[time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse
alan.melia at btinternet.com
Thu Aug 3 17:22:59 EDT 2017
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
----- Original Message -----
From: "John Ackermann N8UR" <jra at febo.com>
To: <time-nuts at febo.com>
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. :-)
> 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.
>> ----- Original Message ----- From: "John Ackermann N8UR" <jra at febo.com>
>> To: "Discussion of precise time and frequency measurement"
>> <time-nuts at febo.com>
>> 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.
>>> -------- Forwarded Message --------
>>> Subject: [hpsdr] SDR experiment for the solar eclipse
>>> Date: Thu, 3 Aug 2017 15:07:57 -0400
>>> From: John Ackermann N8UR <jra at febo.com>
>>> To: FMT-nuts at yahoogroups.com, HPSDR list <hpsdr at 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:
>>> 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.
>>> John N8UR
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