headset question

i saw abot a month back someone posted about making a one eared headset with a mic on the headset. i wasnt too interested at the time, but im flying a 1-26 now and the speaker is horrible. its mounted in the fuselage at about mid wing is very hard to hear, but if i turn it up loud enough to hear someone talking then the 'squawks' echo through the fuselage and hurt my ear. also i have seen a lot of comments on 'boom mics'. is this where the talk button is mounted on the stick? i remember when reading about this headset it had a 'boom mic' ithink that would be real handy. well if anyone could give me some info i would be much delighted.

What I am using with the Microair 760 in my 1-26 is an inexpensive 1-eared headset with a noise-canceling electret mic. It has a clever little pivot in the middle of the headband, so it folds up fairly compactly. The connector is an 1/8 inch stereo phone plug. (tip is mic, middle ring is headphone, shaft is a common ground) These headsets are widely available for use with computer stuff. I've seen them for $15 at Radio Shack. (I think that was a closeout.) I've seen similar ones for ten bucks at an office supply store, and of course you can pay as much more as you can afford. It's pretty comfortable.

The Microair is set up for electret mics, and the 32 ohms or so impedance of the earphone seems to get driven to adequate levels by the headphone output without distorting.

On older, or more conventional airplane radios YMMV. That is, you may need some sort of amplifier for the electret mic to make it look more like the standard carbon microphone, and I believe the nominal impedance of most aviation headsets is either 150 or 300 ohms. An appropriate audio transformer ( generally a little cube less than an inch on a side, and a couple of bucks from Radio Shack or Digi-Key) should take care of the speaker impedance match, or, depending on the design of the audio amplifier in the radio, it might not matter that much. A one transistor amplifier for the electret mic could be wired up on perfboard pretty easily and cheaply.

If this is going into someone else's radio, you will probably need an adapter to plug into the speaker and headphone jacks.

I have my PTT set up on the stick.

Of course, you might want to see if you can't solve your problem more easily just by replacing the speaker. It's entirely possible that the reason it sounds crummy is because the speaker is distorting, rather than it just being the reflections from the tailcone.

Tim Ward

i see what ur looking at, but is there a button somewhere, is there somewhere that u can ad on a button to start transmissions. i think u said something about a PTT mounted on the stick, was that an add on or did it come with it.

Well, that will depend on the radio. I'm not an expert on aviation radios, but as I understand it, in most conventional setups there are two jacks. One takes a two-conductor 1/4 inch phone plug. That's for the headphone(s). The other is a slightly smaller (.210 inch, I believe) phone plug with three conductors. One is ground, one is mic audio, and one is PTT. If you short PTT to ground, the radio will transmit. So you can make an adapter that plugs into the smaller jack, passes through the mic signal and ground to an identical jack, and brings the PTT out to, say, a switch with some velcro on it, that you can attach to the stick. I'm pretty sure something similar to this is available through Aircraft Spruce and Specialty, though I'm not sure of the prices. Try looking at: http://www.aircraftspruce.com/catmain.php? dest=cathome.php

Try not to gulp so much at the prices. Or you could make a little box with two short cords on it that plugs into the standard jacks, and comes out with a PTT and a jack wired for one of those inexpensive headphones I was talking about earlier. The adaptation required, if any, would be inside the box.

Since the PTT is activated by shorting a line to ground, and the switch is normally open, you can have as many PTTs on the line as you could reasonably want, so you might be able to talk someone into putting a PTT on the stick. If done properly, it shouldn't interfere with the use of a hand mike.

Tim Ward