ZL1RS - Amplifiers

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


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Tune flapper capacitor - plate line - loading flapper capacitor


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Tune flapper capacitor


Loading flapper capacitor


Air wound bifilar filament choke - cathode input tuned circuit


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Grid current meter - bias zener and transistor - bias relay