THE ‘UD’:
A LIGHTWEIGHT HANDHELD IAMBIC KEY

Inspired by Up / Down microphone buttons, built by KC8UD

Once I began combining amateur radio with my backpacking hobby I began to see the real advantages of going QRP. Even my little Norcal 40A with a battery, key and antenna weighed in at a little over five pounds. I noticed the difference right away when that extra five plus pounds was along for an extended hike. So I began to search for ways to lighten the load.

I had decided right away, and the scales prove it, that leaving the tuner behind and taking a resonant thin wire antenna saves several ounces. The choice of battery makes a difference not only in weight but also in endurance. Some of the NiMH batteries now days will out perform and weigh less than the lead acid, alkaline or NiCad equivalents.

One day while playing with the menus in my Icom IC-706, I found that the Up/Down buttons on the microphone can be used to operate the iambic keyer. CLICK! The light bulb switched on and the idea hit me. How about a very lightweight hand held key similar to this microphone? The two buttons on the top of the microphone weren’t quite in the right position for comfortable keying so I began exploring my hand posture to see what felt best. I wanted to be able to use my thumb and index finger since that’s what I’m used to when using a paddle.

Just by using what materials I had close by I came up with a key that can be held and comfortably operated in one hand. Voila! The “UD” Key was born by inspiration of the microphone Up / Down buttons. There is no need to set the key down on a flat surface. The hand held key doesn’t require a heavy weighted base or the need to be clamped to some stationary object. There’s no need to hold it with both hands. The operator can sit, stand, walk or even lie down (in the comfort of a warm sleeping bag on a cold night) to operate. On a cold day you can even keep your hands in your pockets and still use the iambic keyer.

The use of extremely lightweight and readily available materials make this iambic key a natural companion for the minimalist who is watching the ounces and the budget. Construction and mastering its use can all be done in less than an hour.

Grab the first two 35mm film canisters you find before they become extremely rare. This is the foundation of the hand held key. After drilling a small hole in the bottom of each canister, you will need three-conductor wire to thread through the holes. Then nest the canisters tightly together. You may want to wrap some plastic tape around them or apply some glue for holding power. I’ve tied a knot in the wire a couple of inches from the end for strain relief to keep it from pulling back through the canisters and breaking lose from the switches.

The switches can be most any momentary push button type switch. You don’t want to use the click on / click off type. I’ve tried several different types of push buttons and the ones I prefer have a little click to them when I push them in. Once they have just the right amount of force placed on them they pop into place and make positive contact. I prefer this type of tactile feedback which is similar to a computer keyboard. Other switches are silent and just push in without any assurance that it’s made good contact and I find that my CW sending is somewhat sloppy in this case. My wife prefers me to use the silent switches so she doesn’t have to listen to the clickity click click late into the night while we’re sharing a tent.

Pull enough wire out the top of the canisters to solder onto both switches. You may want to hold the canister in your hand and mark the mounting positions of the switches according to where you feel they would be most comfortable. Then mount one of the switches part way down the side of the canister. The other gets mounted to the side of a canister lid. With the switch mounted off to one side of the lid, the lid can be rotated to vary the distance between the two switches slightly. This allows you to fine tune the positions for comfort.

The other end of the wire can be soldered to an appropriate connector or even hard wired to your transmitter and leave the connector out of the parts list if you want to save that much weight.

I’ve been using my hand held key for several years now and have never seen anything else like it. I even use it on the base station as well as in the field. Several puzzled onlookers at the Dayton Hamvention questioned what it was until I explained. And then there was always the “Oh Yeah. Now I see.” It may look a little awkward as it breaks away from the traditional paddle key. But if you try it you may find it’s a good thing for you. It does just what I need.

Now with the hand held iambic key, my new cinnamon flavored Rockmite, battery, earbuds, RG-174 coax and half wave 40 meter dipole, my backpacking QRP station is complete. The entire package tickles the scales at less than one pound. This feather weight station works. It’s a kick to operate and it’s hardly a burden to carry on a long trek, even for a minimalist.