Richard Harrison wrote:

I wrote:
"As energy can`t be destroyed it had to be reflected by a hard short or
open." Keith replied:
"Or just stopped and stored."

Wave energy is energy in motion. No motion, no waves.

There is no doubt that energy moves. The point of disagreement is on
how far it moves.

Keith wrote:
"I would strongly suggest that no energy crosses these points in the
line where the voltage and current are always zero since p(t) is always
zero."

See my comment above on power as a function of time. Keith erred in
saying "points in the line where the voltage and current are always
zero", as where SWR volts are zero, amps are max, and vice versa.

This last is true, but p(t) = v(t) * i(t); volts and amps must be
present simultaneously for there to be power.

I wrote:
"If energy were turned around before it reached the end of the line,
nulls more distant from the source than the turnaround point would not
exist."

Keith wrote:
"Not so,---."

There is no argument that can make wave interference where there are no
waves. In a lossless line, pre-existing waves could circulate forever.
But, our discussion relates to effects on actual lines.

There are many assumptions in this discussion which means it only
applies
to ideal lines. The extension to real lines, retains the fundamentals
but the details need tuning.

As a simple example, on a real line, the nulls are never 0.
But including this in the discussion would just make it more difficult
to locate the points of disagreement.

Keith wrote:
"Try visualizing how a step function charges the line."

Totally irrelevant.

Understanding a step will help with understanding line
behaviour. This knowledge can then assist in understanding
sinusoidal steady state.

....Keith