Keith Dysart wrote:
Hecht seems to have sufficient reputation that I trust that he made
this statement in the context of optics and not in the context of
electrical circuits.
EM waves are EM waves, Keith, no matter what the frequency.
EM waves all obey the laws of reflection physics, superposition,
and conservation of energy principle. If you want to prove those
laws to be invalid and replace them with ones of your own design,
be our guest.
But analysis using instantaneous power reveals a different
answer. Which is more likely to be correct?
Analysis using an MFJ-259B on an antenna system reveals a
different impedance than is indicated by a DC ohm-meter.
So what? You used an average power tool, known to be
invalid for instantaneous powers, to incorrectly analyze
instantaneous powers. You are the one who made the error
- not the model. Your error was the (deliberate?) misuse
of the tool in order to try to create your straw man.
Using the power equation, derived from RMS values of
voltage, on instantaneous powers is an invalid thing
to do and will give known erroneous results which are
not the fault of the average power model. The fault is
in the *misuse* of the average power model.
We have already laid your straw man argument to rest
when we discussed the power in standing waves.
1. There is non-zero instantaneous power in standing waves.
2. There is zero average power in standing waves.
Does statement 1 contradict statement 2? Of course not.
They are both true. The same holds true for the present
discussion.
I have a probable explanation for your calculations. I
set the example up such that the average interference
is zero inside the source. It is entirely possible that
localized interference exists within each cycle such
that there is destructive interference for part of the
cycle and constructive interference in another part of
the cycle. In fact, based on the conservation of energy
principle, I am willing to state that is a fact and the
destructive interference magnitude exactly equals the
constructive interference magnitude for each cycle.
--
73, Cecil
http://www.w5dxp.com