Discussion:
Fwd: [hpsdr] SDR experiment for the solar eclipse
(too old to reply)
John Ackermann N8UR
2017-08-03 19:10:25 UTC
Permalink
Raw Message
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 <***@febo.com>
To: FMT-***@yahoogroups.com, HPSDR list <***@lists.openhpsdr.org>

***** 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-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Alan Melia
2017-08-03 19:57:29 UTC
Permalink
Raw Message
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" <***@febo.com>
To: "Discussion of precise time and frequency measurement"
<time-***@febo.com>
Sent: Thursday, August 03, 2017 8:10 PM
Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse
Post by John Ackermann N8UR
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
***** 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!
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
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
John Ackermann N8UR
2017-08-03 20:20:52 UTC
Permalink
Raw Message
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
----
Post by Alan Melia
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
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
Post by John Ackermann N8UR
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
***** 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!
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
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Alan Melia
2017-08-03 21:22:59 UTC
Permalink
Raw Message
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" <***@febo.com>
To: <time-***@febo.com>
Sent: Thursday, August 03, 2017 9:20 PM
Subject: Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse
Post by John Ackermann N8UR
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
----
Post by Alan Melia
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
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
Post by John Ackermann N8UR
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
***** 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!
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
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Tom Van Baak
2017-08-04 14:22:08 UTC
Permalink
Raw Message
Post by John Ackermann N8UR
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-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
jimlux
2017-08-04 15:05:07 UTC
Permalink
Raw Message
Post by Tom Van Baak
Post by John Ackermann N8UR
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,
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-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
iovane--- via time-nuts
2017-08-04 22:59:31 UTC
Permalink
Raw Message
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
Post by Tom Van Baak
Post by John Ackermann N8UR
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,
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
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

jimlux
2017-08-04 00:32:57 UTC
Permalink
Raw Message
Post by John Ackermann N8UR
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/
Post by John Ackermann N8UR
John
-------- Forwarded Message --------
Subject: [hpsdr] SDR experiment for the solar eclipse
Date: Thu, 3 Aug 2017 15:07:57 -0400
***** 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!
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
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Loading...