> Other than taking longer to warm up does anybody see any problems with > this? Basic testing shows the unit seems to work OK. It is reading 1.7 > Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting > the trimmer on the 10544 yet. > > Comments and thoughts appreciated. > > Regards. > > Mark. > VE6NTP >
At http://home.teleport.com/~oldaker/10mhz_construction.htm which has TAPR info, I found this description of the differences. If you have a Thunderbolt or rubidium to feed in to replace the internal oscillator, or you're not concerned about leaving the oven energized 24/7, it probably doesn't make much difference as Rick Karlquist said. "The HP 10811A/B, using an SC-cut resonator, is very similar physically to the HP 10544 that used a AT-cut resonator. The SC-cut crystal has several advantages compared to the AT cut. It has a much smaller temperature coefficient, the resonator can be operated at a higher drive level, which improves the signal-to-noise ratio and short-term frequency stability without degrading the aging rate; it has faster warm up with less frequency overshoot. The SC cut is a doubly rotated resonator and requires much tighter angular tolerances when the crystal is cut from the quartz bar. The SC-cut resonator came into commercial production around 1980. The use of SC-cut resonators in oscillators immediately improved their performance of the stand alone HP 10811 series OCXO installed in their test equipment. In our use we are able to improve on the HP frequency stability specs by a factor of 100 to 1000 depending on conditions." _______________________________________________ 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.
