[time-nuts] OCXO retrace, how long is reasonable?

[Matthias Welwarsky]

Hi Bob,

On Freitag, 4. September 2020 15:03:26 CEST Bob kb8tq wrote:
> Hi
> 
> Best guess is that the oven circuit has “issues”.  If that’s the case, it
> will go on pretty much forever and ever. Without a plot, it’s sort of hard
> to guess ….

Unfortunately, I don't have a longer history on record, my monitoring software 
only logs about the last 7 hours. Hard to tell if the oven has an issue, I 
only checked the power consumption during warm-up, it looked "reasonable", but 
if the regulation is off and the crystal is not at its zero-aging temperature, 
not much I can do. I'll give it another week or two waiting for a sign of 
deceleration. If it doesn't happen, I'll scrap it.

Regards,
Matthias

> 
> Bob
> 
> > On Sep 4, 2020, at 2:50 AM, Matthias Welwarsky <time-nuts at welwarsky.de>
> > wrote:
> > 
> > Hi,
> > 
> > I mentioned in a previous email that I seem to have picked a particularly
> > bad (broken?) OCXO for GPSDO testing. It drifts at a very high rate, from
> > the DAC graph I calculate it is around -4e-4 Hz/hour. It's been on for
> > about 1 week now and the drift doesn't seem to come down, or maybe just
> > marginally.
> > 
> > Of course, this being a surplus OCXO with unknown history, odd startup
> > behavior is somewhat expected but so far I haven't seen anything this
> > drastic.
> > 
> > Could this be OCXO retrace? How long can that phase last? I'm trying to
> > decide if I should give it another week or just scrap it and move on.
> > 
> > Regards,
> > Matthias
> > 
> > 
> > 
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