[hpsdr] SDR experiment for the solar eclipse

[John Ackermann N8UR]

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