NMap the sky
I think I was first introduced to the idea of software-defined radio at What The Hack in 2005. A chap (more than likely Eric Blossom) was going on at some length about passive radar, telemetry and DXing using computers, a thing called GNU Radio and some DC-to-daylight hardware for £Kerching! It sounded like all sorts of jolly expensive fun, and the notion of passive radar I filed away for a story where the bad sorts couldn't find the upstart troublemakers because their radar-seeking missiles had no radar transmitter to seek.
A few weeks ago, jarkman was going on at length about RTL-SDR and cheap Freeview podules. I filed that away because I was in between getting paid.
Since then I've been paid, and indeed accidentally Ebay for a USB podule that will cope with circa 27MHz to 1.7GHz at £12 delivered. Not quite DC to daylight, but not quite £2K either.
(I note that a search of 'ebay RTL' reveals all sorts of Shenzen-sourced things that 'require own welding', but will start at 100KHz where all the valve-pilot wireless lives.)
Thus I have been nmapping bits of the radio spectrum to see what's out there. (That's theoretically where all the airport beacons and pilot/ATC chatter lives.)
One used to be able to spot the radio-ham types as one was driven about as a child, because they were the people with several thumping great aerials in their back gardens. I very much doubt that I'll end up with a rotating Yagi, but a small discone looks like it would be fun to build.
Things:
http://www.sigidwiki.com/wiki/Signal_Identification_Guide
http://www.techmeology.co.uk/gr-scan/
http://superkuh.com/rtlsdr.html
http://kmkeen.com/rtl-power/
https://github.com/keenerd/rtl-sdr-misc/blob/master/heatmap/heatmap.py
% rtl_power -f 24M:32M:8k -e 1h rtty.csv
% heatmap.py rtty.csv rtty.jpg
https://github.com/MalcolmRobb/dump1090
http://antirez.com/news/46
http://helix.air.net.au/index.php/d-i-y-discone-for-rtlsdr/
A few weeks ago, jarkman was going on at length about RTL-SDR and cheap Freeview podules. I filed that away because I was in between getting paid.
Since then I've been paid, and indeed accidentally Ebay for a USB podule that will cope with circa 27MHz to 1.7GHz at £12 delivered. Not quite DC to daylight, but not quite £2K either.
(I note that a search of 'ebay RTL' reveals all sorts of Shenzen-sourced things that 'require own welding', but will start at 100KHz where all the valve-pilot wireless lives.)
Thus I have been nmapping bits of the radio spectrum to see what's out there. (That's theoretically where all the airport beacons and pilot/ATC chatter lives.)
One used to be able to spot the radio-ham types as one was driven about as a child, because they were the people with several thumping great aerials in their back gardens. I very much doubt that I'll end up with a rotating Yagi, but a small discone looks like it would be fun to build.
Things:
http://www.sigidwiki.com/wiki/Signal_Identification_Guide
http://www.techmeology.co.uk/gr-scan/
http://superkuh.com/rtlsdr.html
http://kmkeen.com/rtl-power/
https://github.com/keenerd/rtl-sdr-misc/blob/master/heatmap/heatmap.py
% rtl_power -f 24M:32M:8k -e 1h rtty.csv
% heatmap.py rtty.csv rtty.jpg
https://github.com/MalcolmRobb/dump1090
http://antirez.com/news/46
http://helix.air.net.au/index.php/d-i-y-discone-for-rtlsdr/