This afternoon I found when I connected my brand new Zaon to ship's
power that I had Zaon squelch disease. I ran the factory supplied Zaon
power lead through a 1" long by 1/2" diameter non-split ferrite three
times right next to the power plug, then connected to power and ground
behind the instrument panel. For what it's worth, I hear noise on
123.00 but not on 123.30, while on the ground. In flight all
frequencies were quiet when I was using the internal Zaon batteries.

Tomorrow I'll buy another power tip, and connect it to a shielded two
conductor cable temporarily running directly to the ship's battery. If
that doesn't work, I'll try a 25 V polarized 0.01 uF capacitor in
parallel with a ceramic 0.001 uF capacitor near the power tip, if
Radio Shack has them in stock. If I can find another ferrite I'll put
one on power and one on ground, too.

Wierd - my old Zaon (bought August 2006) never exhibited this problem
in my ASW-19, and it was wired exactly as I wired the new Zaon in my
LS8 today. Similar age Becker AR4201 radios in both the -19 and the
LS8, but maybe there's a different squelch level adjustment and/or
changes to the new Zaon board.

I'll report on the results of my experiments - there may be a delay,
as the temps tomorrow are going to be God awful...

-John