HF linear amplifier circuit


Posted on Feb 6, 2014

The PA output Pi section consists of 2 variable Cs (20 - 120pF and a second (home made) 50 - 450pF switched in for the lower bands by a simply modified 12v power relay). The anode choke (200t, 24swg 5` long on 1` dia PTFE tube stock) is mounted directly onto a 3300pF 10kV doorknob capacitor using a small turned brass ferule. The grid compartment.


HF linear amplifier circuit
Click here to download the full size of the above Circuit.

The main fan blows into the sealed grid compartment, and exits through holes around the grid bases to flow through the PA chimneys. The heater/cathode connections are again made from thin brass strip. The heater choke is wound on ferrite rod (from a scrap transistor radio, bifilar 28t 10swg). The input circuit consists of a 100ohm non-inductive 50Watt resistor (Farnell - about £3) directly across the input. The grid load is also about 100ohm under normal operating conditions so the input VSWR should be quite good.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    VUTRAX PCB CAD
    Digital Encoder with PIC16F57
    Lm318 Microphone preamplifier with tone control circuit and explanation
    hobby-games-modelling
    Simple DC power delay circuit
    Ionization smoke detector circuit using A5367



    Top