[time-nuts] HP 5065A

Bob Camp kb8tq at n1k.org
Wed Mar 16 17:14:57 EDT 2016


Hi

If you have the time to get it going, it’s in deed a good short term stability source. It’s long(er) term stability 
is not as good as a Cesium. Possibly the most interesting thing might be to rip out the silly old synthesizer 
and put in something more modern.

If you decide to “throw it away” there are a number of us who probably will line up by your dumpster :)

Bob 

> On Mar 16, 2016, at 4:24 PM, KA2WEU--- via time-nuts <time-nuts at febo.com> wrote:
> 
> 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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