Rpitx: RF Transmitter for Raspberry Pi

Interesting set of example modulations, especially slow-scan television. You'd need a SDR to recieve that. It looks like this could also be used to transmit for short distances on the 433MHz band used by all sorts of gizmos (wireless doorbells, remote controlled lights etc).

Would be interesting to see example spectra to see how clean this is and what gains there are from simple filters or an antenna smarter than a monopole.

If I remember correctly, the Snowden dumps showed that the NSA could corrupt a processor / motherboard in such a way (overheating via overclocking?) that the computer would turn into a small radio that could transmit for miles. This would allow exfiltration of data even if not connected to the internet.