Frank wrote:
I have trouble with the concept of
"Reflection"; how can charges (electrons) flow in both directions
simultaneously.

Have you ever stood on a cliff overlooking the ocean and seen
ocean waves rolling in and smaller waves rolling back out? The
smaller waves rolling back out to sea are reflections of the
large waves incident upon the shore. The small outflowing wave
meets a large incoming wave and seems to disappear, only to emerge
on the ocean side of the large wave with its identity still intact.

If ocean waves can flow both directions using the same H2O carriers,
why would anyone have difficulty in accepting EM waves flowing
in both directions using the same electron carriers? The energy in
the ocean waves travels much faster than the water molecules. The
energy in an EM wave travels much faster than the electrons.

Ever played with a long rope fastened at one end? You can send a
wave down the rope and receive a reflected wave. If you time it
just right, you can have a forward wave and a reflected wave
meet in the middle of the rope and be unaffected by each other
as long as things remain linear. A forward EM wave has no effect
on a reflected EM wave and vice versa as long as things remain
linear.
--
73, Cecil http://www.qsl.net/w5dxp