Video-only television modulator

How it works

This circuit converts composite video to a television-frequency RF signal. Its tuned inductors and capacitors determine the operating range, and small changes in coil shape or wiring can shift the channel.

It does not carry audio. The archive’s suggested channel ranges and approximately 100 m range are historical notes, not a verified modern operating specification.

On the bench

Tune using appropriate RF equipment and a wired load. Channel allocations and receiver compatibility vary, so do not treat an archived television channel number as authorization to transmit.

Resources & provenance

Rewritten from the original circuits/rfr/hg65q0p_rfr007.php page. Component values and historical performance claims have not been independently bench-tested. The circuit figures have had their watermarks removed.