"dave" wrote in message
. ..
DEFCON 88 wrote:
OK, this deviates somewhat from the topic, but I've always wondered
about window antennas. My Mitsubishi Galant has an antenna embedded in
the rear window. It's not one of those dipoles that you used to (or
still?) see embedded in the front windshield of GM cars. Rather, it
has a peculiar folded design that's hard to describe. It works very
well. I get exceptional reception, especially on AM. In fact, one of
the reasons I chose the Galant is because it had the best AM reception
of all the cars I test drove. What's the theory on these window
antennas? Do they have a pre-amp ahead of the radio?

Mine are crossed active loops at MF frequencies. Folded dipole at FM
freqs.

The old window antennas weren't dipoles at all. Both "elements" were
connected to the center of the lead-in. The only reason for the dipole
appearance was symmetry, which helped to make them less of a distraction to
the driver.