Re: [time-nuts] RFDO - Experience and questions
Actually as I think about it from the earlier part of the thread. Locking to the carrier with a 2-4 second time constant removes the phase modulation since its only in the first 200 ms. The 0 Phase is 800 ms in length or more for all bits. Now to find some nice coils for 162 KHz. Regards Paul On Mon, Mar 6, 2017 at 8:30 PM, paul swed wrote: > A bit more reading if you block the phase comparison from -50ms to 150ms > of the tick you get a 0 carrier phase no modulation. That also explains why > I thought I could here some sort of phase modulation because there is. > So as an example if you use a GPS tick its really simple to block the > phase changes and only measure the 0 phase carrier. Essentially a 200 ms > carrier gap per second. > Thats quite a clean format you have to work with. > Regards > Paul > WB8TSL > > > On Mon, Mar 6, 2017 at 8:19 PM, paul swed wrote: > >> I checked out 162KHz at 2000 local and now have what I believe to be TDF >> using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the >> US or 3400 miles. A comfortable signal at least in the winter. As a >> comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW >> power level like TDF. >> >> Since I had not heard TDF before I listened to Pieters online SDR radio >> to see what to listen for. The easiest point to notice is the 59 second >> phase. Its funny that also seconds 0-10 should be the same phase but it did >> not seem to be true. Unless what I am hearing is the local oscillator of >> Pieters SDR radio. >> >> So thanks for sharing some new knowledge with Time-nuts. >> Regards >> Paul >> WB8TSL >> >> On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer < >> ptdeb...@cs.utwente.nl> wrote: >> >>> >>> On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote: >>> >>> > That's TDF from France. Their equivalent of WWV/MSF/DCF. >>> >>> > Average phase and frequency deviation is >>> > zero over 200msec (see link above for details) >>> >>> This is not quite correct, since the transmitter does not just carry the >>> time data (one bit per second, in the first 200 ms of the second), but >>> also some more data during the next 700 ms of each second. >>> The latter data is coded in a way which does not guarantee that the phase >>> or frequency average is zero other than when averaging over the entire >>> 700 ms block. >>> Then again, I've been told that although there is a nicely defined >>> framing >>> format, in reality it has only ever transmitted idle frames, so in >>> practice >>> it's a fixed pattern which repeats every minute and thus could be >>> cancelled >>> for use as a frequency reference. >>> >>> I have a live online decoder for TDF's signal at >>>http://websdr.ewi.utwente.nl:8901/tdf/ >>> >>> Regards, >>> Pieter-Tjerk, PA3FWM >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/m >>> ailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
A bit more reading if you block the phase comparison from -50ms to 150ms of the tick you get a 0 carrier phase no modulation. That also explains why I thought I could here some sort of phase modulation because there is. So as an example if you use a GPS tick its really simple to block the phase changes and only measure the 0 phase carrier. Essentially a 200 ms carrier gap per second. Thats quite a clean format you have to work with. Regards Paul WB8TSL On Mon, Mar 6, 2017 at 8:19 PM, paul swed wrote: > I checked out 162KHz at 2000 local and now have what I believe to be TDF > using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the > US or 3400 miles. A comfortable signal at least in the winter. As a > comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW > power level like TDF. > > Since I had not heard TDF before I listened to Pieters online SDR radio to > see what to listen for. The easiest point to notice is the 59 second phase. > Its funny that also seconds 0-10 should be the same phase but it did not > seem to be true. Unless what I am hearing is the local oscillator of > Pieters SDR radio. > > So thanks for sharing some new knowledge with Time-nuts. > Regards > Paul > WB8TSL > > On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer < > ptdeb...@cs.utwente.nl> wrote: > >> >> On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote: >> >> > That's TDF from France. Their equivalent of WWV/MSF/DCF. >> >> > Average phase and frequency deviation is >> > zero over 200msec (see link above for details) >> >> This is not quite correct, since the transmitter does not just carry the >> time data (one bit per second, in the first 200 ms of the second), but >> also some more data during the next 700 ms of each second. >> The latter data is coded in a way which does not guarantee that the phase >> or frequency average is zero other than when averaging over the entire >> 700 ms block. >> Then again, I've been told that although there is a nicely defined framing >> format, in reality it has only ever transmitted idle frames, so in >> practice >> it's a fixed pattern which repeats every minute and thus could be >> cancelled >> for use as a frequency reference. >> >> I have a live online decoder for TDF's signal at >>http://websdr.ewi.utwente.nl:8901/tdf/ >> >> Regards, >> Pieter-Tjerk, PA3FWM >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> > > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
I checked out 162KHz at 2000 local and now have what I believe to be TDF using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the US or 3400 miles. A comfortable signal at least in the winter. As a comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW power level like TDF. Since I had not heard TDF before I listened to Pieters online SDR radio to see what to listen for. The easiest point to notice is the 59 second phase. Its funny that also seconds 0-10 should be the same phase but it did not seem to be true. Unless what I am hearing is the local oscillator of Pieters SDR radio. So thanks for sharing some new knowledge with Time-nuts. Regards Paul WB8TSL On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer wrote: > > On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote: > > > That's TDF from France. Their equivalent of WWV/MSF/DCF. > > > Average phase and frequency deviation is > > zero over 200msec (see link above for details) > > This is not quite correct, since the transmitter does not just carry the > time data (one bit per second, in the first 200 ms of the second), but > also some more data during the next 700 ms of each second. > The latter data is coded in a way which does not guarantee that the phase > or frequency average is zero other than when averaging over the entire > 700 ms block. > Then again, I've been told that although there is a nicely defined framing > format, in reality it has only ever transmitted idle frames, so in practice > it's a fixed pattern which repeats every minute and thus could be cancelled > for use as a frequency reference. > > I have a live online decoder for TDF's signal at >http://websdr.ewi.utwente.nl:8901/tdf/ > > Regards, > Pieter-Tjerk, PA3FWM > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt Rollover Testing
Plus Trimble's usage is rather misleading... you can do true overdetermined clock in either a static or moving environment... it properly requires more sats to be tracked than necessary to determine the time. Position hold mode (and Trimble's overdetermined clock mode) requires a fixed location and can work with only one tracked sat,. > I very much prefer the “position hold” term for what it is doing compared to > Trimble’s “overdetermined” description. Overdetermined suggests that it has > more information than it needs to come up with the time. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
On 3/6/2017 3:47 PM, Graham / KE9H wrote: What antenna are you using that you call the "mini-whip?" Specifically, how long is the "whip?" http://dl1dbc.net/SAQ/miniwhip.html 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
Just for the heck of it fired up the hp3586 on 162KHz tuned +/- 2 Khz both a vertical antenna 67 feet and horizontal dipole 160 ft. Nothing at 1800 utc near Boston Ma. But in the sun for another7 hours. Regards Paul WB8TSL On Mon, Mar 6, 2017 at 9:47 AM, Graham / KE9H wrote: > Anders: > > What antenna are you using that you call the "mini-whip?" > > Specifically, how long is the "whip?" > > Thanks, > --- Graham > > == > > On Mon, Mar 6, 2017 at 3:57 AM, Anders Wallin > > wrote: > > > FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few > days > > ago. The signals look like this from our site: > > http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg > > http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg > > http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg > > > > I guess the +/- 40 Hz side-bands on TDF are by design? > > > > I have an SDR set up also, so the gnu-radio demodulators could run in > > parallel on each of these, and the sdr sampling clock could come from a > > local clock. One more project on the to-do list... > > > > Anders > > > > > > On Mon, Mar 6, 2017 at 12:42 AM, Iain Young wrote: > > > > > On 05/03/17 20:23, paul swed wrote: > > > > > > Gilles what signal is that at 162KHz. A European station? Nice thats > its > > C > > >> controlled. > > >> > > > > > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry > > > the AM Station France Inter as well, but that went when France turned > > > off all LW, MW, and LORAN stations at the end of 2016. > > > > > > The Time Signal is Phase Modulated (I have a gnuradio decoder which > > > works very well if anyone is interested) > > > > > > See https://en.wikipedia.org/wiki/TDF_time_signal and > > > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter > > > > > > With no AM modulation, there are obvious benefits with regards to using > > > it as a frequency reference. Average phase and frequency deviation is > > > zero over 200msec (see link above for details) > > > > > > > > > Iain > > > > > > PS, The signal is used by the French railways SNCF, the electricity > > > distributor ENEDIS, airports, hospitals according to the Allouis link > > > above > > > > > > > > > ___ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to https://www.febo.com/cgi-bin/m > > > ailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > > mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote: > That's TDF from France. Their equivalent of WWV/MSF/DCF. > Average phase and frequency deviation is > zero over 200msec (see link above for details) This is not quite correct, since the transmitter does not just carry the time data (one bit per second, in the first 200 ms of the second), but also some more data during the next 700 ms of each second. The latter data is coded in a way which does not guarantee that the phase or frequency average is zero other than when averaging over the entire 700 ms block. Then again, I've been told that although there is a nicely defined framing format, in reality it has only ever transmitted idle frames, so in practice it's a fixed pattern which repeats every minute and thus could be cancelled for use as a frequency reference. I have a live online decoder for TDF's signal at http://websdr.ewi.utwente.nl:8901/tdf/ Regards, Pieter-Tjerk, PA3FWM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 33120A purchase off epay
On 3/5/17 9:14 PM, Christopher Hoover wrote: My HP 33120A Function Generator died. (I'm still trying to fix it, but it isn't obvious what's wrong ... rails check so I'm suspicious the EEPROMs gave up the ghost.) I bought a new one on epay week befor last for a fair price. It arrived and I was surprised/excited to find it had the external reference option. Just what a TimeNut needs. The external ref option wasn't mentioned explicitly in the listing, although I can see it (in retrospect) in one of the pictures. I don't know about on the 33120, but on the 33620 series, the external reference doesn't actually phase lock the internal clock for the ARB. It's more of a frequency reference, and the output is steered to match the frequency of the external reference. (counters and NCOs) The phase noise of the 36620 is entirely determined by the internal oscillator, and the ADEV is a bit tricky - it's like the ADEV of a disciplined oscillator, not a phase locked loop. There are ways to sync multiple 33620 and 33120s (and the earlier 3325) so that you have multiple outputs with a phase coherent relationship. You have to do it manually.. feed them all the same reference, then adjust til they're synced, then they'll stay in sync. Here's Agilent's ap note on externally syncing 33120s http://cp.literature.agilent.com/litweb/pdf/5988-8151EN.pdf about your option 001 http://www.keysight.com/upload/cmc_upload/All/33120A_Opt001.pdf?&cc=US&lc=eng service manual and schematic of your Opt001 http://literature.cdn.keysight.com/litweb/pdf/33120-90022.pdf (From Keysight about the 33620 series: When using an external 10 MHz time base with this instrument, a PLL syncs together the internal oscillator with that external signal, as you have surmised. To my understanding, because of this however, the stability of the function generator’s time base is still dependent on the internal oscillator. If an OCXO is being used in the 33600, the instrument will be limited to a input frequency range of 10 MHz ± 1Hz. Therefore, even if an external input signal at 10 MHz was stable to 10 ppb, for instance, the instrument would still be limited to a 100 ppb stability because of its’ own internal oscillator. This means feeding a more stable reference signal into the function generator, will likely not improve performance. Again, this is to my own understanding of how this instrument works and I am going to double check this with our factory to see if they agree or disagree. I will update you when I have that confirmation. ) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
Anders: What antenna are you using that you call the "mini-whip?" Specifically, how long is the "whip?" Thanks, --- Graham == On Mon, Mar 6, 2017 at 3:57 AM, Anders Wallin wrote: > FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days > ago. The signals look like this from our site: > http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg > http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg > http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg > > I guess the +/- 40 Hz side-bands on TDF are by design? > > I have an SDR set up also, so the gnu-radio demodulators could run in > parallel on each of these, and the sdr sampling clock could come from a > local clock. One more project on the to-do list... > > Anders > > > On Mon, Mar 6, 2017 at 12:42 AM, Iain Young wrote: > > > On 05/03/17 20:23, paul swed wrote: > > > > Gilles what signal is that at 162KHz. A European station? Nice thats its > C > >> controlled. > >> > > > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry > > the AM Station France Inter as well, but that went when France turned > > off all LW, MW, and LORAN stations at the end of 2016. > > > > The Time Signal is Phase Modulated (I have a gnuradio decoder which > > works very well if anyone is interested) > > > > See https://en.wikipedia.org/wiki/TDF_time_signal and > > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter > > > > With no AM modulation, there are obvious benefits with regards to using > > it as a frequency reference. Average phase and frequency deviation is > > zero over 200msec (see link above for details) > > > > > > Iain > > > > PS, The signal is used by the French railways SNCF, the electricity > > distributor ENEDIS, airports, hospitals according to the Allouis link > > above > > > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/m > > ailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
Gilles, I just looked at the signal behavior from the TDFlink you sent.There are 14 seconds worth of very controlled phase. There are additional bits also. As Bob says if the format is controlled you can predict the change and correct the phase. This is exactly what I created for the wwvb BPSK signal in the US about 1-2 years ago. It runs on a small arduino and requires no modification to any of the phase tracking receivers. It super simple with few parts. It was my first arduino project and took maybe a week of time at night. Granted I like the rest of the work you are doing and the prediction concept can very reasonably be put into you software for prediction. You should not need to worry about a unpredictable phase flip. On wwvb there are a couple bits that can not be predicted but never seen that yet. Even if they do a 3-4 second loop constant like all of the old receivers has removes the issue. Plan to warm up the HP3586 tonight and take a listen at 162 KHz in the US. Regards Paul WB8TSL On Mon, Mar 6, 2017 at 4:57 AM, Anders Wallin wrote: > FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days > ago. The signals look like this from our site: > http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg > http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg > http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg > > I guess the +/- 40 Hz side-bands on TDF are by design? > > I have an SDR set up also, so the gnu-radio demodulators could run in > parallel on each of these, and the sdr sampling clock could come from a > local clock. One more project on the to-do list... > > Anders > > > On Mon, Mar 6, 2017 at 12:42 AM, Iain Young wrote: > > > On 05/03/17 20:23, paul swed wrote: > > > > Gilles what signal is that at 162KHz. A European station? Nice thats its > C > >> controlled. > >> > > > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry > > the AM Station France Inter as well, but that went when France turned > > off all LW, MW, and LORAN stations at the end of 2016. > > > > The Time Signal is Phase Modulated (I have a gnuradio decoder which > > works very well if anyone is interested) > > > > See https://en.wikipedia.org/wiki/TDF_time_signal and > > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter > > > > With no AM modulation, there are obvious benefits with regards to using > > it as a frequency reference. Average phase and frequency deviation is > > zero over 200msec (see link above for details) > > > > > > Iain > > > > PS, The signal is used by the French railways SNCF, the electricity > > distributor ENEDIS, airports, hospitals according to the Allouis link > > above > > > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/m > > ailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fwd: Dusty 53131A
Hi, To state the obvious, I think the same goes for 53132A and indeed several others. Cheers, Magnus On 03/06/2017 08:19 AM, Bob Camp wrote: Hi 53131’s are dust magnets. It is not at all uncommon for them to fill up with dust, overheat, and die. Popping them open every 10 years or so to clean them out is well worth the effort. Bob On Mar 5, 2017, at 8:54 PM, Scott Stobbe wrote: Recently the fan in my 53131 has been making a pretty awful sound, so its time to replace it. When I disassembled the counter I found the trim cap had turned into a fur ball. Not that it really matters since it runs on an external reference, but its interesting to see if the dust has any effect. See https://www.flickr.com/photos/147407087@N06/32427230764/. So with the unit disassembled I logged the effect of removing the dust by logging a GPSDO during the cleaning process. Must of the dust was around the shroud of the trim cap. Near the mounting terminals there was fairly minimal amounts of dust. At least in this instance, if the dust had any impact on frequency, its orders of magnitude below the thermal instability of the AT crystal. The crystal appears to be in a to-39 3-lead package. It is also freestanding directly in front of the exhausting cooling fan... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days ago. The signals look like this from our site: http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg I guess the +/- 40 Hz side-bands on TDF are by design? I have an SDR set up also, so the gnu-radio demodulators could run in parallel on each of these, and the sdr sampling clock could come from a local clock. One more project on the to-do list... Anders On Mon, Mar 6, 2017 at 12:42 AM, Iain Young wrote: > On 05/03/17 20:23, paul swed wrote: > > Gilles what signal is that at 162KHz. A European station? Nice thats its C >> controlled. >> > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry > the AM Station France Inter as well, but that went when France turned > off all LW, MW, and LORAN stations at the end of 2016. > > The Time Signal is Phase Modulated (I have a gnuradio decoder which > works very well if anyone is interested) > > See https://en.wikipedia.org/wiki/TDF_time_signal and > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter > > With no AM modulation, there are obvious benefits with regards to using > it as a frequency reference. Average phase and frequency deviation is > zero over 200msec (see link above for details) > > > Iain > > PS, The signal is used by the French railways SNCF, the electricity > distributor ENEDIS, airports, hospitals according to the Allouis link > above > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
Hi Gilles, You Wrote: Indeed, the station is located in central France with a very powerful transmitter (up to 2MW). It covers all Europe and it was a real pain for me when they stopped broadcasting the France Inter Station. I understand the French government have a consultation out about what to use the AM carrier for, so maybe another commercial AM station will pick it up. The longwave signal can be received anywhere, even in the basements (ground effect propagation). No need for an external full sky antenna etc… Hopefully they are still operating and sending the time code. They are. I've written an SDR decoder for it, and with it being Phase Modulated, it doesn't suffer from the varying signal strengths of both MSF and DCF. And actually the signal is much clearer today in 2017 than when it was also amplitude modulated. Good news, but how long will it last ... ? Agreed, it's a nice clean carrier now :) I think it will last a good time, Certainly with some of the things that use it in France, I suspect it will be there for some time to come Best Regards Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt Rollover Testing
Hi > On Mar 6, 2017, at 1:38 AM, Mark Sims wrote: > > Does it have a saved/surveyed position? With a saved position you can > reasonable time performance with 1 sat. Without a saved position all bets > are off, there is no way for the receiver to determine the > receiver/satellite clock difference. > > Trimble reports that the device is in "over-determined clock" mode if that is > how it is configured. Even if it is in "over-determined clock" mode the > receiver may not have enough data to do anything effective. Trimble's > overdetermined clock mode is basically a "position hold" mode. I very much prefer the “position hold” term for what it is doing compared to Trimble’s “overdetermined” description. Overdetermined suggests that it has more information than it needs to come up with the time. Bob > > > >> I just re-checked this with a Resolution-T, and it does go into OD mode with >> all but 1 > SV masked from cold restart using a real SV. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RFDO - Experience and questions
Hi One way to “cheat” at recovering a time signal is to demodulate it with known information. Once you know the information from the first “frame” of data (time, date, etc) you can predict what the information in the next frame will be. Yes it does take a little work. If the signal is completely defined (no extra data about the weather forecast or something like that) you can reduce your bandwidth significantly. Bob > On Mar 5, 2017, at 11:42 PM, Iain Young wrote: > > On 05/03/17 20:23, paul swed wrote: > >> Gilles what signal is that at 162KHz. A European station? Nice thats its C >> controlled. > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry > the AM Station France Inter as well, but that went when France turned > off all LW, MW, and LORAN stations at the end of 2016. > > The Time Signal is Phase Modulated (I have a gnuradio decoder which > works very well if anyone is interested) > > See https://en.wikipedia.org/wiki/TDF_time_signal and > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter > > With no AM modulation, there are obvious benefits with regards to using > it as a frequency reference. Average phase and frequency deviation is > zero over 200msec (see link above for details) > > > Iain > > PS, The signal is used by the French railways SNCF, the electricity > distributor ENEDIS, airports, hospitals according to the Allouis link > above > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 33120A purchase off epay
My HP 33120A Function Generator died. (I'm still trying to fix it, but it isn't obvious what's wrong ... rails check so I'm suspicious the EEPROMs gave up the ghost.) I bought a new one on epay week befor last for a fair price. It arrived and I was surprised/excited to find it had the external reference option. Just what a TimeNut needs. The external ref option wasn't mentioned explicitly in the listing, although I can see it (in retrospect) in one of the pictures. Sweet! -- Christopher. 73 de AI6KG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Fwd: Dusty 53131A
Hi 53131’s are dust magnets. It is not at all uncommon for them to fill up with dust, overheat, and die. Popping them open every 10 years or so to clean them out is well worth the effort. Bob > On Mar 5, 2017, at 8:54 PM, Scott Stobbe wrote: > > Recently the fan in my 53131 has been making a pretty awful sound, so its > time to replace it. When I disassembled the counter I found the trim cap > had turned into a fur ball. Not that it really matters since it runs on an > external reference, but its interesting to see if the dust has any effect. > See https://www.flickr.com/photos/147407087@N06/32427230764/. So with the > unit disassembled I logged the effect of removing the dust by logging a > GPSDO during the cleaning process. > > Must of the dust was around the shroud of the trim cap. Near the mounting > terminals there was fairly minimal amounts of dust. At least in this > instance, if the dust had any impact on frequency, its orders of magnitude > below the thermal instability of the AT crystal. > > The crystal appears to be in a to-39 3-lead package. It is also > freestanding directly in front of the exhausting cooling fan... > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
