G4DCV GS31b 144MHz Amplifier/gs31-16.jpg

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If you do not understand high-voltage safety procedures do not attempt to build a tube amplifier.

The HT voltage will kill

The design objective was for an amplifier with 1kW output at 100% duty cycle. I am nearly there, just a little tweaking to do. Why design for 1kW when the UK only allows 400W output? In the UK we are allowed to take the feeder loss into account and deliver 26dBW (400W) at the antenna feedpoint. In contests we use a 100ft tower and the antenna is fed with 150ft of LDF4-50 with a loss of 1.6dB. 26dBW + 1.6dBW = 27.6dBW = 570W at the shack end of the feeder. Designing for the 1kW level means we can under-run the amplifier for a cleaner signal and it is less likely to break down during contest operation.