David G. Nagel wrote:

Tom

Have you ever sloshed water in a bowl? If you had you would have seen
wave forms going in both directions. First the initial wave crosses the
bowl then reflects off the side of the bowl and returns in the opposite
direction.
This is the same as an EMF wave in an antenna. No violation of any
principles of conservation, in fact it is demanded of the principle.

Dave WD9BDZ


Dave,

You have highlighted a misconception that is common and a great cause of
confusion in this forum.

Yes, the "waves" can do what you say. However, the "waves" are merely
mathematical descriptions of the underlying physical phenomena. There is
simply no such thing as a "wave" all by itself. Instead there are water
waves, electromagnetic field waves, guitar string waves, sound waves,
and so on.

Nature tends to be single valued, at least in the ordinary classical
world. At any specific point in time and space there is only one value
of current, one value of electric field, one value for the motion of a
particle (water molecule, guitar string molecule, etc.), one charge
density, and so on. These values can and do change with differences in
time and space. However, the physical entities do not have two values at
once in the same time and place.

73,
Gene
W4SZ