REFLECTOR:Headset Heartache

Chuck Jensen reflector@tvbf.org
Sat, 20 Sep 2003 19:37:34 -0400


I've been fighting headset noise and need relief, bad.  For several weeks,
after being airborne for a while, a snap-crackle-pop would start in the
headset.  However, I could stop it by resting my leg against the fixture the
headset plugs into that's mounted on the keel.  It wasn't the pressure that
would stop the popping, just the touch.  I could stop it with a light touch
of my finger.  "Untouch it" and it would snap-crackle-pop again until I
touched it again.  I didn't know if I was acting as some kind of capacitor
or ground.  Touching it was effective but after a couple hours, you get a
cramp in your leg.  I checked the fixture and while the soldering wouldn't
win any awards, there was no apparent fatal flaws.  Note: touching any of
the other three head set fixtures would not stop the crackle.

For the last few days of this week, I was in Beaver County, PA.  Besides an
Avionics shop, they have a Community College where they train Controllers.
It was a real kick to set in on the class for an hour or two and listen to
them (attempt to) make return calls to the plane (that the instructor was
imitating).  Some times we forget those talking-a-mile-a-minute controllers
probably started out with the same mumble-and-stumble routine too.  Of
course, the Controllers get better; they get to practice their radio work
every day on the job!

Well, back to the problem.  I decided as long as the plane was going to be
there a couple days, I'd have the "clean up" the headset fixture and solve
the problem, which they did by putting in new jacks and nifty solder
fittings that melt down and fuse the shield and a separate ground wire
together (I'm sure there's a technical name for it) instead of just putting
a big glob of solder on all the ground shields.  It was nice, neat and
pretty when it was done.  Tested it on the ground and it was good-to-go.

When I left today to head south, the crackle started during run up, got
worse during takeoff and was terrible as I started the flight.  Only now, it
wouldn't stop when I touched the headset fixture.  I endured an hour of it
during which I could just barely make out Flight Following.  After about an
hour, the crackling paused occasionally, then stopped altogether for the
next hour.  What a relief!!  Then, after landing, it started up again. 

When I key the mike, the noise stops.  I've checked other electrical
instruments to see if there is any "connection" but nothing seems to affect
it.  No noise on a headset check with engine shutdown.  With engine running,
some noise on the ground but progressively worse at power.  I've swapped and
switched headsets (Lightspeed) but it seems unrelated to those.  A local
Avionics shop has looked at it but hasn't found anything.

I'm looking for ideas.  I'm so desperate, I'll even take bad ones.

Chuck