KC9HFR        
  First Name John
  QTH Mount Pleasant, WI
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AM station of KC9HFR

Transmitter consists of three separate RF decks sharing a common power supply and modulator. RF power amplifier in each deck uses Infineon C3 series superjunction power MOSFETs in a push-pull Class E circuit.

Homebrew power supply for RF decks provides 12 volts for the synthesizer/buffer, 20 volts for the driver, and 40 volts for the power amplifier. Peak limiter supplies 2 volts positive to prevent negative overmodulation of the power amplifier. Power supply for the modulator (not shown) provides 100 volts.

Homebrew 160 meter RF deck uses eight MOSFETs in the power amp. Maximum carrier output is 300 watts.

Homebrew PLL frequency synthesizer provides carrier signal source for the 160 meter deck.

Homebrew 75 Meter RF deck uses eight MOSFETs in the power amp. Maximum carrier output is 300 watts.

Homebrew 40 meter RF deck uses six MOSFETs in the power amp. Carrier power output is 200 watts.

Homebrew audio equipment includes mic preamp, compression amplifier, and modulator. Modulator output stage uses eight ON Semi high power audio transistors, 4 x MJL1302A and 4 x MJL3281A. Maximum continous sine wave output is 250 watts. Modulation is shunt fed via capacitor and modulation choke to the RF power amp.

Microphone is a Shure SM58.

Receivers are an Alinco DX-R8 and a Hallicrafters SX-43.

Main antenna is a homebrew vertical. Homebrew magnetic loop receives 75 meters and 40 meters.

73, John KC9HFR

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  Last update June 27, 2017