On Mar 7, 9:39*am, "noel.wade" wrote:
So in true troubleshooting/gremlin fashion, I spent over an hour
trying to get the radio to make static yesterday, and couldn't. :-P
Argh!

If this is a problem that only appears when I'm airborne, it's going
to be a real pain to track down!
*sigh*

--Noel

Noel

Do you have a transponder? If not ignore the rest of this post.

If you do this could be related to transponder interrogation. Possibly
a combination of noise from two sources breaking squelch.

With a transponder the same basic comments apply, with coupling either
through the power supplies or RF. If you switch briefly to standby in
flight does the noise go away? If so start with the power supplies and
try putting a filter/choke on the transponder power supply leads close
to the unit. Also look at the transponder coax cable for problems.

Ground radars will interrogate your transponder typically at 5 second
(approach radar) or 12 second (area radar) intervals, of course you
may be interrogated by multiple radars and also TCAS and similar
systems (that can be at much higher rates (~1/sec). On the ground you
may be outside of radar interrogation and if your transponder antenna
is under the glider (where it usually should be) may not see TCAS
interrogations on the ground. TCAS interrogations will come and go but
radar will be consistent. Repeatable noise bursts at these kind of
rates can be a clue its transponder related.

Darryl