aussiegeek / wspr

Rust WSPR generation

This library generates frequency shifts required for generating WSPR amateur radio transmissions.

It's return output is a 161 byte array of uint8 values of 0-4, which is the encoded symbol needing to be transmitted. Each symbol is shifted by a multiple of $\frac{12000}{8192}$ (1.46Hz), and transmitted for the reciporical of the tone spacing $\frac{1}{12000/8192}$ (ie. 0.68 seconds)

For example with a base frequency of 7,040,000:

Symbol	Frequency (hz)
0	7,040,000.00
1	7,040,001.46
2	7,040,002.92
3	7,040,004.35

References

1. https://swharden.com/software/FSKview/wspr/
2. https://github.com/swharden/WsprSharp (although I don't think it handles callsign padding correctly)
3. https://gist.github.com/bd1es/a782e2529b8289288fadd35e407f6440
4. https://github.com/kholia/wspr_encoder_web