[AMPS] Full QSK for the SB-200

[Tom Branch]

Greetings,

Getting deeper into amplifier theory--thanks Rich!

Still playing with the idea of full QSK for the SB-200.  I ran across a
circuit in the Hints and Kinks column in the April 82 QST.  The circuit is
a simple design to switch the cathodes of the 572Bs on and off based upon
the presence of RF.  The presence of RF grounds the filament winding and
turns the tube on.  The absence of RF applies +125 volts to switch them
off.  

I'm thinking about combining this circuit with the fast T/R portion of the
Rich Measures' circuit to give the SB-200 full QSK.  Additionally the grid
bias circuit could be permanently grounded instead of running it through
the T/R relay.

Seems reasonable, although I'm not sure what impact it would have long-term
on the 572Bs. I wonder if they are truly "instant on" to support this
concept.

Any thoughts?

73 de Tom, K4NR

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