Roy Lewallen, W7EL wrote:
"I`m not sure why, but most amateurs don`t seem to realize that a whip
isn`t an "antenna" and the car "ground", but each is half of a
dipole-like antenna."

Not exactly..

In a common balanced dipole, each half has the same current quantity and
direction, though in one half the current flows toward the feedpoint
while it flows away in the other half.

From such a dipole, both its halves contribute equally to its radiation.

Action of a common ground plane is different. When its balanced radials
are perpendicular to its whip, radiation from its radials zeros out
leaving the whip to do all the radiation. Ideally, a whip mounted on a
vehicle or directly on the earth behaves the same. It is the whip which
radiates.

An antenna is also called an aerial. It is defined as that part of a
radio station which radiates or receives radio waves into or from space.

An antenna ground system is defined as that portion of an antenna system
closely associated with the earth and including an extensive conducting
surface which may be the earth itself.

Most radio amateurs have it right.

Best regards, Richard Harrison, KB5WZI