What is a Modulator?
A modulator takes in the audio and video (via the video combiner) signals generated byt the MYTH TV box, and converts them to a radio frequency signal suitable for feeding into a television set.
Different modulators will be needed for different television standards, for example, 405 line system A will need a different modulator to 525 line US standard, and the 625 line and 819 line systems have several different modulator requirements.
Where can I get a modulator?
For older, obsolete TV standards, a modulator will almost certainly have to be built, and there are several designs available. The Early Television Foundation supply a part kit which is adapable for the British 405 line system, and early U.S. 525 VHF transmissions.
Some other designs and discussions of 405 line modulators can be found here.
For current standards, modulators can be purchased "off the shelf", from most of the large electronics houses. If you are running the system into a modern set with a SCART type socket, then a modulator is not needed, as the SCART socket allows input of video and audio directly into the set.
A VHF modulator for NTSC 525 line systems is available here.
It is also worth looking at some older test equipment, I have a Philips 5511 pattern generator, which will accept external video and audio inputs, allowing it to be used as a modulator at both VHF and UHF.
Copyright J.Beacon & M.Wroe-Parker 2006