Roy Lewallen wrote:
Sine waves are another problem -- there, we can easily have overlapping
waves traveling in the same direction, so we'll run into trouble if
we're not careful. I haven't worked the problem yet, but when I do, the
energy will all be accounted for. Either the energy ends up spread out
beyond the overlap region, or the energy lost during reflections will
account for the apparent energy difference between the sum of the
energies and the energy of the sum. You can count on it!

An example from optics will make the situation clear.

http://www.w5dxp.com/thinfilm.GIF

At t3, when the 0.009801 watt internal reflection arrives
to interfere with the 0.01 watt external reflection, what
is the resulting reflected power toward the source?

Anyone who can answer that simple question from the field
of optics will understand what happens to the energy in
a transmission line.

Hint: the reflected power is *not* 0.01w - 0.009801w.
--
73, Cecil http://www.w5dxp.com