I'm a rank amateur on the time-nuts scale ... we did some replacements of MTI OCXOs a few years ago, and folded all that info into a manual as we built our own drop-in replacement OCXO modules for some XL Microwave and SRS instruments.
It has some data on trim values for IsoTemp brand OCXOs, etc. that some might find useful. http://www.pumpkininc.com/space/manual/UM-20_Pumpkin_OCXO.pdf ---------------------------------- Andrew E. Kalman, Ph.D. On Thu, Jul 22, 2021 at 9:37 AM Bob kb8tq <[email protected]> wrote: > >> Hi >> >> If you manually set the DAC with the commands LH nicely provides >> (LH is the *best* thing about these TBolts !!!) you will find it runs from >> -5 to +5V. The OCXO should tune linearly over that range ( all of mine >> do). >> >> If you take a saw to the typical TBolt OCXO, you likely will find >> a 10 MHz SC cut crystal in a single oven. The design changed over >> the many years they were supplied. One date coded 1997 is not going >> to be the same as one date coded 2005. >> >> On any OCXO, to see if it’s using a doubler, just hook up a spectrum >> analyzer to the OCXO output. You *will* see the sub-harmonic. Much >> quicker / easier than tearing the thing to pieces. >> >> Bob >> >> > On Jul 22, 2021, at 5:00 AM, Dave B via time-nuts < >> [email protected]> wrote: >> > >> > On 22/07/2021 08:30, [email protected] wrote: >> >> Message: 1 >> >> One more comment on the Vectron OCXO. My Tbolt shows a tuning voltage >> of +0.4 Volt and has 3.6 Hz per Volt. Assuming the OCXO was sold to Trimble >> with 0 V and my unit has at least 12 years on it (4380 days) aging is 3.29 >> E-11 per day. Not bad for an OCXO. >> >> Bert Kehren >> > >> > ------------------------------------------------------------------------ >> > >> > Hi. >> > >> > According to Lady Heather, My T'bolt sits with it's DAC at about 0.2V >> I always wonder about that. >> > >> > From the above comment, is the DAC output (and VCXO input I guess) >> bipolar, as in can range +- some amount from 0V? >> > >> > I've not seen any schematics for them, so in honesty haven't a clue >> what it's likely range is, good bad or indifferent. >> > >> > I did email TVB direct about the possibility of sourcing another one or >> two of them, but as he said (and I guessed) he was swamped with responses. >> > >> > I use mine mainly as a frequency reference, powered on 24/7 >> > >> > Regards to All. >> > >> > Dave G8KBV (In the UK as far as I can tell.) >> > >> > >> > -- >> > Created on and sent from a Unix like PC running and using free and open >> source software: >> > >> > _______________________________________________ >> > time-nuts mailing list -- [email protected] -- To unsubscribe >> send an email to [email protected] >> > To unsubscribe, go to and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- [email protected] -- To unsubscribe >> send an email to [email protected] >> To unsubscribe, go to and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
