On Oct 25, 10:55*am, November Bravo wrote:
I own a Ventus 2CXM built 2007 with a factory installed Walter Dittle
FSG 2T radio. *I use the Sennheiser headphones (factory installation)
during the engine running procedures. *Unfortunately, I have always
had severe interference with the radio tramsmission/reception during
the engine run. *During the engine run, whether idle or full power,
the reception is weak and garbled with a great deal of backround white
noise. *My transmissions are totally garbled, weak, and
uninterpretable even to other aircraft 50 yards away. *When the engine
is not running I have not problems and my fellow pilots report that my
transmissions are strong and clear. *This is becoming a safety problem
while taxing onto the active runway, as our glider airport is now very
busy with power traffic and a new flight school. *Has anyone
encountered this problem and know of a list of things to check before
sending the aircraft to an aviation radio specialist?

John Iacobucci
Grand Rapids, Michigan USA
+1 (616) 485-3980

Do you receive other aircraft clearly when the engine is running? With
white or other noise? That is a good first test to see whether to
suspect the antenna etc. (although it may still be).

If you are not hearing a white noise sound and not an alternator whine
or ignition noise type sound I'd tend to be more suspicious of the
microphone.

Are you using a headset microphone or the boom mike? Does that work
when the engine is not running?

Check that the headset mic and mic select switch are wired correctly
(headset mic goes anywhere, both mic's are not wired in parallel etc.)
and it's not just the boom mic picking up ambient noise. Test by
unplugging the headset mic and testing (you should transmit no audio).

How does the headset mic work without the engine running? If poorly,
is it the type of mic the Dittel expects/is set to?

Try borrowing another headset with mic. and test that.

If this has been happening since delivery from the factory I'd hope
their dealer or the factory will help you debug this.


Darryl