[time-nuts] Thunderbolt oven / non-stable operating temperature
lists at rtty.us
Mon Dec 10 22:22:27 UTC 2012
The oven in the OCXO keeps the crystal at a constant temperature. It is normal for the TBolt it's self to idle 10 to 20C above ambient. The temperature sensor is located near the 9 pin D connector. It shows a temperature somewhere in between the ambient and the OCXO case temperature. Some have mounted speed controlled fans to keep the TBolt case at a constant temperature.
On Dec 10, 2012, at 5:15 PM, Sarah White <kuzetsa at gmail.com> wrote:
> Ended up with a gently used trimble thunderbolt a few months ago, and
> been trying to figure out the best settings to use (time constant,
> damping, etc.) for best performance.
> I got distracted though. There is something which I find rather
> annoying, and I'm spending more time messing with this factor than
> actually observing the performance at different damping / time constant
> / etc...
> The temperature seems to be aprox 20C above ambient temperature rather
> than a steady 40C. I thought the purpose of the oven was to keep the
> temperature stable. When I adjust the thermostat because I'm chilly, the
> thunderbolt gets warmer too (but not by as much)
> I've tried (seemingly, to me) everything:
> light insulation
> putting the unit in a spot away from drafts
> putting the unit in a place away from drafts in a shoebox with light
> insulation with a fan blowing in it (currently in a cupboard in this
> state, and the temp seems to fluctuate the least, but still by more than
> 1-2 degrees centigrade)
> I feel like shouldn't need to fuss with ambient conditions this heavily
> for an OCXO, and find myself researching construction / design for a DIY
> outer-oven to wrap the thunderbolt in.
> Anyone have experience with non-stable temperature on a trimble thunderbolt?
> I've also noticed (monitoring with Lady Heather's Disciplined Oscillator
> Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit
> sometimes flags an alarm briefly (and I rarely ever manage to write it
> down before the screen updates or the alarm goes away) and the last one
> I was able to "catch" before it went away was related to temperature.
> Should I be getting a steady / non-flucturating 40C or something if the
> oven is working normally?
> Thanks in advance,
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts