SSTV, or Slow Scan Television, is a method of sending digital images over radio, or sound. Basically what it does is it takes an image, looks at each pixel and color of the image, and then sends a sound frequency that corresponds to that color in the device picking up the sound. The device that is listening will take the audio in and convert it back to a picture. This was essentially “texting” an image way before phones or anything even existed! Copthorne Macdonald invented SSTV in 1957. Its first major usage was to broadcast and send images from a space probe taking pictures of the moon back to earth. This was used in the Sputnik and Vostok capsules and satellites, before also being used on the Apollo 7 and 8 missions. Amazing that an image can be turned into a series of sounds that can be sent in any way, such as over the radio or played loud from a speaker, and then can be heard by a device and be turned back into an image again. In the modern day, SSTV is actually still used! The International Space Station (ISS) uses it to transmit images of space back to earth. The reason they use this and not something like WiFi, is because the radio waves are very low frequency, meaning that they can travel much longer distances than WiFi can. If you know how, any person can tune in to the broadcast and receive the images from space on their own computer! Many people also run essentially their own radio stations and broadcast images using SSTV on them. This is called Ham Radio, or Amateur Radio. Another thing with all of this, the round trip conversion from image, to audio, to image gives the pictures a very unique retro and glitchy look to them, so it’s cool to see how the pictures turn out! SSTV is fun to mess around with at home, but it is also a useful tool for transferring images over very long distances and radio operators to communicate / share pictures.

For an awesome comic about SSTV, please go to the Litter Box section!