Raspberry Pi as WSPR transmitter up to 250Mhz

There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

73, Guido