[Amps] Johnson Desk KW

[Joe Giacobello]

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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