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Old June 13th 10, 11:35 AM posted to rec.radio.amateur.antenna
K1TTT K1TTT is offline
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First recorded activity by RadioBanter: Apr 2010
Posts: 484
Default Where does it go? (mismatched power)

On Jun 13, 12:00*am, Cecil Moore wrote:
On Jun 12, 4:34*pm, K1TTT wrote:

ok, so you defined a case where the superposition of the reflected and
refracted waves at a discontinuity results in a zero sum. *is that
supposed to prove something? *did i ever say that you could not define
such a case??


I would call two waves superposing to zero indefinitely, "wave
cancellation". If that is not wave cancellation, where did the
reflected and refracted wavefronts go along with their energy
components? The answer to that question will reveal exactly what
happens to the reflected energy.


i don't care, i know that the superimposed voltage or current is
zero. from that i can calculate the power or energy anywhere i
want.

why does anyone care about 'energy' anyway, that is even worse to
think about in transmission lines than power. at least you can
measure, or at least calibrate your meters, in power units. have you
ever seen an amateur station that had an energy meter on their
transmitter? and isn't the term 'reflected energy' kind of an
oxymoron anyway? for energy to be reflected it has to be moving, so
isn't that just another word for power?



Here's a brain teaser for you and others. Given a Z01 to Z02 impedance
discontinuity with a power reflection coefficient of 0.25 at the '+'
discontinuity:

------Z01------+------Z02-------load

Pfor1 in the Z01 section is 100 watts. Pref1 in the Z01 section is
zero watts.

What is Pfor2, Pref2, and the SWR in the Z02 section?
--
73, Cecil, w5dxp.com


so? what does this special case prove that hundreds of others
doesn't?