I've been looking at M21 photos, trying to decide if it has a single balance wheel, or a pair of contra-rotating balance wheels. I just can't tell.
If it's a single wheel, then gently rocking the M21 movement about an axis parallel to that of the balance wheel seems like it could be a viable way to injection lock the M21 to an external standard. This should require no modification of the M21 in any way. And if done in a thoughtful way the M21 could probably even be wound in-situ. Dana K8YUM On Fri, Jan 31, 2020 at 11:51 AM Dan Kemppainen <[email protected]> wrote: > Hi, > > I agree with tom, winding may be an issue. > > If that could be overcome, would it be possible to injection lock the > clock with a piezo or other small mechanical actuator? Something mounted > to the clock body that 'pings' it periodically may all that's needed to > pull it where you want it to go. > > One would think it would be nice to do this project without having to > modify the clock significantly, or risk damaging it. > > If you do succeed I'd be interested in reading the results. A fun > project, in my opinion. > > Dan > > > > > On 1/30/2020 3:18 PM, [email protected] wrote: > > Message: 7 > > Date: Thu, 30 Jan 2020 10:35:11 -0800 > > From: Tom Van Baak<[email protected]> > > To:[email protected] > > Subject: Re: [time-nuts] Cesium Mechanical Chronometer > > Message-ID:<[email protected]> > > Content-Type: text/plain; charset=utf-8; format=flowed > > > > That would be a fun project. There are examples of measuring a M21 on > > Bryan's site: > > > > https://www.bmumford.com/mset/tech/chrono/ > > > > Here are phase and ADEV plots for my M21: > > > > http://leapsecond.com/pages/m21/ > > > > That page also shows you a typical chronometer rate card, which provides > > the key "paper clock" advantage over using the clock dial alone. > > > > I use a piezo pickup to extract timing pulses from the clock. The audio > > waveform isn't pretty but you can form a low jitter 1PPS out of it. > > Laser sensors give a cleaner signal but are more difficult to use with > > an M21. > > > > Running a GPS/CSAC + M21 in a master/slave arrangement should be easy, > > although I don't know how you'll handle the rate card corrections. > > > > Running them in phase lock will be much harder. You can probably > > discipline the CSAC from the M21 using RS232 commands to the CSAC. But > > to discipline the M21 from the CSAC requires that you have a way to > > dynamically adjust the rate of the M21 at ppm levels. That's going to be > > tricky, given that high-end compensated chronometers like this are > > specifically designed to be as immune to internal and external changes > > as possible. One avenue may be the winding interval: notice the slopes > > of the phase plot. > > > > The biggest problem I had with long-term data collection was re-winding > > the chronometer. If you design a non-invasive auto-winder as part of > > your project, please contact me. > > > > /tvb > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
