[wwalker3]

Humorously enough, early television in the UK (from 1929-1935) had only 30 lines of resolution and so could be recorded at audio frequencies onto a "Phonovision" disk. You can see some examples at http://www.tvdawn.com/recordng.htm of the low quality of the results.

For a little while, the BBC did broadcasts of 30-line video using two AM radio frequencies (one for the video, one for the audio) that could be picked up by special recievers.