Introduction

The sending of pictures via radio was being done by radio amateurs long before television began in Australia in 1956. This interesting aspect of Amateur Radio has several variations, from single-frame pictures through to full-color real-time video that can be received on a domestic television receiver with UHF capabilities.

ATV describes television as usually seen in the home. The scan rates are faster than for Fax or SSTV and this infers more bandwidth is required. Bandwidth can be seen as analogous to the hosepipe used for carrying water. The larger the hose diameter the greater the capability to pass water. The higher the frequency of the band used, the higher the amount of picture or other information that can be sent during a time period. Fast Scan television operates in the UHF band 420 to 450MHz and some higher frequency bands ranging from the 23cm, wavelength band 1240 to 1300MHz up to the 3cm Band around 10Ghz. Clearly the potential for quality increases as frequency increases but of course the old saying ‘enough is enough’ applies and the amateur interested in the mode will balance quality needed against the difficulties of assembling equipment to operate at the chosen frequency band.