[time-nuts] time-nuts Digest, Vol 61, Issue 59

Fri Aug 14 19:22:37 UTC 2009

Hi John

The 6CW4 Nuvistor that I know is a metal/ceramic valve by RCA....maybe all at cross purposes !

Yours

Clive Green
CEO 
Quartzlock 
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-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of time-nuts-request at febo.com
Sent: 14 August 2009 18:40
To: time-nuts at febo.com
Subject: time-nuts Digest, Vol 61, Issue 59

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Today's Topics:

   1. Re: on the "E" 117As and 5087As (Pete Lancashire)
   2. Re: time-nuts Digest, Vol 61, Issue 57 (Mark Sims)
   3. Re: Difference in GPS antennas (Pete Lancashire)
   4. Difference in GPS antennas (Mark Sims)
   5. Re: Difference in GPS antennas (Lux, Jim (337C))
   6. Taking apart timing GPS antenna (John Green)
   7. Re: Difference in GPS antennas (Robert Darlington)
   8. Re: Difference in GPS antennas (Dick Moore)
   9. Best way for generating 8994.03 MHz from
      2899.00042272.....MHz? (Javier Serrano)

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

Message: 1
Date: Fri, 14 Aug 2009 09:38:21 -0700
From: "Pete Lancashire" <pete at petelancashire.com>
Subject: Re: [time-nuts] on the "E" 117As and 5087As
To: jfor at quik.com, "Discussion of precise time and frequency
	measurement"	<time-nuts at febo.com>
Message-ID:
	<5c603f05cff512b813d32e7bac6b71d0.squirrel at petelancashire.com>
Content-Type: text/plain;charset=iso-8859-1

I guess I have been lucky, I came across about 6 rolls
a few years ago. I was picking up an instrument I won locally
and as usual I took the time to find the drop boxs/dumpsters.
They along with some other 'trash' such as the SMA terminators,
attenuators, etc were ready to be tossed. To them not enough
to make up a EBay lot.

Another place is from old Ampprobes recorders, the problem there is
the printed scale will be wrong. Before I found my HP rolls I
get those from a local electrical disti who just gave them to me.
They were in cubic feet per minute :-)

-pete

> Does anyone know of a source fot te 117A strip chart paper or the two
> Nuvistors in the active loop?
>
> Thanks,
> -John
>
> ===============
>
>
>> Just passing on the info, no association etc
>>
>> 110421524421 3 ea 5087A's $500 or Make offer
>>  I'm making my own after I get my TBolt in a chassis
>>
>> 110424016673 2 ea 117A's $200 or Make offer
>>  I all ready have one
>>
>> -pete
>
>
>
> _______________________________________________
> 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: 2
Date: Fri, 14 Aug 2009 16:33:26 +0000
From: Mark Sims <holrum at hotmail.com>
Subject: Re: [time-nuts] time-nuts Digest, Vol 61, Issue 57
To: <time-nuts at febo.com>
Message-ID: <BLU125-W20F4BCFE56E6EF9CD4A94BCE020 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"

There is a Leica L1 only survey antenna on Ebay right now for $200 (220451355177) a Javad choke ring unit for $900 (200373329570).   The listings don't have any specs on the operating voltage.  

These are typical prices for what these devices sell for (not a bargain,  not a total rip).  A little patience and shopping around and you could do better.  A Sokkia L1/L2 antenna just sold for $350.  

One issue with them is that survey antennas are usually flat and timing antennas are conical (to shed snow and ice).  If you live up north it could be an issue...

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

Thanks guys. I bookmarked that site. I don't know that I'll be able to find one but at least I know what to look for now.
_________________________________________________________________
Get your vacation photos on your phone!
http://windowsliveformobile.com/en-us/photos/default.aspx?&OCID=0809TL-HM

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

Message: 3
Date: Fri, 14 Aug 2009 09:46:32 -0700
From: "Pete Lancashire" <pete at petelancashire.com>
Subject: Re: [time-nuts] Difference in GPS antennas
To: "Discussion of precise time and frequency measurement"
	<time-nuts at febo.com>
Message-ID:
	<211166fe803baa2594d42ead9debdf15.squirrel at petelancashire.com>
Content-Type: text/plain;charset=iso-8859-1

I have some (well a LOT) of microwave absorber. it looks
like a mix of ferrite and rubber that has been bonded
to a stainless steel cloth (think window screening) in the
middle. About 1/8" thick.

I can get the make, p/n and a picture this weekend if interested.
I remember the company that made it got bought out, which then
got bought out etc and I gave up.

Price would be free+shipping, there are about 400 each
sheets about 30x30 inches. Each sheet must weight 5 lbs.

>
>
> On 8/14/09 9:13 AM, "Mark Sims" <holrum at hotmail.com> wrote:
>
>>
>
>>
>> Some of the data collection runs that I want to do is with the patch
>> mounted
>> on a pizza pan and in a cake pan and see if that helps the performance
>> by
>> faking what a survey antenna does.
>>
>
> If you can scrounge up some suitable RF absorbing material to put on the
> pan, that might be an interesting experiment.  Maybe even something like
> charcoal briquettes (I don't know if the resistivity is right..)
>
>
>
> I've tried the pizza pan thing, but that was because my antenna was a
> magmount, and it was convenient. I didn't see if it gave better
> performance.
> A flat plate might actually be worse than putting the bare antenna up on a
> pole, because it gives strong multipath from a very close reflection
> point.
>
>
> _______________________________________________
> 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: Fri, 14 Aug 2009 16:38:51 +0000
From: Mark Sims <holrum at hotmail.com>
Subject: [time-nuts] Difference in GPS antennas
To: <time-nuts at febo.com>
Message-ID: <BLU125-W184EE189FFB2C0177A791ECE020 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"

I have lots of carbon fiber cloth here (both woven and anisotropic mat).  I know from past experience that it makes a pretty good RF absorber.  I can put a tracking transmitter inside an all metal rocket and still get a good signal.  Put it a a cardboard tube laminated with carbon fiber and the signal just about disappears.

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

If you can scrounge up some suitable RF absorbing material to put on the
pan, that might be an interesting experiment.  Maybe even something like
charcoal briquettes (I don't know if the resistivity is right..)
_________________________________________________________________
Windows Live?: Keep your life in sync.
http://windowslive.com/explore?ocid=PID23384::T:WLMTAGL:ON:WL:en-US:NF_BR_sync:082009

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

Message: 5
Date: Fri, 14 Aug 2009 09:45:48 -0700
From: "Lux, Jim (337C)" <james.p.lux at jpl.nasa.gov>
Subject: Re: [time-nuts] Difference in GPS antennas
To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Message-ID: <C6AAE2CC.9BEC%James.P.Lux at jpl.nasa.gov>
Content-Type: text/plain; charset="iso-8859-1"

That?s probably exactly what you want (as opposed to the foamy stuff like in
anechoic chambers).  Very lossy for the magnetic field, typically, and you
use it to suppress surface waves.

On 8/14/09 9:46 AM, "Pete Lancashire" <pete at petelancashire.com> wrote:

> I have some (well a LOT) of microwave absorber. it looks
> like a mix of ferrite and rubber that has been bonded
> to a stainless steel cloth (think window screening) in the
> middle. About 1/8" thick.

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

Message: 6
Date: Fri, 14 Aug 2009 11:56:50 -0500
From: John Green <wpxs472 at gmail.com>
Subject: [time-nuts] Taking apart timing GPS antenna
To: time-nuts at febo.com
Message-ID:
	<abec162c0908140956i6608f15ei3627f724a3fcd9b3 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hal Murray wrote: How did you get it apart?
The Motorola/Andrew antenna that I have has screws. Best I remember, I just
removed them and yanked the top off. I do believe there was a seal that had
to be overcome.

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

Message: 7
Date: Fri, 14 Aug 2009 11:05:34 -0600
From: Robert Darlington <rdarlington at gmail.com>
Subject: Re: [time-nuts] Difference in GPS antennas
To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Message-ID:
	<b3bd5fcb0908141005r5071ece0j4c5e410254fa6e53 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hrm, I'm looking for a sheet of Eccosorb to make an anechoic chamber (a very
small one) for testing 2.4GHz printed (PCB) antennas.  I'd be interested in
knowing the specs.   The idea with what I'm doing is that I can sweep the
antenna with the network analyzer and still be near the antenna to keep the
cables short, while at the same time not interfere with the measurements.  I
met a guy from Microchip last week that showed me what he was doing and what
works well for him.  He built a box about 8" high and about 5 inch square on
the bottom (inside dimensions).  Even though it's pretty parallel on the
inside, reflection is a minimum because of the material.

-Bob

On Fri, Aug 14, 2009 at 10:46 AM, Pete Lancashire
<pete at petelancashire.com>wrote:

> I have some (well a LOT) of microwave absorber. it looks
> like a mix of ferrite and rubber that has been bonded
> to a stainless steel cloth (think window screening) in the
> middle. About 1/8" thick.
>
> I can get the make, p/n and a picture this weekend if interested.
> I remember the company that made it got bought out, which then
> got bought out etc and I gave up.
>
> Price would be free+shipping, there are about 400 each
> sheets about 30x30 inches. Each sheet must weight 5 lbs.
>
>
> >
> >
> > On 8/14/09 9:13 AM, "Mark Sims" <holrum at hotmail.com> wrote:
> >
> >>
> >
> >>
> >> Some of the data collection runs that I want to do is with the patch
> >> mounted
> >> on a pizza pan and in a cake pan and see if that helps the performance
> >> by
> >> faking what a survey antenna does.
> >>
> >
> > If you can scrounge up some suitable RF absorbing material to put on the
> > pan, that might be an interesting experiment.  Maybe even something like
> > charcoal briquettes (I don't know if the resistivity is right..)
> >
> >
> >
> > I've tried the pizza pan thing, but that was because my antenna was a
> > magmount, and it was convenient. I didn't see if it gave better
> > performance.
> > A flat plate might actually be worse than putting the bare antenna up on
> a
> > pole, because it gives strong multipath from a very close reflection
> > point.
> >
> >
> > _______________________________________________
> > 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.
>

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

Message: 8
Date: Fri, 14 Aug 2009 10:22:54 -0700
From: Dick Moore <richiem at hughes.net>
Subject: Re: [time-nuts] Difference in GPS antennas
To: time-nuts at febo.com
Message-ID: <21A62FCD-5E85-447C-8D2D-A305F0318BE1 at hughes.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

On Aug 14, 2009, at 9:27 AM, time-nuts-request at febo.com wrote:

Maybe why choke rings are rings.
>
>
> Message: 9
> Date: Fri, 14 Aug 2009 09:27:52 -0700
> From: "Lux, Jim (337C)" <james.p.lux at jpl.nasa.gov>
> Subject: Re: [time-nuts] Difference in GPS antennas
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID: <C6AADE98.9BE6%James.P.Lux at jpl.nasa.gov>
> Content-Type: text/plain; charset="iso-8859-1"
>
> clip>>>>
> I've tried the pizza pan thing, but that was because my antenna was a
> magmount, and it was convenient. I didn't see if it gave better  
> performance.
> A flat plate might actually be worse than putting the bare antenna  
> up on a
> pole, because it gives strong multipath from a very close reflection  
> point.

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

Message: 9
Date: Fri, 14 Aug 2009 19:39:46 +0200
From: Javier Serrano <javier.serrano.pareja at gmail.com>
Subject: [time-nuts] Best way for generating 8994.03 MHz from
	2899.00042272.....MHz?
To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Message-ID:
	<83e48fa10908141039i3c3a3116ue54c9e364b46c469 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Dear nuts,

A colleague from a Free Electron Laser lab has the following problem:
he needs to make a frequency to use as an X-band LO that is
*exactly*8994.03 MHz (3*2998.01 MHz) and it
*must* be locked to his S-band LO which is exactly 2998.01*732/757 MHz
(2899.00042272.....MHz). He intends to multiply his S-LO by 3 and that gets
him close, about 297 MHz away. Then he can add another frequency he has(that
is locked to his S-LO) of 241.6..... MHz (2998.01*61/757 MHz to be exact)
and that brings him to about 55 MHz. To generate that 55 MHz he has several
options:
- Cascading two DDS chips to get many bits of frequency resolution and leave
the thing in open loop. I don't like the absence of feedback in this option,
and I have never cascaded DDS chips to achieve an increase in frequency
resolution, although on paper there seems to be no problem. The increase in
accuracy would be such that even in open loop it would take a very very long
time to go out of spec (his spec is 0.01 degrees at X-band, during a whole
year). This time would be long enough for him not to care about it.
- Generating it using a standard PLL with some kind of good quality VCO. He
is concerned by the required VCO quality in this case.
- Combining the two above, i.e. using the DDS as a VCO by controlling its
Frequency Tuning Word, but in a closed loop configuration.

Has anybody out there been confronted to a similar problem? Many thanks in
advance,

Javier

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

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End of time-nuts Digest, Vol 61, Issue 59
*****************************************