This program transmits radio on computers / phones without radio transmitting hardware.
An implementation of TEMPEST with GNU Radio. This is basically a re-implementation of Martin Marinov's excelent TempestSDR in GNU Radio (see https://github.com/martinmarinov/TempestSDR). The reason is that I felt it may be easier to maintain and extend. Note however that the basic ideas were imitated, but the synchronization algorithms are different, and some functionalities (particularly in the GUI) are missing.
Cryptome's page of TEMPEST documents, most of which are declassified NSA docs though there are also mirrors of TEMPEST info from the private sector. Also has a very interesting discussion of how STU-III phones can be accidentally compromised by stray RF. Oops.