Decode UKHASnet packets with a RTL SDR dongle

This is a simple UKHASnet decoder for RTL SDR dongles. Other similar decoder might already exist but this was a way for me to understand the protocol and get used to it.

You need to have a working dongle and rtl_fm running.

Before starting

rtl_test

rtl_test -p 10 to get ppm error or use kalibrate but it did not work for me on OSX.

Get started

make

./UKHASnet-decoder -h

Compiling for Windows

It's possible to Cross Compile a windows .exe version from a Raspberry Pi (or other Linux System). You will need the mingw-w64 toolchain (these are different to the Mingw32 toolchain) and libraries for zlib, openssl and curl. Details for setting up the environment are avaialble at: https://ukhas.net/wiki/guides:rtlsdr_decoder_windows

TODO (see code for details)

• Synchronisation:
  • Add tolerance bit option (and possibly use the preamble for more robustness)
  • Support inverted bits
• Confirm that RFM CRC computation is weird (has someone had some experience with that ?)
• Find better threshold formula to account for packet with no sufficient bit transitions