[time-nuts] Z3805 initial behaviour after power up

Hal Murray hmurray at megapathdsl.net
Wed Jun 17 12:33:39 EDT 2009

> Sure! I had better formulated my question like: A constructor of a
> GPSDO knows, that any OCXO that has been sitting around for years is
> likely to undergo rapid aging when it is first brouht up. When
> Symmetricon choosed to switch to a long time constant early after
> power up, were they perhaps expecting a lower OCXO drift than I am
> observing now? 

Does anybody have any data on the startup transients for a good crystal 
that's been off for a year compared to one that's been off for a week or a 

My guess is that the designers ignored the off-for-a-long-time problem.  It's 
too hard to test and doesn't happen often enough to be important.

Do people who run lots of GPSDOs (telcos) store their spares powered up in 
order to avoid this problem?  If I have 2 units, primary and secondary, and 
the primary dies, will the pick-one software stick with old unit for a while 
after the dead one is replaced even though the "primary" is now working?

These are my opinions, not necessarily my employer's.  I hate spam.

More information about the time-nuts mailing list