One way to add a tuned input with little fuss is to place a "tee"
connector at the input of the SS amp and connect a parallel resonant LC
circuit at the tee. Make the LC circuit have a Q of between 3 to 5 at 50
ohms and you're in business. Use a variable cap such as an Arco
compression trimmer and tune for minimum SWR. This does not need to be a
pi network if you do not need any impedance transformation. If you do
need a pi network, it can still be done externally, but it gets a bit
more complicated.
To multiband it, run a short piece of coax to a switch which selects a
separate LC circuit for each band. This is essentially what I have in my
homebrew 8877 amp, although the circuitry is inside the amp instead of
external to it. You might want two LC circuits on 80 and 160 to cover
the whole band, depending on the Q you choose.
73, Bill W6WRT
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