An analogue method of transmitting still pictures via amateur radio. (TV proper is what on the amateur bands is called FSTV.) Each scanline of the image is converted into an audio tone of varying pitch, followed by a sync pulse to keep the scanlines lined up at the receiving end. There are many different protocols, most of them incompatible, but the most common one, Scottie, encodes varying shades of gray on a scale where a low pitch means black, and a high pitch means white. Colour transmissions are usually achieved by sending the same scanline three times, one with the red portion, one with the green, and one with the blue.

Nowadays, computer software is by far the most common means of sending and receiving SSTV, but before the advent of cheap, good sound cards, people had to use specialized electronics, including cameras and so-called slow scan monitors that would stay illuminated for a long time after the cathode ray had swept over it. The HF bands don't have a lot of available bandwidth, so it takes a couple of minutes to transmit a single image. Radio amateurs who were active on SSTV in elder days often made a habit of turning off the lights in the room so that the image would be visible on the screen a little longer before it disappeared forever.

Sometimes, radio amateurs have entire QSOs entirely on SSTV. People use paint software to write "CQ CQ de AB1XYZ PSE K" on top of images, or neutral backgrounds. Sometimes they are answered by another image, saying things such as "AB1XYZ de AB1UVW TNX CALL UR 579".

Hams also use SSTV to spice up or illustrate conversations they're having on SSB (telephony).

Images that amateurs send on SSTV range from pictures of themselves and their dog, their radio equipment, and the impressive antennas at the nearby MW transmitter site, to outright pornography. That last part is one of the reasons that some people criticize SSTV operators of being lids -- ie. people who make a habit of not following proper etiquette on the air.

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