On Sun, 30 May 2004 16:45:03 -0500, Cecil Moore wrote:

Walter Maxwell wrote:
In two Communications Quarterly issues he said as much, referring to my writings
in Reflections and in QEX.. During our last email communication he reiterated
his comment concerning incompetence, and said he was going to write a definitive
article concerning matching that would prove it, but that this time he wasn't
going to mention me by name.

Walt, as you know, I tangled with Steve over the subject of interference which
he claimed didn't exist at a match point. He later changed his mind and told
me in an email that he needed to rewrite part 3 of his article. Maybe he got
it right on his CDs. _Optics_, by Hecht proves Steve's equations in part 3 to
be the actual interference equations from optics with RF Power substituted for
light Irradiance.

IMO, you and Steve were much closer in principles than either one of you
realized.

Sorry Cecil, I don't think so. Steve has missed the most vital aspect of the
phenomenon--what happens to the energy, or power in the reflected waves on
return to the match point.

He said in Part 3: "... the two rearward traveling waves at the match point
(rearward waves 1 and 2) are 180 degrees out of phase with respect to each
other and a complete cancellation of both waves occurs."

Yes, but Cecil, the cancellation of the waves is only in the rearward direction,
because at the match point the waves and the energy they carry (volts x amps)
are totally reversed. Now to continue what Steve said is: "The result of this
wave cancellation is that the total steady-state rearward-traveling wave has a
net voltage of 0 V nd 0 A, respectively, and an impedance match occurs." No No
No.

As we've discussed earlier, voltage and current cannot both go to zero
simultaneously, except in the rearward direction. When voltage goes to zero at
the match point because the two returning voltages are equal magnitude and of
opposite phase, the current is doubled and the V x I energy in the rearward
traveling waves is totally re-reflected in the forward direction. Steve totally
ignores the energy in the reflected waves, except to say, "A total
re-reflection of the reflected voltage, current and power does not occur at the
match point and it (re-reflection) is not necessary for the impedance match to
occur." This statement is totally untrue, because as I said above, all of the
power in the reflected waves of voltage AND current is totally re-reflected in
the forward direction, the same as if the E and H fields had encountered a
physical short. We all know what happens in this case. The only difference is
that the virtual short established by the wave interference is one way only--to
the rearward traveling waves.

I know you don't agree with me that a one-way virtual short is what causes the
re-reflection, but in a short time I'll be able to prove it to you in a manner
you'll not be able to rebut. Stay tuned.

You said in Reflections II: "With equal magnitudes and opposite phase at the
same point (Point A, the matching point), the sum of the two (rearward-
traveling) waves is zero."

Which means zero impedance, the boundary condition causing the total
re-reflection. This exactly what Slater is implying.

This agrees with J. C. Slater, from _Microwave_Transmissions_, "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."

Cecil, the Slater reference is where I originally obtained this concept for my
QST article that appeared in Oct 1973, nearly 30 years ago. Check the ref number
in Reflections--No. 35.

All three above appear to me to be in agreement so the disagreements are really
about the down-in-the-noise details. Some gurus on this newsgroup disagree with
you, Dr. Best, and J. C. Slater.

Those who disagree with Slater need to refresh their memories with a review of
transmission lines 101. They ain't gonna win.

Others on this newsgroup have been asking about your opinion of conjugately-
matched transmitters. I have no interest in that particular discussion but you
might point out some references.

Cecil, I don't have a particular reference handy, but I can quote some of my own
measurements the others you mention might find of interest.. IMO they'll have a
hard time disgreeing with the data if they don't already believe a transmitter
is conjugately matched to its load when it's delivering all of its available
power at an arbitrarily selected drive level within the normal operating range.
Those who don't believe will get quite a surprise when I reveal what the output
source resistance of the xmtr really is under this condition. Waddya think?

Walt