[Elecraft] External Amp QSK Operation with K2

[Vic Rosenthal]

Clark L. Stewart wrote:
 > I was recently asked a question by a potential K-2 purchaser.  He wants
 > to know:
 >
 > "Is there a digital signal available from the K-2 to allow QSK operation
 > with an external amplifier?"
 >
 > Some amplifiers apparently have special provisions for not allowing
 > themselves to be hot-switched during QSK operations.

The barefoot K2 needs a small (single transistor) circuit added to
provide an amplifier keying output.  This is built into the KPA100.
This circuit is driven from the K2 8R line, which is is sequenced so
that it keys the amplifier significantly before RF output appears from
the K2 and holds until after RF output has stopped.

I've successfully used this method to directly key several different
amplifiers from the K2, some with vacuum-relay QSK and one (Alpha 86)
with PIN diode QSK.  In all cases it's been quite adequate to key the
amplifier at high speeds (40 wpm) without hot switching.

-- 
73,
Vic, K2VCO
Fresno CA