Jim Kelley wrote:
Richard Feynman said there is a probability that reflection will occur
at any point within a partially reflecting media.

Of course, there are always 2nd, 3rd, ... Nth order effects.
On this newsgroup, we are usually talking about first order
effects. I had a recent email exchange with someone talking
about the part of the ground wave that escapes absorption
because of the earth's curvature and is probably ignored
by NEC simulators but not by AM broadcasters.
--
73, Cecil http://www.w5dxp.com