[time-nuts] HP 5065A

Magnus Danielson magnus at rubidium.dyndns.org
Wed Mar 16 17:45:40 EDT 2016


Hi Ulrich,

Indeed. Some LTC and they have very nice performance.
You got a manual to go with it?

Corby has some interesting mods for them, Poul-Henning is looking at 
further improvements.

Cheers,
Magnus

On 03/16/2016 09:24 PM, KA2WEU--- via time-nuts 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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