[Elecraft] External keyer question...

[Kevin Cozens]

At 09:39 AM 02/17/2002 -0700, Steve Banks wrote:
>Has anyone on the reflector ever connected a Heathkit SA-5010 Micromatic
>Keyer to his/her K2?
>
>(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

If the keyer has lines with +20 and -20 I would think it was designed to 
key old tube based rigs. You can't connect either line directly to the K2 
without damaging the K2.

Your best bet is to use the +20V line and build an interface between the 
Heathkit and the K2. You want an output from this interface circuit to be 
designed such that when +20V comes out of the Heathkit to activate the 
transmitter, this results in a transistor conducting to bring the keying 
lines to ground.

I think its probably a good job for an optoisolator. After all, you don't 
want to take a chance of the +20 getting in to your K2.


Cheers!

Kevin.  (http://www.interlog.com/~kcozens/)

Owner of Elecraft K2 #2172        |"What are we going to do today, Borg?"
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