"Roy Lewallen" wrote in message
...
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

Roy is certainly right! The vehicle is the other half of the "dipole". It
is why if you stick a bugcatcher at random on a broomstick, it won't work:
SWR will be thru the roof.. Or you could hang a dipole for a given band
(your choice), then snip off the side that went to the coax shield (or vice
versa). So, yes, the vehicle is the other half of the antenna. You could
even look at it as an right-side up "L"!

73

Jerry
K4KWH