Jerry Stuckle wrote in news:lre73e$jps$1@dont-
email.me:

Even if it were a weak signal added to the audio output, chances are you
wouldn't hear it. As I said before - you were very lucky to hear the
squeal before; very few spurious radiations will have any audio component.

And BTW - your problem with the ground plane was probably corrosion in
the connection, causing the RF to be rectified. But even then,
generally it will not be in the audible frequency range.


Agreed, even the thin oxide layer on the aluminium when new was enough
corrosion. Also, not enough points of contact around the edges of the board
before I fixed it.

About 'lucky', maybe. The rason I brought it up was because the sound WAS
so white-noise like. It seemed to imply a scatter so broad that a careful ear
might detect a far lesser version of the effect.