[time-nuts] How to create a super Rb standard

Angus not.again at btinternet.com
Fri Jan 20 03:12:03 EST 2017

> It looks like their is as infinitely small chance of being able to get 5065.
> So what can be done with the telco Rb's (mine are analog tuned) to 
> wring the best possible performance from them? Sooper Duper power 
> supplies, Peltier (sp) cooling modules?
> Regards,
> Perrier


	I'm always a bit surprised that it's not done more.  Adding
temperature control, air pressure compensation and drift compensation
transforms the medium to long(ish) term performance of a lot of

	A typical Adev plot for a rubidium starts increasing again
after a few 1000's of seconds as environmental factors take their
toll, but with even a simple version of these mods it's more like
days. This makes it a great reference for testing GPS receivers and
GPSDO's among other things.

	A basic setup could be something like an LPRO in a temp
controlled enclosure, with an analogue pressure sensor feeding into an
EFC circuit, both temp controlled with the LPRO. Log it against GPS
and you get the long term (like weeks+) ageing which can then be
removed. Even simpler, you could just log the air pressure and correct
for that too, but that's more of a pain if it's being used as a
general purpose reference.

	Of course, the problem then is testing just how good it is....


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