wrote:
The fact you can't understand simple direct answers does the same.

I love simple answers, Tom. What I don't like are simple-minded
answers based on an invalid model.

When Roy measured current (and I did the same) using inductive coupling
in a current trasformer, a method that requires a time-varying current
to excite the secondary, you dismissed Roy's measurements with some odd
response about him measuring current that doesn't flow.

The inductive coupling does NOT require a time-varying
current. All it requires is a time-varying H-field. That
standing wave H-field is indeed varying but it's not because
current is moving laterally up or down the wire. That H-field is
fixed at a point on the line exchanging energy with the E-field
which is also fixed at the same point. If the H-field is not
moving laterally up or down the wire (it isn't) then the current
is NOT flowing. You must have missed that day in your
fields and waves class.

Take a metal rod. Slip a string through a washer and tie it.
Loop the string onto the metal rod. Put a grommet on the
rod on each side of the string to keep it in one place in
the X dimension on the wire. Now, keeping the X dimension
fixed, swing the loop in the plane of the Y and Z dimensions
and look at it on edge. You are looking at a physical analogy
of the standing wave current at a point on a wire. Is the
string moving? Not in the X dimension which is constant
and fixed by the grommets.

At any point on a wire with standing waves, the E-field
and H-field are not moving laterally up and down the wire. They
are *stationary* at a point on the wire. All that is happening at
that point is the E-field and H-field are swapping energy at the
RF frequency. The current probe naturally picks up those
stationary oscillating fields. You and Roy still don't understand
what it was that was being measured.The current that you and
Roy measured was not flowing. It was just standing there.
That's why they call it a *standing* wave. The currents
that are required to be constant through the coil are the
traveling-wave currents.

A standing wave is not at all a wave in the classic definition
of EM waves. It is simply a superposition of two classic EM
waves flowing in opposite directions. Here's an optical example
of what is happening to you. The yellow light coming from your
TV is an interference pattern between red, blue, and green
light. You are measuring yellow light thinking that's a primary
color. It is not. But you could use your yellow light measurement
to estimate the strength of the primary colors.

The standing-wave current is an interference pattern caused
by superposition of forward and reflected current waves.
Like the yellow light you are seeing, it is not primary, and
like the yellow light, it is an artifact of interference..

In a wire in which one amp is flowing in one direction and one
amp is flowing in the opposite direction, there is no net flow
of current. Therefore, standing wave current has no net flow.
That is obvious from its constant, fixed phase angle which
doesn't change (much).

I already measured the phase of current, and it is nearly zero degrees.

The measured phase of the net standing wave current is near
zero degrees whether a coil exists or not. All it means is that
the net standing wave current is standing still. Basing your
conclusions upon measurements of a current that is not even
flowing is foolish.

I don't know what others think, but it is starting to look to me like
you either don't understand the basics of measurements or you are just
unwilling to learn.

You have been seduced by your model that is known to fail in the
presence of standing waves. Why you cling to such a false prophet
in the real world is beyond me.

I can measure that. My network analyzer measures time delays. The
problem I see is if I take time from my busy schedule and measure it,
you will either call me a liar or say I measured current that doesn't
flow.

If you measure a traveling wave current, you will be measuring a
current that is actually flowing. Your S12 phase shift measurement
showed a -60 to -70 degree phase shift in a 100uH coil at one
MHz. That measurement of yours has already proved that your
lumped-circuit model is invalid. Why didn't you just use the
zero degrees predicted by the lumped-circuit model instead
of measuring it? :-)

Before measuring anything specific I'm going to warn you that I've
measured group delays many times before, and the group delay in an
inductor is significantly less than the group delay in a transmission
line of the same conductor length. I know that from past experience.

I know that, Tom. The point is: If there is any appreciable delay
through the coil, that fact violates the presuppositions of the lumped-
circuit model. Therefore, a lumped-circuit model cannot be used
to explain the characteristics of that real-world coil and especially
not in a standing wave environment.

But if you promise to control yourself and not dismiss a measurement
with personal attacks or insults, and promise to not do an about-face
like you did with Roy and say "you really didn't measure current that
moves with your thing that only measures changing current", I will do
that.

I appreciate that and I would also appreciate it if you didn't pencil
whip the results before reporting them. Please just be honest. I
assume we are both after the truth. And be sure to measure a
coil something of the size of a 75m bugcatcher coil. I think a
75m bugcatcher coil would show more of a delay than a
toroidal inductor of the same inductive reactance.

I really wish some of your ideas were correct. If they were correct, I
would not have thousands of feet of coaxial cables coiled under my
bench. I would not be forcing customers to cut long delay lines when
their equipment could just use a simple wound up piece of enameled
wire.

Surely, you are familiar with helical transmision lines with a very,
very small velocity factor. And Intel does use simple coils as delay
lines in some of their PCB designs.

Does ANYONE on this newsgroup understand Cecil? I need help here.

They are there, Tom. But they just don't want to tangle with a junk
yard dog. Most people don't have a thick enough skin to withstand
your onslaughts. I get a couple of emails a week from those guys.
One distinguished gentleman and well known ham said that you have
never lost an argument, even when you were wrong. I know exactly
what he means.

What a silly statement. We are measuring a time-varying current that
doesn't flow or change!

It's magnitude changes but it indeed doesn't flow or change phase.
It's magnitude changes because the E-field and H-field are continuously
exchanging energy at the frequency of operation. If you understood the
implications of a constant, fixed, unchanging phase, you would know
that.

Yes, if he wrote what you quoted and you didn't lift something out of
context I totally disagree with him.

So be it.

Your lumped-circuit model
is known to fail in the presence of standing waves.

Nonsense.

YOUR LUMPED-CIRCUIT MODEL IS KNOWN TO FAIL
IN THE PRESENCE OF STANDING WAVES!

What is it about that statement that you don't understand? Your
lumped-circuit model presupposes conditions that don't exist
in a standing wave environment. Therefore, it is invalid and
another more powerful model must be chosen.Because your
chosen model is invalid, the validity of everything you say is
questionable.

The lumped-circuit model is a subset of the distributed-network
model. The distributed-network model is a subset of Maxwell's
equations. If you don't understand the limitations of the model,
you will choose to use it under the wrong circumstances. That's
what you, Roy, and others have done.
--
73, Cecil, W5DXP