Car antennas

[Larry Weil]

At 12:04 AM -0400 5/10/10, A. Joseph Ross wrote:
>Having recently been car shopping, I've noticed that radio antennas
>have changed again.   My old car had a retractible whip antenna that
>went up when the radio was turned on and down when it was turned off.
>  I had to replace that once in the life of the car, and it was
>already not going down all the way again.
>
>I notice that a lot of newer cars have a small antenna, about six to
>twelve inches, above the rear window.  I wondered whether that would
>be sufficient for decent reception of AM and FM stations, but when I
>tested this on cars that I test-drove, it seemed to work.  Why is
>this antenna adequate?  Will it also work for satellite radio?
>
>Other cars have an antenna embedded in the rear window.  I had a 1977
>Oldsmobile that had the antenna embedded in the front windshield.  I
>suppose embedding it in the rear window is about the same thing.  The
>antenna looks like a typical FM dipole.  Why does this work for AM as
>well, as it does seem to?
>

The window antennas were notoriously bad, although the later ones 
were amplified.  Usually the amplifier is under the trim near the 
rear of the car.  The short ones are also amplified.  Some of them 
also have a satellite antenna built into the base, though some cars 
use a totally separate antenna for satellite.

-- 
Larry Weil
Lake Wobegone, NH