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Old December 31st 07, 04:55 PM posted to rec.radio.amateur.antenna
Gene Fuller Gene Fuller is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 342
Default Standing-Wave Current vs Traveling-Wave Current

Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Lots of energy is flowing in both directions.
Only the *NET* energy flow is zero.


I guess you still have not gone back to the books to try to understand
what electromagnetic energy is all about. A good review of the
Poynting theorem would help to minimize the sort of nonsense you
spouted above.


You mean like Ramo & Whinnery in "Fields and Waves ..."
2nd edition, page 291? (begin quote)

In such problems we are often most interested in the ratio
of power in the reflected wave to that in the incident wave,
and this ratio is given by the square of the magnitude of
[rho], as can be shown by considering the Poynting vectors:

Pz-/Pz+ = |rho|^2

end quote.

Pz+ is the forward power Poynting vector. Pz- is the reflected
power Poynting vector. The *NET* Poynting vector is the
difference between those two Poynting vectors.

If Pz+ = Pz-, then the net Poynting vector is zero but
the component Poynting vectors still exist. If you disagree,
please take it up with Ramo & Whinnery.


Cecil,

As usual, you have taken something generally accepted as true, and then
you have added your own special spin. You might have noticed that Ramo &
Whinnery did not go into all of the "net" baloney, and neither did HP in
AN-95. That stuff is only in your imagination.

The last I heard, energy is a scalar quantity. In the cases we are
considering, energy is only positive or zero, not negative. How do two
non-negative scalar quantities "flow" past each other, adding up to a
"net" of zero, unless the initial quantities themselves are zero?

I agree that the concepts included in R&W and in AN-95 are widely used.
However, they were never intended to be distorted into your dream world.

The bouncing traveling wave model is an extremely useful mathematical
device. It does not trump physical reality.

73,
Gene
W4SZ