On 15 Nov, 16:13, Roy Lewallen wrote:
Mike Kaliski wrote:

Hi Roy,

He does mention that antennas possess radiation resistance, not to be
confused with and not the same as, characteristic impedence (or
feedpoint impedence) and that the characteristic impedence will vary
along an antennas length.

As for the actual point(s) along an element at which an antenna radiates
(transfers energy to free space) with maximum efficiency, he makes no
comment.

I seriously doubt that there is anything in the article that you would
dispute.

It seems that everyone was so busy laughing on this newsgroup, that no
one has actually provided any information as to whether any detailed
research has ever been carried out as to what is going on within the
radiating elements of an antenna. There is loads of theory in the text
books, but I have yet to see any empirical measurements or results.

If you haven't seen any measurements or results, you haven't looked in
any of the professional publications over the past hundred years or so.
There have been a great number of measurements of antennas made. Of
those, none to my knowledge have ever definitively shown results other
than the textbook theory predicts. That's pretty good confirmation of
the current theory.

If there is merit to alternative theories, they should predict exactly
(or at least within the most precise measurement capabilities we have)
the same results as the current textbook theories, because those
theories agree closely with measurement. That means the alternative
theories must come with equations which can be used to predict antenna
performance as well as what we use now with great success. Vague
hand-waving is adequate to convince a certain number of rraa readers,
but it doesn't go far with those of us who actually design antennas that
have to work.

. . .
I may have submitted the post, tongue in cheek, to stir things up a bit,
but on reflection there seems to be something of merit in the idea. I am
revisiting the appropriate chapters in Kraus and Terman to see where the
error in my logic is. In the absence of any direct evidence of
contradiction, I think it may be worth developing this idea and making a
few measurements of my own to see what the truth of the matter is.

There's a real problem here. Making even half decent measurements of
antennas is an extremely difficult undertaking. People without the
proper equipment, experience, and knowledge of tolerances to be expected
frequently make poor measurements and draw erroneous conclusions from
them. Before you get too involved, I suggest starting with a dipole,
loop, or some other very simple, well understood, and well documented
antenna and see just how good your measurement methods are. If you can't
do those simple antennas properly, then any other measurements you make
shouldn't be trusted. And those are the easiest ones. If you want a real
challenge, try a very short antenna. Just keeping the feedline from
being part of the system can be a nearly insurmountable task, and
measuring a very small resistance in the presence of a very large
reactance isn't easy either. Unless you can deal with these and other
measurement realities, your measurements might be fun, but they won't
mean anything. You can publish on rraa and draw a certain number of oohs
and ahs, but it won't be material for the IEE or IEEE -- not because
they're contradicting conventional theory, but because they're not
representative of reality.

Oh my, you sound so upset.
Your theory used in Eznec was designed
around known "reality" because you found the need to add the proviso
that there was a sino soidal current at all points on the radiator.
Number one, it is not legitamate to add a proviso or a special
condition
to a known law.( Electrical or Mechanical)
Number two It becomes a worse problem when the proviso added is in
error.
Number three, You should not retain a proviso if it proves incorrect .
The fact that present theory has passed the test of time means
nothing.
The threat of retaliation trumps science when humans are concerned.
Gallilao never saw the day that the earth was proven round which
stood the test for a very very long time.
But you could explain to the world how a sino soidal current passes
thru
a distributed capacitance and still retain its properties as it
encounters every segment. This is per the proviso you have placed
with
existing Maxwell's laws with respect to your computor program.
But no you can't! Until then I don't think you are equipped to say
that written theory can be taken as fact.Especially when known laws
are twisted so you can gyrate your program to known reality.
The old saying still stands, Garbage in will produce garbage out
unless the outputs are subject to reprocessing !

Art Unwin...KB9MZ






Amateur radio is supposed to be a learning experience, right? And you
can't learn without making mistakes. After 40 years of following the
diktats of professional communications and electronic theory, I think
the time is right to kick off the traces and challenge some of the
accepted authodoxies. I do know all the conventional stuff, it just
doesn't satisfy my soul.

Have you considered religion? The rules of evidence are much more
relaxed in that environment, so alternative theories are more readily
accepted. Just look at the proliferation of denominations. There's
always room for a few more.

You probably know more about antennas than anyone has a right to know
Roy, but it's a strange universe out there and it's just possible that
there's a few more things to learn yet.

Indeed there are. When you have an alternative theory that agrees as
closely with measured results as the current ones, and which can be used
to predict antenna performance, I'd like to be among the first to read
your paper and benefit. Shoot, I might even incorporate the equations
into EZNEC to make it even more accurate than it is now. I'm a member of
the IEEE Antennas and Propagation, Broadcast, and EMC societies, so I'll
see any papers published in those journals. And I can easily get papers
published by the IEE or other societies. Have at it!

Roy Lewallen, W7EL- Hide quoted text -

- Show quoted text -

"art" wrote in message news:3bd68052-1537-4b55-a745-
snip
Oh my, you sound so upset.
Your theory used in Eznec was designed
around known "reality" because you found the need to add the proviso
that there was a sino soidal current at all points on the radiator.
Number one, it is not legitamate to add a proviso or a special
condition
to a known law.( Electrical or Mechanical)
Number two It becomes a worse problem when the proviso added is in
error.
Number three, You should not retain a proviso if it proves incorrect .
The fact that present theory has passed the test of time means
nothing.
The threat of retaliation trumps science when humans are concerned.
Gallilao never saw the day that the earth was proven round which
stood the test for a very very long time.
But you could explain to the world how a sino soidal current passes
thru
a distributed capacitance and still retain its properties as it
encounters every segment. This is per the proviso you have placed
with
existing Maxwell's laws with respect to your computor program.
But no you can't! Until then I don't think you are equipped to say
that written theory can be taken as fact.Especially when known laws
are twisted so you can gyrate your program to known reality.
The old saying still stands, Garbage in will produce garbage out
unless the outputs are subject to reprocessing !

Art Unwin...KB9MZ

snip


Art,

I'm sure Roy is quite capable of defending himself against your accusations,
but I think you are being a trifle unfair. EZNEC is a simulation designed to
predict the performance of an antenna design. Being a simulation, certain
assumptions and approximations have to be made in order for it to work. The
fact is that in most situations it does provide an accurate prediction of
antenna performance. There are some special circumstances where it won't.

Integral calculus has been described as one of the greatest advances in
mathematical science, but that is still only an approximation method and
nobody complains about that.

Let's all behave and not argue okay?

Best wishes
Mike G0ULI

On 15 Nov, 18:25, "Mike Kaliski" wrote:
"art" wrote in message news:3bd68052-1537-4b55-a745-

snip





Oh my, you sound so upset.
Your theory used in Eznec was designed
around known "reality" because you found the need to add the proviso
that there was a sino soidal current at all points on the radiator.
Number one, it is not legitamate to add a proviso or a special
condition
to a known law.( Electrical or Mechanical)
Number two It becomes a worse problem when the proviso added is in
error.
Number three, You should not retain a proviso if it proves incorrect .
The fact that present theory has passed the test of time means
nothing.
The threat of retaliation trumps science when humans are concerned.
Gallilao never saw the day that the earth was proven round which
stood the test for a very very long time.
But you could explain to the world how a sino soidal current passes
thru
a distributed capacitance and still retain its properties as it
encounters every segment. This is per the proviso you have placed
with
existing Maxwell's laws with respect to your computor program.
But no you can't! Until then I don't think you are equipped to say
that written theory can be taken as fact.Especially when known laws
are twisted so you can gyrate your program to known reality.
The old saying still stands, Garbage in will produce garbage out
unless the outputs are subject to reprocessing !

Art Unwin...KB9MZ

snip

Art,

I'm sure Roy is quite capable of defending himself against your accusations,
but I think you are being a trifle unfair. EZNEC is a simulation designed to
predict the performance of an antenna design. Being a simulation, certain
assumptions and approximations have to be made in order for it to work. The
fact is that in most situations it does provide an accurate prediction of
antenna performance. There are some special circumstances where it won't.

Integral calculus has been described as one of the greatest advances in
mathematical science, but that is still only an approximation method and
nobody complains about that.

Let's all behave and not argue okay?

Best wishes
Mike G0ULI- Hide quoted text -

- Show quoted text -

But I am behaving. I am sure that both Roy and others who deal with
NEC4
will admit that they have played with the truth with respect to
antenna programs.
I would venture to say that computor programs are good at what they do
but
it is for all the wrong reasons. Maxwell's laws are just that..Laws.
It is mathematically fraudulent to add anything to those laws under
the banner of Maxwell.
When Roy left the ARRL circle he challenged antena companies to verify
their claims
with respect to gain. By the same token I am challenging to prove the
veracity
of the additional statement that a sino soidal current is present at
every segment point.
Not is it only mathematically illegal to modify a law the addition
also defies all electrical laws.
A radiator has distributed capacitance and I am not aware that a
capacitor will
allow the passage of a time varying current, this is what the
programing states.
He ofcourse can justify why he did this to the satisfaction of all but
he cannot justify
the insertion of such.
Now my antenna operates quite nicely following another aproachyet Roy
vehamently
derides this new aproach when he himself cannot verify his own
actions.
Fairness can be seen in different ways. He can be belligerent in
analysing my aproach
yet at the same time defend an action that he cannot prove to be true.
A person always has the right to defend himself especially against
those
who are mentally challenged. When he provides how distributed
capacitance does not affect
the time varient that Maxwell states is a titular point of his laws I
will readily
retract that remark. Until that time I will defend the veracity of my
aproach which
succesfully produces antennas and arrays in a smaller volume that
present theory
predicts as impossible. As an adder, I am discussing antennas and not
"systems" as Roy
would imply.
Nothing personal, Like Reagan I like verification since trust
does not prove to be enough and I will always defend if I am attacked.
Best regards
Cheers with a Black and Tan
Art Unwin.....KB9MZ...xg

Art wrote:
"By the same token I am challenging to prove the veracity of the
statement that a sino soidal current is present at every segment point."

An antenna is generally a linear passive device meaning that a
sinusoidal wave entering an antenna produces sinusoidal fields which
induce sinusoidal voltages and currents in the distant receiving
antenna.

Sinusoidal voltages appear at every point on such an antenna and
sinusoidal currents pass over the surface of every point of the antenna.
Insulators of course interrupt conduction currents and allow the rise of
voltage gradients.

Induced currents are produced by the electric field of the wave in the
insulation of free space by the displacement (capacitive action) current
of an antenna. Maxwell speculated that displacement generated a magnetic
field same as conduction did, and that was the secret of radiation. He
was proved correct. A magnetic field generated an electric field and an
electric field generated a magnetic field so that the two fields locked
and traveling together go on ond on forever.

Most antennas have two waves traveling in opposite directions, an
incident wave and a reflected wave. Both pass through every point on the
antenna conductor.

A directional coupler can access the wave traveling in one direction
while ignoring the wave traveling in the opposite direction.

Large variations in voltage appearing on the antenna make the familiar
standing wave pattern but this is not a true picture of the individual
waves making up the combined wave. The effective values of the incident
and reflected waves decline steadily but gradually along the antenna as
they travel in opposite directions.

A sinusoidal current is present at every segment point and only slowly
changes from point to point. Two sine waves of the same frequency always
combine at a point to create another sine wave of the same frequency.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

A magnetic field generated an electric field and an
electric field generated a magnetic field so that the two fields locked
and traveling together go on ond on forever.
...
Best regards, Richard Harrison, KB5WZI


From the above, are the two in a constant state of interaction? The
magnetic reversing to electric--the electric reversing to magnetic?

Or, is their relationship static to one another?

Regards,
JS

John Smith wrote:
"From the above, are the two in a constant state of interaction?"

On page 1 of Terman`s "Electronic and Radio Engineering":
"These waves, which are commonly called radio waves, travel with the
velocity of light and consist of magnetic and electric fields that are
at right angles to each other and are at right angles to the direction
of travel. If these electric and magnetic fields could actually be seen,
the wave would have the appearance indicated in Fig. 1-1."

Maxwell`s first field equation says that a changing magnetic field will
produce an electric field. The second equation says that a changing
electric field will produce a magnetic field.

The alternating magnetic field creates an alternating electric field in
the space surrounding it. Due to the alternation of the electric field
an alternating displacement current will exist in space, which will give
rise to another alternating magnetic field in the space surrounding the
displacement current, etc., etc., etc..

Maxwell`s proof is courtesy B. Whitfield Griffirh, Jr.`s
"Radio-Electronic Transmission Fundamentals", now in reprint by Scitech
Publidhing, Inc..

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

...
The alternating magnetic field creates an alternating electric field in
the space surrounding it. Due to the alternation of the electric field
an alternating displacement current will exist in space, which will give
rise to another alternating magnetic field in the space surrounding the
displacement current, etc., etc., etc..

Maxwell`s proof is courtesy B. Whitfield Griffirh, Jr.`s
"Radio-Electronic Transmission Fundamentals", now in reprint by Scitech
Publidhing, Inc..

Best regards, Richard Harrison, KB5WZI


Richard;

Thanks for taking the time to post that data.

Of course, in my "addled way of thinking", I still see the probability
of a media in which these actions are taking place (electric to magnetic
and magnetic to electric )--such as when you swing a wire (media)
through a magnetic field.

But, really, it is all still a question ... anyway, pondering keeps me
outta the bars. :-)

Regards,
JS

Richard Harrison wrote:
Maxwell`s first field equation says that a changing magnetic field will
produce an electric field. The second equation says that a changing
electric field will produce a magnetic field.

Does this cause and effect chain of events result in a
phase lag between the electric and magnetic fields?
--
73, Cecil http://www.w5dxp.com

art wrote:
By the same token I am challenging to prove the
veracity of the additional statement that a sino
soidal current is present at every segment point.

If one threads a toroidal transformer over
a dipole wire, one will observe a sinusoidal
waveform (if the source is sinusoidal).
--
73, Cecil http://www.w5dxp.com

Mike Kaliski wrote:

...
I'm sure Roy is quite capable of defending himself against your
accusations, but I think you are being a trifle unfair. EZNEC is a
simulation designed to predict the performance of an antenna design.
...
Best wishes
Mike G0ULI

No need for any defense; EZNEC (and other apps) are the "state of the
art" as far as hams are concerned--they are more than adequate for our
needs. Too bad so many view this/these discussions as an "attack."

These "arguments" are only an attempt to peer over the horizon on
possible new discoveries and inner workings of antennas.

Nothing in my posts are meant to be an attack on EZNEC, Roy, or for that
matter, any others and those who use them to construct and place into
service the antennas in common use and which perform well. I am sure
most others are of a like mind.

Arts' feathers have just been ruffled ... something we all have been
guilty of--at one time or another.

Regards,
JS