[time-nuts] Another "atomic" clock question
hmurray at megapathdsl.net
Sun Mar 2 02:45:25 EST 2014
bob91343 at yahoo.com said:
> Okay you want numbers. Well, I think 10 ppb or thereabouts should do it.
> Somewhere there is a discontinuity in accuracy plotted against cost and I
> don't want to cross that barrier just yet. If I can get 1 ppb without a big
> increase in cost, I'll take that.
How good is your crystal?
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
If you are running ntpd, turn on loopstats and measure the temperature...
I've been watching a 3 MHz ovenized crystal. It was something like 4 for $25
from ebay. It's a 2 in sq can, over an inch high. It's got a few ppb of
noise over minutes/hours and a few more ppb of drift/wander over days/months.
It took several weeks to stabilize after power on.
These are my opinions. I hate spam.
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