Wednesday 12 September 2012

ADS-B using Ubuntu and the RTL2832

The next task for the RTL2832 was  to decode aircraft transmitting A-DSB using Ubuntu. Doug G4DZU had previously pointed me at a link with an idiots guide to doing it , so it was time to try
Installing gnuradio took one line (and patience):-

wget && chmod a+x ./build-gnuradio && ./build-gnuradio

dinner and desert  and a coffee later it finished. Time to see if it worked:-

rtl_test -t
Found 1 device(s):
  0:  Generic RTL2832U (e.g. hama nano)
Using device 0: Generic RTL2832U (e.g. hama nano)
Found Elonics E4000 tuner
Supported gain values (14): -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 29.0 34.0 42.0 
Benchmarking E4000 PLL...
[E4K] PLL not locked for 52000000 Hz!
[E4K] PLL not locked for 2217000000 Hz!
[E4K] PLL not locked for 1109000000 Hz!
[E4K] PLL not locked for 1249000000 Hz!
E4K range: 53 to 2216 MHz
E4K L-band gap: 1109 to 1249 MHz

looks like mine works 53-1108MHz & 1250-2216MHz, Impressive!

next install gr-air-modes:-

git clone
cd gr-air-modes/
mkdir build
cd build
cmake ..
sudo make install
sudo ldconfig
Launching the programme with -d -P 
with a piece of wire in the rtl283 antenna socket resulted in decodes from one aircraft almost overhead. Time for a better 1090MHz antenna. The J pole previously used was easy to build from 2 pieces of semi rigid cable so time to make another.It was tuned with a tracking generator/directional coupler/ spectrum analyser and achieved 32dB retun loss after tweaking. Putting this on the end of 35' of cable in the loft resulted in many more decodes and a torrent of data in the terminal:- 

Next time to plot the data. The article  pointed to Virtual radar server at so this was installed. Launching it with and clicking on the http link for local host resulted in the following map with 8 aircraft:-

The rtl2832 is not as sensitive as the Modesbeast I also have but it is only 5% of the cost!

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