On May 31, 2:42*pm, Cecil Moore wrote:
On May 31, 9:09*am, K1TTT wrote:

ah, but in this case consider that you have a pint of blue water
moving to the right and a pint of red water moving to the left to be a
better analogy to currents of the waves moving forward and backward in
the coax. *there are then 3 possibilities:

No, no, no. I am NOT talking about forward and reflected waves moving
in opposite directions. I am talking about two coherent, collimated
waves *MOVING IN THE SAME DIRECTION* in an RF transmission line away
from an impedance discontinuity - either two waves moving forward
toward the load or two waves moving backwards in the opposite
direction toward the source. Such multiple wavefronts occur at
impedance discontinuities because of multiple reflections.

Forward and reflected waves (waves moving in opposite directions in a
constant Z0 environment) do NOT interact. At an impedance
discontinuity, the component reflections and transmissive waves do
interact if they are coherent, collimated, and MOVING IN THE SAME
DIRECTION.
--
73, Cecil, w5dxp.com

add another condition and i might buy it... their polarization must be
the same... if you satisfy ALL those conditions then i believe you
would not be able to separate the waves and you could combine their
amplitudes. but that still doesn't mean they are interacting, just
that their fields always happen to be aligned... now if you are an
engineer like i am and deal with macroscopic processes i would
consider it perfectly logical to add the fields in a linear medium and
carry on with a single wave in each direction created by an infinite
series of reflections... HOWEVER, if i switch my hat to the scientist
part of my job title and i was working in photons I would come to a
point where it would be impossible to divide the last photon and
things would fall apart.... fortunately the ham/engineer side usually
outvotes the scientist part and i take the infinite summation and call
it a day.