These AM Transmitters operate between 900KHz and 1750KHz on the Medium Waveband (AM Band) and beyond.

These heritage transmitters are based on a design which I built back in the mid 1970’s and is from a design which was published in ‘Short-Wave Magazine’ in the 1950’s which was called ‘Top-Band Transmitter’, although the original had a Crystal or VFO valve front end.

This Transmitter circuit design employs a CMOS Phase Locked Loop oscillator circuit for accuracy and ease of frequency selection. A binary code is created by the 8 position DIP switch. It is also very stable and therefore does not drift off frequency. The Phase Lock circuit provides selection in either 9KHz steps for UK/European Union or 10KHz steps for USA. A suitable Crystal is used for either is selected at time of ordering.

This oscillator feeds the RF driver stage which uses an EF91 Pentode which then feeds the 5763 (QV03-10) Beam Tetrode output valve which can produce about 10Watts RF at this frequency.