SSTV
From HF Underground
Slow Scan Television (SSTV) is a method of transmitting pictures on a narrow voice channel. While it is used primarily by hams, pirate radio operators occasionally transmit pictures on shortwave by this method. The signal can be decoded from SSB reception by running the audio output from the receiver to a PC sound card, and using software designed to convert the signal to an image. In a pinch, a microphone connected to the sound card can be held up to the receiver's speaker. A decent, free software package for receiving SSTV is MMSSTV.
