Gene Fuller wrote:
Cecil Moore wrote:
For the record, I have not used field vectors at all
during this discussion. Everything I have ever posted
have used phasors. From the IEEE Dictionary, "E and H
are the electric and magnetic field vectors in phasor
notation". That is what I have been doing all along.

The "notation" is not the most important part. "Phasor notation" is
simply a means expressing the phase in terms of complex numbers. The
vector *direction* is all-important. That is the essential "vector" part
of the Poynting analysis. The vector *direction* is not addressed at all
by the phase or by phasor notation. Depending on the exact notation, the
vector "magnitude" may be described by phasor notation. If one is going
to correctly perform Poynting analysis, it is necessary to consider
field vectors. There is no alternative.

You apparently did not bother to read the IEEE Dictionary
definition above. Please do it and while you are at it,
would you please explain what the "complex conjugate"
means when one is not dealing with phasors? Exactly what
is the complex conjugate of a vector in free x,y,z space?
For instance, what is the complex conjugate of a vector
running from 0,0,0 to 1,2,3?

From "Optics" by Hecht: "Therefore, its instantaneous
value [for the Poynting vector] would be an impractical
quantity to measure directly. This suggests that we
employ an averaging procedure." Virtually every time
I have used the term, "Poynting vector", I have been
talking about the average value, not the instantaneous
value.

Most of this discussion has been based upon a disagreement between your
insistence that the instantaneous Poynting vector for a standing wave is
always zero at all times and places, compared to my insistence that it
is not zero at all times and places.

Either I misspoke or else you misunderstood. Phasor
magnitudes are usually RMS values, i.e. average
values.

If I ever said anything about the instantaneous Poynting
vector, it was a mistake. Every time I said "Poynting
vector", I was referring to the average Poynting vector.
I tend to agree with Hecht - the instantaneous Poynting
vector is impractical to work with.

I always deal with phasors and averages. When I realized
that Keith was talking about instantaneous values, I
backed out of the discussion. I do not agree or disagree
with anyone about instantaneous values. I just think they
are of very limited usefulness in this discussion. It is
the average values that are important here.

So I repeat: The average energy flow in a standing wave
is zero so the average Poynting vector for a standing
wave is zero. That was the only point I was trying to make.
V*I*cos(A) are RMS phasors.
--
73, Cecil http://www.w5dxp.com