On Fri, 24 Apr 2009 17:54:12 -0700, "Mike Noel"
wrote:

My Telex 30 headset and SL30 nav/com have developed a loud and annoying
oscillation during xmit. The tone is both obvious in the headset side-tone
and also is heard by other's listening on the frequency.

I've tried two other headsets (a DRE ENR and a non-ANR headset) and both
work fine with the SL30. My com2 is a King 97a and it works fine with all
of my headsets, including the Telex.

The problem seems to have developed in stages over the past several months.
First I was noticing the Telex and SL30 would occasionally give my voice a
hollow sound for the first few transmissions of the day, then sound fine.
Finally last week the tower controller mentioned the squeal which I was also
noticing. It tends to go away after a bit but it sounded odd for the entire
flight.

Has anyone experienced a similar problem? I'm hoping to try a few other
brands of headsets this weekend to see if the headset is the likely culprit.

Best Regards,
Mike.

http://flickr.com/photos/mikenoel/


sure have and Jim Weir gave me the answer twice, about 8 years apart.
corrosion between the antenna wire and the antenna mount causes the rf
to fail to make it into the antenna so it gets radiated inside the
aircraft, gets picked up in the mike boom and feeds back through the
radio as an unholy squeal.
in my case the antenna mount and the base to the wire are both brass
so a good going over with brasso and a toothbrush has cleaned away the
crud and restored the radio to perfect service each time.

the second time while beavering away I though 'I've had to do this
before????' ages later the memory of the first time returned.

thanks Jim

Stealth Pilot