High frequency power amplifier circuit
The amplifier works off 24V DC. Adjust potmeter VR1 for maximum power output. The RFC coil comprises 15 turns of 36SWG wire wound over a TV ferrite balun core. Coil L1 has 30 turns (15T+15T) of 24SWG copper-enameled wire wound over a 1.5cm dia. plastic tube. It is centre-tapped, with air core connected to the collector of transistor T1. Coil L2 has five turns of 24SWG wire wound over L1 centre. Transistor T2 should be mounted on a 3mm thick aluminium heat-sink.
The article was published in February 2007 and has recently been updated.