Some years ago, before we had locked LOs for transverters, the Am. Microwave community used clip-on crystal heaters. These were a PTC thermistor with a turnover around 35 - 40C. They were usually used on 5th or 7th overtone crystals around 100MHz designed for 20C operation, so weren't ideal, but could maintain a crystal more on frequency that just open to the the air temp. Perhaps used on a watch crystal thay would work more effectively.
Not sure where you'd get them from now, though. Andy www.g4jnt.com On Fri, 26 Nov 2021 at 16:46, David G. McGaw <david.g.mc...@dartmouth.edu> wrote: > But not in a chronometer. They usually use something in the MHz range. > > 32kHz crystals are not very stable over temperature. Watches rely on > you wearing it for much of the day, keeping it at a nearly constant > temperature and putting it on your bed stand at night, also presumably > fairly constant. Unfortunately they have been adopted for computer Real > Time Clocks, which is why most computers do not keep very good time. > > David N1HAC > > On 11/26/21 9:14 AM, Scott McGrath wrote: > > Usually in analog quartz clocks oscillator frequency is around 32khz > > > > Content by Scott > > Typos by Siri > > > > On Nov 26, 2021, at 9:09 AM, Peter Torry via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > Hello list, > > > > I am restoring a Seiko Quartz QM10 Marine Chronometer that is currently > inoperative. Preliminary investigations would indicate that the oscillator > (TO5 header) isn't functioning therefore I am seeking any information as to > its nominal frequency and whether it is just a crystal or an oscillator. I > can follow the cmos dividers OK but a schematic diagram would be most > useful. > > > > Any help or pointers much appreciated. > > > > Kind regards > > > > Peter UK > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-le...@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-le...@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.