Tom Horne wrote:

OK Roy you lost me.

I'll confess that I'm one of those new no code guys that concentrated on
the answer pool for three months in order to get an Extra Class license.
What I'm trying to do now is relearn enough electronics to become a
competent communicator for EMCOM purposes. You see back when I was last
in radio your transmitter would keep you warm and provide enough light
to read the manual by. Now it is thirty years since my Novice license
expired and not only are the newer radios all solid state they do most
of their signal processing digitally. By my point of view that only
makes me as yet not fully trained rather than the devils personal
representative in amateur radio.

Fortunately, antennas still operate the same way they did back when
rectifiers glowed blue. In fact, the same as they did when you had to
poke a catwhisker around your rectifier.

Are you being serious when you say that much of the difference in the
mobile rigs performance may be the vehicle on which it and therefore
it's antenna are mounted?

Yes.

IS the body of my half ton cargo van doing a
substantial amount of the job of radiating my signal?

Yes.

If I mounted the
same antenna with the same mount on my Saturn should I see a difference
on a field strength meter that is the same distance to the centimeter
from the antenna over the same parking lot with the antenna over exactly
the same spot?

Yes.

Declaring a vehicle to be "ground" doesn't give it magic properties.
It's a conductor, just like the antenna. Exactly the same current that
flows upward on your antenna flows downward along your vehicle. The
vehicle and "antenna" comprise an asymmetrical dipole, and neither half
is inherently more or less important than the other.

Roy Lewallen, W7EL