Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse
there is no reason for an eclipse to affect time. However, working on the 1999 data made available by the German group, I had found a periodicity in the noise in one of the time series. In particular, a pattern (a peak) was repeated every 35 minutes, which was the periodicity recorded by a gravimeter in Trieste (Italy) http://xoomer.virgilio.it/iovane/xtrieste.htm I discarded those data because they didn't match in time the Trieste's disturbances. I suspect that an eclipse-related cause might affect in some way the atomic clock circuitry (or even magnetic shielding) with a (weak) possibility of causing artifacts. Keep an open eye. i8iov > > Il 4 agosto 2017 alle 16.22 Tom Van Baak ha scritto: > > > > > > We were originally going to put a 5071A-locked beacon on three ham > > bands, but decided WWV and CHU would be better sources, and > > logistics > > were turning into a problem: I'm going to be doing my wideband > > recording > > from a cottage in northern Michigan. But I'm still a time-nut, so > > the > > receiver will be GPSDO-controlled, and there will be a stratum 1 NTP > > server in the cottage to provide timestamps. :-) > > > > John > > > > > > Hi John, > > My favorite write-up about atomic clocks and eclipses (a null result) is > at: > > http://www2.mpq.mpg.de/~haensch/oldStuff/eclipse/eclipse.html > > There you will find a good summary, thorough methodology, and many plots > for the 1999 eclipse. Plus they posted all the raw data (H-maser, cesium, > rubidium), a time-nuts dream. There is no model for why an eclipse should > affect time at the atomic (quantum) level so a null result is fine. If > nothing else, it sets an upper bound on measurement precision or a lower > bound on clock anomalies, if they exist. > > Much more dramatic is what an eclipse might do to the ionosphere, as this > may affect both GPS and HF radio. So I'm very please to see the ham community > milking this rare opportunity for all it's worth. > > /tvb > > ___ > 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: [hpsdr] SDR experiment for the solar eclipse
On 8/4/17 7:22 AM, Tom Van Baak wrote: We were originally going to put a 5071A-locked beacon on three ham bands, but decided WWV and CHU would be better sources, and logistics were turning into a problem: I'm going to be doing my wideband recording from a cottage in northern Michigan. But I'm still a time-nut, so the receiver will be GPSDO-controlled, and there will be a stratum 1 NTP server in the cottage to provide timestamps. :-) John Hi John, My favorite write-up about atomic clocks and eclipses (a null result) is at: http://www2.mpq.mpg.de/~haensch/oldStuff/eclipse/eclipse.html There you will find a good summary, thorough methodology, and many plots for the 1999 eclipse. Plus they posted all the raw data (H-maser, cesium, rubidium), a time-nuts dream. There is no model for why an eclipse should affect time at the atomic (quantum) level so a null result is fine. If nothing else, it sets an upper bound on measurement precision or a lower bound on clock anomalies, if they exist. Much more dramatic is what an eclipse might do to the ionosphere, as this may affect both GPS and HF radio. So I'm very please to see the ham community milking this rare opportunity for all it's worth. It is of great interest - the fact that we have an ionosphere (which helps keep us alive) also is one of the bigger factors in accurate time distribution from space since the medium is refractive - not only does it change the speed at which a wave propagates through, but the propagation path is not a straight line. The ionization is almost entirely due to the sun. There is some small effect from terrestrial upper atmosphere phenomena propagating upwards, and then there's also human caused changes (HAARP and other heaters, rocket launched clouds of easily ionizable material, and the occasional high energy nuclear reaction in the upper atmosphere/space). There's a lot that is unknown about the time constants of the ionization and deionization, since the usual situation is that you gradually reduce the solar input (sunset) and increase it some 12 hours later. And there's not, often, the chance to have a "step function" in the solar illumination vs horizontal distance. The real challenge is that it's a short event - with conventional ionosondes, the sweep is minutes long (which is fine given the usual slow diurnal variation), which is significantly longer than the duration of totality. That long slow sweep makes synchronization less critical - if you start off by a few milliseconds, as long as your receiver bandwidth is wide enough, you still capture the sweep. It's not going to happen this time, but something where "all frequencies get measured every few seconds" would be wonderful. There are some ionosondes using a broadband PN waveform. And there's some interesting propagation experiments that have been done over the Cascade mountain range using TV and Radio stations as a form of pseudo random transmit signal. But you could do a real interesting science experiment with several dozen (or hundred) RTL-SDR receivers, a good oscillator for timing, and a data logger spread over several thousand km. In conjunction with the existing ionosondes, you could collect a lot of oblique measurements of the ionosphere during the eclipse. Then would come (years of) post processing - ___ 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: [hpsdr] SDR experiment for the solar eclipse
> We were originally going to put a 5071A-locked beacon on three ham > bands, but decided WWV and CHU would be better sources, and logistics > were turning into a problem: I'm going to be doing my wideband recording > from a cottage in northern Michigan. But I'm still a time-nut, so the > receiver will be GPSDO-controlled, and there will be a stratum 1 NTP > server in the cottage to provide timestamps. :-) > > John Hi John, My favorite write-up about atomic clocks and eclipses (a null result) is at: http://www2.mpq.mpg.de/~haensch/oldStuff/eclipse/eclipse.html There you will find a good summary, thorough methodology, and many plots for the 1999 eclipse. Plus they posted all the raw data (H-maser, cesium, rubidium), a time-nuts dream. There is no model for why an eclipse should affect time at the atomic (quantum) level so a null result is fine. If nothing else, it sets an upper bound on measurement precision or a lower bound on clock anomalies, if they exist. Much more dramatic is what an eclipse might do to the ionosphere, as this may affect both GPS and HF radio. So I'm very please to see the ham community milking this rare opportunity for all it's worth. /tvb ___ 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: [hpsdr] SDR experiment for the solar eclipse
On 8/3/17 12:10 PM, John Ackermann N8UR wrote: This is a little off-topic, but thought some of the group might be interested... so please forgive the interruption. Here's a time-nuts connection some ionosphere scientists I've been working with suggest that you sync your SDR and make it receive ionosonde transmissions. These are precisely timed to start at the top of the minute (hence the utility of a decent clock). They also have well characterized transmit power and pattern. There are open source implementations of chirpsounder receivers for GNURadio and for platforms like USRPs. Juha Vierinen at Univ of Tromso, Norway has been very active in this. https://hackaday.com/author/jvierine/ http://www.sgo.fi/~j/gnu_chirp_sounder/ John Forwarded Message Subject: [hpsdr] SDR experiment for the solar eclipse Date: Thu, 3 Aug 2017 15:07:57 -0400 From: John Ackermann N8UR To: fmt-n...@yahoogroups.com, HPSDR list * High Performance Software Defined Radio Discussion List * I've been working with the "HamSci" group to set up an experiment for the solar eclipse: wideband recording of several HF bands before, during, and after the eclipse to look for propagation changes (or anything else that happens). All are welcome to participate in the experiment, and this is a *perfect* application for our SDRs! Here's the HamSci web page: http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment Various SDRs and programs have wideband recording capability. Radios that support the HPSDR "old protocol" (which include Hermes-based boards as well as the Red Pitaya and possibly others) can do an even better trick: they can record multiple slices of the HF band simultaneously, thanks to work by Tom McDermott N5EG. Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should handle 3 (not tested), and the Red Pitaya can support 6 (tested). This means that we can record most of the 80M band, and all of 40, 30, and 20M, in one gulp to look for effects of the eclipse -- frequency shift, propagation enhancement/reduction, noise floor, etc. I've written a Gnuradio .grc program that used N5EG's driver to record multiple receivers. By default it's configured for four receivers on 80/40/30/20M, but that's easy to change. I'll be posting that software to the TAPR github at https://github.com/TAPR as soon as we've done a bit more testing. This software runs on Linux and may work on Windows (I haven't had a chance to try, but Gnuradio has been ported to Windows). Recording 4 384kHz channels does take some computing horsepower and uses a lot of disk space -- about 3MB per receiver per second. My prior-generation i7 machine with solid state drive seems to handle it OK. If you're interested in participating in this experiment, please (a) check out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or two to grab the software and docs; and (c) feel free to contact me directly with any questions. 73, John N8UR ___ 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: [hpsdr] SDR experiment for the solar eclipse
Hi John appreciate the problems at HF, and Boulder is very close to the track of the totality to use WWVB Enjoy the event hope you record some interesting effects. Best Wishes Alan G3NYK - Original Message - From: "John Ackermann N8UR" To: Sent: Thursday, August 03, 2017 9:20 PM Subject: Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse That experiment is happening, too. Folks will be monitoring WWV and CHU in narrowband mode with the same tools they use in the frequency measuring tests. (You can't really do direct phase comparisons on HF frequencies because between the noise and the ionospheric effects, including doppler shift, it's really hard to lock to the RF cycle the way you can at VLF.) We were originally going to put a 5071A-locked beacon on three ham bands, but decided WWV and CHU would be better sources, and logistics were turning into a problem: I'm going to be doing my wideband recording from a cottage in northern Michigan. But I'm still a time-nut, so the receiver will be GPSDO-controlled, and there will be a stratum 1 NTP server in the cottage to provide timestamps. :-) John On 08/03/2017 03:57 PM, Alan Melia wrote: A Time Nut would measure phase change across the path of totality using GPS locked SDR receivers :-)) As was done on the Eclipse that passed between the UK and Iceland a couple of years ago. Keflavik NRK's ionospheric signal was returned from inside the path of totality to most of the north of the UK, giving a good measure of the change in height of the "apparent reflection height" in the D-layer. The quoted program looks a bit scattergun..lets record everthing and see what's there. Hopefully it will involve a lot of school kids and maybe interest them in science and electronics. If it does that it will be more useful that we could imagine. Alan G3NYK - Original Message - From: "John Ackermann N8UR" To: "Discussion of precise time and frequency measurement" Sent: Thursday, August 03, 2017 8:10 PM Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse This is a little off-topic, but thought some of the group might be interested... so please forgive the interruption. John Forwarded Message Subject: [hpsdr] SDR experiment for the solar eclipse Date: Thu, 3 Aug 2017 15:07:57 -0400 From: John Ackermann N8UR To: fmt-n...@yahoogroups.com, HPSDR list * High Performance Software Defined Radio Discussion List * I've been working with the "HamSci" group to set up an experiment for the solar eclipse: wideband recording of several HF bands before, during, and after the eclipse to look for propagation changes (or anything else that happens). All are welcome to participate in the experiment, and this is a *perfect* application for our SDRs! Here's the HamSci web page: http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment Various SDRs and programs have wideband recording capability. Radios that support the HPSDR "old protocol" (which include Hermes-based boards as well as the Red Pitaya and possibly others) can do an even better trick: they can record multiple slices of the HF band simultaneously, thanks to work by Tom McDermott N5EG. Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should handle 3 (not tested), and the Red Pitaya can support 6 (tested). This means that we can record most of the 80M band, and all of 40, 30, and 20M, in one gulp to look for effects of the eclipse -- frequency shift, propagation enhancement/reduction, noise floor, etc. I've written a Gnuradio .grc program that used N5EG's driver to record multiple receivers. By default it's configured for four receivers on 80/40/30/20M, but that's easy to change. I'll be posting that software to the TAPR github at https://github.com/TAPR as soon as we've done a bit more testing. This software runs on Linux and may work on Windows (I haven't had a chance to try, but Gnuradio has been ported to Windows). Recording 4 384kHz channels does take some computing horsepower and uses a lot of disk space -- about 3MB per receiver per second. My prior-generation i7 machine with solid state drive seems to handle it OK. If you're interested in participating in this experiment, please (a) check out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or two to grab the software and docs; and (c) feel free to contact me directly with any questions. 73, John N8UR ___ 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://ww
Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse
That experiment is happening, too. Folks will be monitoring WWV and CHU in narrowband mode with the same tools they use in the frequency measuring tests. (You can't really do direct phase comparisons on HF frequencies because between the noise and the ionospheric effects, including doppler shift, it's really hard to lock to the RF cycle the way you can at VLF.) We were originally going to put a 5071A-locked beacon on three ham bands, but decided WWV and CHU would be better sources, and logistics were turning into a problem: I'm going to be doing my wideband recording from a cottage in northern Michigan. But I'm still a time-nut, so the receiver will be GPSDO-controlled, and there will be a stratum 1 NTP server in the cottage to provide timestamps. :-) John On 08/03/2017 03:57 PM, Alan Melia wrote: A Time Nut would measure phase change across the path of totality using GPS locked SDR receivers :-)) As was done on the Eclipse that passed between the UK and Iceland a couple of years ago. Keflavik NRK's ionospheric signal was returned from inside the path of totality to most of the north of the UK, giving a good measure of the change in height of the "apparent reflection height" in the D-layer. The quoted program looks a bit scattergun..lets record everthing and see what's there. Hopefully it will involve a lot of school kids and maybe interest them in science and electronics. If it does that it will be more useful that we could imagine. Alan G3NYK - Original Message - From: "John Ackermann N8UR" To: "Discussion of precise time and frequency measurement" Sent: Thursday, August 03, 2017 8:10 PM Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse This is a little off-topic, but thought some of the group might be interested... so please forgive the interruption. John Forwarded Message Subject: [hpsdr] SDR experiment for the solar eclipse Date: Thu, 3 Aug 2017 15:07:57 -0400 From: John Ackermann N8UR To: fmt-n...@yahoogroups.com, HPSDR list * High Performance Software Defined Radio Discussion List * I've been working with the "HamSci" group to set up an experiment for the solar eclipse: wideband recording of several HF bands before, during, and after the eclipse to look for propagation changes (or anything else that happens). All are welcome to participate in the experiment, and this is a *perfect* application for our SDRs! Here's the HamSci web page: http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment Various SDRs and programs have wideband recording capability. Radios that support the HPSDR "old protocol" (which include Hermes-based boards as well as the Red Pitaya and possibly others) can do an even better trick: they can record multiple slices of the HF band simultaneously, thanks to work by Tom McDermott N5EG. Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should handle 3 (not tested), and the Red Pitaya can support 6 (tested). This means that we can record most of the 80M band, and all of 40, 30, and 20M, in one gulp to look for effects of the eclipse -- frequency shift, propagation enhancement/reduction, noise floor, etc. I've written a Gnuradio .grc program that used N5EG's driver to record multiple receivers. By default it's configured for four receivers on 80/40/30/20M, but that's easy to change. I'll be posting that software to the TAPR github at https://github.com/TAPR as soon as we've done a bit more testing. This software runs on Linux and may work on Windows (I haven't had a chance to try, but Gnuradio has been ported to Windows). Recording 4 384kHz channels does take some computing horsepower and uses a lot of disk space -- about 3MB per receiver per second. My prior-generation i7 machine with solid state drive seems to handle it OK. If you're interested in participating in this experiment, please (a) check out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or two to grab the software and docs; and (c) feel free to contact me directly with any questions. 73, John N8UR ___ 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] Fwd: [hpsdr] SDR experiment for the solar eclipse
A Time Nut would measure phase change across the path of totality using GPS locked SDR receivers :-)) As was done on the Eclipse that passed between the UK and Iceland a couple of years ago. Keflavik NRK's ionospheric signal was returned from inside the path of totality to most of the north of the UK, giving a good measure of the change in height of the "apparent reflection height" in the D-layer. The quoted program looks a bit scattergun..lets record everthing and see what's there. Hopefully it will involve a lot of school kids and maybe interest them in science and electronics. If it does that it will be more useful that we could imagine. Alan G3NYK - Original Message - From: "John Ackermann N8UR" To: "Discussion of precise time and frequency measurement" Sent: Thursday, August 03, 2017 8:10 PM Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse This is a little off-topic, but thought some of the group might be interested... so please forgive the interruption. John Forwarded Message Subject: [hpsdr] SDR experiment for the solar eclipse Date: Thu, 3 Aug 2017 15:07:57 -0400 From: John Ackermann N8UR To: fmt-n...@yahoogroups.com, HPSDR list * High Performance Software Defined Radio Discussion List * I've been working with the "HamSci" group to set up an experiment for the solar eclipse: wideband recording of several HF bands before, during, and after the eclipse to look for propagation changes (or anything else that happens). All are welcome to participate in the experiment, and this is a *perfect* application for our SDRs! Here's the HamSci web page: http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment Various SDRs and programs have wideband recording capability. Radios that support the HPSDR "old protocol" (which include Hermes-based boards as well as the Red Pitaya and possibly others) can do an even better trick: they can record multiple slices of the HF band simultaneously, thanks to work by Tom McDermott N5EG. Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should handle 3 (not tested), and the Red Pitaya can support 6 (tested). This means that we can record most of the 80M band, and all of 40, 30, and 20M, in one gulp to look for effects of the eclipse -- frequency shift, propagation enhancement/reduction, noise floor, etc. I've written a Gnuradio .grc program that used N5EG's driver to record multiple receivers. By default it's configured for four receivers on 80/40/30/20M, but that's easy to change. I'll be posting that software to the TAPR github at https://github.com/TAPR as soon as we've done a bit more testing. This software runs on Linux and may work on Windows (I haven't had a chance to try, but Gnuradio has been ported to Windows). Recording 4 384kHz channels does take some computing horsepower and uses a lot of disk space -- about 3MB per receiver per second. My prior-generation i7 machine with solid state drive seems to handle it OK. If you're interested in participating in this experiment, please (a) check out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or two to grab the software and docs; and (c) feel free to contact me directly with any questions. 73, John N8UR ___ 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] Fwd: [hpsdr] SDR experiment for the solar eclipse
This is a little off-topic, but thought some of the group might be interested... so please forgive the interruption. John Forwarded Message Subject: [hpsdr] SDR experiment for the solar eclipse Date: Thu, 3 Aug 2017 15:07:57 -0400 From: John Ackermann N8UR To: fmt-n...@yahoogroups.com, HPSDR list * High Performance Software Defined Radio Discussion List * I've been working with the "HamSci" group to set up an experiment for the solar eclipse: wideband recording of several HF bands before, during, and after the eclipse to look for propagation changes (or anything else that happens). All are welcome to participate in the experiment, and this is a *perfect* application for our SDRs! Here's the HamSci web page: http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment Various SDRs and programs have wideband recording capability. Radios that support the HPSDR "old protocol" (which include Hermes-based boards as well as the Red Pitaya and possibly others) can do an even better trick: they can record multiple slices of the HF band simultaneously, thanks to work by Tom McDermott N5EG. Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should handle 3 (not tested), and the Red Pitaya can support 6 (tested). This means that we can record most of the 80M band, and all of 40, 30, and 20M, in one gulp to look for effects of the eclipse -- frequency shift, propagation enhancement/reduction, noise floor, etc. I've written a Gnuradio .grc program that used N5EG's driver to record multiple receivers. By default it's configured for four receivers on 80/40/30/20M, but that's easy to change. I'll be posting that software to the TAPR github at https://github.com/TAPR as soon as we've done a bit more testing. This software runs on Linux and may work on Windows (I haven't had a chance to try, but Gnuradio has been ported to Windows). Recording 4 384kHz channels does take some computing horsepower and uses a lot of disk space -- about 3MB per receiver per second. My prior-generation i7 machine with solid state drive seems to handle it OK. If you're interested in participating in this experiment, please (a) check out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or two to grab the software and docs; and (c) feel free to contact me directly with any questions. 73, John N8UR ___ 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.
