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F5OEO / rpitx

RF transmitter for Raspberry Pi
GNU General Public License v3.0
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afsk for APRS ? #261

Open hemna opened 3 years ago

hemna commented 3 years ago

I couldn't tell, but does rpitx support sending 1200 baud AFSK for transmitting APRS packets?

comicsansgreenki commented 3 years ago

It does (if you want it NFM-encoded, like a normal APRS transciever), but currently, I have no knowledge of how one could get direwolf's PTT to start and stop the NFM transmission. Other than the constant carrier issue, you could get it to work by doing this:

  1. start direwolf
  2. feed soundcard audio stream to a modified version of testnfm.sh Said modded version could be: 
    (while true; do arecord -r 48000 -f S16_LE -c 1 -; done) | csdr convert_i16_f \
| csdr gain_ff 7000 | csdr convert_f_samplerf 20833 \
| sudo rpitx -i- -m RF -f "$1"

    The audio stream comes from arecord—you can replace this command with any audio source, as long as the input is WAV 48000 Hz, Signed 16-bit Little Endian, 1 channel.