Monday, March 17, 2014
A New CW Keying Control for Studio A...
For some time, I've been wrestling with routing the CW-to-Computer Interface, the Straight Key, and the keyer to various rigs, depending on the rig/band I was working. I finally decided to do something about it. I built a little CW Keying Control box in one evening, totally from junk box parts. This allows me to use my keyer, CW keyboard, and any straight key with any rig in the shack. No more plugging/unplugging cables when I switch rigs. I discovered that I had to build a little interface for the IC-211, so I just enclosed it in shrink wrap and tossed it behind the rig.
The internals of the CW Keying Control are pretty simple... A 3 position rotary switch, a pair of 1/4" phone jacks for the CW-Computer Interface and external keyer interface, .01uF cap to minimize key clicks, all in an old Radio Shack enclosure that was re-purposed from a previous project.
The IC-211 @M SSB/CW rig has a goofy keying circuit that doesn't provide enough unkeyed voltage at the CW jack to allow switching by the 2N2222 transistor in the computer interface. I built a little one-off interface to take care of those keying duties, and enclosed it in a piece of clear heat shrink tubing, since it was dedicated to the IC-211 and was going to be installed behind that rig.
The control box was finished in about 1 hour, complete with a re-purposed knob from an old junker and some High Tech Redneck labeling. Even the 1/4" phone plugs were all re-purposed from various bits of scrap around the shop...notice how each is a different style.
I installed the control under the 1st shelf at the operating position in Studio A. It looks right at home with the other home brew interfaces and vintage items that are mounted there for ease of operating.
Once everything was tested, I got on the air and put it to use. Wow...what a difference such a simple accessory can make in your shack. I don't know why I waited all these years to 'get around' to building this, but I'm glad I used this rainy afternoon to build this little piece!
Here's a rough schematic of the keyer interface I designed and built for the Icom IC-221 2m SSB rig. The CW keying circuit in that rig has to be pulled down to 0vdc to work correctly, and the solid state device in my computer interface only pulled it down to .6 vdc. I whipped this up, wrapped it in clear heat shrink tubing, and tossed it behind the rig. Works great!