Hi, This is to share current results on a "Long Wave RadioFrequency Standard" project I have been pursuing for a while. Attached are typical ADEV plots and a block diagram of the system. I live in a crowded city (Paris, France) with no - or very limited - access to open sky. Not good for GPS. However a long wave broadcasting public service is (still) available, broadcasting time signal for clocks. The transmitter is located in Allouis, central France (200km for Paris). The signal is quite powerful (1MW) and the carrier (162kHz ) is stabilized with a Cesium-standard. I decided to test how far I could go in disciplining a local VCO with this signal. As well known, long wave RF has interesting features: - Signal is available (almost) everywhere, anytime, in the country especially inside buildings (even underground !) - Quite stable and strong ground wave in day time. - Relatively easy antenna and RF signal processing (ferrite rod) And there are naturally a number of drawbacks (especially with the Allouis signal) such as: - Much more unstable signal at night (interferences with ionospheric path) - Large phase modulation of the carrier (time signals bits +/- 1 rad phase modulated). - RF perturbations on the signal path. -Stop broadcasting for maintenance every Tuesday morning…. Design of the « LWRFDO » was derived and inspired from many references (including this list naturally). Principles are summarized in the attached pdf, with the following specific feature to get rid of the phase modulation: The incoming signal has large sections of « un-modulated » segments between the time signal bits. (Including a whole quiet section during the 59th second) Such « quiet zones » are detected - where the 162kHz base carrier is untouched - and measurement of phase difference with a local OCXO is then performed inside these quiet zones. Then PI controller to a 20bits DAC (see picture). Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 » graph (day time only). « DN123 » is a three days uninterrupted run, combining day and night signals, showing the impact of night instabilities. The frequency standard stability at the transmitter site is given for 10e-12. LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a 100s) with a TICC, So I believe 10-11 is not far from the best one could get. Which is actually not too bad, isn’t it ? Still working on improving the OCXCO (currently home brewed) Comment and suggestions welcomed, Gilles.

Hi, 800Kw according to the press release of ANFR. I doubt it is the best choice : DCF77 is more precise (active hydrogen maser) but a little bit more distant... But the phase lock of a quartz on a VLF signal is not as easy. There is a considerable phase shift in the evening and in the morning with the sun position, big instabilities at these moments and you have a hudge difference between day and night (10 e-9/8)... Have a look at the Adret receiver 4101 with its step motor phase lock...The engineering of the ferrite road antenna is very tricky : temperature coefficient of the ferrite, subtle tiny out of resonnace tuning, problem of the interferences from domestic electrnic pollution (computers with sync of monitors, led drivers...). The archiyecture of the receiver is also tricky : no AGC (introduces phaseshift), heavy filtering (where : antenna, receiver...) On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <clemgill@gmail.com> wrote: Hi, This is to share current results on a "Long Wave RadioFrequency Standard" project I have been pursuing for a while. Attached are typical ADEV plots and a block diagram of the system. I live in a crowded city (Paris, France) with no - or very limited - access to open sky. Not good for GPS. However a long wave broadcasting public service is (still) available, broadcasting time signal for clocks. The transmitter is located in Allouis, central France (200km for Paris). The signal is quite powerful (1MW) and the carrier (162kHz ) is stabilized with a Cesium-standard. I decided to test how far I could go in disciplining a local VCO with this signal. As well known, long wave RF has interesting features: - Signal is available (almost) everywhere, anytime, in the country especially inside buildings (even underground !) - Quite stable and strong ground wave in day time. - Relatively easy antenna and RF signal processing (ferrite rod) And there are naturally a number of drawbacks (especially with the Allouis signal) such as: - Much more unstable signal at night (interferences with ionospheric path) - Large phase modulation of the carrier (time signals bits +/- 1 rad phase modulated). - RF perturbations on the signal path. -Stop broadcasting for maintenance every Tuesday morning…. Design of the « LWRFDO » was derived and inspired from many references (including this list naturally). Principles are summarized in the attached pdf, with the following specific feature to get rid of the phase modulation: The incoming signal has large sections of « un-modulated » segments between the time signal bits. (Including a whole quiet section during the 59th second) Such « quiet zones » are detected - where the 162kHz base carrier is untouched - and measurement of phase difference with a local OCXO is then performed inside these quiet zones. Then PI controller to a 20bits DAC (see picture). Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 » graph (day time only). « DN123 » is a three days uninterrupted run, combining day and night signals, showing the impact of night instabilities. The frequency standard stability at the transmitter site  is given for 10e-12. LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a 100s) with a TICC, So I believe 10-11 is not far from the best one could get. Which is actually not too bad, isn’t it ? Still working on improving the OCXCO (currently home brewed) Comment and suggestions welcomed, Gilles. _______________________________________________ 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.

Hi Very cool !!! The red trace is obviously the one to focus on. Some sort of digital loop that only operates under the “known good” conditions would seem to make sense. Thanks for sharing Bob > On Jan 15, 2021, at 9:51 AM, Gilles Clement <clemgill@gmail.com> wrote: > > Hi, > > This is to share current results on a "Long Wave RadioFrequency Standard" project I have been pursuing for a while. > Attached are typical ADEV plots and a block diagram of the system. > > I live in a crowded city (Paris, France) with no - or very limited - access to open sky. Not good for GPS. > However a long wave broadcasting public service is (still) available, broadcasting time signal for clocks. > The transmitter is located in Allouis, central France (200km for Paris). > The signal is quite powerful (1MW) and the carrier (162kHz ) is stabilized with a Cesium-standard. > > I decided to test how far I could go in disciplining a local VCO with this signal. > > As well known, long wave RF has interesting features: > - Signal is available (almost) everywhere, anytime, in the country especially inside buildings (even underground !) > - Quite stable and strong ground wave in day time. > - Relatively easy antenna and RF signal processing (ferrite rod) > And there are naturally a number of drawbacks (especially with the Allouis signal) such as: > - Much more unstable signal at night (interferences with ionospheric path) > - Large phase modulation of the carrier (time signals bits +/- 1 rad phase modulated). > - RF perturbations on the signal path. > -Stop broadcasting for maintenance every Tuesday morning…. > > Design of the « LWRFDO » was derived and inspired from many references (including this list naturally). > Principles are summarized in the attached pdf, with the following specific feature to get rid of the phase modulation: > The incoming signal has large sections of « un-modulated » segments between the time signal bits. > (Including a whole quiet section during the 59th second) > Such « quiet zones » are detected - where the 162kHz base carrier is untouched - and measurement of phase difference > with a local OCXO is then performed inside these quiet zones. Then PI controller to a 20bits DAC (see picture). > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 » graph (day time only). > « DN123 » is a three days uninterrupted run, combining day and night signals, showing the impact of night instabilities. > The frequency standard stability at the transmitter site is given for 10e-12. > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a 100s) with a TICC, > So I believe 10-11 is not far from the best one could get. > Which is actually not too bad, isn’t it ? > > Still working on improving the OCXCO (currently home brewed) > > Comment and suggestions welcomed, > Gilles. > > <Timelab 162kHz_LWRFDO-1.jpg><162kHz LWRFD0 bloc diagram.pdf> > > > > > > > _______________________________________________ > 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.

I guess I would ask what the goal of the effort might be. It seems like a good answer. One thing I was amazed buy was that back in the 1960s HP wrote some papers on using WWVB. What they did was check the offset at distance everyday about the same time. This offered quite a bit more accuracy and avoided all of the night propagation effects. Essentially from day to day the path is about the same. If your system is stable enough could you simply put it in holdover at night? The other question I had is how do you then use the locked crystal oscillator at 5.184 Mhz? Does it somehow divide down to a useful number? Nice project and good luck. Looking forward to hearing more. Regards Paul WB8TSL On Fri, Jan 15, 2021 at 11:02 AM JF PICARD via time-nuts < time-nuts@lists.febo.com> wrote: > Hi, > 800Kw according to the press release of ANFR. I doubt it is the best > choice : DCF77 is more precise (active hydrogen maser) but a little bit > more distant... > But the phase lock of a quartz on a VLF signal is not as easy. There is a > considerable phase shift in the evening and in the morning with the sun > position, big instabilities at these moments and you have a hudge > difference between day and night (10 e-9/8)... Have a look at the Adret > receiver 4101 with its step motor phase lock...The engineering of the > ferrite road antenna is very tricky : temperature coefficient of the > ferrite, subtle tiny out of resonnace tuning, problem of the interferences > from domestic electrnic pollution (computers with sync of monitors, led > drivers...). The archiyecture of the receiver is also tricky : no AGC > (introduces phaseshift), heavy filtering (where : antenna, receiver...) > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < > clemgill@gmail.com> wrote: > > Hi, > > This is to share current results on a "Long Wave RadioFrequency Standard" > project I have been pursuing for a while. > Attached are typical ADEV plots and a block diagram of the system. > > I live in a crowded city (Paris, France) with no - or very limited - > access to open sky. Not good for GPS. > However a long wave broadcasting public service is (still) available, > broadcasting time signal for clocks. > The transmitter is located in Allouis, central France (200km for Paris). > The signal is quite powerful (1MW) and the carrier (162kHz ) is stabilized > with a Cesium-standard. > > I decided to test how far I could go in disciplining a local VCO with this > signal. > > As well known, long wave RF has interesting features: > - Signal is available (almost) everywhere, anytime, in the country > especially inside buildings (even underground !) > - Quite stable and strong ground wave in day time. > - Relatively easy antenna and RF signal processing (ferrite rod) > And there are naturally a number of drawbacks (especially with the Allouis > signal) such as: > - Much more unstable signal at night (interferences with ionospheric path) > - Large phase modulation of the carrier (time signals bits +/- 1 rad phase > modulated). > - RF perturbations on the signal path. > -Stop broadcasting for maintenance every Tuesday morning…. > > Design of the « LWRFDO » was derived and inspired from many references > (including this list naturally). > Principles are summarized in the attached pdf, with the following specific > feature to get rid of the phase modulation: > The incoming signal has large sections of « un-modulated » segments > between the time signal bits. > (Including a whole quiet section during the 59th second) > Such « quiet zones » are detected - where the 162kHz base carrier is > untouched - and measurement of phase difference > with a local OCXO is then performed inside these quiet zones. Then PI > controller to a 20bits DAC (see picture). > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 » > graph (day time only). > « DN123 » is a three days uninterrupted run, combining day and night > signals, showing the impact of night instabilities. > The frequency standard stability at the transmitter site is given for > 10e-12. > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a > 100s) with a TICC, > So I believe 10-11 is not far from the best one could get. > Which is actually not too bad, isn’t it ? > > Still working on improving the OCXCO (currently home brewed) > > Comment and suggestions welcomed, > Gilles. > > > > > > > > > _______________________________________________ > 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. >

Hi JF, DCF77 is more distant, less powerful and probably more polluted (77kHz). Anyhow I would probably not be able to measure better than 10e-11 with current setup (need a better reference) Indeed a good and stable phase lock was not easy to reach. I experienced the day and night huge differences (as documented in post) but nothing specific to phase shifts during sunrise or sunset. No big difficulties with the ferrite antenna and the receiver design either (thanks to good stuff from the old radio days probably). Found that magnetic field antenna (ie: ferrite) appeared much less sensitive to pollution than electric field antennas. Naturally bad experience with Led bulbs and vapor gas lamps. You have to chase them all and change to old filament lamps in and around the lab. No issues with computers though. What I found most challenging (and hence interesting) was the following : - Temperature control, high resolution and high stability (Crystal oscillator but also for the controller parts, ADC, DAC… ) - PI loop stability (very tricky) - Matching theory with practice (still work in progress…!) - Understanding the logic and physics behind behaviors, the real root cause of problems, and especially why a « really clever » enhancement - more than often - actually leads to… performance degradation... Gilles. > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts <time-nuts@lists.febo.com> a écrit : > > Hi, > 800Kw according to the press release of ANFR. I doubt it is the best choice : DCF77 is more precise (active hydrogen maser) but a little bit more distant... > But the phase lock of a quartz on a VLF signal is not as easy. There is a considerable phase shift in the evening and in the morning with the sun position, big instabilities at these moments and you have a hudge difference between day and night (10 e-9/8)... Have a look at the Adret receiver 4101 with its step motor phase lock...The engineering of the ferrite road antenna is very tricky : temperature coefficient of the ferrite, subtle tiny out of resonnace tuning, problem of the interferences from domestic electrnic pollution (computers with sync of monitors, led drivers...). The archiyecture of the receiver is also tricky : no AGC (introduces phaseshift), heavy filtering (where : antenna, receiver...) > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <clemgill@gmail.com> wrote: > > Hi, > > This is to share current results on a "Long Wave RadioFrequency Standard" project I have been pursuing for a while. > Attached are typical ADEV plots and a block diagram of the system. > > I live in a crowded city (Paris, France) with no - or very limited - access to open sky. Not good for GPS. > However a long wave broadcasting public service is (still) available, broadcasting time signal for clocks. > The transmitter is located in Allouis, central France (200km for Paris). > The signal is quite powerful (1MW) and the carrier (162kHz ) is stabilized with a Cesium-standard. > > I decided to test how far I could go in disciplining a local VCO with this signal. > > As well known, long wave RF has interesting features: > - Signal is available (almost) everywhere, anytime, in the country especially inside buildings (even underground !) > - Quite stable and strong ground wave in day time. > - Relatively easy antenna and RF signal processing (ferrite rod) > And there are naturally a number of drawbacks (especially with the Allouis signal) such as: > - Much more unstable signal at night (interferences with ionospheric path) > - Large phase modulation of the carrier (time signals bits +/- 1 rad phase modulated). > - RF perturbations on the signal path. > -Stop broadcasting for maintenance every Tuesday morning…. > > Design of the « LWRFDO » was derived and inspired from many references (including this list naturally). > Principles are summarized in the attached pdf, with the following specific feature to get rid of the phase modulation: > The incoming signal has large sections of « un-modulated » segments between the time signal bits. > (Including a whole quiet section during the 59th second) > Such « quiet zones » are detected - where the 162kHz base carrier is untouched - and measurement of phase difference > with a local OCXO is then performed inside these quiet zones. Then PI controller to a 20bits DAC (see picture). > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 » graph (day time only). > « DN123 » is a three days uninterrupted run, combining day and night signals, showing the impact of night instabilities. > The frequency standard stability at the transmitter site is given for 10e-12. > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a 100s) with a TICC, > So I believe 10-11 is not far from the best one could get. > Which is actually not too bad, isn’t it ? > > Still working on improving the OCXCO (currently home brewed) > > Comment and suggestions welcomed, > Gilles. > > > > > > > > > _______________________________________________ > 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.

 On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <

I did a plot of the phase of the UK 198kHz longwave transmission to me, a path of about 150km, compared against an HP5061A Caesium standard N early 24 hours duration, covering night time and day time propagation in October. You can observe the wild wandering of both phase and amplitude during night time due to skywave/groundwave interaction as the ionosphere shifts around. Plot also at http://www.g4jnt.com/DropF/droitwichplot2a.bmp if the attachment doesn't get through [image: DroitwichPlot2a.bmp] Andy www.g4jnt.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Fri, 15 Jan 2021 at 21:55, Gilles Clement <clemgill@gmail.com> wrote: > Hi JF, > DCF77 is more distant, less powerful and probably more polluted (77kHz). > Anyhow I would probably not be able to measure better than 10e-11 with > current setup (need a better reference) > Indeed a good and stable phase lock was not easy to reach. > I experienced the day and night huge differences (as documented in post) > but nothing specific to phase shifts during sunrise or sunset. > No big difficulties with the ferrite antenna and the receiver design > either (thanks to good stuff from the old radio days probably). > Found that magnetic field antenna (ie: ferrite) appeared much less > sensitive to pollution than electric field antennas. > Naturally bad experience with Led bulbs and vapor gas lamps. You have to > chase them all and change to old filament lamps in and around the lab. No > issues with computers though. > What I found most challenging (and hence interesting) was the following : > - Temperature control, high resolution and high stability (Crystal > oscillator but also for the controller parts, ADC, DAC… ) > - PI loop stability (very tricky) > - Matching theory with practice (still work in progress…!) > - Understanding the logic and physics behind behaviors, the real root > cause of problems, > and especially why a « really clever » enhancement - more than often - > actually leads to… performance degradation... > Gilles. > > > > > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts < > time-nuts@lists.febo.com> a écrit : > > > > Hi, > > 800Kw according to the press release of ANFR. I doubt it is the best > choice : DCF77 is more precise (active hydrogen maser) but a little bit > more distant... > > But the phase lock of a quartz on a VLF signal is not as easy. There is > a considerable phase shift in the evening and in the morning with the sun > position, big instabilities at these moments and you have a hudge > difference between day and night (10 e-9/8)... Have a look at the Adret > receiver 4101 with its step motor phase lock...The engineering of the > ferrite road antenna is very tricky : temperature coefficient of the > ferrite, subtle tiny out of resonnace tuning, problem of the interferences > from domestic electrnic pollution (computers with sync of monitors, led > drivers...). The archiyecture of the receiver is also tricky : no AGC > (introduces phaseshift), heavy filtering (where : antenna, receiver...) > > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < > clemgill@gmail.com> wrote: > > > > Hi, > > > > This is to share current results on a "Long Wave RadioFrequency > Standard" project I have been pursuing for a while. > > Attached are typical ADEV plots and a block diagram of the system. > > > > I live in a crowded city (Paris, France) with no - or very limited - > access to open sky. Not good for GPS. > > However a long wave broadcasting public service is (still) available, > broadcasting time signal for clocks. > > The transmitter is located in Allouis, central France (200km for Paris). > > The signal is quite powerful (1MW) and the carrier (162kHz ) is > stabilized with a Cesium-standard. > > > > I decided to test how far I could go in disciplining a local VCO with > this signal. > > > > As well known, long wave RF has interesting features: > > - Signal is available (almost) everywhere, anytime, in the country > especially inside buildings (even underground !) > > - Quite stable and strong ground wave in day time. > > - Relatively easy antenna and RF signal processing (ferrite rod) > > And there are naturally a number of drawbacks (especially with the > Allouis signal) such as: > > - Much more unstable signal at night (interferences with ionospheric > path) > > - Large phase modulation of the carrier (time signals bits +/- 1 rad > phase modulated). > > - RF perturbations on the signal path. > > -Stop broadcasting for maintenance every Tuesday morning…. > > > > Design of the « LWRFDO » was derived and inspired from many references > (including this list naturally). > > Principles are summarized in the attached pdf, with the following > specific feature to get rid of the phase modulation: > > The incoming signal has large sections of « un-modulated » segments > between the time signal bits. > > (Including a whole quiet section during the 59th second) > > Such « quiet zones » are detected - where the 162kHz base carrier is > untouched - and measurement of phase difference > > with a local OCXO is then performed inside these quiet zones. Then PI > controller to a 20bits DAC (see picture). > > > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 > » graph (day time only). > > « DN123 » is a three days uninterrupted run, combining day and night > signals, showing the impact of night instabilities. > > The frequency standard stability at the transmitter site is given for > 10e-12. > > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a > 100s) with a TICC, > > So I believe 10-11 is not far from the best one could get. > > Which is actually not too bad, isn’t it ? > > > > Still working on improving the OCXCO (currently home brewed) > > > > Comment and suggestions welcomed, > > Gilles. > > > > > > > > > > > > > > > > > > _______________________________________________ > > 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. > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

 On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <

Longwave phase is dependent on the weather between your receiver and the transmitter... On 2021-01-15 15:13, Andy Talbot wrote: > I did a plot of the phase of the UK 198kHz longwave transmission to me, > a > path of about 150km, compared against an HP5061A Caesium standard > N > > early 24 hours duration, covering night time and day time propagation > in > October. > > You can observe the wild wandering of both phase and amplitude during > night time due to skywave/groundwave interaction as the ionosphere > shifts > around. > > Plot also at > http://www.g4jnt.com/DropF/droitwichplot2a.bmp > if the attachment doesn't get through > > > [image: DroitwichPlot2a.bmp] > Andy > www.g4jnt.com > > > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > On Fri, 15 Jan 2021 at 21:55, Gilles Clement <clemgill@gmail.com> > wrote: > >> Hi JF, >> DCF77 is more distant, less powerful and probably more polluted >> (77kHz). >> Anyhow I would probably not be able to measure better than 10e-11 with >> current setup (need a better reference) >> Indeed a good and stable phase lock was not easy to reach. >> I experienced the day and night huge differences (as documented in >> post) >> but nothing specific to phase shifts during sunrise or sunset. >> No big difficulties with the ferrite antenna and the receiver design >> either (thanks to good stuff from the old radio days probably). >> Found that magnetic field antenna (ie: ferrite) appeared much less >> sensitive to pollution than electric field antennas. >> Naturally bad experience with Led bulbs and vapor gas lamps. You have >> to >> chase them all and change to old filament lamps in and around the lab. >> No >> issues with computers though. >> What I found most challenging (and hence interesting) was the >> following : >> - Temperature control, high resolution and high stability (Crystal >> oscillator but also for the controller parts, ADC, DAC… ) >> - PI loop stability (very tricky) >> - Matching theory with practice (still work in progress…!) >> - Understanding the logic and physics behind behaviors, the real root >> cause of problems, >> and especially why a « really clever » enhancement - more than often - >> actually leads to… performance degradation... >> Gilles. >> >> >> >> > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts < >> time-nuts@lists.febo.com> a écrit : >> > >> > Hi, >> > 800Kw according to the press release of ANFR. I doubt it is the best >> choice : DCF77 is more precise (active hydrogen maser) but a little >> bit >> more distant... >> > But the phase lock of a quartz on a VLF signal is not as easy. There is >> a considerable phase shift in the evening and in the morning with the >> sun >> position, big instabilities at these moments and you have a hudge >> difference between day and night (10 e-9/8)... Have a look at the >> Adret >> receiver 4101 with its step motor phase lock...The engineering of the >> ferrite road antenna is very tricky : temperature coefficient of the >> ferrite, subtle tiny out of resonnace tuning, problem of the >> interferences >> from domestic electrnic pollution (computers with sync of monitors, >> led >> drivers...). The archiyecture of the receiver is also tricky : no AGC >> (introduces phaseshift), heavy filtering (where : antenna, >> receiver...) >> > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < >> clemgill@gmail.com> wrote: >> > >> > Hi, >> > >> > This is to share current results on a "Long Wave RadioFrequency >> Standard" project I have been pursuing for a while. >> > Attached are typical ADEV plots and a block diagram of the system. >> > >> > I live in a crowded city (Paris, France) with no - or very limited - >> access to open sky. Not good for GPS. >> > However a long wave broadcasting public service is (still) available, >> broadcasting time signal for clocks. >> > The transmitter is located in Allouis, central France (200km for Paris). >> > The signal is quite powerful (1MW) and the carrier (162kHz ) is >> stabilized with a Cesium-standard. >> > >> > I decided to test how far I could go in disciplining a local VCO with >> this signal. >> > >> > As well known, long wave RF has interesting features: >> > - Signal is available (almost) everywhere, anytime, in the country >> especially inside buildings (even underground !) >> > - Quite stable and strong ground wave in day time. >> > - Relatively easy antenna and RF signal processing (ferrite rod) >> > And there are naturally a number of drawbacks (especially with the >> Allouis signal) such as: >> > - Much more unstable signal at night (interferences with ionospheric >> path) >> > - Large phase modulation of the carrier (time signals bits +/- 1 rad >> phase modulated). >> > - RF perturbations on the signal path. >> > -Stop broadcasting for maintenance every Tuesday morning…. >> > >> > Design of the « LWRFDO » was derived and inspired from many references >> (including this list naturally). >> > Principles are summarized in the attached pdf, with the following >> specific feature to get rid of the phase modulation: >> > The incoming signal has large sections of « un-modulated » segments >> between the time signal bits. >> > (Including a whole quiet section during the 59th second) >> > Such « quiet zones » are detected - where the 162kHz base carrier is >> untouched - and measurement of phase difference >> > with a local OCXO is then performed inside these quiet zones. Then PI >> controller to a 20bits DAC (see picture). >> > >> > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 >> » graph (day time only). >> > « DN123 » is a three days uninterrupted run, combining day and night >> signals, showing the impact of night instabilities. >> > The frequency standard stability at the transmitter site is given for >> 10e-12. >> > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a >> 100s) with a TICC, >> > So I believe 10-11 is not far from the best one could get. >> > Which is actually not too bad, isn’t it ? >> > >> > Still working on improving the OCXCO (currently home brewed) >> > >> > Comment and suggestions welcomed, >> > Gilles. >> > >> > >> > >> > >> > >> > >> > >> > >> > _______________________________________________ >> > 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. >> > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > _______________________________________________ > 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. -- ------------ The whole world is a straight man. ---------------------- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304

 On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <

What was the program that you used for the plot please? Regards Paul WB8TSL On Fri, Jan 15, 2021 at 5:54 PM Andy Talbot <andy.g4jnt@gmail.com> wrote: > I did a plot of the phase of the UK 198kHz longwave transmission to me, a > path of about 150km, compared against an HP5061A Caesium standard > N > > early 24 hours duration, covering night time and day time propagation in > October. > > You can observe the wild wandering of both phase and amplitude during > night time due to skywave/groundwave interaction as the ionosphere shifts > around. > > Plot also at > http://www.g4jnt.com/DropF/droitwichplot2a.bmp > if the attachment doesn't get through > > > [image: DroitwichPlot2a.bmp] > Andy > www.g4jnt.com > > > > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > Virus-free. > www.avg.com > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > On Fri, 15 Jan 2021 at 21:55, Gilles Clement <clemgill@gmail.com> wrote: > > > Hi JF, > > DCF77 is more distant, less powerful and probably more polluted (77kHz). > > Anyhow I would probably not be able to measure better than 10e-11 with > > current setup (need a better reference) > > Indeed a good and stable phase lock was not easy to reach. > > I experienced the day and night huge differences (as documented in post) > > but nothing specific to phase shifts during sunrise or sunset. > > No big difficulties with the ferrite antenna and the receiver design > > either (thanks to good stuff from the old radio days probably). > > Found that magnetic field antenna (ie: ferrite) appeared much less > > sensitive to pollution than electric field antennas. > > Naturally bad experience with Led bulbs and vapor gas lamps. You have to > > chase them all and change to old filament lamps in and around the lab. No > > issues with computers though. > > What I found most challenging (and hence interesting) was the following : > > - Temperature control, high resolution and high stability (Crystal > > oscillator but also for the controller parts, ADC, DAC… ) > > - PI loop stability (very tricky) > > - Matching theory with practice (still work in progress…!) > > - Understanding the logic and physics behind behaviors, the real root > > cause of problems, > > and especially why a « really clever » enhancement - more than often - > > actually leads to… performance degradation... > > Gilles. > > > > > > > > > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts < > > time-nuts@lists.febo.com> a écrit : > > > > > > Hi, > > > 800Kw according to the press release of ANFR. I doubt it is the best > > choice : DCF77 is more precise (active hydrogen maser) but a little bit > > more distant... > > > But the phase lock of a quartz on a VLF signal is not as easy. There is > > a considerable phase shift in the evening and in the morning with the sun > > position, big instabilities at these moments and you have a hudge > > difference between day and night (10 e-9/8)... Have a look at the Adret > > receiver 4101 with its step motor phase lock...The engineering of the > > ferrite road antenna is very tricky : temperature coefficient of the > > ferrite, subtle tiny out of resonnace tuning, problem of the > interferences > > from domestic electrnic pollution (computers with sync of monitors, led > > drivers...). The archiyecture of the receiver is also tricky : no AGC > > (introduces phaseshift), heavy filtering (where : antenna, receiver...) > > > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < > > clemgill@gmail.com> wrote: > > > > > > Hi, > > > > > > This is to share current results on a "Long Wave RadioFrequency > > Standard" project I have been pursuing for a while. > > > Attached are typical ADEV plots and a block diagram of the system. > > > > > > I live in a crowded city (Paris, France) with no - or very limited - > > access to open sky. Not good for GPS. > > > However a long wave broadcasting public service is (still) available, > > broadcasting time signal for clocks. > > > The transmitter is located in Allouis, central France (200km for > Paris). > > > The signal is quite powerful (1MW) and the carrier (162kHz ) is > > stabilized with a Cesium-standard. > > > > > > I decided to test how far I could go in disciplining a local VCO with > > this signal. > > > > > > As well known, long wave RF has interesting features: > > > - Signal is available (almost) everywhere, anytime, in the country > > especially inside buildings (even underground !) > > > - Quite stable and strong ground wave in day time. > > > - Relatively easy antenna and RF signal processing (ferrite rod) > > > And there are naturally a number of drawbacks (especially with the > > Allouis signal) such as: > > > - Much more unstable signal at night (interferences with ionospheric > > path) > > > - Large phase modulation of the carrier (time signals bits +/- 1 rad > > phase modulated). > > > - RF perturbations on the signal path. > > > -Stop broadcasting for maintenance every Tuesday morning…. > > > > > > Design of the « LWRFDO » was derived and inspired from many references > > (including this list naturally). > > > Principles are summarized in the attached pdf, with the following > > specific feature to get rid of the phase modulation: > > > The incoming signal has large sections of « un-modulated » segments > > between the time signal bits. > > > (Including a whole quiet section during the 59th second) > > > Such « quiet zones » are detected - where the 162kHz base carrier is > > untouched - and measurement of phase difference > > > with a local OCXO is then performed inside these quiet zones. Then PI > > controller to a 20bits DAC (see picture). > > > > > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 > > » graph (day time only). > > > « DN123 » is a three days uninterrupted run, combining day and night > > signals, showing the impact of night instabilities. > > > The frequency standard stability at the transmitter site is given for > > 10e-12. > > > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability > a > > 100s) with a TICC, > > > So I believe 10-11 is not far from the best one could get. > > > Which is actually not too bad, isn’t it ? > > > > > > Still working on improving the OCXCO (currently home brewed) > > > > > > Comment and suggestions welcomed, > > > Gilles. > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > 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. > > > > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > Virus-free. > www.avg.com > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > _______________________________________________ > 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. >

 On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <

Sorry, forgot to include the cite: LATHAM, D. Diurnal Frequency Variation and Refraction Index. Nature Physical Science 234, 157–158 (1971). https://doi.org/10.1038/physci234157a0 Don On 2021-01-15 15:13, Andy Talbot wrote: > I did a plot of the phase of the UK 198kHz longwave transmission to me, > a > path of about 150km, compared against an HP5061A Caesium standard > N > > early 24 hours duration, covering night time and day time propagation > in > October. > > You can observe the wild wandering of both phase and amplitude during > night time due to skywave/groundwave interaction as the ionosphere > shifts > around. > > Plot also at > http://www.g4jnt.com/DropF/droitwichplot2a.bmp > if the attachment doesn't get through > > > [image: DroitwichPlot2a.bmp] > Andy > www.g4jnt.com > > > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > On Fri, 15 Jan 2021 at 21:55, Gilles Clement <clemgill@gmail.com> > wrote: > >> Hi JF, >> DCF77 is more distant, less powerful and probably more polluted >> (77kHz). >> Anyhow I would probably not be able to measure better than 10e-11 with >> current setup (need a better reference) >> Indeed a good and stable phase lock was not easy to reach. >> I experienced the day and night huge differences (as documented in >> post) >> but nothing specific to phase shifts during sunrise or sunset. >> No big difficulties with the ferrite antenna and the receiver design >> either (thanks to good stuff from the old radio days probably). >> Found that magnetic field antenna (ie: ferrite) appeared much less >> sensitive to pollution than electric field antennas. >> Naturally bad experience with Led bulbs and vapor gas lamps. You have >> to >> chase them all and change to old filament lamps in and around the lab. >> No >> issues with computers though. >> What I found most challenging (and hence interesting) was the >> following : >> - Temperature control, high resolution and high stability (Crystal >> oscillator but also for the controller parts, ADC, DAC… ) >> - PI loop stability (very tricky) >> - Matching theory with practice (still work in progress…!) >> - Understanding the logic and physics behind behaviors, the real root >> cause of problems, >> and especially why a « really clever » enhancement - more than often - >> actually leads to… performance degradation... >> Gilles. >> >> >> >> > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts < >> time-nuts@lists.febo.com> a écrit : >> > >> > Hi, >> > 800Kw according to the press release of ANFR. I doubt it is the best >> choice : DCF77 is more precise (active hydrogen maser) but a little >> bit >> more distant... >> > But the phase lock of a quartz on a VLF signal is not as easy. There is >> a considerable phase shift in the evening and in the morning with the >> sun >> position, big instabilities at these moments and you have a hudge >> difference between day and night (10 e-9/8)... Have a look at the >> Adret >> receiver 4101 with its step motor phase lock...The engineering of the >> ferrite road antenna is very tricky : temperature coefficient of the >> ferrite, subtle tiny out of resonnace tuning, problem of the >> interferences >> from domestic electrnic pollution (computers with sync of monitors, >> led >> drivers...). The archiyecture of the receiver is also tricky : no AGC >> (introduces phaseshift), heavy filtering (where : antenna, >> receiver...) >> > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < >> clemgill@gmail.com> wrote: >> > >> > Hi, >> > >> > This is to share current results on a "Long Wave RadioFrequency >> Standard" project I have been pursuing for a while. >> > Attached are typical ADEV plots and a block diagram of the system. >> > >> > I live in a crowded city (Paris, France) with no - or very limited - >> access to open sky. Not good for GPS. >> > However a long wave broadcasting public service is (still) available, >> broadcasting time signal for clocks. >> > The transmitter is located in Allouis, central France (200km for Paris). >> > The signal is quite powerful (1MW) and the carrier (162kHz ) is >> stabilized with a Cesium-standard. >> > >> > I decided to test how far I could go in disciplining a local VCO with >> this signal. >> > >> > As well known, long wave RF has interesting features: >> > - Signal is available (almost) everywhere, anytime, in the country >> especially inside buildings (even underground !) >> > - Quite stable and strong ground wave in day time. >> > - Relatively easy antenna and RF signal processing (ferrite rod) >> > And there are naturally a number of drawbacks (especially with the >> Allouis signal) such as: >> > - Much more unstable signal at night (interferences with ionospheric >> path) >> > - Large phase modulation of the carrier (time signals bits +/- 1 rad >> phase modulated). >> > - RF perturbations on the signal path. >> > -Stop broadcasting for maintenance every Tuesday morning…. >> > >> > Design of the « LWRFDO » was derived and inspired from many references >> (including this list naturally). >> > Principles are summarized in the attached pdf, with the following >> specific feature to get rid of the phase modulation: >> > The incoming signal has large sections of « un-modulated » segments >> between the time signal bits. >> > (Including a whole quiet section during the 59th second) >> > Such « quiet zones » are detected - where the 162kHz base carrier is >> untouched - and measurement of phase difference >> > with a local OCXO is then performed inside these quiet zones. Then PI >> controller to a 20bits DAC (see picture). >> > >> > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « D2 >> » graph (day time only). >> > « DN123 » is a three days uninterrupted run, combining day and night >> signals, showing the impact of night instabilities. >> > The frequency standard stability at the transmitter site is given for >> 10e-12. >> > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 stability a >> 100s) with a TICC, >> > So I believe 10-11 is not far from the best one could get. >> > Which is actually not too bad, isn’t it ? >> > >> > Still working on improving the OCXCO (currently home brewed) >> > >> > Comment and suggestions welcomed, >> > Gilles. >> > >> > >> > >> > >> > >> > >> > >> > >> > _______________________________________________ >> > 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. >> > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > _______________________________________________ > 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. -- ------------ The whole world is a straight man. ---------------------- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304

 On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <

It's a custom LF receiver I put together, a direct conversion downconverter to 1kHz. Then bandpass sampling to an I/Q data steam, at 12 bit resolution sent using RS422 o a PC. All frequency conversion and sampling is locked to a master 10MHz clock. The interface also includes time stamping from a GPS module. PC software takes the data steam, applies a small optional frequency offset, needed to take out DDS frequency setting resolution, displays raw input on a vector scope. It then decimated filters the data down to sampling rate in teh Hz to sub-Hz region for storage and further analysis of display. I originally designed the S/W for use with the Ebnaut LF data comms work, hence the reference to .WAV files with time stamped file names but its more use as a general tool for monitoroing LF signals. You can find details here http://g4jnt.com/Coherent_LF_Receiver.pdf and there's a better write up in Jan 2021 edition of RadCom (RSGB Members' magazine) Andy www.g4jnt.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Fri, 15 Jan 2021 at 23:55, paul swed <paulswedb@gmail.com> wrote: > What was the program that you used for the plot please? > Regards > Paul > WB8TSL > > On Fri, Jan 15, 2021 at 5:54 PM Andy Talbot <andy.g4jnt@gmail.com> wrote: > > > I did a plot of the phase of the UK 198kHz longwave transmission to me, a > > path of about 150km, compared against an HP5061A Caesium standard > > N > > > > early 24 hours duration, covering night time and day time propagation in > > October. > > > > You can observe the wild wandering of both phase and amplitude during > > night time due to skywave/groundwave interaction as the ionosphere shifts > > around. > > > > Plot also at > > http://www.g4jnt.com/DropF/droitwichplot2a.bmp > > if the attachment doesn't get through > > > > > > [image: DroitwichPlot2a.bmp] > > Andy > > www.g4jnt.com > > > > > > > > < > > > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > > > Virus-free. > > www.avg.com > > < > > > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > > > On Fri, 15 Jan 2021 at 21:55, Gilles Clement <clemgill@gmail.com> wrote: > > > > > Hi JF, > > > DCF77 is more distant, less powerful and probably more polluted > (77kHz). > > > Anyhow I would probably not be able to measure better than 10e-11 with > > > current setup (need a better reference) > > > Indeed a good and stable phase lock was not easy to reach. > > > I experienced the day and night huge differences (as documented in > post) > > > but nothing specific to phase shifts during sunrise or sunset. > > > No big difficulties with the ferrite antenna and the receiver design > > > either (thanks to good stuff from the old radio days probably). > > > Found that magnetic field antenna (ie: ferrite) appeared much less > > > sensitive to pollution than electric field antennas. > > > Naturally bad experience with Led bulbs and vapor gas lamps. You have > to > > > chase them all and change to old filament lamps in and around the lab. > No > > > issues with computers though. > > > What I found most challenging (and hence interesting) was the > following : > > > - Temperature control, high resolution and high stability (Crystal > > > oscillator but also for the controller parts, ADC, DAC… ) > > > - PI loop stability (very tricky) > > > - Matching theory with practice (still work in progress…!) > > > - Understanding the logic and physics behind behaviors, the real root > > > cause of problems, > > > and especially why a « really clever » enhancement - more than often - > > > actually leads to… performance degradation... > > > Gilles. > > > > > > > > > > > > > Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts < > > > time-nuts@lists.febo.com> a écrit : > > > > > > > > Hi, > > > > 800Kw according to the press release of ANFR. I doubt it is the best > > > choice : DCF77 is more precise (active hydrogen maser) but a little bit > > > more distant... > > > > But the phase lock of a quartz on a VLF signal is not as easy. There > is > > > a considerable phase shift in the evening and in the morning with the > sun > > > position, big instabilities at these moments and you have a hudge > > > difference between day and night (10 e-9/8)... Have a look at the Adret > > > receiver 4101 with its step motor phase lock...The engineering of the > > > ferrite road antenna is very tricky : temperature coefficient of the > > > ferrite, subtle tiny out of resonnace tuning, problem of the > > interferences > > > from domestic electrnic pollution (computers with sync of monitors, led > > > drivers...). The archiyecture of the receiver is also tricky : no AGC > > > (introduces phaseshift), heavy filtering (where : antenna, receiver...) > > > > On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement < > > > clemgill@gmail.com> wrote: > > > > > > > > Hi, > > > > > > > > This is to share current results on a "Long Wave RadioFrequency > > > Standard" project I have been pursuing for a while. > > > > Attached are typical ADEV plots and a block diagram of the system. > > > > > > > > I live in a crowded city (Paris, France) with no - or very limited - > > > access to open sky. Not good for GPS. > > > > However a long wave broadcasting public service is (still) available, > > > broadcasting time signal for clocks. > > > > The transmitter is located in Allouis, central France (200km for > > Paris). > > > > The signal is quite powerful (1MW) and the carrier (162kHz ) is > > > stabilized with a Cesium-standard. > > > > > > > > I decided to test how far I could go in disciplining a local VCO with > > > this signal. > > > > > > > > As well known, long wave RF has interesting features: > > > > - Signal is available (almost) everywhere, anytime, in the country > > > especially inside buildings (even underground !) > > > > - Quite stable and strong ground wave in day time. > > > > - Relatively easy antenna and RF signal processing (ferrite rod) > > > > And there are naturally a number of drawbacks (especially with the > > > Allouis signal) such as: > > > > - Much more unstable signal at night (interferences with ionospheric > > > path) > > > > - Large phase modulation of the carrier (time signals bits +/- 1 rad > > > phase modulated). > > > > - RF perturbations on the signal path. > > > > -Stop broadcasting for maintenance every Tuesday morning…. > > > > > > > > Design of the « LWRFDO » was derived and inspired from many > references > > > (including this list naturally). > > > > Principles are summarized in the attached pdf, with the following > > > specific feature to get rid of the phase modulation: > > > > The incoming signal has large sections of « un-modulated » segments > > > between the time signal bits. > > > > (Including a whole quiet section during the 59th second) > > > > Such « quiet zones » are detected - where the 162kHz base carrier is > > > untouched - and measurement of phase difference > > > > with a local OCXO is then performed inside these quiet zones. Then PI > > > controller to a 20bits DAC (see picture). > > > > > > > > Latest results show ADEV approaching 10E-11 at 1000 seconds on the « > D2 > > > » graph (day time only). > > > > « DN123 » is a three days uninterrupted run, combining day and night > > > signals, showing the impact of night instabilities. > > > > The frequency standard stability at the transmitter site is given > for > > > 10e-12. > > > > LWRFDO PPS is measured against an HP10811A PPS (about 10e-11 > stability > > a > > > 100s) with a TICC, > > > > So I believe 10-11 is not far from the best one could get. > > > > Which is actually not too bad, isn’t it ? > > > > > > > > Still working on improving the OCXCO (currently home brewed) > > > > > > > > Comment and suggestions welcomed, > > > > Gilles. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > 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. > > > > > > > < > > > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > > > Virus-free. > > www.avg.com > > < > > > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > _______________________________________________ > > 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. > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>