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,
[email protected] 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:[email protected]>
Skickat: den 14 mars 2016 02:01
Till: Discussion of precise time and frequency
measurement<mailto:[email protected]>
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 <[email protected]>
wrote:
--------
In message <[email protected]>, [email protected]
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
[email protected] | 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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