[Elecraft] [K2] Using the K2 with KXPA100

[Matt VK2RQ]

Having just completed the build of a basic K2 kit, I was keen to see if I could use it with my KXPA100/KXAT100 combination to provide more power and take advantage of the KXPA100's automatic ATU. However, the basic K2 doesn't provide the keying output necessary to key the amp.

There is a keying circuit for the K2 described on the Elecraft webpage:
http://www.elecraft.com/Apps/Amp_keying_ckt.htm

It is a pretty neat implementation, but the layout and connections on the perf board are not described in detail, so I wrote up what I did to implement the keying circuit:
http://www.mwrs.org.au/2014/04/20/elecraft-k2-amplifier-keying-circuit/

The circuit works really well, and it is very nice the way the KXPA100 senses the band and the KXAT100 automatically recalls the required ATU settings for that band. 

73, Matt VK2RQ