Bob wrote:
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.
If I'm not mistaken, that is largely because they used several different (part number) OCXOs. I'm not sure it's so much a progression over time as it is evidence of "special" models built to user specifications. The ones I've seen with any specific OCXO seem to perform similarly to others with that same OCXO. [1]
[1] Except that, as I've noted before, there seem to be two distinct groups of the P/N 37265 OCXOs, one group with tempco about 100x better than the other, larger group. Other than the tempcos, these two groups seem to perform similarly. My working hypothesis is that all 37265s are supposed to perform like the low-tempco units, but that the ovens in the high-tempco units are not adjusted correctly to the turnover temperature of the crystals. I did hack into one of the high-tempco units and, after some experimentation, was able to get its tempco down into the ballpark of the low-tempco units by adjusting the oven temperature (but an anecdotal result for one unit doesn't prove anything). I have not been able to discern any pattern WRT date codes or serial numbers between these two groups, but my sample size is probably too small to reveal one even if it were there.
Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
