[time-nuts] Making a HP 10811 better

EWKehren at aol.com EWKehren at aol.com
Mon Mar 29 17:32:14 UTC 2010


I would not feel comfortable tearing into the unit.
 Controlling its environment and power to it yes.
 I did that with a 10811 and a 10544 years ago by drilling a 20 foot  hole 
in my Dallas backyard lowering the units in it with support electronics in  
place and sealing the shaft with individual sand bags each with a numbered  
string, so I could pull them out one at time when I had to get to them. Did 
not  have the equipment I have today but I did manage to borrow a 5061A for 
set up.  Here in Miami being right on the water it is not an option. When I 
relocate  from Miami to dryer grounds I may repeat it with a Rubidium.
Bert
 
 
In a message dated 3/28/2010 11:52:14 A.M. Eastern Daylight Time,  
warrensjmail-one at yahoo.com writes:

Bert  asked

> "why would  I  want to mess with them at all if  they are already under 
> 1E-12?"

Don't know about  you, The reason I'd mess with them is cause I'm nuts 
and can make them  even better.
And Allan variance is not everything.
Have you plotted  their Freq change over time with better than 1E-12 
resolution?
If you  are a True NUT, I'm betting you would see things that would make 
you  
sick.
Things such as line freq spurs, Freq jumps, the effects of:  changing 
temperature, changing PS, changing time, changing Load, partial  injection 
locking to other osc friends around them, and maybe even to the  changing 
moon.

Don't forget the Basic Nut Cake pledge.
If it can  be made better then it is not good enough

Or for the more practical  answer;
Cause I can make mine good enough with some help from two of its  friends, 
named GPS and Rb, that I do not need a Cs primary  standard.

ws

*********************

> Good  morning
> I have a more fundamental question. Having three 10811-5071  all with 
Allan
> Variance from 1 to 100 Hz well below 1 E-12 one as low  as 6 E-13 why 
would
> I  want to mess with them at all?
>  Bert Kehren
>
********************
> In a message dated  3/28/2010 8:32:12 A.M. Eastern Daylight Time,
> lists at rtty.us  writes:
>
> Hi
>
> If your zero g axis only works over  a 1/100 G range, you  are looking at
> something other than  acceleration. If you have found an axis  with a 
zero, 
> it
>  should be a just as much a null at 1 mG as at 1 G as at 10  G's. It's  
also
> possible that your "zero" is actually a minimum below your test  
> resolution
> and higher G's bring it up to the point you can  measure it. There's  no
> guarantee of a zero being  there.
>
> Hitting the oscillator makes it  vibrate in all  three axis, that's not
> going to be suppressed regardless of   which way you have it mounted.
>
> Bob
>
> On Mar 28,  2010, at 12:42 AM,  WarrenS wrote:
>
>>
>>  Humm,
>> Have to admit, I did not  consider that as a  possibility before.
>> Maybe when I tap on it, its not   microphonics after all that cause the
> freq to modulate, but the  vibration of  the inside stuff that is warming 
> it  up.
>> For every action there is a  reaction and for every   nut there is a
> wing-it-nut.
>>
>>   ws
>> *****************
>> Hi
>>
>> If  that's the result  you are getting, you are measuring something  
other
> than G sensitivity.  Temperature effects  possibly.
>>
>> Bob
>>
>>   ****************
>> On Mar 27, 2010, at 11:02 PM, WarrenS  wrote:
>>
>>>
>>> Just a friendly comment  about the Zero G turn over  point and  
Vibration
>>>
>>> Like Zero temp turn over,  Special  orientation of the OSC ONLY works
> good over a VERY SMALL  range, (maybe a 1/100  of G change)
>>> It would not help  vibration and has no effect on  microphonics which 
are
> likely a  bigger problem anyway.
>>> Try taping  you Osc, It's freq  will go crazy if monitoring it at high
> resolutions and   bandwidths
>>>
>>>  ws
>>>
>>>   ************************
>>>
>>>  Hi
>>>
>>>  The concrete basement floor is your  friend.
>>>
>>> Stay as  far away from the blower  on the furnace as you can. If you 
have
> a drop forge  in the  basement avoid it as well :)....
>>>
>>> You  will  indeed have a seismograph, but not a very useful one.  
There's
> not a lot of G's  at seismic frequencies unless you live  in an active
> earthquake region. The  fundamentals of G's and  displacement vs 
frequency 
> are in
> your favor in that   respect.
>>>
>>>  Bob
>>>
>>>
>>> On  Mar 27, 2010, at  12:42 PM, Stanley Reynolds wrote:
>>>
>>>> Is the  source of the vibration important ? I'm thinking that  any
>  vibration that is not on the same axis as gravity. Walking across the 
lab  
> vs a
> fan that is out of balance close by. Would a suspended  mass mounting help
> with vibration isolation and damping with rubber  pads and springs or 
would
> that just make a seismograph  ?
>>>>
>>>>   Stanley
>>>>
>>>>
>>>> -----  Original  Message ----
>>>> From: Peter Vince <pvince  at  theiet.org>
>>>> To: Discussion of precise time and  frequency  measurement <time-nuts 
at
>  febo.com>
>>>> Sent: Sat, March 27,  2010 10:51:07  AM
>>>> Subject: Re: [time-nuts] Making a HP 10811   better
>>>>
>>>>  Warren,
>>>>
>>>>   If you turn over  an oscillator, is the frequency  change
>>>> completely  reversible (to your "under 1e-12  resolution") when it  is
>>>> restored?  Thinking aloud, if an  hour-glass  is turned over twice, the
>>>> final level will be the   same, but the grains will be mixed.  A quartz
>>>>  crystal,  however, is solid, so hopefully nothing actually  moves.
>>>>  Presumably the zero-G axis is with the axis  of oscillation at  90
>>>> degrees to  gravity?
>>>>
>>>>   Peter (the  "other" one  :-)
>>>>
>>>>
>>>>
>>>>>  Another thing I use it  for is to test high resolution Freq  meters.
>>>>> Using a  calibrated wedge that I can then  slide under one edge of the
> zero-G
>>>>> Osc box, I  can
>>>>> make small,  variable, repeatable, freq  changes of under 1e-12
> resolution,
>>>>> something  pretty hard to do  otherwise.
>>>>> If I want to make  BIG changes like 1e-10, I can  rotate the box on 
any
> of  its
>>>>> sides and still use the   wedge,
>>>>> and for a quick check of new equipment, I just  turn  the box over
> which then
>>>>> gives a  couple of parts in 1e-9  freq change.
>>>>> It makes a  weird but simple and indispensable  variable freq source
> that  is
>>>>> useful for many things, such  as checking the  LOOP TC of a TBolt.
>>
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