Hi > On Jan 19, 2017, at 2:42 PM, Bryan _ <[email protected]> wrote: > > Wouldn't designing circuitry and PCB's be easier with 10Mhz vs 100Mhz? Maybe > not so much now but then.
Design in general might be a bit easier at the lower frequency “way back when”. I’ve never run into it as an issue or consideration since the mid 1960’s though. Bob > > > -=Bryan=- > > > ________________________________ > From: time-nuts <[email protected]> on behalf of Charles Steinmetz > <[email protected]> > Sent: January 19, 2017 4:13 AM > To: [email protected] > Subject: Re: [time-nuts] 10MHz to 25MHz > > Chris wrote: > >> I have always wondered why we build our "standard" with such a low >> frequency. Why not a 100MHz GPSDO? Why 10MHz > > Quartz crystals work better at lower frequencies, predominantly because > they have higher Q. 10MHz was chosen because it is low enough for > excellent performance but high enough to be directly useful (since an > accident of biology gave us ten fingers, we've created a base-10 world > and powers of 10 are favored in almost everything). > > In prior times, 5MHz crystals held this position, and before that, 1MHz. > There is a good argument even today that the best 2.5MHz or 5MHz > crystals are better than the best 10MHz crystals, but not by enough to > make 2.5MHz or 5MHz standards popular any longer. > > One lonely data point, which proves nothing: My best crystal oscillator > is a Symmetricom clone of the double-oven HP 10811s (it came out of an > HP GPSDO, so apparently HP at one time used them interchangeably with > the 10811). That OCXO uses a 5MHz crystal and a frequency doubler to > produce its 10MHz output. > > Best Regards, > > Charles > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > time-nuts Info Page - American Febo > Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > www.febo.com > time-nuts is a low volume, high SNR list for the discussion of precise time > and frequency measurement and related topics. To see the collection of prior > postings to ... > > > > 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. _______________________________________________ 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.
