[time-nuts] Making the most of SRS Rb source

Mike Nolan nolan at naic.edu
Wed Jan 18 20:58:00 EST 2006


Hi,


You should definately ask the VLBI people how to deal with the maser.
You definately don't want to touch the frequency reference during an
observation. They really do need the 10^-15 short-term stability. They
can solve for pretty substantial frequency offsets (and linear drifts)
after the fact, but phase noise will kill the experiment.

If you want a GPS-disciplined Rb, you'd probably be better off buying
one than fiddling with yours if it's really running the telescope.
But I suspect you can do better yourself with practice.  Is this the 12m?

When we got our maser, we did about what you suggest: futz with it
for a month and get it stabilized, then leave it alone as much as you
can. We reset the time if it gets off by 250 ns, and the frequency occasionally.
Mostly, log what you do, or the pulsar timing people will have a
fit. You may not get much pulsar timing at 100 GHz, but the pulsar folk
have their hands in all pies.

Sorry if this information is redundant, but and experiment that's blown
becaus of a bad frequency reference is a bummer.

Cheers,

-Mike

-- 
Mike Nolan +1 787 878 2612x334 Fax: +1 787 878 1861 nolan at naic.edu
Arecibo Observatory, HC 3 Box 53995, Arecibo, Puerto Rico 00612 USA




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