[time-nuts] Rubidium stability

Didier Juges didier at cox.net
Sun Apr 29 10:10:06 EDT 2007


Jerry,

80 Hz is much more than either device should exhibit. There is something 
seriously wrong, and if you have a short wave receiver that can receive 
WWV at 10 MHz (AM is fine), you should try to listen to the beat 
frequency between WWV and either oscillator. That will tell you which is 
off.

You may have to use a small piece of wire plugged into the BNC of either 
oscillator as an antenna. adjust the length and/or separation with your 
receiver to adjust the level so that you hear a beat frequency with WWV.

Alternately, try to borrow a known good counter from someone local. In 
either case, an oscilloscope would help check the outputs. When an 
oscillator is way off in frequency, the signal may not look right on the 
scope.

Didier

JOS Earthlink wrote:
> 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
>
>
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