[Elecraft] External keyer question...

[Steve Banks]

Hi All-

Has anyone on the reflector ever connected a Heathkit SA-5010 Micromatic
Keyer to his/her K2?

Being something of a collector/restorer of anything long-of-tooth, I
recently dug out my old SA-5010 (circa 1980) and fitted/modified an
appropriate 3-pin connector and cable to it (a modified Futaba aileron servo
extension cable) with an appropriate 1/8" stereo plug to connect to my
Schurr paddle.

My question is which keying line to use to key the K2 directly from one of
the SA-5010's keying outputs. There are two of them, one - and one + .  Each
of them terminates in an RCA phono-type plug on the keyer's rear apron.
I'll be glad to remeasure the keyed output voltage from the SA-5010 if it's
needed.  (My recollection from bench-testing the keyer a couple of weeks ago
was that both lines provide about +20 or -20 VDC when the keyer is keyed,
but I don't recall for sure

I can build up the "auto detect" device requiring two diodes as illustrated
on the K2 Manual (p. 92) with no problem. But my concern is which of the
SA-5010 keying lines to use to connect to the K2. The two diodes shown in
the K2 illustration may not like one or the other of them.

Anyone have any suggestions?

Thanks for any comments.

73

Steve Banks
K0PQ
K2 S/N 1599