On Apr 20, 5:54 pm, Owen Duffy wrote:

Some of the problems in the analysis are as a result of trying
to determine conditions at a point, which can have no area, and
presumably no power, but yet E field and H field.

It is usual, I believe, to talk about power density. Volts per meter
times amps per meter is watts per square meter. It's not watts at a
point, or along a line, but over an area. Of course, you have to be
careful what you mean by that. The actual value of the power density
will be a function of position and time, of course, and will in
general be different at one point than at a point a meter, a
millimeter, or a micron removed. It can also be useful to add the
dimension of frequency: the power density is also a function of
frequency.

I think the discussion is mainly exploring a detailed definition of the
concept of superposition of radio waves. It seems to mean different
things to different people, but it is used as if it has a shared meaning.

One of the points of the "fields are interpreted by some as physical,
and by others as mathematical abstractions," which is a preamble to
further antenna discussions in the book I'm thinking of, is that it
doesn't matter which way you view them; if both camps describe their
behaviour the same way, the observable result is the same.

Cheers,
Tom