ZL1RS - Amplifiers

K1AGB 144 MHz 8877 Amplifier


K1AGB 8877 144 MHz Amplifier

Built from K1AGB's 1974 QST article and used for 2m EME in CW mode in the late 1980's. With about 3600V on the anode and 75W of drive it produced about 2kW of RF output. At the time I requested and was granted a special high power permit from the 'Radio Inspectors office' to use this amplifier.

Front. Anode and grid current meters - Load control vernier drive - Input tune knob - Tune control vernier drive

Back. BNC input socket - Ceramic feedthru HT - N-Type output socket

Blower - Filament transformer - Anode current meter

Aluminium plate line / Teflon sandwich plate coupling capacitor

HT bypass sandwich capacitor - PCB with Teflon sheet dielectric


Tune flapper capacitor - plate line - loading flapper capacitor


Tune flapper capacitor

Loading flapper capacitor

Air wound bifilar filament choke - cathode input tuned circuit


Grid current meter - bias zener and transistor - bias relay

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