Re: [time-nuts] time-nuts Digest, Vol 186, Issue 41 Double Oven
Interesting project. Would a CSAC actually fit? Last I heard these are ridiculously expen$ive (£1000+) assuming you can get one. They are also restricted in some countries it seems. -Andre -- Message: 1 Date: Thu, 30 Jan 2020 12:29:56 -0500 From: Bob kb8tq To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Cesium Mechanical Chronometer Message-ID: Content-Type: text/plain; charset=utf-8 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 End of time-nuts Digest, Vol 186, Issue 41 ** ___ 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] PCB layout question for GPSDO
Hi Tobias, IT drop should have been IR drop. --mike On Fri, Jan 31, 2020 at 7:14 AM Mike Ingle wrote: > Hi Tobias, > > I agree with Tom, that I also like PTC fuses, but don't forget that they > have a sometimes significant IT drop. Been there, been burned. > > --mike > > > On Fri, Jan 31, 2020 at 3:36 AM tom burkart wrote: > >> Hi Tobias, >> additional answers below: >> >> Quoting Tobias Pluess : >> >> > a) is it acceptable to route some signals under the GPS module? As >> > one can see, the signals I have routed under the GPS module go to >> > the front panel interface, i.e. they are not highspeed signals or >> > so, but I still wonder whether you experts would worry about it >> > (like "oh no, routing anything near the GPS module will disturb it >> > and decreases its sensitivity" or something). >> This violates constraints as set out in the Ublox hardware integration >> manual. >> >> > b) would you worry about the switching regulators? I know linear >> > would be better, but the professional GPSDOs also have switchers, >> > and besides that a linear regulator would not be so nice because my >> > power supply will be at least 15 volts. >> I would, but it can be dealt with. >> >> > c) is the usage of a RS232 chip a good idea or would you kick that >> > out because they produce such massive amounts of EMI that it will >> > disturb my GPS module or OCXO? >> Keeping it away from sensitive circuits will probably suffice. >> >> > d) is it a wise idea to use an LC filter for the OCXO power supply, >> > or does this lead to another rabbit hole because the inductors will >> > pick up magnetic fields (50 Hz...) and modulate the OCXO? >> All depends whether you will bath the whole thing in 50Hz stray >> magnetic fields. ;-) >> >> > e) anything else important I forgot? >> - Please double check your wiring of the GPS module it looks back to >> front. >> - In some places your ground layer is severely broken up to reduce its >> effectiveness. >> - Your antenna seems very close to the 1pps output and has traces >> underneath it >> - I quite like resettable PTC fuses (no need to replace) >> >> Tom >> >> >> >> ___ >> 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] PCB layout question for GPSDO
Hi Tobias, I agree with Tom, that I also like PTC fuses, but don't forget that they have a sometimes significant IT drop. Been there, been burned. --mike On Fri, Jan 31, 2020 at 3:36 AM tom burkart wrote: > Hi Tobias, > additional answers below: > > Quoting Tobias Pluess : > > > a) is it acceptable to route some signals under the GPS module? As > > one can see, the signals I have routed under the GPS module go to > > the front panel interface, i.e. they are not highspeed signals or > > so, but I still wonder whether you experts would worry about it > > (like "oh no, routing anything near the GPS module will disturb it > > and decreases its sensitivity" or something). > This violates constraints as set out in the Ublox hardware integration > manual. > > > b) would you worry about the switching regulators? I know linear > > would be better, but the professional GPSDOs also have switchers, > > and besides that a linear regulator would not be so nice because my > > power supply will be at least 15 volts. > I would, but it can be dealt with. > > > c) is the usage of a RS232 chip a good idea or would you kick that > > out because they produce such massive amounts of EMI that it will > > disturb my GPS module or OCXO? > Keeping it away from sensitive circuits will probably suffice. > > > d) is it a wise idea to use an LC filter for the OCXO power supply, > > or does this lead to another rabbit hole because the inductors will > > pick up magnetic fields (50 Hz...) and modulate the OCXO? > All depends whether you will bath the whole thing in 50Hz stray > magnetic fields. ;-) > > > e) anything else important I forgot? > - Please double check your wiring of the GPS module it looks back to front. > - In some places your ground layer is severely broken up to reduce its > effectiveness. > - Your antenna seems very close to the 1pps output and has traces > underneath it > - I quite like resettable PTC fuses (no need to replace) > > Tom > > > > ___ > 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] digital pots Part 2
Helipots are wonderful, old-school parts that are hard to beat - except for being quite expensive (but, they always were, relatively). As others have mentioned, there are many advantages of these over digital ones, for manually-adjusted functions. I would never use anything but a wirewound pot for manual fine tuning of LF/DC high precision circuits. For me, it's a no-brainer though, since I have lots and lots of helipots and WW trimmers, salvaged over many years. They are expensive new, but it seems to me there should be plenty of salvaged or NOS for much less. If you just need an adjustment, it's pretty straightforward, with a spinning knob. If you want some sort of indicator, then also consider available dials, which can show show relative rotation to ten to twenty turns or so, with drum or clock-type readout, or even mechanical-digital (odometer style), and other variations - some dials may cost more than the pot. I think the typical, most common and useful resistance value for helipots is around 5-50 k. As you go down in resistance, the mechanical resolution gets worse, because bigger manganin wire is needed to form the resistor. As you go up in resistance (I think around 100-500 k is typically the highest available), the resolution gets better, but the net source resistance of the wiper and noise go up. Another option may be to use WW multi-turn trimmer pots, if the adjustment needed is more like an occasional tweak with a screwdriver rather than a knob or dial. These are available up to twenty turns or so, and can be in board- or panel-mount styles. They likely are a lot cheaper than full-sized pots, but with lesser performance TC and power rating. Ed ___ 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] PCB layout question for GPSDO
Hi Tobias, additional answers below: Quoting Tobias Pluess : a) is it acceptable to route some signals under the GPS module? As one can see, the signals I have routed under the GPS module go to the front panel interface, i.e. they are not highspeed signals or so, but I still wonder whether you experts would worry about it (like "oh no, routing anything near the GPS module will disturb it and decreases its sensitivity" or something). This violates constraints as set out in the Ublox hardware integration manual. b) would you worry about the switching regulators? I know linear would be better, but the professional GPSDOs also have switchers, and besides that a linear regulator would not be so nice because my power supply will be at least 15 volts. I would, but it can be dealt with. c) is the usage of a RS232 chip a good idea or would you kick that out because they produce such massive amounts of EMI that it will disturb my GPS module or OCXO? Keeping it away from sensitive circuits will probably suffice. d) is it a wise idea to use an LC filter for the OCXO power supply, or does this lead to another rabbit hole because the inductors will pick up magnetic fields (50 Hz...) and modulate the OCXO? All depends whether you will bath the whole thing in 50Hz stray magnetic fields. ;-) e) anything else important I forgot? - Please double check your wiring of the GPS module it looks back to front. - In some places your ground layer is severely broken up to reduce its effectiveness. - Your antenna seems very close to the 1pps output and has traces underneath it - I quite like resettable PTC fuses (no need to replace) Tom ___ 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] PCB layout question for GPSDO
Hi > On Jan 30, 2020, at 3:20 PM, Tobias Pluess wrote: > > Hi guys > I have almost finished the layout for my new GPSDO having a TDC. I have > attached a screenshot of the PCB layout, for which I have some questions. > > First I will explain a bit what is on the board. > The connector X2 (top left) is a interface connector where I will connect a > flat flexible cable to a front panel board, which is still to be made. In > case the GPSDO will be mounted in a benchtop housing or so, one might want a > front panel with some status display or even a set of buttons to change > settings (e.g. change the PLL filter time constant). > > Next to it are the SMA connectors for the antenna and for the 1PPS output, as > well as two 10MHz outputs. The ICs N10 and N3 are output amplifiers which > should provide some 40ish dB of isolation between the OCXO and the two > outputs (such that the OCXO should not see it when a load is connected or > disconnected). > > D10 and D8 are two assembly variants which allow to install different OCXOs, > I have currently planned to add an OSA 8663 OCXO. The DAC and filter stuff to > control the EFC pin is on the right side. > > In the lower right corner is a voltage regulator for 12V (I will perhaps use > a 7812 for that) and some LC filters. > > X1 is the JTAG connector which allows to download/debug the software to the > microcontroller (D1 near the centre). > > D3 is a RS232 interface chip which allows the GPSDO to be connected to a PC > COM port for monitoring. > > The power supply, which is 15 volts, comes in at the lower left corner; there > is a fuse (because the GPSDO will be left on basically forever, I think a > fuse is a must, isn't it) and some large input filter cap. > > To generate the 3.3 volts for the logic, a switching regulator (Traco TSR1) > is used (N7); the regulator N9 generates 5 volts which is used for both the > active antenna supply as well as the 1PPS output. > > The active antenna supply can be selected between 3.3 volts and 5 volts by > means of a jumper. > > The GPS module itself, which will be a LEA M8T, is D4 (quite obvious, I > guess). > > My questions are the following: > a) is it acceptable to route some signals under the GPS module? As one can > see, the signals I have routed under the GPS module go to the front panel > interface, i.e. they are not highspeed signals or so, but I still wonder > whether you experts would worry about it (like "oh no, routing anything near > the GPS module will disturb it and decreases its sensitivity" or something). If you look at the layout guidelines for the GPS modules they all pretty much say “don’t do this”. If you have a 8 layer board and the traces are 7 layers down, that may not be worth noting. If it’s a more normal board, probably worth paying attention to. The RF input obviously needs to be isolated …. > > b) would you worry about the switching regulators? I know linear would be > better, but the professional GPSDOs also have switchers, and besides that a > linear regulator would not be so nice because my power supply will be at > least 15 volts. There are also commercial GPSDO’s that have major spur issues. It all depends on what you are trying to do. How important are spurs? > > c) is the usage of a RS232 chip a good idea or would you kick that out > because they produce such massive amounts of EMI that it will disturb my GPS > module or OCXO? The real question is - what’s the alternative? RS-232 is what people want to use. > > d) is it a wise idea to use an LC filter for the OCXO power supply, or does > this lead to another rabbit hole because the inductors will pick up magnetic > fields (50 Hz...) and modulate the OCXO? Mag into the isolation coil? Not an issue. > > e) anything else important I forgot? Lots and lots of things to worry about ….. Bob > > Many thanks for some hints to my design. > > Best > Tobias > HB9FSX > > ___ > 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] PCB layout question for GPSDO (Tobias Pluess)
On 31/1/20 7:18 am, time-nuts-requ...@lists.febo.com wrote: -- Message: 8 Date: Thu, 30 Jan 2020 20:20:08 + From: Tobias Pluess b) would you worry about the switching regulators? I know linear would be better, but the professional GPSDOs also have switchers, and besides that a linear regulator would not be so nice because my power supply will be at least 15 volts. c) is the usage of a RS232 chip a good idea or would you kick that out because they produce such massive amounts of EMI that it will disturb my GPS module or OCXO? Keeping a switching regulator quiet is a world (rabbit hole) all of its own. This can be magnetic as much as electrical, so requires both electrical and magnetic shielding. I believe there are quiet modules on the market, but am not across them these days. Quiet here is a relative term. There has been comment about even the low power RS232 +5 to -5 converters (MAX232 & such) being noisy for an RF environment. John ___ 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] PCB layout question for GPSDO
If you are concerned about phase noise, choose your regulator carefully. Even many linear regulators are noisy enough to degrade phase noise. There are lots of low noise regulators to choose from. Regards, Mark On Thu, Jan 30, 2020, 1:18 PM Tobias Pluess wrote: > Hi guys > I have almost finished the layout for my new GPSDO having a TDC. I have > attached a screenshot of the PCB layout, for which I have some questions. > > First I will explain a bit what is on the board. > The connector X2 (top left) is a interface connector where I will connect > a flat flexible cable to a front panel board, which is still to be made. In > case the GPSDO will be mounted in a benchtop housing or so, one might want > a front panel with some status display or even a set of buttons to change > settings (e.g. change the PLL filter time constant). > > Next to it are the SMA connectors for the antenna and for the 1PPS output, > as well as two 10MHz outputs. The ICs N10 and N3 are output amplifiers > which should provide some 40ish dB of isolation between the OCXO and the > two outputs (such that the OCXO should not see it when a load is connected > or disconnected). > > D10 and D8 are two assembly variants which allow to install different > OCXOs, I have currently planned to add an OSA 8663 OCXO. The DAC and filter > stuff to control the EFC pin is on the right side. > > In the lower right corner is a voltage regulator for 12V (I will perhaps > use a 7812 for that) and some LC filters. > > X1 is the JTAG connector which allows to download/debug the software to > the microcontroller (D1 near the centre). > > D3 is a RS232 interface chip which allows the GPSDO to be connected to a > PC COM port for monitoring. > > The power supply, which is 15 volts, comes in at the lower left corner; > there is a fuse (because the GPSDO will be left on basically forever, I > think a fuse is a must, isn't it) and some large input filter cap. > > To generate the 3.3 volts for the logic, a switching regulator (Traco > TSR1) is used (N7); the regulator N9 generates 5 volts which is used for > both the active antenna supply as well as the 1PPS output. > > The active antenna supply can be selected between 3.3 volts and 5 volts by > means of a jumper. > > The GPS module itself, which will be a LEA M8T, is D4 (quite obvious, I > guess). > > My questions are the following: > a) is it acceptable to route some signals under the GPS module? As one can > see, the signals I have routed under the GPS module go to the front panel > interface, i.e. they are not highspeed signals or so, but I still wonder > whether you experts would worry about it (like "oh no, routing anything > near the GPS module will disturb it and decreases its sensitivity" or > something). > > b) would you worry about the switching regulators? I know linear would be > better, but the professional GPSDOs also have switchers, and besides that a > linear regulator would not be so nice because my power supply will be at > least 15 volts. > > c) is the usage of a RS232 chip a good idea or would you kick that out > because they produce such massive amounts of EMI that it will disturb my > GPS module or OCXO? > > d) is it a wise idea to use an LC filter for the OCXO power supply, or > does this lead to another rabbit hole because the inductors will pick up > magnetic fields (50 Hz...) and modulate the OCXO? > > e) anything else important I forgot? > > Many thanks for some hints to my design. > > Best > Tobias > HB9FSX > > ___ > 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
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
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
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.
[time-nuts] FE-5440A , TD-1251/U manuals
Hello; Looking for the manuals for the TD-1251/U version of the FE-5440A Master Regulating Clock. Does any one have either a paper of PDF copy? Tried FEI and got the cold shoulder, tried Newport Aero nothing, tried US military manual office too old.. TO 49B3-36-1 OP TO 49B3-36-2 Service Thanks!! ___ 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
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
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] Looking for HP GPS splitter board
Hi John, Many years ago we supplied a number of these HP 2 and 4 channel PC assemblies to TAPR. I believe that Steve Bible also received some of these directly from us. Art -Original Message- From: time-nuts On Behalf Of John Ackermann N8UR Sent: Thursday, January 30, 2020 7:52 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Looking for HP GPS splitter board This is a long shot, but... A long while ago TAPR obtained and then sold some printed circuit boards that were intended to go into HP GPS antenna splitters. The boards were about 1.5 by 3.5 inches and had all the parts mounted for a 4 port splitter, but with no connectors attached. The part number on the board was 58516-60001, Rev. G. I would dearly like to find one or two of these boards to use in a project. If anyone has any they are willing to sell, please contact me off list. Thanks! John jra at febo dot com ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=01%7C01%7Cart%40synergy-gps.com%7Caf397685a3dc41edfc8608d7a59c700c%7Cc81f9fdec0e04d8c95779afaa0cad9ed%7C1&sdata=5ZBwRq%2FilMSHT273fO7Z5Jy4JdGb9UNI3%2FERtw9yRFg%3D&reserved=0 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] Looking for HP GPS splitter board
This is a long shot, but... A long while ago TAPR obtained and then sold some printed circuit boards that were intended to go into HP GPS antenna splitters. The boards were about 1.5 by 3.5 inches and had all the parts mounted for a 4 port splitter, but with no connectors attached. The part number on the board was 58516-60001, Rev. G. I would dearly like to find one or two of these boards to use in a project. If anyone has any they are willing to sell, please contact me off list. Thanks! John jra at febo dot com ___ 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] 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] Algorithm in use by chrony and OpenNTPD
Hi Watson, On 2020-01-30 07:30, Watson Ladd wrote: > Dear fellow nuts, > > I'm trying to find any sources on the clock discipline and source filtering > algorithm that chrony and OpenNTPD use. It's different from the one ntpd > uses that Mills described, which is much more like a PLL one might build. You should start off by reading the many small articles that Poul-Henning has written, they are here: http://phk.freebsd.dk/time/ What he does is in his own words, non-magical, and I agree. Cheers, Magnus ___ 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] Algorithm in use by chrony and OpenNTPD
Dear fellow nuts, I'm trying to find any sources on the clock discipline and source filtering algorithm that chrony and OpenNTPD use. It's different from the one ntpd uses that Mills described, which is much more like a PLL one might build. Sincerely, Watson ___ 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.
