[time-nuts] 10811 foam enclosure
mikes at flatsurface.com
Mon Jan 10 01:43:30 UTC 2011
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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