REFLECTOR:Headset Heartache

Scott Derrick reflector@tvbf.org
Tue, 23 Sep 2003 09:30:45 -0600


This sure sounds like you have a ground loop problem.  

Check your ground connections.  Be sure the radio and intercom have a really good common ground.  Be sure the frames, trays, etc are all grounded.

Scott


On Sat, 20 Sep 2003 19:37:34 -0400, Chuck Jensen wrote:
> 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
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