Wes Stewart wrote:

Maybe part of the myth is that the antenna must be resonant to work.
Nothing could be further from the truth.

Has the radiator current distribution changed? No. Does the inductor
in the L-network "make up" some number of electrical degrees in the
radiator? Not from my viewpoint.

I think there are two problems:

1.) Cecil wants everyone to start using reflection wave models to
analyze every antenna system in the world.

2.) Many people think a very short monopole antenna that is resonant is
still 90 electrical degrees long, and that the inductor makes up the
missing number of degrees, and the current taper across that inductor
is some form of sine shaped curve.

Cecil is free to use whatever tools he likes. He doesn't work for me,
and (thank God) I don't have to work for him! What he wants me or
others to do is a moot point.

I am concerned about the commonly held but very incorrect view that
current travels through an inductor turn-by-turn, and that a loading
inductor somehow shifts the phase of and/or level of current to "make
up for missing degrees".

My only concern is people not understanding how an inductor and short
antenna actually behaves. That problem is worth attention.

73 Tom

wrote:
1.) Cecil wants everyone to start using reflection wave models to
analyze every antenna system in the world.

No, I simply want you and others to stop using a known invalid
model for every standing wave antenna system in the world.
This is a quote from the first web page below: The capital
letters are where the author used bold italics for emphasis.

"... - no wave interferrence and no standing waves can be
present on lumped elements. The problem has been that many
experimenters working with self-resonant helices have
PURSUED THE CONCEPT OF COIL SELF-
CAPACITANCE WITHOUT REALLY UNDERSTANDING
WHERE THE NOTION COMES FROM OR WHY IT WAS
EVER INVOKED BY ENGINEERS. For that, they will have
to go read R.W.P. King's wonderful old book, "Electromagnetic
Engineering, McGraw-Hill, 1945. ... On page 465, the Harvard
Professor points out that, for coils whose *wire length* exceeds
1/6 wavelength, ...'an adequate representation of the reactance
of a coil with a nonuniformly distributed currentr is NOT
POSSIBLE in terms of a coil with a uniform current [a lumped
element inductance] ...' Period. Resonant FIELDS present
surprises to engineers with limited training."

Certainly sounds like he is talking about you, Tom. "Electronic
Engineering" was written before you were born. Why are you
ignorant of the technical facts presented in it?

http://www.ttr.com/corum/index.htm

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf

The .pdf paper is a pier-reviewed publication by the IEEE. Here's
what it says about the model you have chosen to use.

"Of course, the uniform current assumption has no validity for coils
operating anywhere near self-resonance!"

"The failure of any limped element circuit model to describe the
real world lies at its core inherent *presupposition*: the speed of
light is presumed to be infinite in the wave equation. ... Consequently,
lumped element circuit theory does not (and cannot) accurately
embody a world of second order partial differential equations in
space and time."

"The concept of coil "self-capacitance" is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior."

"There are a great number of formulae for coil self-capacitance.
None are of particular value for quarter-wave helical resonators
anywhere near the 90 degree point."

"The delusion is that the short coil is then made to operate in the
lumped element regime ...".

That you refuse to give up on an invalid method in the face of
overwhelming evidence is amazing.

What he wants me or others to do is a moot point.

Afraid of what you will find? The first web page above says:
"Lumped circuit theory isn't absolute truth, it's only an analytical
theory - and in these resonators we have the case where this
sophmore theory fails experimentally." Do the experiment, Tom,
and discover exactly how sophmorish you are being.

I am concerned about the commonly held but very incorrect view that
current travels through an inductor turn-by-turn, and that a loading
inductor somehow shifts the phase of and/or level of current to "make
up for missing degrees".

Tom, that's what any matching network does. Loading coils are no
exception.

My only concern is people not understanding how an inductor and short
antenna actually behaves.

I am concerned about you not understanding, Tom. Don't
you believe the information posted on those web pages above. Don't
you think a peer-reviewed IEEE publication that disagrees with you
is worth a second thought from you. Don't you think ignoring the
knowledge published by experts in the field is a little naive?
--
73, Cecil, W5DXP

Cecil,

A few random comments:

* I have done a number of "peer reviews" for IEEE and AIP publications
as well as other publications. I have seen comments from the other
reviewers. In general peer review is better than nothing, but in many
cases it doesn't mean diddly.

* The Tesla coil crowd seems to contain an unusually large fringe. I
know nothing of the authors of your latest bible, but in any case I was
not particularly impressed with their credentials or their paper. I love
the part, "Lumped circuit theory isn't absolute truth, it's only an
analytical theory about lumped models". As if their work is somehow
absolute truth. (Back to the previous bullet: I have never seen any
serious peer-reviewed paper that would contain such a statement.)

* No one is his right mind would think that a Tesla coil with a
gazillion closely spaced turns is equivalent to a bugcatcher coil. No
one should think that an axial mode helical antenna is equivalent to an
ordinary loading coil either.

* You are waaaay too hung up on the subject of standing waves vs.
traveling waves. You may have noticed that the standard treatments of
antennas in texts and other references barely mention the terms. They
merely discuss the actual current in the antenna. The fundamentally
important entity in radiation is accelerated charge, just as Tom noted.
At any point in an antenna, such as the loaded monopole discussed here,
there is simply a current, not a traveling wave or a standing wave. If
you could examine the antenna microscopically at a single point you
would find electrons sloshing back and forth. You could not tell if the
current was represented by a standing wave or a traveling wave. The
standing wave description relates to the overall amplitude
characteristic of the current when you look at the entire antenna. This
amplitude characteristic is certainly important in calculation of
details of the radiation field, but it does not change the fundamental
property of radiation or the physical processes ongoing in the antenna.
It is just plain silly to argue that a standing wave is totally inert
and does not flow back and forth.

* Distributed or network models are mathematically convenient for
treating complex problems. However, they add precisely zero new
information to the underlying physical reality described by Maxwell's
equations. They offer no new physics beyond lumped models. They can be
misapplied just the same as lumped models can be misapplied. It is
generally best to drive a nail with a hammer, but a monkey wrench will
also do the job. It is best to choose the most efficient tool, but that
does not mean others won't work.

73,
Gene
W4SZ


Cecil Moore wrote:
wrote:

1.) Cecil wants everyone to start using reflection wave models to
analyze every antenna system in the world.


No, I simply want you and others to stop using a known invalid
model for every standing wave antenna system in the world.
This is a quote from the first web page below: The capital
letters are where the author used bold italics for emphasis.

"... - no wave interferrence and no standing waves can be
present on lumped elements. The problem has been that many
experimenters working with self-resonant helices have
PURSUED THE CONCEPT OF COIL SELF-
CAPACITANCE WITHOUT REALLY UNDERSTANDING
WHERE THE NOTION COMES FROM OR WHY IT WAS
EVER INVOKED BY ENGINEERS. For that, they will have
to go read R.W.P. King's wonderful old book, "Electromagnetic
Engineering, McGraw-Hill, 1945. ... On page 465, the Harvard
Professor points out that, for coils whose *wire length* exceeds
1/6 wavelength, ...'an adequate representation of the reactance
of a coil with a nonuniformly distributed currentr is NOT
POSSIBLE in terms of a coil with a uniform current [a lumped
element inductance] ...' Period. Resonant FIELDS present
surprises to engineers with limited training."

Certainly sounds like he is talking about you, Tom. "Electronic
Engineering" was written before you were born. Why are you
ignorant of the technical facts presented in it?

http://www.ttr.com/corum/index.htm

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf

The .pdf paper is a pier-reviewed publication by the IEEE. Here's
what it says about the model you have chosen to use.

"Of course, the uniform current assumption has no validity for coils
operating anywhere near self-resonance!"

"The failure of any limped element circuit model to describe the
real world lies at its core inherent *presupposition*: the speed of
light is presumed to be infinite in the wave equation. ... Consequently,
lumped element circuit theory does not (and cannot) accurately
embody a world of second order partial differential equations in
space and time."

"The concept of coil "self-capacitance" is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior."

"There are a great number of formulae for coil self-capacitance.
None are of particular value for quarter-wave helical resonators
anywhere near the 90 degree point."

"The delusion is that the short coil is then made to operate in the
lumped element regime ...".

That you refuse to give up on an invalid method in the face of
overwhelming evidence is amazing.


What he wants me or others to do is a moot point.


Afraid of what you will find? The first web page above says:
"Lumped circuit theory isn't absolute truth, it's only an analytical
theory - and in these resonators we have the case where this
sophmore theory fails experimentally." Do the experiment, Tom,
and discover exactly how sophmorish you are being.


I am concerned about the commonly held but very incorrect view that
current travels through an inductor turn-by-turn, and that a loading
inductor somehow shifts the phase of and/or level of current to "make
up for missing degrees".


Tom, that's what any matching network does. Loading coils are no
exception.


My only concern is people not understanding how an inductor and short
antenna actually behaves.


I am concerned about you not understanding, Tom. Don't
you believe the information posted on those web pages above. Don't
you think a peer-reviewed IEEE publication that disagrees with you
is worth a second thought from you. Don't you think ignoring the
knowledge published by experts in the field is a little naive?
--
73, Cecil, W5DXP

Gene Fuller wrote:

Cecil Moore wrote:
. . .
"... - no wave interferrence and no standing waves can be
present on lumped elements. The problem has been that many
experimenters working with self-resonant helices have
PURSUED THE CONCEPT OF COIL SELF-
CAPACITANCE WITHOUT REALLY UNDERSTANDING
WHERE THE NOTION COMES FROM OR WHY IT WAS
EVER INVOKED BY ENGINEERS. For that, they will have
to go read R.W.P. King's wonderful old book, "Electromagnetic
Engineering, McGraw-Hill, 1945. ... On page 465, the Harvard
Professor points out that, for coils whose *wire length* exceeds
1/6 wavelength, ...'an adequate representation of the reactance
of a coil with a nonuniformly distributed currentr is NOT
POSSIBLE in terms of a coil with a uniform current [a lumped
element inductance] ...' Period. Resonant FIELDS present
surprises to engineers with limited training."

Certainly sounds like he is talking about you, Tom. "Electronic
Engineering" was written before you were born. Why are you
ignorant of the technical facts presented in it?

I have this book. The condition for the quoted result isn't simply that
the length of wire in the coil be adequately long, but also that the
coil be wound loosely enough so that the coupling between turns is poor
enough to allow a particular nonuniform current distribution. It applies
to a "loosely wound helix." The quote is within a section titled
"'Lumped' Constants in Near-zone circuits", which contains a detailed
analysis of just what conditions can cause an inductor to have unequal
input and output currents, but primarily how the currents can be unequal
even in the absence of an external field. In particular, the author
describes an inductor in which the coupling between turns isn't
sufficient to force equal currents at the coil ends. Qualitatively, this
should be pretty obvious: If we begin with a long wire (in terms of
wavelength), the current will vary along its length. As we wind it into
a loose coil, mutual coupling between turns will create inductance and
make the current more uniform, but with a distribution still resembling
that of the straight wire. It's this situation that the quotation
applies to -- an inductor so loosely wound that its current distribution
resembles a straight wire more than an inductance. He does go on to say
that if the winding is tighter but still not ideal, the resulting
non-uniform current, which has a different distribution (greater at the
center than at the ends), can be modeled by means of a lumped self
capacitance. Only if we have perfect coupling between turns (as a toroid
very nearly represents) will we truly have equal currents at input and
output, for the reasons Tom recently explained. This is the idealized
inductance which some of the contributers to this discussion are having
trouble understanding.

The mathematical treatment in King is quite complex. But nowhere does he
mention any traveling, reflected, or standing current, power, or energy
waves, or that an inductance behaves any differently in an antenna than
in a lumped circuit. It simply isn't necessary or relevant to explaining
the operation of either an ideal or non-ideal inductor. Nor does he
dispute the fact that the currents into and out of an ideal inductance
are equal. And of course there's no mention of the mysterious "resonant
fields" which probably do surprise engineers, as does the metaphysics
being promoted here.

Roy Lewallen, W7EL

Roy Lewallen wrote:
It applies to a "loosely wound helix."

Please define the point at which a "loosely wound helix" with
a varying current turns into this lumped-circuit device that
forces equal currents through the coil. Is a 75m bugcatcher
coil a "loosely wound helix" or a "lumped-circuit"?
(My 75m bugcatcher coil is about 1/6 wavelength of wire.)

Only if we have perfect coupling between turns (as a toroid
very nearly represents) will we truly have equal currents at input and
output, for the reasons Tom recently explained. This is the idealized
inductance which some of the contributers to this discussion are having
trouble understanding.

Unfortunately, an idealized inductance is like a lossless transmission
line - it exists only in the human mind. What I would like to know is
what is the real-world phase shift through your toroidal inductor when
there is only a traveling wave (no standing wave). We can then use
the laws of reflection physics to determine what effect that phase
shift has on the amplitude of the standing wave current which is the
phasor sum of the forward current and reflected current. I'm actually
going to make those measurements as soon as I get off my old lazy ass.

Seems to me that although a toroidal current pickup may not have the
same magnitude characteristics because of variations in the permeability,
the phase would suffer no such effects. Am I correct on that point?
I'm somewhat handicapped in having no current probes for my 100 MHz
Leader and acquiring them would put a big dent in my Social Security
check. :-)

What I am toying with is a 6m rhombic. I could run it as a terminated
traveling-wave antenna or unterminate it and have a standing-wave
antenna. I could move all kinds of coil(s) up and down the the elements
to place them at nodes or loops or in-between and take measurements.
What do you think?
--
73, Cecil http://www.qsl.net/w5dxp

Hi Cecil

I have a HP8405A Vector Voltmeter I'll give you and even pay the shipping
if that is of any help with the measurements.

Jerry



"Cecil Moore" wrote in message
om...
Roy Lewallen wrote:
It applies to a "loosely wound helix."

Please define the point at which a "loosely wound helix" with
a varying current turns into this lumped-circuit device that
forces equal currents through the coil. Is a 75m bugcatcher
coil a "loosely wound helix" or a "lumped-circuit"?
(My 75m bugcatcher coil is about 1/6 wavelength of wire.)

Only if we have perfect coupling between turns (as a toroid very nearly
represents) will we truly have equal currents at input and output, for
the reasons Tom recently explained. This is the idealized inductance
which some of the contributers to this discussion are having trouble
understanding.

Unfortunately, an idealized inductance is like a lossless transmission
line - it exists only in the human mind. What I would like to know is
what is the real-world phase shift through your toroidal inductor when
there is only a traveling wave (no standing wave). We can then use
the laws of reflection physics to determine what effect that phase
shift has on the amplitude of the standing wave current which is the
phasor sum of the forward current and reflected current. I'm actually
going to make those measurements as soon as I get off my old lazy ass.

Seems to me that although a toroidal current pickup may not have the
same magnitude characteristics because of variations in the permeability,
the phase would suffer no such effects. Am I correct on that point?
I'm somewhat handicapped in having no current probes for my 100 MHz
Leader and acquiring them would put a big dent in my Social Security
check. :-)

What I am toying with is a 6m rhombic. I could run it as a terminated
traveling-wave antenna or unterminate it and have a standing-wave
antenna. I could move all kinds of coil(s) up and down the the elements
to place them at nodes or loops or in-between and take measurements.
What do you think?
--
73, Cecil http://www.qsl.net/w5dxp

Jerry Martes wrote:
I have a HP8405A Vector Voltmeter I'll give you and even pay the shipping
if that is of any help with the measurements.

Wow, thanks for the offer. That would certainly be more
accurate than eyeballing an o'scope. Do you think the
use of such would prove me right or wrong? Does the
VV compare two signals and report the phase difference?
Are the probes differential or coaxial? I've never used
a VV.
--
73, Cecil http://www.qsl.net/w5dxp

On Fri, 10 Mar 2006 03:12:11 GMT, "Jerry Martes"
wrote:

I have a HP8405A Vector Voltmeter I'll give you and even pay the shipping
if that is of any help with the measurements.

Hi Jerry,

So, any taker?

73's
Richard, KB7QHC

Roy Lewallen, W7EL wrote:
"The mathematical treatment in King is quite complex. But nowhere does
he mention any traveling, reflected, or standing current, power, or
energy waves, or that inductance behaves any differently in an antenna
than in a lumped circuit.."

Maybe something was overlooked. The above is just more squid ink.

Kraus characterizes inductors as helices. At one extreme they are
stretched into straifht wires. At the other they collapse into single
loops.

After years of wrangling it is time to admit that the old authors are
right.

King and Wing were associates at Harvard.

Alexander H. Wing wrote on page 3 of "Transmission Lines, Antennas, and
Wave Guides":
"5. Distributed constants - The Transmission line cannot be analyzed as
a simple series circuit, because the current in the wires is not
everywhere the same."

J.D. Kraus wrote on page 185 of his 1950 edition of "Antennas":
"Thus, a helix with circumference too small for the axial mode of
radiation (circumferennce less than 2/3 wavelength) has a nearly
sinusoidal current distribution, caused by alternate reinforcement and
cancellation of two oppositely directed traveling waves on the helix of
nearly equal amplitude Izero as suggested in Fig. 7-13c. Both traveling
waves are of the Tzero transmission mode type."

I expedct no one will throw in the towel, but do expect more squirts of
squid ink.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
J.D. Kraus wrote on page 185 of his 1950 edition of "Antennas":
"Thus, a helix with circumference too small for the axial mode of
radiation (circumferennce less than 2/3 wavelength) has a nearly
sinusoidal current distribution, caused by alternate reinforcement and
cancellation of two oppositely directed traveling waves on the helix of
nearly equal amplitude Izero as suggested in Fig. 7-13c. Both traveling
waves are of the Tzero transmission mode type."

Over on qrz.com, Tom was trying to prove Kraus wrong when he said in
"Antennas for All Applications", 3rd edition: "A coil (or trap) can
also act as a 180 degree phase shifter as in the collinear array
of 4 in-phase 1/2WL elements in Fig. 23-21B. Here the elements
present a high impedance to the coil which may be resonated without
an external capacitor due to its distributed capacitance. The coil
may also be thought of as a coiled-up 1/2WL element."

In trying to prove one could not obtain Kraus' 180 degree phase shift
with a coil [because everyone knows the phase shift is always zero],
Tom accidentally let slip the following - quoted from qrz.com:

W8JI wrote:
"By the way, I swept S12 phase with my network analyzer on a
100uH inductor a few hours ago while working on a phasing
system. The phase shift through that series inductor was about
-60 or -70 degrees on 1 MHz, ... "

Say what? Tom reporting a phase shift through an inductor? Will
miracles never cease?
--
73, Cecil http://www.qsl.net/w5dxp