[time-nuts] 10811 foam enclosure

Bob Camp lists at rtty.us
Mon Jan 10 12:59:42 UTC 2011


The spec they were after was a warmup to "on frequency +/- 1x10^-8" from -40 C sort of thing. I believe the warmup  time was under 15 minutes, but I don't know the exact number. 


On Jan 9, 2011, at 8:43 PM, Mike S wrote:

> At 06:36 PM 1/9/2011, Tom Van Baak wrote...
>> The outer oven was a hack so Z3801A could meet telecom cell tower cold weather warm-up specs. In other words, the better performance they were looking for in that case was warm-up time; not a tempco or frequency stability spec.
> The Nortel GPSR (Z3801A) had a very loose warm up spec, which wouldn't have required a double oven by itself: "The GPSR will be permitted a 24 hour warm-up/training period in the event of a power loss and the 24 hour holdover requirement shall be met following this training period."
> The other basic requirement was "+/-1 us traceable to and synchronous with Universal Coordinated Time (UTC) with at least one satellite in view." Again, a double oven wouldn't be required for that - the GPS receive itself should do better.
> OTOH, it had a spec of +/- 7 us for a 24 hour holdover, which required a double oven. 
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