Hi The Trimble TBolts were made over a long period of time. If you compare “early” (90’s) units to the “late” (~2005) units there are differences in performance.
Bob > On Feb 11, 2016, at 12:16 AM, Charles Steinmetz <csteinm...@yandex.com> wrote: > > Bob wrote: > >> I'll see if I can figure out which of these is retracing the "wrong" way and >> put it in a unit. I'll let it cook for a couple of days and then post a >> plot. Like I said, these are all Trimble 34310-T, though I know that there >> were at least two manufacturers for that part number. They were all >> positive EFC devices with more or less the same frequency range. > > I would expect all OCXOs with the same part number to have the same type of > crystal (though maybe not from the same manufacturer), so they should all be > the same (within some distribution around nominal) WRT the *warmup* drift. > As to the actual (post-warmup) *retrace* drift, there is no right or wrong > direction. If you let an OCXO go cold 100 times, wait a day or more (each > time), and then power it up, it will likely retrace up sometimes and down > other times. One of my 10811s pretty much alternates from one cold start to > the next (but I very rarely power it down). > > Once again, crystals are very individual devices with very individual > personalities, and they are often unpredictable. They are made to be powered > up and left undisturbed for months/years/decades. Use them that way, > evaluate them that way, and don't waste time puzzling about what they do for > the first month after you power them up. It does not make any sense to power > them on and off "rapidly" (off for less than a week, on for less than a week) > and try to draw conclusions about anything that matters with respect to their > performance. > > Best regards, > > Charles > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
