[time-nuts] Rubidium stability

[JOS Earthlink]

Hi Group,

I'm a newbiew and just bought a Lucent RFG-RB rubidium source on Ebay from a
reliable seller.  I am observing a daily variability of about 80Hz and
hourly variability of a few Hz with a calibrated HP 5334B counter (with oven
oscillator option).  The counter and rubidium source have been powered on
for over a week in my basement workgroup which has a stable ambient
temperature.  I'm using a cannnibalized power supply from an HP-5328A (all
the caps replaced) for the 24v rubidium power source ... its supposed to be
a quite stable PSU.

Is this variability more likely due to the rubidium source (failing bulb) or
due to problems with the 5334B counter?

Any advice appreciated.

Jerry
K1JOS