
From: drfrank.stellmach at freenet.de (Dr. Frank Stellmach)
Date: Sun, 30 Nov 2008 18:29:05 +0100
Subject: [time-nuts] VRefs - I'm a bigger Voltnut than a timenut..
References: 4932AEB6.30905@freenet.de
Message-ID: <4932CD61.9080308@freenet.de>

@Bill Ezell:

Well, I have the same motivation to invest time and money into "precision".

I started with metrology working in a German Airforce cal lab  in 1980.
We had all that goddie equipment, ie. a bank of Weston standard cells, 
the Fluke cal system, DCF receiver, a HP caesium standard, and so on. 
This cal lab was tightly associated with our PTB.
In a "secret" lab they obviously made some tests on the new Josephson 
junction standard, as they transferred the Volt from this lab to our 
facility with a Fluke 731A, and they were very proud of that.

 From then on, the ppm quest never let me go.
It's biggest fun for me to design standards on my own, not only to 
collect and repair old ones.

I've already read about the Datron standards, but didn't know details, 
and that it's so sophisticated. It's inner principle of dividing the 
reference is identical to the Fluke 5720A, I think.

Do you have a detailed schematic of the LTZ reference circuitry in the 
Datron?
This cannot be found in the manuals of HP3458 or Fluke 7000.

In Germany there is no big chance for getting surplus standards for a 
reasonable price.
It's a pity..

Frank



From cdelect at juno.com  Sun Nov 30 18:36:07 2008
From: cdelect at juno.com (Corby Dawson)
Date: Sun, 30 Nov 2008 10:36:07 -0800
Subject: [time-nuts] Thoughts on Cs tube failure modes
Message-ID: <20081130.103607.436.0.cdelect@juno.com>

John,

What you describe with the ion pump curent is normal if the tube has been
powerd off for a long time.

Th mainframe normally would turn the oven and ionizer filaments off when
the ion pump current pegged.

After minutes (can be quite a few minutes) the ion pump current will drop
as it pumps the surge of outgassing from the heated filaments.

The cycle repeats and can take a couple days on a stubborn tube.

You bypassed that circuit so I'm not sure how much gas you introduced.

If after a couple days the current is still pegged try connecting an
external high voltage supply of around +3000VDC that can provide at least
5ma. (turn unit off)

Let it run overnight and if the current comes down reconnect the internal
power supply and turn the mainframe back on.

You probably will see it peg again and the see the oven shut down (it
happens fast!), just leave it on and it should start cycling and
eventually the filaments will reach the oven set points and have
outgassed enough so that the protective circuit will not trip.

Then you can try to see if the rest of the tube has any life. (you may
have to reduce the oven set resistor to 130 ohms as well as reducing its
companion overtemp resistor. This is the value the Navy uses to get the
last bit of life out of the tube, don't do it if you can get the rated
beam current at the original value!)

If you email me I can give you my evening phone number if you need some
more info.

Corby Dawson
cdelect at juno.com




 
____________________________________________________________
Click here to find the perfect picture with our powerful photo search features.
http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw1aBm8XXBA9eC72NBG9alhmVMe3ZD9uri8B4mlt3xxDXctvb/


From wje at quackers.net  Sun Nov 30 18:25:39 2008
From: wje at quackers.net (wje)
Date: Sun, 30 Nov 2008 13:25:39 -0500
Subject: [time-nuts] VRefs - I'm a bigger Voltnut than a timenut..
In-Reply-To: <4932CD61.9080308@freenet.de>
References: 4932AEB6.30905@freenet.de <4932CD61.9080308@freenet.de>
Message-ID: <4932DAA3.6070809@quackers.net>

Yes, I do have full schematics for the Datron refs, including the 
LTZ1000 circuitry. It isn't the same as that in the LTZ1000 data sheet. 
I'll dig out my manuals. If you'd like a copy, email your postal address 
and I'll copy the page and send it to you:

wje at quackers.net

I've built a few standards myself. My latest was one using 16 399's. I 
shamelessly stole some circuit designs from a Fluke reference to provide 
sense-current compensation, etc. It was a lot of fun.

Bill Ezell
----------
They said 'Windows or better'
so I used Linux.



Dr. Frank Stellmach wrote:
> @Bill Ezell:
>
> Well, I have the same motivation to invest time and money into "precision".
>
> I started with metrology working in a German Airforce cal lab  in 1980.
> We had all that goddie equipment, ie. a bank of Weston standard cells, 
> the Fluke cal system, DCF receiver, a HP caesium standard, and so on. 
> This cal lab was tightly associated with our PTB.
> In a "secret" lab they obviously made some tests on the new Josephson 
> junction standard, as they transferred the Volt from this lab to our 
> facility with a Fluke 731A, and they were very proud of that.
>
>  From then on, the ppm quest never let me go.
> It's biggest fun for me to design standards on my own, not only to 
> collect and repair old ones.
>
> I've already read about the Datron standards, but didn't know details, 
> and that it's so sophisticated. It's inner principle of dividing the 
> reference is identical to the Fluke 5720A, I think.
>
> Do you have a detailed schematic of the LTZ reference circuitry in the 
> Datron?
> This cannot be found in the manuals of HP3458 or Fluke 7000.
>
> In Germany there is no big chance for getting surplus standards for a 
> reasonable price.
> It's a pity..
>
> Frank
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>   


From martinrh45 at googlemail.com  Sun Nov 30 21:07:46 2008
From: martinrh45 at googlemail.com (Martin Richmond-Hardy)
Date: Sun, 30 Nov 2008 21:07:46 +0000
Subject: [time-nuts] Trimble  NTPX26AB
Message-ID: <FC3DF1B7-2B9C-4454-AC61-E2BB32B69770@googlemail.com>

Newbie time-nut here. I recently acquired a Trimple GPS-disciplined  
Oscillator "C" (Seem to be a few on eBay) and have scoured the  
Internet for information. Nearest look-almost-alike seems to be the HP  
Z3801A but gather is doesn't speak Trimble protocol.
Have noted http://www.febo.com/pipermail/time-nuts/2007-February/024213.html
I'm intending to use it mainly as a 10MHz source.
1. Does any one have/can point me to a pdf version of the Trimble  
manual? (I've tried the Trimble site)
2. Does the Thunderbolt software Tboltmon.exe work with this unit?
3. Any other advise?
Thanks

73 de
Martin Richmond-Hardy G8BHC
QTH: JO02pa
Skype: callto://martinrh45





From bill at iaxs.net  Sun Nov 30 21:16:20 2008
From: bill at iaxs.net (Bill Hawkins)
Date: Sun, 30 Nov 2008 15:16:20 -0600
Subject: [time-nuts] Voltage standards
In-Reply-To: <4931EBF4.7030700@xtra.co.nz>
References: <050701c9525d$dd015ce0$6401a8c0@WSOffice><4931AA86.4090804@xtra.co.nz>
	<4931EBF4.7030700@xtra.co.nz>
Message-ID: <D489674BFEBB4A77AF5A503AF16A4FA6@cyrus>

Group,

The subject elicited a fine hardware discussion, as always.

There was some casual talk about measuring fractions of
microvolts, implying 10E-7 or -8 accuracy.

There are lots of possible thermoelectric effects that may be
in series with the source.

Without describing how it's done, what is the lower measuring
limit in nanovolts? That's the limit where the last digit
moves randomly by more than one increment. Does the method
involve cryogenics?

I'd look it up, but I expect some of you are more current
with the science than anything I could find with Google.

Given that extreme accuracy and stability are expensive, what
can an amateur do for less than, say, $500 or 400 Euros?

Thanks for any enlightenment.
Bill Hawkins





From hmurray at megapathdsl.net  Sun Nov 30 21:55:10 2008
From: hmurray at megapathdsl.net (Hal Murray)
Date: Sun, 30 Nov 2008 13:55:10 -0800
Subject: [time-nuts] Trimble NTPX26AB
In-Reply-To: Message from Martin Richmond-Hardy <martinrh45@googlemail.com> 
	of "Sun, 30 Nov 2008 21:07:46 GMT."
	<FC3DF1B7-2B9C-4454-AC61-E2BB32B69770@googlemail.com> 
Message-ID: <20081130215511.0C0F3BCD5@ip-64-139-1-69.sjc.megapath.net>


> Newbie time-nut here. I recently acquired a Trimple GPS-disciplined
> Oscillator "C" (Seem to be a few on eBay) and have scoured the
> Internet for information. Nearest look-almost-alike seems to be the HP
> Z3801A but gather is doesn't speak Trimble protocol. 

If It has the same physical package as a Z3801A, I'd guess it was targeted at 
the cell phone tower market and probably speaks the same protocol, or a 
subset of the Z3801A commands.

Have you tried the Z3801A software?  I have a copy of something called 
satstat.

You can try it with your favorite terminal emulator.  19.2, 7bit, odd parity.

I think it will say something on power up.  You can check that with a scope.

If you feed it ":SYSTEM:STATUS?" and cr/lf, it might give you back a screen 
full of info.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.





From bruce.griffiths at xtra.co.nz  Sun Nov 30 22:00:25 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 01 Dec 2008 11:00:25 +1300
Subject: [time-nuts] Voltage standards
In-Reply-To: <D489674BFEBB4A77AF5A503AF16A4FA6@cyrus>
References: <050701c9525d$dd015ce0$6401a8c0@WSOffice><4931AA86.4090804@xtra.co.nz>	<4931EBF4.7030700@xtra.co.nz>
	<D489674BFEBB4A77AF5A503AF16A4FA6@cyrus>
Message-ID: <49330CF9.5040205@xtra.co.nz>

Bill Hawkins wrote:
> Group,
>
> The subject elicited a fine hardware discussion, as always.
>
> There was some casual talk about measuring fractions of
> microvolts, implying 10E-7 or -8 accuracy.
>
> There are lots of possible thermoelectric effects that may be
> in series with the source.
>
> Without describing how it's done, what is the lower measuring
> limit in nanovolts? That's the limit where the last digit
> moves randomly by more than one increment. Does the method
> involve cryogenics?
>
> I'd look it up, but I expect some of you are more current
> with the science than anything I could find with Google.
>
> Given that extreme accuracy and stability are expensive, what
> can an amateur do for less than, say, $500 or 400 Euros?
>
> Thanks for any enlightenment.
> Bill Hawkins
>
>   
Bill

The lower limit depends on the detector or DVM used, together with ones
skill in eliminating thermoelectric effects.
With a sufficiently low noise front end detecting changes of 10nV or
less at room temperature is possible if the sources being compared are
sufficiently stable.
An ordinary DVM wont suffice (at least without a low noise preamp).

An LTZ1000 standard is feasible for for around $100, however whether you
get a really good one or one that just mets its specs depends on luck.

Building a null detector with say 10 nanovolt sensitivity is also possible.
Picovolt sensitivity usually requires cryogenic cooling.

With luck you may even be able to obtain an Fluke 720 KVD.
Failing that it is possible to build a 20 bit monotonic DAC with ppm
stability without requiring precision resistors.

Cryogenic standards arent really feasible for home use as most require
liquid helium coolant.

However graphene has supposedly exhibited the quantum Hall effect at
room temperature.

Bruce


From imp at bsdimp.com  Sun Nov 30 22:13:28 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sun, 30 Nov 2008 15:13:28 -0700 (MST)
Subject: [time-nuts] Voltage standards
In-Reply-To: <49330CF9.5040205@xtra.co.nz>
References: <4931EBF4.7030700@xtra.co.nz>
	<D489674BFEBB4A77AF5A503AF16A4FA6@cyrus>
	<49330CF9.5040205@xtra.co.nz>
Message-ID: <20081130.151328.1120076896.imp@bsdimp.com>

In message: <49330CF9.5040205 at xtra.co.nz>
            Bruce Griffiths <bruce.griffiths at xtra.co.nz> writes:
: Cryogenic standards arent really feasible for home use as most require
: liquid helium coolant.

This has got to be one of the best lines in a time-nuts email :)

Warner


From richiem at hughes.net  Sun Nov 30 22:20:39 2008
From: richiem at hughes.net (Richard Moore)
Date: Sun, 30 Nov 2008 14:20:39 -0800
Subject: [time-nuts] V refs
In-Reply-To: <mailman.3.1228046401.12766.time-nuts@febo.com>
References: <mailman.3.1228046401.12766.time-nuts@febo.com>
Message-ID: <66B84822-1F19-44E7-B2BA-C76B765FF2D3@hughes.net>


On Nov 30, 2008, at 4:00 AM, Bruce wrote:

> Message: 1
> Date: Sun, 30 Nov 2008 17:26:28 +1300
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> Subject: Re: [time-nuts] V refs
>

> <clip>
> Does the Datron use a series stack of zeners or does it use the once
> popular ring of 2 reference circuit?
>
> Bruce

Bruce, the 1082 uses two sets of two zeners in series. Each series  
set of zeners has its own current setting resistor set. The out put  
from each zener string is fed thru a 9.1k resistor into the + input  
of an opamp mixer which drives an emitter follower, and that drives  
the current setting resistors for the zeners, and, divided down, the  
ref. output for the meter. The system actually works very well, but  
given the ages of these meters, I suspect that the zero TC current  
point of the zeners might need tweaking. The opamp is a Fairchild  
uA714CH. I'm not familiar with its noise performance or, in this  
system, its input temp characteristics -- I'll bet this also would be  
a good spot for a chopper amp, if I switch to a LTZ1000....

Dick Moore


From cgreen at quartzlock.com  Sun Nov 30 22:41:34 2008
From: cgreen at quartzlock.com (Clive Green)
Date: Sun, 30 Nov 2008 22:41:34 -0000
Subject: [time-nuts] bootstrap voltage standard to frequency standatrd
Message-ID: <015201c9533c$cc754370$655fca50$@com>

Josephson Junction is the ultimate way to reference Voltage to Frequency.
Mother nature having blessed us with time & frequency / ways of atomically
referencing it so that this parameter may be generated & measured as a more
accurate/lower offset/repeatable/stable way than any other parameter. Most
other parameters can also be referenced to frequency.

 

Clive Green

CEO 

Quartzlock 

+ Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England

(: +44 (0) 1803 862 062 7: +44 (0) 1803 867 962

?:  <mailto:nlaw at quartzlock.com> cgreen at quartzlock.com ?:
<http://www.quartzlock.com> www.quartzlock.com

Skype: clive.green.skype Messenger: cgreen at quartzlock.com

Registered office: Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England
Registered in England

 P Think Environment, print only if necessary.

 

This is an e-mail from Quartzlock (UK) Limited, its contents (including all
attachments) and any files transmitted with it are confidential and intended
solely for the individual(s) to which it is addressed and may also be
privileged. It may not be copied or printed by anyone other than the
addressee and may not be disclosed or distributed in any way.  If you have
received this e-mail in error please inform Quartzlock (UK) Limited and
delete it from your mailbox or any other storage devices.

 

Although this e-mail and any attachments are believed to be free of any
virus or other defects which might affect any computer or IT system into
which they are received, no responsibility is accepted by Quartzlock (UK)
Limited or any of its directors, staff or associated businesses or contacts
for any loss or damage arising in any way from the receipt or use thereof.

 

Opinions, conclusions and other information expressed in this message are
not given or endorsed by Quartzlock (UK) Limited unless otherwise indicated
by an authorised representative independent of this message.

 


From bruce.griffiths at xtra.co.nz  Sun Nov 30 22:53:32 2008
From: bruce.griffiths at xtra.co.nz (Bruce Griffiths)
Date: Mon, 01 Dec 2008 11:53:32 +1300
Subject: [time-nuts] V refs
In-Reply-To: <66B84822-1F19-44E7-B2BA-C76B765FF2D3@hughes.net>
References: <mailman.3.1228046401.12766.time-nuts@febo.com>
	<66B84822-1F19-44E7-B2BA-C76B765FF2D3@hughes.net>
Message-ID: <4933196C.9030304@xtra.co.nz>

Richard Moore wrote:
> On Nov 30, 2008, at 4:00 AM, Bruce wrote:
>
>   
>> Message: 1
>> Date: Sun, 30 Nov 2008 17:26:28 +1300
>> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
>> Subject: Re: [time-nuts] V refs
>>
>>     
>
>   
>> <clip>
>> Does the Datron use a series stack of zeners or does it use the once
>> popular ring of 2 reference circuit?
>>
>> Bruce
>>     
>
> Bruce, the 1082 uses two sets of two zeners in series. Each series  
> set of zeners has its own current setting resistor set. The out put  
> from each zener string is fed thru a 9.1k resistor into the + input  
> of an opamp mixer which drives an emitter follower, and that drives  
> the current setting resistors for the zeners, and, divided down, the  
> ref. output for the meter. The system actually works very well, but  
> given the ages of these meters, I suspect that the zero TC current  
> point of the zeners might need tweaking. The opamp is a Fairchild  
> uA714CH. I'm not familiar with its noise performance or, in this  
> system, its input temp characteristics -- I'll bet this also would be  
> a good spot for a chopper amp, if I switch to a LTZ1000....
>
> Dick Moore
>
>   
Dick

The uA714 is claimed to be an OP07 equivalent.
A chopper stabilised amplifier would have lower drift and flicker noise,
however the zener drift and flicker noise probably dominates.

Stacking LTZ1000's in the same way is a little tricky.
The only satisfactory method I have devised so far uses a PJFET as a
voltage controlled resistor to sink the zener current whilst allowing it
to be reused to bias lower LTZ1000s in the series stack.

Bruce


From richiem at hughes.net  Sun Nov 30 22:58:25 2008
From: richiem at hughes.net (Richard Moore)
Date: Sun, 30 Nov 2008 14:58:25 -0800
Subject: [time-nuts] V refs -- Frank S and Bill E
In-Reply-To: <mailman.481.1228079785.2542.time-nuts@febo.com>
References: <mailman.481.1228079785.2542.time-nuts@febo.com>
Message-ID: <C86C3119-2884-4FF7-944B-04EF271B4127@hughes.net>

Frank wrote:
> <clip> The 5720A uses a stacked double Zener reference on a  
> proprietary hybrid
> circuitry, giving 1-2 ppm/year stability, the 7001 and 732B use the
> LTZ1000 (Zener above BE junction), as the 3458A, the 732A uses the
> Motorola device (Zener below BE junction), and the elder 332D and 335D
> use similar, but less longterm stable references.
> ------------------------------

My Fluke 332D uses the Motorola IC (zener below) in a small Klixon  
oven which seems to be an on-off type with relatively poor temp  
control. Of course none of the divider string resistors or other  
circuits are in a temp-controlled space. I've found it very hard to  
keep that box under 10ppm over even short periods. It mostly sits.  
Did I mention its very big and heavy? It does supply 50mA at 1100V  
though.

Bill wrote:
<clip>
> These use a rather clever way of generating 1V and 1.18 volts without
> significant division error. The 10V reference is sampled by a
> pulse-width modulator whose duty cycle is crystal-controlled and
> programmable. The result is then LP filtered using an active filter  
> and
> tracks the primary reference to better than 1ppm.
>
> Bill Ezell
> ---------

All of the newer Fluke calibrators use the PWM/LP filter method to  
vary output, as does my Valhalla 2701C DC 6-1/2 digit, 100mV-1000V  
reference. The Valhalla has an LM299 for its reference, and given its  
generally good overall performance, would be a good candidate for an  
LTZ1000 transplant. Another project.

Dick Moore


From jmiles at pop.net  Sun Nov 30 23:31:32 2008
From: jmiles at pop.net (John Miles)
Date: Sun, 30 Nov 2008 15:31:32 -0800
Subject: [time-nuts] Thoughts on Cs tube failure modes
In-Reply-To: <20081130.103607.436.0.cdelect@juno.com>
Message-ID: <PKEGJHPHLLBACEOICCBJEECOPHAB.jmiles@pop.net>

Hmm!  I appreciate the tip.  I'll confess it didn't occur to me to try to
force more current through the ion pump.  The supply I was using was limited
to about 300 uA, but I took your advice and tried a beefier one, set to 3
kV.  As I increased the current limit from 0 towards 5 mA, the ion-pump
current fell back to ~25 uA once I reached 1000 uA.

At the rate I was adjusting the current-limit control on the Glassman
supply, this occured about 10 seconds after power-up.  It seems stable now
at 25 uA, several minutes later.

I didn't leave the hot-wire ionizer energized for more than 10-15 seconds,
all told.  I'll let the ion pump run for a few hours, and then try the
hot-wire ionizer again.  Should I bother with the other supplies (Cs oven
heater, EM, mass spec), or is it reasonable to recondition the tube using
only the ion pump and hot-wire ionizer terminals?

Keep in mind that I don't have a 5062C mainframe, just the Cs tube and some
bench supplies.  I'm essentially recreating Tom's experiment from
http://www.leapsecond.com/pages/cspeak/ but without benefit of an actual
clock mainframe.  So I don't have a filament shutdown/recycle controller in
the picture.  Obviously that would be needed if I were to actually build a
clock around the tube, but for now, I just want to see if the tube is
functional at all, and determine its figure of merit.

-- john, KE5FX



> John,
>
> What you describe with the ion pump curent is normal if the tube has been
> powerd off for a long time.
>
> Th mainframe normally would turn the oven and ionizer filaments off when
> the ion pump current pegged.
>
> After minutes (can be quite a few minutes) the ion pump current will drop
> as it pumps the surge of outgassing from the heated filaments.
>
> The cycle repeats and can take a couple days on a stubborn tube.
>
> You bypassed that circuit so I'm not sure how much gas you introduced.
>
> If after a couple days the current is still pegged try connecting an
> external high voltage supply of around +3000VDC that can provide at least
> 5ma. (turn unit off)
>
> Let it run overnight and if the current comes down reconnect the internal
> power supply and turn the mainframe back on.
>
> You probably will see it peg again and the see the oven shut down (it
> happens fast!), just leave it on and it should start cycling and
> eventually the filaments will reach the oven set points and have
> outgassed enough so that the protective circuit will not trip.
>
> Then you can try to see if the rest of the tube has any life. (you may
> have to reduce the oven set resistor to 130 ohms as well as reducing its
> companion overtemp resistor. This is the value the Navy uses to get the
> last bit of life out of the tube, don't do it if you can get the rated
> beam current at the original value!)
>
> If you email me I can give you my evening phone number if you need some
> more info.
>



From slburris at gmail.com  Sun Nov 30 23:38:53 2008
From: slburris at gmail.com (Scott Burris)
Date: Sun, 30 Nov 2008 15:38:53 -0800
Subject: [time-nuts] bootstrap voltage standard to frequency standatrd
In-Reply-To: <015201c9533c$cc754370$655fca50$@com>
References: <015201c9533c$cc754370$655fca50$@com>
Message-ID: <4933240D.6070106@gmail.com>

As the original poster, I was hoping for something a hobbyist could 
build and run at (or close to) room temperature.  Without resorting to 
calibration.  Maybe in another decade.

Still, looking at the various tangents this question has spun off
is fascinating.  I always find myself learning new things listening
to the time-nuts list!

Scott

Clive Green wrote:
> Josephson Junction is the ultimate way to reference Voltage to Frequency.
> Mother nature having blessed us with time & frequency / ways of atomically
> referencing it so that this parameter may be generated & measured as a more
> accurate/lower offset/repeatable/stable way than any other parameter. Most
> other parameters can also be referenced to frequency.
> 
>  
> 
> Clive Green
> 
> CEO 
> 
> Quartzlock 
> 
> + Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England
> 
> (: +44 (0) 1803 862 062 7: +44 (0) 1803 867 962
> 
> ?:  <mailto:nlaw at quartzlock.com> cgreen at quartzlock.com ?:
> <http://www.quartzlock.com> www.quartzlock.com
> 
> Skype: clive.green.skype Messenger: cgreen at quartzlock.com
> 
> Registered office: Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH England
> Registered in England
> 
>  P Think Environment, print only if necessary.
> 
>  
> 
> This is an e-mail from Quartzlock (UK) Limited, its contents (including all
> attachments) and any files transmitted with it are confidential and intended
> solely for the individual(s) to which it is addressed and may also be
> privileged. It may not be copied or printed by anyone other than the
> addressee and may not be disclosed or distributed in any way.  If you have
> received this e-mail in error please inform Quartzlock (UK) Limited and
> delete it from your mailbox or any other storage devices.
> 
>  
> 
> Although this e-mail and any attachments are believed to be free of any
> virus or other defects which might affect any computer or IT system into
> which they are received, no responsibility is accepted by Quartzlock (UK)
> Limited or any of its directors, staff or associated businesses or contacts
> for any loss or damage arising in any way from the receipt or use thereof.
> 
>  
> 
> Opinions, conclusions and other information expressed in this message are
> not given or endorsed by Quartzlock (UK) Limited unless otherwise indicated
> by an authorised representative independent of this message.
> 
>  
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.22.1228098481.2539.time-nuts@febo.com>

If you want to reduce the measurement noise of a system you need to do =
one or more of the following:

Lower the source impedance, by reducing the resistance of the thing you =
are measuring
Lower the Bandwidth, by filtering over a longer time period
Lower the temperature, by making it colder.

Doing even any one of these things enough will in theory let the noise =
approach zero, When you do two (or all three) at once the noise will =
approach zero sooner.
see "Johnson-Nyquist noise" for the details


From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.23.1228098481.2539.time-nuts@febo.com>

the difference between two voltage sources if one uses a lot of care and =
applies some form of extra filtering.=20
A  1nV  (1e-9) is way below the noise level of any voltage standard that =
puts out volts.
This means reference measurements are not limited by the noise level =
when using a good but simple setup until the references gets to be in =
the 3e-10 precision range.


The answer to "What can an amateur do to get a good low noise reference =
for less than, say, $500"
IS shop at the US eBay site.

WarrenS

***********************
----- Original Message -----=20
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'" =
<time-nuts at febo.com>
Sent: Sunday, November 30, 2008 1:16 PM
Subject: Re: [time-nuts] Voltage standards


> Group,
>=20
> The subject elicited a fine hardware discussion, as always.
>=20
> There was some casual talk about measuring fractions of
> microvolts, implying 10E-7 or -8 accuracy.
>=20
> There are lots of possible thermoelectric effects that may be
> in series with the source.
>=20
> Without describing how it's done, what is the lower measuring
> limit in nanovolts? That's the limit where the last digit
> moves randomly by more than one increment. Does the method
> involve cryogenics?
>=20
> I'd look it up, but I expect some of you are more current
> with the science than anything I could find with Google.
>=20
> Given that extreme accuracy and stability are expensive, what
> can an amateur do for less than, say, $500 or 400 Euros?
>=20
> Thanks for any enlightenment.
> Bill Hawkins
>=20
>=20
>=20
>=20
>=20
>

From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.27.1228159332.2539.time-nuts@febo.com>

used in a GPSDO the LESS there is the need to use a high resolution Dac.
The FS725 rubidium with it's 2e-9 external EFC range, would not seem=20
to need more than the most simple 12 to 16 bit EXTERNAL tracking Dac.=20
True that its internal Dac needs to have very high resolution if it is =
used=20
to lock an internal VCXO that has a range of say 1e-6.

Question:  Is the Aging rate of these low noise OCXO units poor enough =20
that you could not use a couple of fixed precision resistor and/or a pot =

for course adjustment and reduce the EFC range of the DAC by say 1/100 =
?.=20
Are there low noise OCXO (that are being used in GPSDO) whose long term=20
drift over say 6 months would need more than 1E-8 or so of  'automatic' =
turning?

And concerning the 10811A. Should one consider reducing its EFC=20
tuning range by say 2 to 20 to ease the requirements of the Dac?=20
Even if the EFC tuning range was reduced by just a factor of two,=20
It could then be done with just a standard 0 to 5 volt Dac =20
instead of the -5 to +5 that I saw suggested by its spec.
I would think that a well aged unit would be much better than its worse =
case=20
spec of 1E-7 per year, And even if not, I'm guessing  that many of the =
time-nuts,=20
would be very welling to trade off  it needing a have few extra manual =
adjustments=20
in order to get better performance.

WarrenS

*****************
----- Original Message -----=20
From: "Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
To: "Discussion of precise time and frequency measurement" =
<time-nuts at febo.com>
Sent: Monday, December 01, 2008 3:38 AM
Subject: Re: [time-nuts] V standards


> Mike
>>   >Mike
>>
>>   > In testing  high resolution DACs (20+ bits) used in  GPSDOs  etc =
a
>>   > high resolution DVM (or equivalent) with low noise and  good =
short
>>   > term stability is useful if not essential.
>>
>>   > Monotonicity and  perhaps linearity together with good  short =
term
>>   > stability are generally more important than absolute accuracy.
>>
>>   > Higher resolution is usually accompanied with higher accuracy.
>>
>>   > DVMs like the 3457A. 3456A etc dont have sufficiently low noise =
or
>>   > good enough  short  term stability for testing  DACs  with  24 =
bit
>>   > resolution.
>>
>>   >Bruce
>>
>>   I wonder if 20+ bits is even realistic for a frequency reference.
>>
>>   That would  give a LSB of 1/2^20=3D9.53e-7, or 1ppm, and  none  of =
the
>>   voltage references  discussed will maintain this accuracy  over =
long
>>   periods.
>>
>>  =20
> 24 bit resolution isnt required when using a 10811A class OCXO with a
> total EFC adjustment range of about 1E-7.
> Even 20 bits is a bit more resolution than actually required in this =
case.
> However there are low noise OCXOs with EFC adjustment ranges of 1E-6 =
or
> more.
> In a GPSDO long term stability of the EFC DAC offset and gain isnt
> critical except when the GPSDO is in holdover.
>>   And what would a 24-bit DAC be used for? From  previous =
discussions,
>>   high accuracy sources, like H-Masers are not adjusted. And  it =
would
>>   seem silly to put such a high resolution DAC on a OCXO.  That =
leaves
>>   Cesium, which  I understand are used in GPS satellites  and  do =
need
>>   adjustment, but  I  don't   have   any   information  on  the =
tuning
>>   sensitivity to figure the effect 1 LSB would have on the frequency.
>>
>>   I haven't had much luck finding a true 24-bit DAC. There  are =
plenty
>>   of stereo dacs, but they can have gain drifts of 100ppm/C,  which =
is
>>   useless for a reference.
>>
>>  =20
> No you have to build your own.
> The trick is doing it without requiring impossibly accurate and stable
> resistors or resistor ratios etc.
> Since the DAC update rate is relatively slow in such applications
> (GPSDO) indirect techniques that are inherently monotonic can be used.
> The FS725 rubidium standard has an internal 22 bit DAC.
> Hydrogen masers usually include similarly high resolution DACs.
> Such DACs are usually constructed by combining the outputs of 2 lower
> resolution DACs with some overlap.
> The drawback being the relatively large differential nonlinearity when
> the MSDAC output changes.
> This increases the settling time of the discipling loop in the =
vicinity
> of such changes.
> However such MSDAC output changes don't occur very often.
> Another application for such high resolution DACs is in accelerator =
beam
> steering.
> In this case frequent calibration is used together with suitable
> software to avoid such large differential nonlinearities.
>=20
>>   With a  5V reference, a 24-bit DAC would give a LSB  of =
5e9/2^24=3D298
>>   nanovolts. If  I had to test one, and didn't have a  3458A,  I =
could
>>   use a 3456A. It has a resolution of 100nV on the 100mV range,  so =
it
>>   could verify the bottom portion of the DAC from zero to  100mV. =
Once
>>   the lower  8 bits are confirmed good, the rest of the  DAC  could =
be
>>   checked by  exercising each high-order bit singly,  then  in =
various
>>   combinations with the other bits.
>>
>>  =20
> I had such techniques in mind for checking the monotonicity.
> Could also check against a KVD (e.g. Fluke 720A).
> However the shipping charges are rather high.
> It is possible to achieve a readout resolution of 100nV using a 3457A =
on
> the 3V range.
> However this is only available via the GPIB.
> Similarly even a 34401A can achieve a resolution of 100nV on the 10V
> range but only via either the GPIB or its serial interface.
> However the 300nV LSB is uncomfortably close to the DVM noise level =
and
> DVM drift isn't insignificant.
> For this application the DAC transfer function only has to be =
monotonic
> so testing requirements are somewhat relaxed.
>>   Another method  would  be  to use two 24-bit DACs  and  a  AD8571 =
to
>>   measure the  difference between them. The AD8571 could be  set  to =
a
>>   gain of  100,  so  298nV becomes 29.8uV  which  is  well  within =
the
>>   capability of a 3456A.
>>
>>  =20
> The LTC1151 is perhaps a better choice in some respects in that it  =
can
> use -15V and +15V supplies allowing a greater input voltage range
> simplifying the input overvoltage protection.
> Although the AD8571 power supply could be bootstrapped to achieve a =
much
> larger input range.
> Even lower drift and noise is possible if one builds one's own chopper
> stabilised preamp.
>>   The test  would  be  to  set  both  DACs  to  zero  and  measure =
the
>>   difference in output voltage. It should be close to zero.
>>
>>   Next, set  the LSB of the reference DAC to 1. The 3456A  should =
read
>>   close to 29.8uV.
>>
>>   Then set  the LSB of the test DAC to 1. The 3456A should  read =
close
>>   to zero.
>>
>>   Follow this  procedure  with   each   bit   in  turn  to  verify =
the
>>   functionality, then  test various combinations to check  for  two =
or
>>   more bits  that  are  stuck  together.  The  LSB  could  be  used =
in
>>   conjunction with  the  bit being tested  to  prevent  saturating =
the
>>   AD8571.
>>
>>   The above tests are not as good as a dedicated test for  a =
precision
>>   DAC, but might serve in lieu of spending $4k to $7k for a 3568A.
>>
>>   Regards,
>>
>>   Mike Monett
>>
>>  =20
> Bruce
>=20
>=20
>


From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.28.1228220608.2539.time-nuts@febo.com>

become=20
the 15th bit, connect a resistor value of 32,768 *R (320K) from I/O pin =
to the 10 Ohm=20

From bogus@does.not.exist.com  Sun Nov  2 21:23:46 2008
From: bogus@does.not.exist.com ()
Date: Sun, 02 Nov 2008 21:23:46 -0000
Subject: No subject
Message-ID: <mailman.29.1228220608.2539.time-nuts@febo.com>

65,500*R  I/O to output.=20
Standard 1% resistors are way more than accurate enough.

If you need more than three Bits, It probable pays to use PWM.=20
To add a PWM use Two equal value resistor in series,=20
with a  total value of 16,384*R connected to a  =20
PWM signal of any freq and add a filter cap between their center and =
ground=20
to filter the small amount of noise that the PWM will be adding.

Note:
For most circuits you do not need to actually add the output resistor,=20
there is always some places to add a little offset to.
All you need to do then, is find a place that you can change the offset=20
value of the DAC output, and add a small filtered current into it thru a =
resistor / filter divider.
The total zero range you need to add will depend on the number of Dac =
bits you have.

As an example to expand a 5 volt 14 bit Dac, to 16 (or to 24) bits, =
connect=20
the additional Dac thru a RCR filter to a point that will change the=20
Main Dac's output to offset by up to 0.3051 mV (minus the value of one =
of the added bits)

One way to turn a Really good 18 bit Dac into 24 + bits, is scale a 6 =
bit Dac=20
thru a resistor to some place on the 18 bit dac that will add 0 to 18.78 =
uV=20
+ - < 1/2% of offset onto the 18 bit Dac's output.

Have Fun
WarrenS

*****************************

Poul, how do I PWM a DAC that is itself a PWM device? This question =20
is prompted by the DAC I'm using in Bert Zauhar's FLL GPSDO, which is =20
a dithered 10-bit DAC in a PIC chip that results in 14-bit =20
resolution. I'd like to have a simple way to get 2 to 4 extra bits of =20
resolution out of this. Can you recommend some design resources to do =20
this?

Dick Moore