Tempest for Eliza is a Program that uses your computer monitor
to send out AM radio signals. You can then hear computer
generated music in your radio.
this document first describes tempest for eliza, the old program that
plays music like your cellphone does when you get a phonecall. then it
describes tempest for mp3 which you can use to play mp3 files
It should not do any damage. It probably puts different display patterns on the screen that concentrate the EMI radiation at one frequency in the AM broadcast band. It probably varies the pattern so that the amplitude of the radiation varies with the audio level. I suspect that it has high audio distortion, but the specifications for AM broadcast transmitters is 5% distortion.