Re: [Amps] Rm resistor

["Phil Clements" <philk5pc@tyler.net>]

> The question was whether a midpoint resistor was needed when tuning 
> a PI-L
> network - surely it isn't whatever the amplifier configuration.
>
> Steve

Very true, Steve.
I have witnessed several Henry amps in the design stage at the 
factory.
That is exactly the way Paul Johnson does it. Tube and tank 
configuration has nothing to do with this process.

1. Install resistor from plate cap to ground = in value to plate load 
impedance.
2. Attach analyzer to output connector. Key relay, or jump across it.
3. Set Pi and/or L coils for proper inductance for desired Q on 
frequency of interest. (Eimac suggests Q of 10)
4. Preset tune and load caps to approximate values that formula 
suggests.
5. Adjust tune and load caps until 1:1 vswr is indicated on analyzer. 
You are done!


(((73)))
Phil, K5PC




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