christofire wrote:
. . .
* HP is less effective than VP for VHF communication with mobiles because
the ever-present ground reflection has reversed polarity (i.e. it's in
antiphase with the signal propagating over a direct path).
. . .

Reflection of a CP wave results in a reversed CP wave only when the
reflection is directly normal to the reflecting surface. That's not at
all the case for typical ground reflections. What you actually get from
ground reflections is an elliptically polarized wave, likely having the
same sense as the impinging wave. In experiments I ran about 35 years
ago, I found nearly linearly polarized waves resulting from reflection
of a CP wave from a vehicle top.

A little time spent with a modeling program such as EZNEC+ can be very
educational in understanding the generation and reflection of CP waves.

Roy Lewallen, W7EL