Tempest-style
phreaking of your monitor can actually produce an
AM broadcast.
Quoting mr. Eric Thiele, the "
Eliza for Tempest" program author:
All electronic devices send out eletromagnetic waves. So does your monitor and your monitor does it all the time at very high frequencies. High enough for your short wave AM radio. All you have to do is display the "correct" image on your screen and your monitor will emit the "right" signals. Tempest for Eliza displays pictures on your screen, one for each note in the song.
This method takes advatage of the background EM radiation from your monitor to disrupt other communication. Unfortunlately, most new monitors are too shielded to sabotage unwanted radio transmissions, but it can still be fun to experiment with.
This program is available for download here: http://www.erikyyy.de/tempest/