I bought an inexpensive $15 headset for my Elecraft K3, but didn't want to use VOX because of in-shack "QRM." For the 2007 Sweepstakes I used an MH2 in the front mic jack as the PTT button, but decided to try for something better.

A couple of days later I was near a Radio Shack, and stopped in. You can do the same thing with parts from cheaper sources, including your own junk box, but in the component drawer I found the following parts:


The K3 has an RCA jack for PTT, but I didn't remember that.

Don't make my mistake; use a shielded RCA cable and eliminate these remaining items:


I don't know if I got the idea to put the switch in the coax boot from reading it somewhere, or if it occurred to me when I was looking at the parts, but it fits great.

I removed the nut from the switch and ran the cable through. There's not enough room in the boot to tie the cable in a knot, so I used a few layers of electrical tape to provide strain relief. Then I soldered the white wire to pin 5 (GND) and the red wire to pin 4 (PTT) and was in business! Pin 5 is labelled on the connector back, and you can read it with a magnifying glass. Pin 4 is right next to it.


Finished product