Home computers have started to find their way in to Amateur television, this is an extension of general radio related use in the last few years.

The 6502 based BBC Microcomputer was very popular with ATV'ers in the late 1980's as a composite video feed can be easily extracted without the need for any additional hardware. The only very simple modification was to add a small capacitor on to the underside of the PCB to gain colour output. You could also add a simple Genlock circuit board inside the BBC case, the effects that then became possible were quite impressive for such a simple and inexpensive set-up.

The Commodore Amiga range of machines was the next generation of home computers to be pressed into service, generating Callsigns and Captions using a variety of graphical packages. They are available on the second hand market now for approximately £50.

To enable through video signals to be idented etc, you will need some additional hardware in the form of a Genlock. The Genlock takes a video feed, usaully of composite nature and locks the machines internal video circuitry to your external source feed. Using this system you can superimpose graphics over any of your video signals. A typical Amiga Genlock device is shown in the picture below.

It is now possible to harness the power of the humble home P.C to generate composite video using a scan converter. These range in price from below £100 right up to £2500 for professional studio grade equipment. The scan converter takes the PC's RGB signals and converts them in to composite 1V P-P video complete with all timing conversions, this can then be fed into any equipment that can process a normal composite signal. With the advent of realistically priced hardware for the PC a whole new world is born. With specialist graphics software like Newtek Lightwave 5.0 we can create stunning commercial grade graphical/effects productions.