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--- project:sdr:tetrapol:howto [2016/03/31 17:35] – demod.py example usage jenda
+++ project:sdr:tetrapol:howto [2016/04/19 03:08] (current) – [Tools usage] ok, round it ;) jenda
@@ Line 1: / Line 1: @@
+===== Software How To =====
+On Debian install libcmocka-dev libglib2.0-dev libjson-c-dev.
+Clone the repository, do what README says.
+==== Tools usage ====
+  * The scripts in **demod/** directory eat data from SDR and spit out demodulated bits.
+  * **apps/tetrapol_dump** eats these bits and decodes metadata. Use -t TCH or -t CCH to decode the right channel (switch to the other one if it does not work).
+Scan for Tetrapol traffic. It is 12.5kHz wide buzzing (when demodulated as FM) usually in the 380-420MHz band.
+Compute the ARFCN of your station. We believe it is (f-358400000)/12500. E.g. a station at 394425 kHz is channel number 2882.
+Run the demodulator, passing tetrapol_dump to its pipe. E.g.
+<code>./demod.py -c 2882 -p 44 -g 40 -O "tetrapol_dump -t TCH"</code>
+To save raw bits for further experiments, you can for example add the "tee" command to the pipe.
+If the dumping mysteriously fails, you probably have wrong type of channel. There are CCH channels (broadcast and control messages) and TCH channels (actual traffic is happening here).