On 18 jun, 12:26, Cecil Moore wrote:
On Jun 18, 6:00*am, Keith Dysart wrote:

"Is this a situation
where the computed reflected power represents something real?"
because if it does not, the original question is moot.

It certainly depends upon your definition of "power" and that
definition is different between pure physics and RF engineering. One
of the accepted definitions of "power" in "The IEEE Dictionary"
contradicts the definition of "power" given in my college physics
book. "The IEEE Dictionary" says that flowing energy passing a fixed
measurement point is power, by definition.

If there is anything at all that can be measured, it must necessarily
contain energy. If the EM energy is moving, it is power, by IEEE
definition. If you disagree, take it up with The IEEE.

So the actual question that needs to be answered is: Does the
electromagnetic reflected wave contain energy traveling at the speed
of light in the medium? The answer is yes, being photonic in nature,
an EM wave must necessarily contain an ExH power density and,
consisting of photons, must necessarily be traveling at the speed of
light in the medium. The EM wave will continue to travel in the
direction of energy flow at the speed of light in the medium until it
encounters an impedance discontinuity which causes a reflection and/or
interference.

There is really no difference in a forward wave and a reflected wave
except for the direction of travel. They both contain an associated
ExH power density. One can set up identical signal generators at each
end of a transmission line to emulate forward and reflected waves.
Which generator yields forward waves and which generator yields
reflected waves? It doesn't really matter because direction is only a
convention.
--
73, Cecil, w5dxp.com

Hello friends. good day for you.

I am glad that I have not bothered with my joke, Keith! :) I was to
do some comments to your and Roy posts, but I prefer to ask questions
rather than giving personal opinions :)
.....
Please Cecil, friend, do not mention photons and optics (do not bother
me, don't worry), I believe you better play your game without such
things. I know is like fighting with one arm tied, but I think you
can, make an effort :)

Please Owen explain to me what is "negative power".

In the other thread you said = "The notion that reflected power is
simply and always absorbed in the real source resistance is quite
wrong. Sure you can build special cases where that might happen, but
there is more to it. Thinking of the reflected wave as 'reflected
power' leads to some of the misconception.
Then I asked; "remember me what reflected power definition are you
using here and expand the sentence idea".
I did not ask for the quoting, I ask (again) for your concept of
Reflected Power. I do not sure if you accept (or not) the very notion
of reflected power as legitimate. The sentence it is not clear enough
to me.

Please, tell us if you accept the idea of two very directive
electromagnetic waves from different sources flowing in opposite
directions as carring independent energy (with different frequencies
at first) and information, and the posibbility that energy be
dissipated and/or transmitted by de opposite system and the
information being recovered in both ends.
If your answer is yes, then tell us if you conceive such similar
system using a same wave guide to simultaneously vinculate both
system.

73 - Miguel - LU6ETJ

PS: Roy, friend, take it ease (is OK, or polite say "take it easy?),
references to the article were only to complement (bring close?) some
useful notions related, mentioning a possible common reference (my
english books are few, old and possibly useless as reference
nowadays)