Q I’ve heard of ATV repeaters, but is there such a thing as a slow-scan TV (SSTV) repeater?
A SSTV repeaters do exist, although they are really simplex repeaters by definition, not duplex systems that transmit and receive at the same time. SSTV repeaters receive images, store them briefly, then retransmit—often on the same frequency.
Some SSTV repeaters are controlled through a tone-access system. You transmit a 1750-Hz tone to get the repeater’s attention and, if the frequency is not already in use, the repeater will send a Morse “K” back to you. This means that you have about 10 seconds to begin transmitting your image. When you’ve completed the transmission, the repeater will retransmit the image in the same mode it was sent. In other words, if you used Martin 1, for example, the repeater will retransmit in Martin 1.
There are some SSTV repeaters that are open at all times and do not use a tone access system. They will accept and retransmit images whenever the frequency is clear. Most SSTV repeaters also send ID beacons at regular intervals. You can learn more about SSTV repeaters on the Web at http://www.mscan.com/mscan/repeaters.html.
From QST January 2000
