Walter Maxwell wrote:
Cecil, at this point I'm not clear what's happening in your above example. Where
and what is the phase reference for these two waves? It appears to me that the
reference phase must be that of the source wave, because the voltage and current
in both rearward traveling waves are 180 degrees out of phase. Educate me on how
the cancellation takes place and how the energy reverses direction.

J. C. Slater explains how the cancellation takes place.
"The method of eliminating reflections is based on the interference
between waves. Two waves half a wavelength apart are in opposite
phases, and the sum of them, if their amplitudes are numerically
equal, is zero. The fundamental principle behind the elimination of
reflections is then to have each reflected wave canceled by another
wave of equal amplitude and opposite phase."

Note that the above applies to both voltage waves and current waves.
Both voltage and current go to zero during complete destructive interference,
i.e. both E-field and H-field go to zero during complete destructive
interference.

It seems to me the out of phase voltage yields a short circuit, while the out of
phase current yields an open circuit. How can both exist simultaneously?

They can't, and that's my argument. It's easy to understand. If the two rearward-
traveling voltages are 180 degrees out of phase then the two rearward-traveling
currents MUST also be 180 degrees out of phase, since the reflected current is
ALWAYS 180 degrees out of phase with the reflected voltage. If one looks only
at the voltages, one will say it's a short-circuit. If one looks only at the
currents, one will say it's an open-circuit.

And further, what circuit can produce these two waves simultaneously?

According to J. C. Slater (and Reflections II, page 23-9) a match point
produces these two waves simultaneously, two reflected voltages 180 degrees
out of phase and two reflected currents 180 degrees out of phase.

In addition, I believe your example has changed the subject. My discourse
concerns what occurs to an EM wave when it encounters a short circuit.

There is no argument about what happens at a short circuit. What I am saying
is that a match point is NOT a short circuit.

In this
case you're going to have to prove to me that both E and H fields go to zero.
IMO it can't happen.

J. C. Slater says that's what happens in the above quote. Voltages 1/2WL apart
in time cancel to zero. Currents 1/2WL apart in time cancel to zero.

So my argument with you, Cecil, is that I maintain the H field doubles on
encountering a short circuit, while you maintain that both E and H fields go to
zero. What's your answer to this dilemma?

My argument is that it is NOT a short circuit. It is "complete destructive
interference" as explained in _Optics_, by Hecht where both the E-field and
B-field go to zero. J. C. Slater says that the two rearward-traveling voltages
are 180 degrees out of phase and the two rearward-traveling currents are 180
degrees out of phase. So whatever happens to the voltage also happens to the
current, i.e. destructive interference takes both voltage and current to zero.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----