Owen Duffy wrote:
Cecil Moore wrote in
EM wave energy necessarily travels at the speed of light.
There is exactly the amount of EM wave energy contained
in a transmission line to support the forward power and
reflected power.

You are not suggesting that the energy contained in a transmission line in
the steady state in the general case is constant, are you?

Obviously, a leading question. :-) I'm not talking
about instantaneous values here. All my statements
apply only to values averaged over an integer
number of RF cycles in one second.

What I am saying
is that a transmission line obeys the conservation
of energy principle. Whatever energy has not gone
somewhere else is still in the transmission line
and is exactly the sum of the energy required by the
forward wave plus the energy required by the reflected
wave. The steady-state energy stored in a transmission
line with reflections is greater than the steady-
state energy delivered to the load. The extra energy
was sourced during the transient build-up state and
has not yet been delivered to the load. The argument
that 100 watts in and 100 watts out (during steady-
state) doesn't leave any energy left over for the
reflected waves is invalid. Below I give an example
of 100 watts in and 100 watts out with 300 joules
stored in the forward and reflected waves.

I think it would be safe to say that for any one-
wavelength section of line, the average energy
content is constant during steady-state and is
exactly the amount of energy required to support
the forward traveling wave and reflected traveling
wave.

Here's a graphic that I earlier provided that
illustrates the energy buildup to steady-state.

http://www.w5dxp.com/1secsgat.gif
--
73, Cecil http://www.w5dxp.com