Hello home builders, here is the matching amplifier for the ALTOIDS Tin FM Transmitter. More of the same here, another repackaging of famous Veronica equipment. This amplifier is basically the 5 watt amplifier section from a Veronica 5 watt VCO transmitter. At 13.5 vdc its output, with the matching exciter, is about 3.5 watts, clean and stable with cooling provided by a 1 inch fan.
Circuit Description: The amplifier, uses a MRF237 (equiv to NTE341) transistor, operating in class C, with a output up to 3-4 watts in the 88-108 MHz range. This clean design includes a built in 7 element lowpass filter. Special attention is given to keeping the rf off the dc line with rf chokes h1 (2t 30awg on fb), h2 (14t 30awg on 2.2k with fb on each end) and h3 (5t 30awg on fb). They are not critical and are easy to make but be sure to get ferite beads of #43 type material and that they are large enough to get 5 turns of 30awg wire through them.
