Diversity FM and automotive antenna ?'s

Archived from groups: rec.audio.tech (More info?)

....my car came OEM with diversity reception, the only problem now is I
put in an aftermarket radio which uses only one antenna. The car uses 2
in the glass style antennas, one in the front of the car, one in the
rear of the car. I tried to use just one of the antennas with the
aftermarket radio and it seems as though the front antennas is good for
the upper 1/2 the FM band and the rear one is good for the lower 1/2.
If I plug both in at the same time, the reception is very "multipathy",
probably because both antennas are used at the same time effectively
picking up alot of garbage and cancellation. Overall, the reception is
very poor.

I was thinking if there is an externalbrain that could be used as the
diversity switcher. Is there such a thing?

Unfortunately I think this may have to be done in conjunction with the
radio since it is probably specific to which frequency the radio is
tuned in on but I'd though I'd ask anyway.

I tried one "solution" is one of these small amplified antennas that
tape onto the windshield. Unfortunately, the unit was alot smaller then
I had expected, it is probably 1/8 if not 1/16 wavelength. It is
amplified but it works worse then the OEM antennas.

PS I'm looking into other antenna options as well. the car is a plastic
body on frame design (chevy corvette), it does not really have a large
"ground plane" so to speak, other then the frame of the car itself. I
really dont want to put any huge antennas on the outside of the car
either, although the convertible models did have a powered "whip" style
antennas I'm not too inclined to punch a hole in my car to put it on.

I'm thinking about boat antennas since many boats are of similar
composite body/metal frame designs.

The rear bumper of the car has a very large area behind it, I think I
may be able to fit even a 1/2 wavelength antenna back there, but
horizontally. Can anybody recommend either an antenna thats premade or
one that I can fabricate that will work well for my application?