Thorp Air Command - T18.net

Here is a question in regards to Radio transmission: I have an I-COM Radio, it receives and transmits well. When I am Idling around it does fine when I transmit, I get no fuzzy stuff into my headphones, after I leave the ground and turn cross wind,the Lycasaurus is wound up,when I call out crosswind position I have fuzzy noise in my headset. The same holds true at cruise, it receives well, but when I transmit, I get the funny fuzzy crackling in my headset. When I get, into the pattern to return to field,no fuzzy crackling in the headset because the RPMS are at 1500. In Short, high RPMS =fuzzy in the headset during transmission, Where in the devil is this noise comming from? At low RPMS all is well, at high RPMS the fuzzy gets very annoying.........Who can answer this one? Dan

Dan,
Double check the ground on the shield on the alternator line, make sure it's only shielded at one end. Also check the shielding ground on your headset lines, same think on one end only. No ground loops.

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

Will do lee, I have shielded the alt wiring and P- leads will look at the Mic and Phone wiring. Upon further research seems the IC - A200 Has a gain adjust for the Mic and the Phones on top of the radio housing under 2silver stickers, This Fuzz that I am getting doesn't seem to be anything elec as it sounds like the Mic is being put into the wind. I found a guy on vans forum, same radio, same sound and it intensifies at higher RPM and vanishes at the lower. It would appear that my cockpit is too noisy and the gain may have to be adjusted,,,,,very tricky......It will have to be out of the slot to adjust.......didn't want to hear that.......Dan

Sounds like squelch problem on the intercom ? Adjust ? Or maybe a bad mic muff . On a recent flight my copilot lost the mike muff and it was impossible to communicate due to the cockpit noise .

RB POW !

I too had the same problem. I have two sets of ANR headsets and the ear muffs lost the ability to seal, replaced muffs, problem solved.

I lost my Mic muff at San Louis, it was old and cracked so had to replace it, my ear muffs are worn a tad but they are the third set that I have purchased. I have tried the wifes head set they are exactly like mine, and have gotten the same results. I continued my search some more and found out the Icom -I200 is nortorious for having this problem and it needs some adjustment. As soon as you push the PTT, the cockpit noise just goes through the Mic and into your head set. One adjustment is the Gain, the next adjust id for background noise cant remember what it is called and then there is a third screw for somting else will have to look at all of it again. Its not that much of a problem, but I am getting a few years on me and I don't have perfect hearing so it gets agrivating. Guess Im just turnin into an old Codger!!! (No comments on that Rich).........Dan

I completely removed the fuzz from the headphones during transmit this morning, my research paid off. It was the Mic gain adjustment, I went too low with it on the first go around and raised it up just a hair. When I transmit now the sound in my headset is crystal clear, with the lycasaurus runnin full bore, it has never been this clear, I have put up with that racket the last 4years and all it was, an adjustment of approx 1/16 turn on an adjustment pot. I had a half dozen radio checks from other air craft and was reported loud and clear. I suspected our headsets, because Iras Zulus did not have fuzz in the headset when I used them in my plane, this led me to more research, seems the Zulus have what's called a box control that filters everything from the mic other Than what is being said, for lack of a better way to put it. I found more cases where Pilots have had to adjust their Mic Gain on radios other than the make and model that I have, some can be adjusted from the front controls on the radio but mine was a manual adjustment from the top of the radio housing. Maybe this info will help someone else..............Dan