C implementation of a lightweight FT8 encoder, appropriate for microcontrollers. The encoding process is relatively light on resources, and an Arduino should be perfectly capable of running this code.
Currently the basic message set for establishing QSOs, as well as telemetry and free-text message modes are supported:
- CQ {call} {grid}, e.g. CQ CA0LL GG77
- CQ {xy} {call} {grid}, e.g. CQ JA CA0LL GG77
- {call} {call} {report}, e.g. CA0LL OT7ER R-07
- {call} {call} 73/RRR/RR73, e.g. OT7ER CA0LL 73
- Free-text messages (up to 13 characters from a limited alphabet) (decoding only, untested)
- Telemetry data (71 bits as 18 hex symbols)
Encoding works for FT8. For encoding there is a console application provided which serves mostly as test code.
To build on linux: run make. Then run gen_ft8 (run it without parameters to check what parameters are supported).
Brian Mathews gives thanks to:
- Kārlis Goba who wrote the original work and did the very heavy lifting. All I've done is make derivative versions of the original. Either by porting to other platforms (ex. C#) or by slimming down the code for certain narrow use cases (ex. encode only, FT8 only, Free-Text only, etc.)
Kārlis Goba gives thanks to:
- my contributors who have provided me with various improvements which have often been beyond my skill set.
- Robert Morris, AB1HL, whose Python code (https://github.com/rtmrtmrtmrtm/weakmon) inspired this and helped to test various parts of the code.
- Mark Borgerding for his FFT implementation (https://github.com/mborgerding/kissfft). I have included a portion of his code.
- WSJT-X authors, who developed a very interesting and novel communications protocol
The details of FT4 and FT8 procotols and decoding/encoding are described here: https://physics.princeton.edu/pulsar/k1jt/FT4_FT8_QEX.pdf
Karlis Goba, YL3JG