Hot-wired A4 antenna

[Jay@aol.com]

I'm still having no luck with my antenna, so I thought I'd check again and
see if anyone's got any good ideas.

I replaced my stock A4 stereo (non-Bose) with a Sony.  The reception was
adequate, though not startling, before.  Now, it's horrible - the signal
strength pulses high and low every time I move ten feet.

I thought I might have disconnected something important when I unplugged the
Audi stereo, so I traced the wiring from the antenna amp all the way forward
to the head unit.  There are four connectors on the antenna amp box (it's in
a green plastic case on the driver's side, behind the plastic trim around the
rear windshield).  One is the power for the window defroster (which
apparently is integrated with the antenna, and is not just sharing windshield
space).  One is the coax antenna out.  The other two are a red wire to the
antenna itself, printed on the windshield, and a white wire which serves as
"switched power in".

This white wire is connected to my Sony's "power antenna" lead, and is indeed
drawing 67ma when I turn the stereo on.  Disconnecting it causes a big drop
in quality, so I'm definitely getting SOME amplification.  Dan Masi suggested
the Sony might not be giving it enough power; I connected the lead directly
to the cigarette lighter, and it still drew only 61ma.  

So I'm lost.  I would have thought the "switched power" was only a signal for
a relay, but that'd mean it draws power through the rear-window defrost
power.  Which would mean you can't get distant stations except when it's cold
and foggy out.  Which is stupid.

Anyone have any ideas?

Jay