[time-nuts] GPStar Plus: Rubidium, anyone?

Arthur Dent golgarfrincham at yahoo.com
Wed Feb 13 08:01:25 EST 2013


Despite what has been previously posted I’ve found my 565s 
to be very good frequency references for my counters and they 
seem to compare well to the Thunderbolts. I haven’t run any 
long term checks but comparing Tbolts to 565s on my scope 
from time to time I’ve never seen any jumps or significant 
frequency drift (at 5ns/cm). The 565s generally report parts in 
E-12 to E-14 depending on conditions.

In regard to replacing the crystal oscillator with a rubidium, I 
tried that once using an X72 and wasn’t impressed. It worked 
o.k. but as you can see from the manual specs below the only 
gain would be during long periods of signal loss or ‘coasting’. 
As long as you have a signal the average accuracy will be the 
same and I feel the OCXO could possibly be a little less noisy 
and perhaps have better short term stability although I never 
checked it. 

-Arthur

565
(High Performance Quartz)
Accuracy Error
Time Locked................................1 X 10-12 (1 day average)
Coasting..................................... 5 X 10-10/day

(Rubidium)
Accuracy Error
Time Locked................................1 X 10-12 (1 day average)
Coasting..................................... 2 X 10-11 /day


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