"Roy Lewallen" wrote
If you do a bit of analysis with a modeling program, I think you'll find
that if you generate a circularly polarized signal, it'll become nearly
linearly polarized once it reflects from the ground. ... There might
be a way to generate a signal that's circularly polarized after
reflection, but I don't know how to do it.
________

Roy, won't a c-pol signal remain c-pol after a low-angle terrain reflection,
except that its rotation sense is reversed? (The magnitudes of the v-pol
and h-pol reflection components are nearly the same, but there is a
180-degree phase reversal in the v-pol reflection with respect to the h-pol
reflection.)

This has been applied with good results in analog TV broadcasts using c-pol,
because a c-pol receiving antenna rejects reflections of the transmitted
signal -- which effectively reduces the multipath "ghosts" seen on a TV set
when linearly polarized receive antennas are used.

RF