A few years ago, after the buttons on the stock Blaupunkt Monterey
gave out, I put a new radio in my 1986 944 (a 951, actually, but
I don't think that matters for this discussion). Recently, I decided
to move that radio to my other car, so I got a new Blaupunkt Hamburg
for the Porsche.

Ever since the original Monterey was replaced, I've had some
intermittent problems that I believe are related to the antenna
preamp. According to Walt's excellent 944 stereo FAQ:

"Starting with the 85/2 944, an in-glass windshield 'active' antenna
system was used. Under the dash, between the glove box and the passenger
side fender, there is a small preamplifier - made by Fuba. This amplifier
is powered by a lead, which runs alongside the coax leading to the
radio. It connects, through the wiring harness, to the 'power antenna'
lead on the radio in order to get power whenever the radio is turned on."

http://www.connact.com/~kgross/FAQ/944faqst.html

Most of the time, non-local stations come in just fine on the radio.
But sometimes, I can barely hear them. I can actually hear the problem
coming and going; it's like someone turning a switch on and off.
Sometimes it goes on or off when I go over bumpy road, but other
times, that doesn't affect it. I swear that sometimes it even
changes state when the car sits overnight; fine one day, not fine
the next. That actually has me wondering whether the problem is
electrical rather than mechanical in nature, but I'm just not sure.

When this first started happening (shortly after the installation
of the Becker radio), my mechanic poked around for a couple of hours
but couldn't solve the problem. I don't know exactly what he did,
but he's very knowledgeable about Porsches, so I imagine that checking
the connection to the preamp would have been the first thing on his list.

Should I crawl under the dashboard, look for the preamp, and try
jiggling the connector myself? Is it possible that something *inside*
the preamp is being intermittent?

FYI, the guys who installed the new radio used the wiring harness
that was already there, so if something in the harness is flaky,
that could be what's perpetuating the problem. Unfortunately,
because it's intermittent, I can't just put a multimeter on it,
check for good connectivity, and call the results authoritative.

Thanks for any suggestions you can offer to fix this annoying problem!

Patty