Image transmission by radio (SSTV):

The SSTV (Slow Scan TV) is an analog mode which consists in transmits little pictures through the radio.

Several methods exist, resolutions and different transmission time, some black and white, some in color.
The duration of transmission is about 1min 30 in these modes.

The fact that it is an analog transmission, and not a digital transmission, means that a picture is not transmitted as a sequence of 0 and 1, but as a mix of tones. The image appears as of the receipt, without error correction, parasites, or holes reception, translates into effect "snow" more or less important on the lines being displayed.
The SSTV is very useful when you want to make a contact with other people, just send an image on a frequency and wait until receiving another of another person. So after you can collect a lot of pictures that show the establishment of the radio contact between two persons.

To transform a classic image into mix of tones, you have to connect the transceiver to a pc and then choose a frequency (generally in amateur band), after you can use software such as Multipsk or Chromapix who will handle the encoding.

 

 

 

 

 

 

 

As can be noted in the example below, a weak received signal affects the quality of the image.
The images below were received a few months ago on the 3MHz band.
The quality of signal reception was not very good due to poor wave propagation this day.