[time-nuts] Cesium Mechanical Chronometer
> > And now for something completely different: I am working on a quixotic > project to control a standard, detent-escapement marine chronometer (e.g., > Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this > makes no sense--but, then, we're timenuts. I want the mechanical > chronometer to function normally if the CSAC signal, presumably a 1pps > pulse, is lost. The CSAC will be GPS disciplined, so during normal > operation, with an operating GPS constellation, the time is referenced to > UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal > drives the chronometer; if all electronics are lost, the chronometer hangs > in as a mechanical chronometer. Has anyone any experience with > electrically controlling (or disciplining) a marine chronometer? > > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Historically they would have tracked any deviation between the chronometer and radio standards by updating the rate card, and only rarely adjusted the chronometer time or rate itself. I would suggest a more interesting project, is to monitor the ticking of the Chonometer vs your CSAC (possibly acoustically?) and prepare your own digital rate card. Tim N3QE On Thu, Jan 30, 2020 at 10:50 AM Tom Bales wrote: > > > > And now for something completely different: I am working on a quixotic > > project to control a standard, detent-escapement marine chronometer > (e.g., > > Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this > > makes no sense--but, then, we're timenuts. I want the mechanical > > chronometer to function normally if the CSAC signal, presumably a 1pps > > pulse, is lost. The CSAC will be GPS disciplined, so during normal > > operation, with an operating GPS constellation, the time is referenced to > > UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal > > drives the chronometer; if all electronics are lost, the chronometer > hangs > > in as a mechanical chronometer. Has anyone any experience with > > electrically controlling (or disciplining) a marine chronometer? > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Hi There’s not a lot of “room” inside the typical Hamilton chronometer. Simply getting an electronic drive gizmo inside (and wires out) would be a major task. Having it work properly with the drive coming and going ….wow …. The detent setup is a very fiddly bit in these devices. My *guess* is that a CSAC on a couple of batteries will run longer than the chronometer (before it needs to be wound). If auto winding is part of the mix, that gets even more into the … wow … region. Bob > On Jan 30, 2020, at 10:49 AM, Tom Bales wrote: > >> >> And now for something completely different: I am working on a quixotic >> project to control a standard, detent-escapement marine chronometer (e.g., >> Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this >> makes no sense--but, then, we're timenuts. I want the mechanical >> chronometer to function normally if the CSAC signal, presumably a 1pps >> pulse, is lost. The CSAC will be GPS disciplined, so during normal >> operation, with an operating GPS constellation, the time is referenced to >> UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal >> drives the chronometer; if all electronics are lost, the chronometer hangs >> in as a mechanical chronometer. Has anyone any experience with >> electrically controlling (or disciplining) a marine chronometer? >> >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Just a thought, as I have no experience with mechanical clocks. Couple your atomic clock 1pps signal to a mechanism that weakly mechanically couples to your chronometer spring-mass-escapement system in some way (assuming 1 tick per second natural frequency for your chronometer). Rely on the entrainment phenomenon to synchronize the mechanical clock to the electrical signal. Cheers! From: time-nuts on behalf of Tom Bales Sent: Thursday, January 30, 2020 4:49 PM To: time-nuts@lists.febo.com Subject: [time-nuts] Cesium Mechanical Chronometer > > And now for something completely different: I am working on a quixotic > project to control a standard, detent-escapement marine chronometer (e.g., > Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this > makes no sense--but, then, we're timenuts. I want the mechanical > chronometer to function normally if the CSAC signal, presumably a 1pps > pulse, is lost. The CSAC will be GPS disciplined, so during normal > operation, with an operating GPS constellation, the time is referenced to > UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal > drives the chronometer; if all electronics are lost, the chronometer hangs > in as a mechanical chronometer. Has anyone any experience with > electrically controlling (or disciplining) a marine chronometer? > > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
On 1/30/20 9:29 AM, Bob kb8tq wrote: Hi There’s not a lot of “room” inside the typical Hamilton chronometer. Simply getting an electronic drive gizmo inside (and wires out) would be a major task. Having it work properly with the drive coming and going ….wow …. The detent setup is a very fiddly bit in these devices. My *guess* is that a CSAC on a couple of batteries will run longer than the chronometer (before it needs to be wound). If auto winding is part of the mix, that gets even more into the … wow … region. winding without inducing vibrations that affect the rate of the clock? Although I assume Harrison designed for this? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
I don't know about older marine chronometers but modern ones tick much faster than 1 pps. Most are designed to tick 28800 pph, which is 8 ticks per second. One jump per second is pretty much a quartz watch thing. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Thursday, January 30, 2020, 12:44:49 PM EST, Bill Slade wrote: Just a thought, as I have no experience with mechanical clocks. Couple your atomic clock 1pps signal to a mechanism that weakly mechanically couples to your chronometer spring-mass-escapement system in some way (assuming 1 tick per second natural frequency for your chronometer). Rely on the entrainment phenomenon to synchronize the mechanical clock to the electrical signal. Cheers! From: time-nuts on behalf of Tom Bales Sent: Thursday, January 30, 2020 4:49 PM To: time-nuts@lists.febo.com Subject: [time-nuts] Cesium Mechanical Chronometer > > And now for something completely different: I am working on a quixotic > project to control a standard, detent-escapement marine chronometer (e.g., > Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this > makes no sense--but, then, we're timenuts. I want the mechanical > chronometer to function normally if the CSAC signal, presumably a 1pps > pulse, is lost. The CSAC will be GPS disciplined, so during normal > operation, with an operating GPS constellation, the time is referenced to > UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal > drives the chronometer; if all electronics are lost, the chronometer hangs > in as a mechanical chronometer. Has anyone any experience with > electrically controlling (or disciplining) a marine chronometer? > > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Hi > On Jan 30, 2020, at 1:31 PM, jimlux wrote: > > On 1/30/20 9:29 AM, Bob kb8tq wrote: >> Hi >> There’s not a lot of “room” inside the typical Hamilton chronometer. Simply >> getting >> an electronic drive gizmo inside (and wires out) would be a major task. >> Having it work >> properly with the drive coming and going ….wow …. The detent setup is a very >> fiddly >> bit in these devices. >> My *guess* is that a CSAC on a couple of batteries will run longer than the >> chronometer >> (before it needs to be wound). If auto winding is part of the mix, that gets >> even more into the >> … wow … region. > > winding without inducing vibrations that affect the rate of the clock? > Although I assume Harrison designed for this? …… and winding without damaging anything. Bob > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
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 On 1/30/2020 7:49 AM, Tom Bales wrote: And now for something completely different: I am working on a quixotic project to control a standard, detent-escapement marine chronometer (e.g., Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this makes no sense--but, then, we're timenuts. I want the mechanical chronometer to function normally if the CSAC signal, presumably a 1pps pulse, is lost. The CSAC will be GPS disciplined, so during normal operation, with an operating GPS constellation, the time is referenced to UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal drives the chronometer; if all electronics are lost, the chronometer hangs in as a mechanical chronometer. Has anyone any experience with electrically controlling (or disciplining) a marine chronometer? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Remember you ‘beat’ a clock using a audio amplifier and a standard signal there is a screw which adjusts the tension on the escapement spring, Now you could use a reduction drive to turn the screw or take direct control of the escapement spring using the mechanical ‘ticks’ of the escapement as the input to a control loop Content by Scott Typos by Siri > On Jan 30, 2020, at 7:05 PM, Tom Van Baak wrote: > 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 On 1/30/2020 7:49 AM, Tom Bales wrote: >> And now for something completely different: I am working on a quixotic >> project to control a standard, detent-escapement marine chronometer (e.g., >> Hamilton 21) with a CSAC cesium atomic clock module. Yes, I know this >> makes no sense--but, then, we're timenuts. I want the mechanical >> chronometer to function normally if the CSAC signal, presumably a 1pps >> pulse, is lost. The CSAC will be GPS disciplined, so during normal >> operation, with an operating GPS constellation, the time is referenced to >> UTC via GPS; if GPS is lost, then the CSAC takes over and its 1pps signal >> drives the chronometer; if all electronics are lost, the chronometer hangs >> in as a mechanical chronometer. Has anyone any experience with >> electrically controlling (or disciplining) a marine chronometer? >> >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
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, time-nuts-requ...@lists.febo.com wrote: Message: 7 Date: Thu, 30 Jan 2020 10:35:11 -0800 From: Tom Van Baak To:time-nuts@lists.febo.com Subject: Re: [time-nuts] Cesium Mechanical Chronometer Message-ID: 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 -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
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 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, time-nuts-requ...@lists.febo.com wrote: > > Message: 7 > > Date: Thu, 30 Jan 2020 10:35:11 -0800 > > From: Tom Van Baak > > To:time-nuts@lists.febo.com > > Subject: Re: [time-nuts] Cesium Mechanical Chronometer > > Message-ID: > > 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 -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
> > Many thanks for everyone's response on my cesium-synchronized mechanical > chronometer project. I'll keep the group informed of progress. Some > responses to your questions and suggestions: - My current plan is to use a chronometer that has been adjusted for rate and is close to dead-on. Of course, they're never dead-on, and that's why keeping track of the rate is important. I haven't dismissed the idea of actually disciplining the chrono from the CSAC, but since this chrono's rate adjustment involves screws on the balance wheel (it has a free-sprung helical balance spring without any means of adjustment), that would be a great challenge. Perhaps the best would be for the CSAC system to maintain a "rate card" of the chronometer, so that when all the electronics fail, and the user is left with only the chrono, at least they would have a really good knowledge of its rate and variation. Doing so would require a feedback signal from the chrono, which could be acoustic or photoelectric. The electronic rate card could be updated now and then by turning off the sync impulse to the chrono and listening for the ticks to move relative to the 1pps. - The chrono would need a bigger box in order to incorporate the CSAC/GPS system, microcontroller, and--the biggest part--backup batteries. That's part of the fun, and I'm thinking to mount the gimballed chrono in a purpose-built enclosure that will hold everything. Connections to the chrono will have to be very flexible FFC or silicone wire. - I thiink auto-winding is a definite requirement. The engineering challenge is to couple a small gearmotor to the winding system without disabling the manual-winding system that uses a ratcheted key. Winding noise should be short in duration, so it probably won't affect the time sync. People have wound chronos by turning them upside down in the gimbals and poking a key through a hole for a long time without any big issues. - Coupling to the chrono balance and escapement might be difficult, or it might be easy. If it takes hours or days to synchronize, that's OK, I think. My guess is that anything that generates a slight impulse in the direction of the escapement detent or a torque pulse to couple to the balance will work well enough--a tiny little linear or rotary electromagnetic actuator should work. We'll see. - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps signal will probably work fine. - The idea that TVB suggests of disciplining the CSAC to match the chrono is fascinating, indeed. Hadn't thought of that one. It would be the easiest way to keep the chrono and CSAC in sync, and it would still use the traditional rate-card method of keeping track of the actual time. H. - Yes, the CSAC modules are expensive! Over $5k currently. It seems like during the evaluation period the company sold them "at a discount" in order to build applications and sales (or so the court documents say). Let me know if anyone sees a gyneesium one on *bay. I thought long and hard before buying it, but idle hands are the devil's cash register. (Oh, oh!--now I have an excuse to buy an HP 53230!) In my initial measurements of rate (after GPS disciplining for 24 hours) the CSAC freewheels within 1.7ms/yr. Probably good enough. Needs longer testing. - The M21 has a single balance wheel consisting of an Invar spoke and a stainless steel ring (it was Hamilton's magical way of doing temperature compensation to match the balance spring. The Russian knock-offs have a standard bi-metal split balance wheel. The Hamiltons beat just about anything in performance. Besides, "Murica!". ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
Hi If the idea is to generate a rate card and keep it up to date ….. I think that can be done with just the GPS. The CSAC really does not add a lot that I can see to that case. Of course I may have (yet again) missed something …. == The very standard / “old school” approach for this is a microphone on the case of the M21. These days feed the mic preamp output into a cheap micro along with the GPS info and away you go. Spit the results out to a little OLED display maybe ….. Bob > On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: > >> >> Many thanks for everyone's response on my cesium-synchronized mechanical >> chronometer project. I'll keep the group informed of progress. Some >> responses to your questions and suggestions: > > > - My current plan is to use a chronometer that has been adjusted for > rate and is close to dead-on. Of course, they're never dead-on, and that's > why keeping track of the rate is important. I haven't dismissed the idea > of actually disciplining the chrono from the CSAC, but since this chrono's > rate adjustment involves screws on the balance wheel (it has a free-sprung > helical balance spring without any means of adjustment), that would be a > great challenge. Perhaps the best would be for the CSAC system to maintain > a "rate card" of the chronometer, so that when all the electronics fail, > and the user is left with only the chrono, at least they would have a > really good knowledge of its rate and variation. Doing so would require a > feedback signal from the chrono, which could be acoustic or photoelectric. > The electronic rate card could be updated now and then by turning off the > sync impulse to the chrono and listening for the ticks to move relative to > the 1pps. > - The chrono would need a bigger box in order to incorporate the > CSAC/GPS system, microcontroller, and--the biggest part--backup batteries. > That's part of the fun, and I'm thinking to mount the gimballed chrono in a > purpose-built enclosure that will hold everything. Connections to the > chrono will have to be very flexible FFC or silicone wire. > - I thiink auto-winding is a definite requirement. The engineering > challenge is to couple a small gearmotor to the winding system without > disabling the manual-winding system that uses a ratcheted key. Winding > noise should be short in duration, so it probably won't affect the time > sync. People have wound chronos by turning them upside down in the gimbals > and poking a key through a hole for a long time without any big issues. > - Coupling to the chrono balance and escapement might be difficult, or > it might be easy. If it takes hours or days to synchronize, that's OK, I > think. My guess is that anything that generates a slight impulse in the > direction of the escapement detent or a torque pulse to couple to the > balance will work well enough--a tiny little linear or rotary > electromagnetic actuator should work. We'll see. > - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps signal > will probably work fine. > - The idea that TVB suggests of disciplining the CSAC to match the > chrono is fascinating, indeed. Hadn't thought of that one. It would be > the easiest way to keep the chrono and CSAC in sync, and it would still use > the traditional rate-card method of keeping track of the actual time. > H. > - Yes, the CSAC modules are expensive! Over $5k currently. It seems > like during the evaluation period the company sold them "at a discount" in > order to build applications and sales (or so the court documents say). Let > me know if anyone sees a gyneesium one on *bay. I thought long and hard > before buying it, but idle hands are the devil's cash register. (Oh, > oh!--now I have an excuse to buy an HP 53230!) In my initial measurements > of rate (after GPS disciplining for 24 hours) the CSAC freewheels within > 1.7ms/yr. Probably good enough. Needs longer testing. > - The M21 has a single balance wheel consisting of an Invar spoke and a > stainless steel ring (it was Hamilton's magical way of doing temperature > compensation to match the balance spring. The Russian knock-offs have a > standard bi-metal split balance wheel. The Hamiltons beat just about > anything in performance. Besides, "Murica!". > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Cesium Mechanical Chronometer
I'm wondering about the balance wheel, if it's ferromagnetic (has iron or steel in it, which would probably make this idea not work), or if it's perhaps all aluminum or similar non-magnetic material. Adding a constant magnetic field from a coil and electric current source would provide a magnetic induction-induced drag on the balance wheel and slow it down (hopefully not so much that it stops). Setting the chronometer to normally run slightly fast would allow it to be slowed down and regulated by the strength of the magnetic field on the balance wheel. On Sat, Feb 1, 2020 at 3:06 PM Bob kb8tq wrote: > > Hi > > If the idea is to generate a rate card and keep it up to date ….. I think that > can be done with just the GPS. The CSAC really does not add a lot that > I can see to that case. > > Of course I may have (yet again) missed something …. > > == > > The very standard / “old school” approach for this is a microphone on the > case > of the M21. These days feed the mic preamp output into a cheap micro along > with the GPS info and away you go. Spit the results out to a little OLED > display > maybe ….. > > Bob > > > On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: > > > >> > >> Many thanks for everyone's response on my cesium-synchronized mechanical > >> chronometer project. I'll keep the group informed of progress. Some > >> responses to your questions and suggestions: > > > > > > - My current plan is to use a chronometer that has been adjusted for > > rate and is close to dead-on. Of course, they're never dead-on, and > > that's > > why keeping track of the rate is important. I haven't dismissed the idea > > of actually disciplining the chrono from the CSAC, but since this chrono's > > rate adjustment involves screws on the balance wheel (it has a free-sprung > > helical balance spring without any means of adjustment), that would be a > > great challenge. Perhaps the best would be for the CSAC system to > > maintain > > a "rate card" of the chronometer, so that when all the electronics fail, > > and the user is left with only the chrono, at least they would have a > > really good knowledge of its rate and variation. Doing so would require a > > feedback signal from the chrono, which could be acoustic or photoelectric. > > The electronic rate card could be updated now and then by turning off the > > sync impulse to the chrono and listening for the ticks to move relative to > > the 1pps. > > - The chrono would need a bigger box in order to incorporate the > > CSAC/GPS system, microcontroller, and--the biggest part--backup batteries. > > That's part of the fun, and I'm thinking to mount the gimballed chrono in > > a > > purpose-built enclosure that will hold everything. Connections to the > > chrono will have to be very flexible FFC or silicone wire. > > - I thiink auto-winding is a definite requirement. The engineering > > challenge is to couple a small gearmotor to the winding system without > > disabling the manual-winding system that uses a ratcheted key. Winding > > noise should be short in duration, so it probably won't affect the time > > sync. People have wound chronos by turning them upside down in the > > gimbals > > and poking a key through a hole for a long time without any big issues. > > - Coupling to the chrono balance and escapement might be difficult, or > > it might be easy. If it takes hours or days to synchronize, that's OK, I > > think. My guess is that anything that generates a slight impulse in the > > direction of the escapement detent or a torque pulse to couple to the > > balance will work well enough--a tiny little linear or rotary > > electromagnetic actuator should work. We'll see. > > - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps signal > > will probably work fine. > > - The idea that TVB suggests of disciplining the CSAC to match the > > chrono is fascinating, indeed. Hadn't thought of that one. It would be > > the easiest way to keep the chrono and CSAC in sync, and it would still > > use > > the traditional rate-card method of keeping track of the actual time. > > H. > > - Yes, the CSAC modules are expensive! Over $5k currently. It seems > > like during the evaluation period the company sold them "at a discount" in > > order to build applications and sales (or so the court documents say). > > Let > > me know if anyone sees a gyneesium one on *bay. I thought long and hard > > before buying it, but idle hands are the devil's cash register. (Oh, > > oh!--now I have an excuse to buy an HP 53230!) In my initial measurements > > of rate (after GPS disciplining for 24 hours) the CSAC freewheels within > > 1.7ms/yr. Probably good enough. Needs longer testing. > > - The M21 has a single balance wheel consisting of an Invar spoke and a > > stainless steel ring (it was Hamilton's magical way of doing temperature > > compensation
Re: [time-nuts] Cesium Mechanical Chronometer
Hi Keep in mind that these particular chronometers were designed (as best as was possible) to be impervious to outside influences. Mag fields, rocking back and forth, orientation changes all should have whatever the lowest impact you could make them have. Bob > On Feb 1, 2020, at 9:58 PM, Ben Bradley wrote: > > I'm wondering about the balance wheel, if it's ferromagnetic (has iron > or steel in it, which would probably make this idea not work), or if > it's perhaps all aluminum or similar non-magnetic material. Adding a > constant magnetic field from a coil and electric current source would > provide a magnetic induction-induced drag on the balance wheel and > slow it down (hopefully not so much that it stops). Setting the > chronometer to normally run slightly fast would allow it to be slowed > down and regulated by the strength of the magnetic field on the > balance wheel. > > On Sat, Feb 1, 2020 at 3:06 PM Bob kb8tq wrote: >> >> Hi >> >> If the idea is to generate a rate card and keep it up to date ….. I think >> that >> can be done with just the GPS. The CSAC really does not add a lot that >> I can see to that case. >> >> Of course I may have (yet again) missed something …. >> >> == >> >> The very standard / “old school” approach for this is a microphone on the >> case >> of the M21. These days feed the mic preamp output into a cheap micro along >> with the GPS info and away you go. Spit the results out to a little OLED >> display >> maybe ….. >> >> Bob >> >>> On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: >>> Many thanks for everyone's response on my cesium-synchronized mechanical chronometer project. I'll keep the group informed of progress. Some responses to your questions and suggestions: >>> >>> >>> - My current plan is to use a chronometer that has been adjusted for >>> rate and is close to dead-on. Of course, they're never dead-on, and that's >>> why keeping track of the rate is important. I haven't dismissed the idea >>> of actually disciplining the chrono from the CSAC, but since this chrono's >>> rate adjustment involves screws on the balance wheel (it has a free-sprung >>> helical balance spring without any means of adjustment), that would be a >>> great challenge. Perhaps the best would be for the CSAC system to maintain >>> a "rate card" of the chronometer, so that when all the electronics fail, >>> and the user is left with only the chrono, at least they would have a >>> really good knowledge of its rate and variation. Doing so would require a >>> feedback signal from the chrono, which could be acoustic or photoelectric. >>> The electronic rate card could be updated now and then by turning off the >>> sync impulse to the chrono and listening for the ticks to move relative to >>> the 1pps. >>> - The chrono would need a bigger box in order to incorporate the >>> CSAC/GPS system, microcontroller, and--the biggest part--backup batteries. >>> That's part of the fun, and I'm thinking to mount the gimballed chrono in a >>> purpose-built enclosure that will hold everything. Connections to the >>> chrono will have to be very flexible FFC or silicone wire. >>> - I thiink auto-winding is a definite requirement. The engineering >>> challenge is to couple a small gearmotor to the winding system without >>> disabling the manual-winding system that uses a ratcheted key. Winding >>> noise should be short in duration, so it probably won't affect the time >>> sync. People have wound chronos by turning them upside down in the gimbals >>> and poking a key through a hole for a long time without any big issues. >>> - Coupling to the chrono balance and escapement might be difficult, or >>> it might be easy. If it takes hours or days to synchronize, that's OK, I >>> think. My guess is that anything that generates a slight impulse in the >>> direction of the escapement detent or a torque pulse to couple to the >>> balance will work well enough--a tiny little linear or rotary >>> electromagnetic actuator should work. We'll see. >>> - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps signal >>> will probably work fine. >>> - The idea that TVB suggests of disciplining the CSAC to match the >>> chrono is fascinating, indeed. Hadn't thought of that one. It would be >>> the easiest way to keep the chrono and CSAC in sync, and it would still use >>> the traditional rate-card method of keeping track of the actual time. >>> H. >>> - Yes, the CSAC modules are expensive! Over $5k currently. It seems >>> like during the evaluation period the company sold them "at a discount" in >>> order to build applications and sales (or so the court documents say). Let >>> me know if anyone sees a gyneesium one on *bay. I thought long and hard >>> before buying it, but idle hands are the devil's cash register. (Oh, >>> oh!--now I have an excuse to buy an HP 53230!) In my initial measurements >>> of rate (afte
Re: [time-nuts] Cesium Mechanical Chronometer
I understand, though I was thinking a small coil could be placed inside the case near the balance wheel. Worst case it seems fully reversible (depending on mounting the coil and a small hole for the wires to come out) and worth a try. On Sat, Feb 1, 2020 at 10:31 PM Bob kb8tq wrote: > > Hi > > Keep in mind that these particular chronometers were designed (as best as > was possible) to be impervious to outside influences. Mag fields, rocking back > and forth, orientation changes all should have whatever the lowest impact you > could make them have. > > Bob > > > On Feb 1, 2020, at 9:58 PM, Ben Bradley wrote: > > > > I'm wondering about the balance wheel, if it's ferromagnetic (has iron > > or steel in it, which would probably make this idea not work), or if > > it's perhaps all aluminum or similar non-magnetic material. Adding a > > constant magnetic field from a coil and electric current source would > > provide a magnetic induction-induced drag on the balance wheel and > > slow it down (hopefully not so much that it stops). Setting the > > chronometer to normally run slightly fast would allow it to be slowed > > down and regulated by the strength of the magnetic field on the > > balance wheel. > > > > On Sat, Feb 1, 2020 at 3:06 PM Bob kb8tq wrote: > >> > >> Hi > >> > >> If the idea is to generate a rate card and keep it up to date ….. I think > >> that > >> can be done with just the GPS. The CSAC really does not add a lot that > >> I can see to that case. > >> > >> Of course I may have (yet again) missed something …. > >> > >> == > >> > >> The very standard / “old school” approach for this is a microphone on the > >> case > >> of the M21. These days feed the mic preamp output into a cheap micro along > >> with the GPS info and away you go. Spit the results out to a little OLED > >> display > >> maybe ….. > >> > >> Bob > >> > >>> On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: > >>> > > Many thanks for everyone's response on my cesium-synchronized mechanical > chronometer project. I'll keep the group informed of progress. Some > responses to your questions and suggestions: > >>> > >>> > >>> - My current plan is to use a chronometer that has been adjusted for > >>> rate and is close to dead-on. Of course, they're never dead-on, and > >>> that's > >>> why keeping track of the rate is important. I haven't dismissed the idea > >>> of actually disciplining the chrono from the CSAC, but since this > >>> chrono's > >>> rate adjustment involves screws on the balance wheel (it has a > >>> free-sprung > >>> helical balance spring without any means of adjustment), that would be a > >>> great challenge. Perhaps the best would be for the CSAC system to > >>> maintain > >>> a "rate card" of the chronometer, so that when all the electronics fail, > >>> and the user is left with only the chrono, at least they would have a > >>> really good knowledge of its rate and variation. Doing so would require > >>> a > >>> feedback signal from the chrono, which could be acoustic or > >>> photoelectric. > >>> The electronic rate card could be updated now and then by turning off the > >>> sync impulse to the chrono and listening for the ticks to move relative > >>> to > >>> the 1pps. > >>> - The chrono would need a bigger box in order to incorporate the > >>> CSAC/GPS system, microcontroller, and--the biggest part--backup > >>> batteries. > >>> That's part of the fun, and I'm thinking to mount the gimballed chrono > >>> in a > >>> purpose-built enclosure that will hold everything. Connections to the > >>> chrono will have to be very flexible FFC or silicone wire. > >>> - I thiink auto-winding is a definite requirement. The engineering > >>> challenge is to couple a small gearmotor to the winding system without > >>> disabling the manual-winding system that uses a ratcheted key. Winding > >>> noise should be short in duration, so it probably won't affect the time > >>> sync. People have wound chronos by turning them upside down in the > >>> gimbals > >>> and poking a key through a hole for a long time without any big issues. > >>> - Coupling to the chrono balance and escapement might be difficult, or > >>> it might be easy. If it takes hours or days to synchronize, that's OK, I > >>> think. My guess is that anything that generates a slight impulse in the > >>> direction of the escapement detent or a torque pulse to couple to the > >>> balance will work well enough--a tiny little linear or rotary > >>> electromagnetic actuator should work. We'll see. > >>> - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps signal > >>> will probably work fine. > >>> - The idea that TVB suggests of disciplining the CSAC to match the > >>> chrono is fascinating, indeed. Hadn't thought of that one. It would be > >>> the easiest way to keep the chrono and CSAC in sync, and it would still > >>> use > >>> the traditional rate-card method of keeping
Re: [time-nuts] Cesium Mechanical Chronometer
I used to collect old watches. Most mechanical parts are made of brass, and rest of it are some type of steel (including stainless) Getting any part of it magnetized is a major issue in mechanical watches. Undoing the change may include demagnetizing the whole watch, which a watch maker can do. Typically, a marine chronometers are mounted on a rotatable mount, so that the face of it will always face up. When tuning a watch, a watch maker does it face up, face down, right side up, right side down, etc, etc, etc. The oscillation rate of the balance wheel will change depending on orientation. Some VERY expensive mechanical watches has a part called tourbillon to compensate it. Assuming the clock does not have it, (and M21 does not, as far as I know) and if it can be WELL characterized, perhaps this tendency can be used to synchronize it with an external source. About winding, winder for mechanical (and not automatic) watches do exist. They attach to the crown (of the watch) and rotates it. There is a timer and slip mechanism to prevent over-winding. Typically, a crown of an automatic (self-winding) watches free spin with a clicking sound, and plain mechanical watches just stop, and won't let you wind any further. I have never seen a mechanism to wind key type winding mechanism. By the way I have a railroad watch that is well over 100 years old. It keeps +/- 1 second per day. Amazing feat using purely mechanical parts. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Saturday, February 1, 2020, 10:40:14 PM EST, Ben Bradley wrote: I understand, though I was thinking a small coil could be placed inside the case near the balance wheel. Worst case it seems fully reversible (depending on mounting the coil and a small hole for the wires to come out) and worth a try. On Sat, Feb 1, 2020 at 10:31 PM Bob kb8tq wrote: > > Hi > > Keep in mind that these particular chronometers were designed (as best as > was possible) to be impervious to outside influences. Mag fields, rocking back > and forth, orientation changes all should have whatever the lowest impact you > could make them have. > > Bob > > > On Feb 1, 2020, at 9:58 PM, Ben Bradley wrote: > > > > I'm wondering about the balance wheel, if it's ferromagnetic (has iron > > or steel in it, which would probably make this idea not work), or if > > it's perhaps all aluminum or similar non-magnetic material. Adding a > > constant magnetic field from a coil and electric current source would > > provide a magnetic induction-induced drag on the balance wheel and > > slow it down (hopefully not so much that it stops). Setting the > > chronometer to normally run slightly fast would allow it to be slowed > > down and regulated by the strength of the magnetic field on the > > balance wheel. > > > > On Sat, Feb 1, 2020 at 3:06 PM Bob kb8tq wrote: > >> > >> Hi > >> > >> If the idea is to generate a rate card and keep it up to date ….. I think > >> that > >> can be done with just the GPS. The CSAC really does not add a lot that > >> I can see to that case. > >> > >> Of course I may have (yet again) missed something …. > >> > >> == > >> > >> The very standard / “old school” approach for this is a microphone on the > >> case > >> of the M21. These days feed the mic preamp output into a cheap micro along > >> with the GPS info and away you go. Spit the results out to a little OLED > >> display > >> maybe ….. > >> > >> Bob > >> > >>> On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: > >>> > > Many thanks for everyone's response on my cesium-synchronized mechanical > chronometer project. I'll keep the group informed of progress. Some > responses to your questions and suggestions: > >>> > >>> > >>> - My current plan is to use a chronometer that has been adjusted for > >>> rate and is close to dead-on. Of course, they're never dead-on, and > >>>that's > >>> why keeping track of the rate is important. I haven't dismissed the idea > >>> of actually disciplining the chrono from the CSAC, but since this > >>>chrono's > >>> rate adjustment involves screws on the balance wheel (it has a > >>>free-sprung > >>> helical balance spring without any means of adjustment), that would be a > >>> great challenge. Perhaps the best would be for the CSAC system to > >>>maintain > >>> a "rate card" of the chronometer, so that when all the electronics fail, > >>> and the user is left with only the chrono, at least they would have a > >>> really good knowledge of its rate and variation. Doing so would require > >>>a > >>> feedback signal from the chrono, which could be acoustic or > >>>photoelectric. > >>> The electronic rate card could be updated now and then by turning off the > >>> sync impulse to the chrono and listening for the ticks to move relative > >>>to > >>> the 1pps. > >>> - The chrono would need a bigger box in order to incorporate the > >>> CSAC/GPS system, mi
Re: [time-nuts] Cesium Mechanical Chronometer
I believe that attempting to tune any resonator by damping (Q-spoiling) said resonator by adding drag would be a mistake. It would not likely be very effective at tuning, and has great potential for degrading the frequency stability. Hence my preference for injection locking by rocking about an axis parallel to the balance wheel's axis of rotation. If there's only a single balance wheel, the watch should be responsive to this motion regardless of claims to the contrary. For several years I've had grandiose notions of locking a grandfather clock to a stable external reference, but think it will be a tougher nut to crack subject to constraints against modifying it at all. Perhaps mounting it on a motor-driven horizontal translator? Dana On Sat, Feb 1, 2020 at 8:59 PM Ben Bradley wrote: > I'm wondering about the balance wheel, if it's ferromagnetic (has iron > or steel in it, which would probably make this idea not work), or if > it's perhaps all aluminum or similar non-magnetic material. Adding a > constant magnetic field from a coil and electric current source would > provide a magnetic induction-induced drag on the balance wheel and > slow it down (hopefully not so much that it stops). Setting the > chronometer to normally run slightly fast would allow it to be slowed > down and regulated by the strength of the magnetic field on the > balance wheel. > > On Sat, Feb 1, 2020 at 3:06 PM Bob kb8tq wrote: > > > > Hi > > > > If the idea is to generate a rate card and keep it up to date ….. I > think that > > can be done with just the GPS. The CSAC really does not add a lot that > > I can see to that case. > > > > Of course I may have (yet again) missed something …. > > > > == > > > > The very standard / “old school” approach for this is a microphone on > the case > > of the M21. These days feed the mic preamp output into a cheap micro > along > > with the GPS info and away you go. Spit the results out to a little > OLED display > > maybe ….. > > > > Bob > > > > > On Feb 1, 2020, at 1:39 PM, Tom Bales wrote: > > > > > >> > > >> Many thanks for everyone's response on my cesium-synchronized > mechanical > > >> chronometer project. I'll keep the group informed of progress. Some > > >> responses to your questions and suggestions: > > > > > > > > > - My current plan is to use a chronometer that has been adjusted for > > > rate and is close to dead-on. Of course, they're never dead-on, and > that's > > > why keeping track of the rate is important. I haven't dismissed the > idea > > > of actually disciplining the chrono from the CSAC, but since this > chrono's > > > rate adjustment involves screws on the balance wheel (it has a > free-sprung > > > helical balance spring without any means of adjustment), that would > be a > > > great challenge. Perhaps the best would be for the CSAC system to > maintain > > > a "rate card" of the chronometer, so that when all the electronics > fail, > > > and the user is left with only the chrono, at least they would have a > > > really good knowledge of its rate and variation. Doing so would > require a > > > feedback signal from the chrono, which could be acoustic or > photoelectric. > > > The electronic rate card could be updated now and then by turning > off the > > > sync impulse to the chrono and listening for the ticks to move > relative to > > > the 1pps. > > > - The chrono would need a bigger box in order to incorporate the > > > CSAC/GPS system, microcontroller, and--the biggest part--backup > batteries. > > > That's part of the fun, and I'm thinking to mount the gimballed > chrono in a > > > purpose-built enclosure that will hold everything. Connections to > the > > > chrono will have to be very flexible FFC or silicone wire. > > > - I thiink auto-winding is a definite requirement. The engineering > > > challenge is to couple a small gearmotor to the winding system > without > > > disabling the manual-winding system that uses a ratcheted key. > Winding > > > noise should be short in duration, so it probably won't affect the > time > > > sync. People have wound chronos by turning them upside down in the > gimbals > > > and poking a key through a hole for a long time without any big > issues. > > > - Coupling to the chrono balance and escapement might be difficult, > or > > > it might be easy. If it takes hours or days to synchronize, that's > OK, I > > > think. My guess is that anything that generates a slight impulse in > the > > > direction of the escapement detent or a torque pulse to couple to the > > > balance will work well enough--a tiny little linear or rotary > > > electromagnetic actuator should work. We'll see. > > > - The Hamilton M21 chrono beats at 2Hz, so driving it with a 1pps > signal > > > will probably work fine. > > > - The idea that TVB suggests of disciplining the CSAC to match the > > > chrono is fascinating, indeed. Hadn't thought of that one. It > wou
Re: [time-nuts] Cesium Mechanical Chronometer
k8yumdoo...@gmail.com said: > For several years I've had grandiose notions of locking a grandfather clock > to a stable external reference, but think it will be a tougher nut to crack > subject to constraints against modifying it at all. Perhaps mounting it on a > motor-driven horizontal translator? If it's a good clock, you probably don't have to move it very far. You could also tilt it. It would be neat to measure how far you can pull a clock with a given amplitude displacement. There are many good videos on YouTube showing injection locking of metronomes. The simplest is to put them on a light weight board sitting on a pair of empty soda/beer cans. You can easily see them rocking back and forth. The other approach to mounting is to suspend the support board on strings. It would be neat to do something similar with grandfather clocks. Lomis had 3 Shortt clocks mounted on bedrock. They would get synchronized unless they were facing at 120 degrees to eachother. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
