[time-nuts] HP 5065A

KA2WEU at aol.com KA2WEU at aol.com
Wed Mar 16 16:24:12 EDT 2016


In my closet I found one of these, any merit to play with it  ?
 
Ulrich 
 
 
In a message dated 3/14/2016 5:00:28 P.M. Eastern Daylight Time,  
lars.walenius at hotmail.com writes:

Hi

Shouldn´t 5x10^-11 over 50C be 1x10^-12 / C? So with  2-4°C variation it is 
2-4x10^-12.

What about pressure variations for  the HP5065 and other Rb´s? My LPRO have 
about 7x10^-14/mBar (hPa) so with  15-20mbar change, that can happen quite 
quick, it is also in the ^-12 range.  The tempco for my LPRO is 7x10^-13/°C 
and drift in the high ^-14 per day so my  GPSDO controller mostly fights the 
temperature and pressure variations I  think. I like having a GPS 
disciplined Rb as I haven´t had to adjust it during  the last years. Of course a OCXO 
based GPSDO will also stay on frequency. For  me the Rb have been good when 
I have tested GPS modules and GPSDO´s just out  of curiosity. In hold mode 
it have been useful to get the ADEV out to say  10000 secs (low ^-13).

Lars

Från: Bob  Camp<mailto:kb8tq at n1k.org>
Skickat: den 14 mars 2016 02:01
Till:  Discussion of precise time and frequency  
measurement<mailto:time-nuts at febo.com>
Ämne: Re: [time-nuts] HP 5065A  repair

Hi

Some math:

5x10^-11 over 50C

You have  1x10^-13 / C

If you have pretty good HVAC you get 2C cycles. On a  typical home system, 
you get 2X that or more.

Net is a bump at 2x10^-13  (or more).

That assumes no hysteresis. (Hint: there always is  hysteresis).

That assumes you have no rate dependent effects. (… they  almost always are 
present ..).

If you are at 10X the data sheet level,  the bump is more like 2x10^-12 (or 
more). Either one will likely show up on a  good test plot.

Can you take care of all this? Of course you can. Does  modeling and 
correcting all this fall into the “quick and easy fix” category?  Nope, not at 
all. The thread is about a request for a simple approach to an Rb  setup. That 
sort of thing does not include fancy models and all sorts of  corrections.

Bob



> On Mar 13, 2016, at 5:10 PM,  Poul-Henning Kamp <phk at phk.freebsd.dk> 
wrote:
>
>  --------
> In message <AABMQMGVVAUQCPK2 at smtpout04.dca.untd.com>,  cdelect at juno.com 
writes:
>
>> As far a tempco goes, unless your  lab swings tens of degrees will you
>> really see it?
>
>  Well, I do...
>
> My air-con is far from optimal, but it clearly  makes a very obvious
> bump in my AVAR plots.
>
>
>  --
> 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.
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> time-nuts mailing list  -- time-nuts at febo.com
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