Bill, I believe that this is the same arrangement used in the Viking
Thunderbolt. I don't have mine anymore, but it always worked well. I
think the Desk KW is just the Tbolt mounted in a desk. The guys on the
Johnson mailing list can also probably help.
73, Joe
Bill Fuqua wrote:
Got a Johnson Desk KW and notice something unusual about the
design. The RF amplifier has a linked variable capacitor and inductor
in plate PI output circuit which switches out the variable capacitor
for frequencies above 13MHz. So the PI output ckt from there up made
of the plate-ground capacitance the roller inductor and output
capacitors. I have only seen this sort of thing one place before in a
Mil. transmitter with a pair of 4CX300s in it. It had switched fixed
capacitors for plate side of the PI network, variable inductor with a
few switched inductors and variable output capacitor with some
switched fixed ones.
Well anyway, has anyone had some experience with the desk KW
amplifier? And have anything to say about the PI output? network?
73
Bill wa4lav
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