462 TinyWSPR
462 : TinyWSPR
- Author: asinghani
- Description: Tiny WSPR Beacon
- GitHub repository
- Clock: 0 Hz
How it works
Tiny WSPR Beacon for transmitting Weak Signal Propagation Reporter radio signals. Recommended for 20m and 40m bands.
How to test
Use the "config in" pins to input one byte of config data at a time. Input the 6-letter callsign as ASCII characters, padded as is standard for WSPR. Input the 4-letter grid square with the second and third character swapped (i.e. FN01 -> F0N1). Input the power level as a single byte in dBm. It must end in a 0, 3, or 7 for proper decoding. Input the symbol time (the number of clock cycles in 0.6827 seconds) as a 4-byte, big-endian value. Input the divisor (2^32 * (transmit_freq / clk_freq)) as a 4-byte, big-endian value. Input the deviation (2^32 * (1.4648 / clk_freq)) as a 2-byte, big-endian value. Wait until exactly one second after an even-numbered UTC minute, then raise the RF start pin. It is recommended to do this using a GPS-based timekeeping source.
External hardware
An external lowpass filter to remove harmonics is absolutely required, as this design uses a square-wave transmitter that generates harmonics well outside the legal limit. An appropriately tuned antenna for the band being used is also necessary in order to transmit effectively.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | Config valid | RF out | config[0] |
| 1 | Config start | RF out (mirror) | config[1] |
| 2 | RF start transmit | unused | config[2] |
| 3 | unused | unused | config[3] |
| 4 | unused | unused | config[4] |
| 5 | unused | unused | config[5] |
| 6 | unused | Debug out | config[6] |
| 7 | unused | Debug out | config[7] |