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 <j...@febo.com>
To: fmt-n...@yahoogroups.com, HPSDR list <hp...@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
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