Tom Donaly, KA6RUH wrote:
"There is nothing in the natural world that can double itself and go in
the opposite direction at the same time."

Watch water waves slam into a bulkhead and you can see the reflected
waves interfere with the incident waves as they travel in the opposite
directions.

Electrical waves, incident and reflected, pass through each other too.
In the antenna or transmission line, the charge is impelled by the
energy supplied by the generator to move back and forth on the surface
of the wire at the radio frequency rate.

The incident wave and the reflected wave on a transmission line travel
in opposite directions. At certain points along the line the voltages in
the waves will be in phase and will add, while in other points they will
be out of phase and subtract. The points along the line where the two
voltages are in phase are points of maximum voltage and minimum current
and are spaced one half wavelength apart. The points along the line
where the two voltages are 180-degrees out of phase are points of
minimum voltage and maximum current and are also one half wavelength
apart. The distance between alternate points is one-quarter wavelength.

The reflection of a radio wave is a natural occurrence. When the voltage
produced by the incident wave hits the open-circuit of a wire it doubles
itself and starts a wave propagating in the opposite direction while the
incident waves are yet arriving at the open-circuit.

Best regards, Richard Harrison, KB5WZI