Hi The speed of sound in quartz varies by axis, but only by about 2:1. The same basic physics that gets you a fundamental 5 MHz crystal that is at thickness Z gives you some dimension on a 5 KHz crystal that’s close to 1000 * Z. Very low frequency crystals pretty much have to be designed so they resonate on a “long” axis of the blank. If they don’t then the blank / enclosure / price gets crazy big.
If you want to calculate just how long this or that resonance might be: http://www.mt-berlin.com/frames_ao/descriptions/sio2.htm Has all the numbers you would need. Bob > On Jan 10, 2015, at 2:06 AM, David J Taylor <[email protected]> > wrote: > > Hi Tom dividing down wasn't always necessary I have sample from the UK GPO > Crystal Factory of NT-cut bars, quartz tuning fork, and Gapped Ring > crystals, the latter marked 400cps (pre Hertz :-)) ) I think these are > post WWII because they are mounted in IO base GT style tube envelopes. > Dividers were achieved with neons and locked multivibrators, where > necessary, I believe. > [] > Alan > G3NYK > ================================ > > I have one "500 c/s" GEC crystal in an octal base which is thinner than a "60 > Kc/s" one, so a different mode. Never had it working, though. > > 73, > David GM8ARV > -- > SatSignal Software - Quality software written to your requirements > Web: http://www.satsignal.eu > Email: [email protected] > _______________________________________________ > 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. _______________________________________________ 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.
