"axolotl" wrote in message
...
Robert Swinney wrote:

Terman's comments reflect the general premise of most of the foregoing
thread. That is: Broadcast antennas are best when they are composed of
a wire vertically mounted.


The question (or statement) as I understood it from the OP, was that if
you didn't consider the body of the car a "ground plane" (presumably at MF
frequencies) you don't know how radio signals function. I guess I have to
be among the unknowing, which is a shame since I've been spec'ing and
measuring antennas for ground vehicle and aircraft applications for too
many years.


I can't say for certain that
diversity antennas aren't used for broadcast reception, although I doubt
it.

Space diversity FM broadcast antenna systems are fairly common in autos to
reduce the effects of multipath. These are generally pretty simple systems
with two antennas, with the receiver being switched to whichever antenna
has the strongest signal. The first factory supplied system that I heard
of was the Saab, about 8 or 10 years ago.

Do you miss the fun at the antenna factory?

Kevin Gallimore

Kevin

You probably got a mixture of messages while reading these posts. But, I
would put myself amoungst thoes who wouldnt find value in using the term
"ground plane" when working with a conductor thats shorter than a few
electrical degrees at the frequency of interest.
I would not (hopefully ever) write that "someone doesnt understand how
radio waves work".
I expect to benefit from any experience others might have for getting the
maximum peerformance from short AM and FM antennas.

My news group provider shows thr OP to be Andrew V, who wants to provide
his home with adequet RF into his radios on both AM and FM. I jumped in
with some advice that doesnt seem to be acceptable to all readers. It is
my assumption that all the information submitted so far by me is absolutely
correct. But, I have no quarrel with anyone who wants to theorize that a
1/100th wave long conductor is a "ground plane". That terminology just
doesnt fit with my knowledge.

What would you consider the minimum length of a conductor that fits the
definition of "ground plane"?

Jerry