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Old July 18th 05, 08:51 PM
Jim Kelley
 
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Cecil Moore wrote:

Jim Kelley wrote:

Richard Clark wrote:

Jim Kelley wrote:

Born and Wolf has an interesting comment in the section on total
reflection. "...the electromagnetic field in the second medium does
not disappear, only there is no longer a flow of energy across the
boundary."


your source, and yet unable or unwilling to confront this single
observation.



Apparently that would mean the waves aren't traveling at the speed of
light and it would violate his "waves cannot exist without energy" law
of physics, so therefore the book is wrong.



Wrong. All it means is that reflected energy doesn't make it across
the match point.


It says, and means more than just that, obviously.


"... when two waves of equal amplitude and wavelength that are 180-degrees
out of phase with each other meet, they are (canceled but) not actually
annihilated. All of the photon energy present in these waves must somehow
be recovered or redistributed in a new direction, according to the law of
energy conservation. (There are only two directions available in a
transmission
line.) Instead, upon meeting, the photons are redistributed to regions that
permit constructive interference, so the effect should be considered as a
redistribution of light waves and photon energy (back toward the load)
rather
than the spontaneous construction or destruction of light." (Words in
parentheses
are mine added for clarity.)


Interesting to note that the interference phenomenon is often described
as a redistribution, but is never described in any reference as a
reflection, or re-reflection as you have done. The reason is that when
light destructively interferes in some direction, it simply does not go
in that direction. It doesn't, contrary to your assertion, first go in
the reflected direction, say oooops, then turn around in mid-air and go
in the other direction. The reflection is prevented. Comprende senor?
The Bird wattmeter can be misleading in this regard. It measures the
effect of a field (sometimes like the one in Born and Wolf that doesn't
have transfer of energy associated with it), and in every case assumes
energy and power. But it's simple minded so it has an excuse.

73, ac6xg