Cecil,

What you are missing is the flux inside the coil links all the turns at
light speed. When it does that, current appears at nearly the same
instant of time (light speed over the spatial distance of the inductor)
in all areas that are linked by flux.

The flux coupling also tries to equalize currents throughout every area
of the coil.

Charge conservation also dictates that any current flowing into the
coil has to be equalled by a like current flowing out the other
terminal, less any displacement currents caused by stray capacitance
(electric fields) to the outside world.

We cannot have a two terminal "black box" with confined fields that
behaves any other way, standing waves or not.

The only flaws in having zero current phase shift and zero current
difference are the less-than-perfect flux coupling and
less-than-perfect confinement of the electric field. Any deviation from
following perfect two-terminal rules are directly tied to the ratio of
load impedance on the inductor to the stray capacitance to the outside
world, and of course less than perfect flux linkage from end-to-end in
the coil.

People can often better understand the limits when things are taken to
an extreme.

Imagine a helical whip antenna. It is a very poorly constructed
"loading coil". It has nearly infinite termination impedance at the
open end, and very poor mutual coupling from turn to turn. The form
factor is very distorted, far from being equal in diameter and length.
The ratio of distributed capacitance to termination capacitance is very
large, it can be nearly infinite.

A loading inductor or helical whip like this behaves nearly like an
antenna.

The opposite would be a toroid, with a very compact form and almost
total confinement of fields. Standing waves or not, as long as it is
not near self-resonance it has evenly distributed current inside and at
each terminal.

Most well-designed efficient short antennas use a loading coil having
very nearly equal currents at each terminal. Current equality actually
is a good way to determine a properly designed loading coil.

If you can stay on topic and we process only one point at a tme, I'm
sure you will be able to learn how this works. If you see any flaw in
how I just described inductor behavior, please point it out. Once we
agree how an inductor works everything else will fall into place.

73 Tom

wrote:
What you are missing is the flux inside the coil links all the turns at
light speed. When it does that, current appears at nearly the same
instant of time (light speed over the spatial distance of the inductor)
in all areas that are linked by flux.

I am not missing the flux linkage. What you are missing is the known
phase lag that the current undergoes compared to the voltage. Whatever
voltage phase shift you measured (60 degrees), the lagging current
phase shift is likely to be more than double that value. Hint: an
ideal inductor forces the current to lag the voltage by 90 degrees.
If the current propagates at the speed of light, the voltage propagates
much faster than the speed of light so it can lead the current. Please
explain that one to us.

The flux coupling also tries to equalize currents throughout every area
of the coil.

A well known fact. It applies to the forward current and reflected
current, not to the standing wave current which is not flowing
into or out of the coil at all. There is no net charge flow in
a standing wave and therefore, no net current flow. At any point
on a 1/2WL thin wire dipole, the only thing happening is that the
energy is migrating between the H-field and the E-field. There is
zero energy flow away from that point in either direction. That's
why the phase angle of the reflected current is constant and fixed
at zero degrees. It is simply not flowing. What is flowing is the
forward and reflected component currents which indeed to obey all
the rules you have listed here.

Charge conservation also dictates that any current flowing into the
coil has to be equalled by a like current flowing out the other
terminal, less any displacement currents caused by stray capacitance
(electric fields) to the outside world.

Absolutely no argument here. Even assuming the coil is lossless, the
magnitude of the forward current flowing into the coil is equal to
the magnitude of the forward current flowing out of the coil. Likewise
for the reflected current. So this part of your argument is somewhat
irrelevant. What you seem to be missing is the phase shift in those
component currents.

We cannot have a two terminal "black box" with confined fields that
behaves any other way, standing waves or not.

If a piece of transmission that is an appreciable percentage of a
wavelength is coiled into a coil that is an appreciable percentage
of a wavelength, why is it surprising to you that the coil responds
somewhat like the piece of wire that it replaces? The answer is that
you assumed the proof in your argument. It goes something like this:

A lumped inductance doesn't have any magnitude change or phase shift
through the coil. A bugcatcher loading coil is a lumped inductance.
Therefore, a bugcatcher loading coil doesn't have any magnitude change
or phase shift through the coil. The first proof that you offered some
months ago was that the lumped inductance modeled in EZNEC didn't show
any magnitude change or phase shift. Do you see the fallacy in your
thought processes? You assumed the proof in your argument and you
are still falling into that logical trap. Is it any surprise that
a software program shows no magnitude change or phase shift? Please
open up your mind and think the unthinkable. You will be rewarded.

The only flaws in having zero current phase shift and zero current
difference are the less-than-perfect flux coupling and
less-than-perfect confinement of the electric field.

There you go, assuming the proof in your argument. A lossless non-
radiating transmission line doesn't even obey those rules. Why should
you expect a real-world coil made from that transmission line wire to
obey those rules? Before you respond with the 2-terminal Vs 4-terminal
argument, please realize that a horizontal #14 wire 30 ft. above ground
is considered to be a single-wire transmission line with a Z0 of around
600 ohms. Thus, a horizontal dipole is simply a lossy transmission line.

If you would like, I can quote Balanis on all of this.

Any deviation from
following perfect two-terminal rules are directly tied to the ratio of
load impedance on the inductor to the stray capacitance to the outside
world, and of course less than perfect flux linkage from end-to-end in
the coil.

Assuming the proof again. 1/4WL apart in a lossless, non-radiating
transmission line, the standing wave currents are wildly different.
Why are you surprised when we take that 1/4WL of wire, wind it into
a coil, and achieve a lot of the same conditions?

If you can stay on topic and we process only one point at a tme, I'm
sure you will be able to learn how this works.

I'm certainly game for that. We can start by agreeing that the forward
current through a loading coil has the same magnitude at each end of
the coil but suffers a phase shift through the coil. You measured a
voltage phase shift of 60 degrees through a 100uH coil at 1 MHz. Since
the current lags the voltage in a coil, the current phase shift has to
have been greater than 60 degrees, maybe even 120+ degrees depending
upon the Q of the coil. Tom, even I can measure the traveling wave
current phase shift in a 75m bugcatcher coil so please don't insult
my intelligence by asserting that a phase shift doesn't exist.

If a coil could eliminate phase shifts, Intel would be using them in
their computer busses. The truth is, a coil in a computer bus
increases the phase shift, not decreases it. So please give us a
break on that irrational concept. You have been fooled by your model.
--
73, Cecil http://www.qsl.net/w5dxp

Tom, W8JI wrote:
"What you are missing is the flux inside the coil links all the turns at
light speed. When it does that, current appears at nearly the same
instant of time (light speed over the spatial distance of the inductor)
in all areas that are linked by flux."

Are any famous authors protagonists of that theory?

One author, Bill Orr, W6SAI writes in the 22nd edition of "Radio
Handbook" on page 5.11:
"Spaced closely around the beam (in a TWT) is a circuit, in this case a
helix of tightly wound wire, capable of propagating a slow wave. The r-f
energy travels along the wire at the velocity of light but, because of
the helical path, the energy progresses along the length of the tube at
a considerably lower velocity that is determined by the pitch of the
helix.

Maybe Varian has a paper on this (just my speculation).

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Are any famous authors protagonists of that theory?

In "Fields and Waves in Modern Radio", Ramo and Whinnery, 2nd
edition, there is a section titled: "9-16 The Idealized Helix
and Other Slow-Wave Structures". Quoting: "A rough picture
would convince one that the wave should follow the *wire* with
about the velocity of light, ..."

From the IEEE Dictionary: "slow-wave circuit - A circuit whose
phase velocity is much slower than the velocity of light. For
example, for suitably chosen helixes the wave can be considered
to travel on the *wire* at the velocity of light but the phase
velocity is less than the velocity of light by the factor that
the pitch is less than the circumference."

a 75m bugcatcher loading coil is a slow wave structure with
a velocity factor around 0.017 (calculated and measured).
--
73, Cecil http://www.qsl.net/w5dxp

Everybody quotes from Bibles.

Which reduces the authors to the same standard of conversation as
transpires on this newsgroup.

Has nobody any confidence in what he is saying and feels in need of
support from the angeles.

-------------------------------------------------------------------

Reg Edwards wrote:
Has nobody any confidence in what he is saying and feels in need of
support from the angeles.

"angeles"? Resorting to Spanish is no help. The present
question is, "can EZNEC be trusted"? We already know
your opinion. :-)
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote
Reg Edwards wrote:
Has nobody any confidence in what he is saying and feels in need
of
support from the angeles.

"angeles"? Resorting to Spanish is no help. The present
question is, "can EZNEC be trusted"? We already know
your opinion. :-)
========================================

Dear Cec,

- - - and what is my opinon which everybody is supposed to know?
C'mon then. Be truthful. Out with it!
----
Reg.

Reg Edwards wrote:
- - - and what is my opinon which everybody is supposed to know?
C'mon then. Be truthful. Out with it!

Your opinion of EZNEC is recorded for posterity on Google.
Who am I to embellish it?
--
73, Cecil http://www.qsl.net/w5dxp

On Mon, 20 Mar 2006 17:52:29 GMT, Cecil Moore
wrote:
The present question is, "can EZNEC be trusted"?
This repugnant "question" borders on, and crosses into ignorance for
the sake of arguing.

Richard Clark wrote:

Cecil Moore wrote:
The present question is, "can EZNEC be trusted"?

This repugnant "question" borders on, and crosses into ignorance for
the sake of arguing.

It was a rhetorical question, Richard. If the creator of EZNEC
disagrees with his own creation, what does that imply?
--
73, Cecil http://www.qsl.net/w5dxp