[time-nuts] 9390 GPS RX
ed_palmer at sasktel.net
Wed May 29 11:47:04 EDT 2013
On 5/29/2013 4:27 AM, Mark C. Stephens wrote:
> Well, what do you know, I turned it up on its end with the heatsink end on a heatsink and overnight it locked dead on 10Mhz.
> Well as far as I can go, 10Mhz exactly, to 10 digits.
Do you mean you didn't have a heatsink on it before? That would be very
bad. It would cause overheating.
Very nice. I've got 3 FRKs. None of them have a lamp voltage that high.
> HDev=1.78E-12 @ 700 Seconds so it's still a teensy weensy wobbly.
How did you measure this? Provide details, please. I was measuring
mine by measuring the time interval between the FRK and a Z3801A GPSDO.
Then I realized that I might be seeing the GPSDO so I replaced it with
my best OCXO. After I remove drift from the results, I'm seeing AlDev
of about 2e-12 @ 1000 sec. and still trending down after about 16 hours
of runtime. Total Deviation (Timelab doesn't have it) measures about
9e-13 @ 10K sec.
> Long term stability is awful. 4.7E-11 @ 1:12 before I gave up on it while I was ahead..
> I wonder if the stability is correctable?
I'm not sure what you're saying. 4.7e-11 @ what? I haven't studied
long-term drift on my house standard, but I would expect that it would
take a while for it to settle down. In any case the 9390 will correct
that. If you log any data that the 9390 can provide you might end up
with a good data record showing how stability changes with runtime.
> Also, I was 'gating' my timer to quickly before so some of the previous the readings have been out by miles.
Yes, one bad setting can spoil a data run.
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