On Jun 12, 2:55*pm, "Brenda Ann"
wrote:
"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.

The embedded Wire Windshield Antennas used
two very thin parallel wires and the two created
a larger signal capture area plus the two provided
some redundancy if one should break.

The newer Printed-On Window Wire Antennas
{Circuit Trace (Wire) on Glass}
have a great sectional width {less likely to break}
and go around and/or across the Window.
At least that is how the one we have in the rear
side window of the Ford Windstar Van is laid-out
it come in {starts} from a single contact point and
goes almost all the way around the rear-side
Window with a 1/2" gap between the far-ends;
plus there is an extra leg starting in one corner
of the Window that goes across the Window at
a Diagonal Angle; and yet another extra leg
starting at the opposite corner of the Window that
goes across the Window at a Horizontal Angle.

* Sort of a bent & folded Window Windom Antenni

FWIW the Ford Windstar Van's Rear-Side Window
Antenna seams to work very well down in the SF
Bay Area but poorly up here in the mountains :
While the Solid Metal Whips and the Wire Wrapped
Whip Antennas seam to do as well in the SFBA
and much better up here in the Sierras. This may
be due to the fact that the Whips actually project
out away from the Body {counterpoise} of the Car
and are physically by-design a better EMF "Probe"
then the Foil-on-a-Window Antennas.

and that's how i hear it on the radio ~ RHF