RPITX - a transmitter along frequencies from 130kHz to 500MHz
Great news. Raspberry Pi can now emit RF signals along a much wider range than previously publicized. It is three years since a team at Robotics Imperial College London wrote PiFM, a FM transmitter based on C and Python for the Raspberry Pi. a radio amateur. It is able to transmit at lower frequencies than even the HackRF, as it includes frequencies between 130kHz and 1MHz, though it is not capable of transmitting above 500MHz at this point. Innovations in electronics are still possible on Raspberry Pi, a modest platform for the auteur with the modest budget and a deep understanding of a well-documented interface and architecture. RPITX is available from GitHub. A third argument in the fcntl function open lacked in several source files (9th november 2015) and I had to set these to get rid of errors and be able to compile. Still I received warnings. I was able to emit a signal at both low and high frequencies. Enough to generate a RF field for the purpose of jamming, but of a questionable quality in some parts of the spectrum. Lots of harmonics, as reported on HackADay. Use ffmpeg (installed by default in Ubuntu Mate) to convert wav files to 48K and transform the file using pissb (included on GitHub) rpitx takes an IQ file as argument. The setup is rather simple although the code may be reduced if you wish to apply rpitx for a single purpose.