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Cecil Moore May 14th 06 11:23 PM

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Roy Lewallen wrote:
Egad. Of course I reject the notion that there's "phase information in
the standing wave current magnitude".


I should have provided a reference in my earlier posting. Your
above statement disagrees with Kraus. On page 464 of "Antennas
for All Applications", 3rd edition, Kraus shows the relative
current amplitude for a 1/2WL thin-wire dipole. He says on that
page that the magnitude is a sinusoidal function.

Would you care to explain how a sinusoidal magnitude function
is NOT associated with phase?

For everyone else: Roy had ploinked me so he never sees my
references. Therefore, he disagrees with Kraus over and over
and over.
--
73, Cecil http://www.qsl.net/w5dxp

Tom Donaly May 15th 06 12:36 AM

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Cecil Moore wrote:
Roy Lewallen wrote:

Egad. Of course I reject the notion that there's "phase information in
the standing wave current magnitude".



I should have provided a reference in my earlier posting. Your
above statement disagrees with Kraus. On page 464 of "Antennas
for All Applications", 3rd edition, Kraus shows the relative
current amplitude for a 1/2WL thin-wire dipole. He says on that
page that the magnitude is a sinusoidal function.

Would you care to explain how a sinusoidal magnitude function
is NOT associated with phase?

For everyone else: Roy had ploinked me so he never sees my
references. Therefore, he disagrees with Kraus over and over
and over.


What is a "sinusoidal magnitude function," Cecil? I don't have
Kraus, so I'll take your word for it that he wrote that the current
on a 1/2 WL thin wire dipole can be represented as a sine function.
Good. I can now throw away my EZNEC. I doubt very much if any of
the people who disagree with you really write anything that
contradicts Kraus or any of the other textbook writers. Selective
quoting is another low trick you like to play, Cecil. You must have
learned it in Bible class.
73,
Tom Donaly, KA6RUH

Cecil Moore May 15th 06 12:46 AM

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Tom Donaly wrote:
What is a "sinusoidal magnitude function," Cecil?


Y = sin(X)

The magnitude 'Y' is equal to the sine of an angle,
'X', in degrees.

Wouldn't you agree with me that it is ridiculously
ignorant to assert that the magnitude 'Y' has nothing
to do with the phase angle 'X', i.e. that there's no
"phase information in the ... magnitude".
--
73, Cecil http://www.qsl.net/w5dxp

Roy Lewallen May 15th 06 02:20 AM

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Tom Donaly wrote:
Cecil Moore wrote:

For everyone else: Roy had ploinked me so he never sees my
references. Therefore, he disagrees with Kraus over and over
and over.


I don't recall ever having disagreed with anything I've read in Kraus. I
do, however, frequently disagree with the misinterpretations and
misquotations of Kraus and many other references which Cecil has made.

His frequent claims of "If you disagree with me, you disagree with
[Kraus, Maxwell, Balanis, Hecht, Heaviside, Terman, God, whoever] are
total baloney (to use a much kinder term than it deserves).

Yes, I plonked Cecil a couple of years ago. Seeing only the occasional
text quoted by others of his bizarre ramblings is more than enough.
Those which I do see reinforce my belief that I'm certainly not missing
anything of technical or educational merit.

Roy Lewallen, W7EL

Cecil Moore May 15th 06 03:58 AM

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Roy Lewallen wrote:
I don't recall ever having disagreed with anything I've read in Kraus.


Your posting below disagrees with the information on page 464
of "Antennas for all Applications", 3rd edition.

Of course I reject the notion that there's "phase information in the
standing wave current magnitude".


The standing wave current magnitude is sinusoidal, according
to Kraus. How can you possibly have a sinusoidal wave without
an associated phase angle?

For a 1/2WL thin-wire dipole:
If the source current is 1.0 at 0 deg at t=0, the magnitude
of the standing wave current is cos(X) where X is the number
of degrees from the source. Your statement that there is no
phase information in a cosine function is absolutely false.

In fact, in the above example the arc-cosine of the standing
wave magnitude is the phase angle of the reflected current.
The negative of that angle is the phase angle of the forward
current.
--
73, Cecil http://www.qsl.net/w5dxp

[email protected] May 15th 06 02:09 PM

FIGHT! FIGHT! FIGHT!
 
Well,
It looks like Dave successfully excited some natural frequencies in the
group for some weekend entertainment. Congratulations.
73,
Glenn AC7ZN


[email protected] May 15th 06 02:41 PM

FIGHT! FIGHT! FIGHT!
 
Oh, and by the way, natural frequencies cannot exist without forward,
and reflected...
:-


Tom Donaly May 15th 06 03:15 PM

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Cecil Moore wrote:
Tom Donaly wrote:

What is a "sinusoidal magnitude function," Cecil?



Y = sin(X)

The magnitude 'Y' is equal to the sine of an angle,
'X', in degrees.

Wouldn't you agree with me that it is ridiculously
ignorant to assert that the magnitude 'Y' has nothing
to do with the phase angle 'X', i.e. that there's no
"phase information in the ... magnitude".


Actually, I don't think it's "ridiculously ignorant" at
all. If all you have is the value of current at one point,
you can't possibly tell anything about the phase. You need
to compare it to something - itself even - somewhere or sometime else in
order to have an idea of phase. Here's what I mean: suppose I have a
piece of wire of unknown length, excited by an unknown frequency, and
picking a random point on the wire I measure 1.73 amps. What is the
phase? You're trying to square the circle and hear the sound of one
hand clapping at one and the same time, Cecil. Of course, in your
case, you know the length of the wire, the frequency of the wave and
its wavelength, and you think you know the current distribution
on the wire (a half wavelength dipole) so you don't need anything
but a ruler to find what you're looking for. Of course, you have to
decide what you mean by the term "phase." Try not to get a permanent
headache thinking about it.
73,
Tom Donaly, KA6RUH

Yuri Blanarovich May 15th 06 03:15 PM

FIGHT! FIGHT! FIGHT!
 

wrote in message
oups.com...
Oh, and by the way, natural frequencies cannot exist without forward,
and reflected...
:-


If there is reflector (impedance bump) in their way.
If W8JI waves are not reflected or opposed, then they would propagate
merrily into the ethernity and become the law of the RF jungle and other
pagan believers would worship them and praise the radio guru.
Waves have frequencies and sines/cosines, so this is related to antennas,
unless, of course there are those who "know better" :-)
Jus' stirring the pot...

Yuri da BUm



Tom Donaly May 15th 06 03:26 PM

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Roy Lewallen wrote:

Tom Donaly wrote:

Cecil Moore wrote:


For everyone else: Roy had ploinked me so he never sees my
references. Therefore, he disagrees with Kraus over and over
and over.



I don't recall ever having disagreed with anything I've read in Kraus. I
do, however, frequently disagree with the misinterpretations and
misquotations of Kraus and many other references which Cecil has made.

His frequent claims of "If you disagree with me, you disagree with
[Kraus, Maxwell, Balanis, Hecht, Heaviside, Terman, God, whoever] are
total baloney (to use a much kinder term than it deserves).

Yes, I plonked Cecil a couple of years ago. Seeing only the occasional
text quoted by others of his bizarre ramblings is more than enough.
Those which I do see reinforce my belief that I'm certainly not missing
anything of technical or educational merit.

Roy Lewallen, W7EL


For someone like me, Cecil can be (but usually isn't) a very useful
crackpot. I can be pretty sure he's wrong, but the process of educating
myself into turning that hunch into a dead certainty that I can prove
to everyone (except him) can be enlightening.
73,
Tom Donaly, KA6RUH

Gene Fuller May 15th 06 04:02 PM

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Cecil Moore wrote:
Gene Fuller wrote:

I do not disagree with anything you have said.



Please answer this question. Does the amplitude of the
standing wave current contain any phase information?

You have previously asserted that it does. Roy says
it doesn't. Time to chose between technical fact
and agreeing with your friend (who is technically
incorrect).


Cecil,

You win!

You have now set the new world record in misquoting. You might want to
give a call to the fine folks at Guinness.

73,
Gene
W4SZ

Cecil Moore May 15th 06 04:07 PM

FIGHT! FIGHT! FIGHT!
 
wrote:
It looks like Dave successfully excited some natural frequencies in the
group for some weekend entertainment. Congratulations.


I don't see how there can be any argument. The standing wave
current envelope magnitude pattern pictured in Kraus is a cosine
function where the angle of the cosine function is the number of
degrees away from the feedpoint. If the feedpoint current is 1.0
amps at 0 degrees, the standing wave current magnitude in Kraus'
1/2WL thin-wire dipole has the following pattern.

degrees away
from feedpoint current magnitude
0 1.000 amps
30 0.866 amps
45 0.707 amps
60 0.500 amps
90 0.000 amps

How can anyone defend an argument asserting that standing wave
current magnitude contains no phase angle information? The arc-
cosine of the standing wave current magnitude above *IS* the
number of degrees of phase angle away from the feedpoint. Since
the antenna is an archetypical standing wave antenna, that phase
angle is also the absolute magnitude of the forward and reflected
current phase angles where those phase angles have opposite signs.
--
73, Cecil
http://www.qsl.net/w5dxp

Cecil Moore May 15th 06 04:31 PM

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Tom Donaly wrote:
If all you have is the value of current at one point,
you can't possibly tell anything about the phase.


But the value of current at one point is *NOT* all we have
so your supposition is irrelevant. After a century of theory
by some of the most brilliant human minds, we know virtually
everything there is to know about a 1/2WL thin-wire dipole.
We know there *IS* indeed phase information in the standing
wave current magnitude just Kraus graphed it in his book.

You need
to compare it to something - itself even - somewhere or sometime else in
order to have an idea of phase.


The standard thing to compare it to is the feedpoint current,
e.g. provided by EZNEC, usually 1.0 amps at 0 degrees.

Here's what I mean: suppose I have a
piece of wire of unknown length, excited by an unknown frequency, and
picking a random point on the wire I measure 1.73 amps. What is the
phase? You're trying to square the circle and hear the sound of one
hand clapping at one and the same time, Cecil.


First, you insult me with irrelevant ad hominem attacks ...

Of course, in your
case, you know the length of the wire, the frequency of the wave and
its wavelength, and you think you know the current distribution
on the wire (a half wavelength dipole) so you don't need anything
but a ruler to find what you're looking for.


And second, you agree with Kraus and me ...

Here is a chart regarding Kraus' 1/2WL thin-wire dipole copied from
my other posting. Please tell us what is wrong with it and exactly
why the standing wave current magnitude doesn't tell us how many
degrees away the feedpoint is for the formula I = Io*cos(X).

X degrees away standing wave arc-cosine of the
from feedpoint current magnitude current magnitude
0 1.000 amps 0 deg
30 0.866 amps 30 deg
45 0.707 amps 45 deg
60 0.500 amps 60 deg
90 0.000 amps 90 deg

Do you really think it is a mere coincidence that column 1 and
column 3 are identical???
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 15th 06 04:48 PM

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Tom Donaly wrote:
For someone like me, Cecil can be (but usually isn't) a very useful
crackpot. I can be pretty sure he's wrong, but the process of educating
myself into turning that hunch into a dead certainty that I can prove
to everyone (except him) can be enlightening.


Now's your chance to enlighten us, Tom. Please explain again
how the standing wave current magnitude on a 1/2WL thin-wire
dipole doesn't depend upon how many degrees it is away from
the feed point, i.e. doesn't contain any phase information.

While you are at it, please explain exactly how Kraus is mistaken
about this antenna when he plots the standing wave current as
I = cos(X) where X is the number of degrees away from the
feedpoint and feedpoint current equals 1 amp at 0 degrees.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 15th 06 04:58 PM

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Gene Fuller wrote:

Cecil Moore wrote:
Please answer this question. Does the amplitude of the
standing wave current contain any phase information?

You have previously asserted that it does. Roy says
it doesn't. Time to chose between technical fact
and agreeing with your friend (who is technically
incorrect).


Cecil, You win!
You have now set the new world record in misquoting. You might want to
give a call to the fine folks at Guinness.


It was a simple yes/no question, Gene. That you refuse to
answer speaks volumes so I will ask it once again, copying
from a previous posting that you ignored.

Just insert an 'X' for the one you agree with. If you don't
respond, I will add this to a long list of questions that
I have asked that the "experts" are afraid to answer.

_____ Standing wave current magnitude contains some phase
information.

_____ Standing wave current magnitude contains zero phase
information.
--
73, Cecil http://www.qsl.net/w5dxp

Tom Donaly May 15th 06 05:29 PM

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Cecil Moore wrote:
Tom Donaly wrote:

If all you have is the value of current at one point,
you can't possibly tell anything about the phase.



But the value of current at one point is *NOT* all we have
so your supposition is irrelevant. After a century of theory
by some of the most brilliant human minds, we know virtually
everything there is to know about a 1/2WL thin-wire dipole.
We know there *IS* indeed phase information in the standing
wave current magnitude just Kraus graphed it in his book.

You need
to compare it to something - itself even - somewhere or sometime else
in order to have an idea of phase.



The standard thing to compare it to is the feedpoint current,
e.g. provided by EZNEC, usually 1.0 amps at 0 degrees.

Here's what I mean: suppose I have a
piece of wire of unknown length, excited by an unknown frequency, and
picking a random point on the wire I measure 1.73 amps. What is the
phase? You're trying to square the circle and hear the sound of one
hand clapping at one and the same time, Cecil.



First, you insult me with irrelevant ad hominem attacks ...

Of course, in your
case, you know the length of the wire, the frequency of the wave and
its wavelength, and you think you know the current distribution
on the wire (a half wavelength dipole) so you don't need anything
but a ruler to find what you're looking for.



And second, you agree with Kraus and me ...

Here is a chart regarding Kraus' 1/2WL thin-wire dipole copied from
my other posting. Please tell us what is wrong with it and exactly
why the standing wave current magnitude doesn't tell us how many
degrees away the feedpoint is for the formula I = Io*cos(X).

X degrees away standing wave arc-cosine of the
from feedpoint current magnitude current magnitude
0 1.000 amps 0 deg
30 0.866 amps 30 deg
45 0.707 amps 45 deg
60 0.500 amps 60 deg
90 0.000 amps 90 deg

Do you really think it is a mere coincidence that column 1 and
column 3 are identical???


Cecil, you can always know something you already know. Knowing that your
antenna is 1/2 wavelength long gives you all the information you need
for your definition of phase. By the way, where did you get that table,
from EZNEC?
73,
Tom Donaly, KA6RUH

Tom Donaly May 15th 06 06:09 PM

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Cecil Moore wrote:

Tom Donaly wrote:

For someone like me, Cecil can be (but usually isn't) a very useful
crackpot. I can be pretty sure he's wrong, but the process of educating
myself into turning that hunch into a dead certainty that I can prove
to everyone (except him) can be enlightening.



Now's your chance to enlighten us, Tom. Please explain again
how the standing wave current magnitude on a 1/2WL thin-wire
dipole doesn't depend upon how many degrees it is away from
the feed point, i.e. doesn't contain any phase information.

While you are at it, please explain exactly how Kraus is mistaken
about this antenna when he plots the standing wave current as
I = cos(X) where X is the number of degrees away from the
feedpoint and feedpoint current equals 1 amp at 0 degrees.


I didn't say that the value of the standing wave current on a
1/2 wavelength dipole doesn't vary with length. I did say that
just measuring the value at some point doesn't give you all the
information you need to calculate the phase. Of course, you already
know the phase, because you defined the antenna as 1/2
wavelength, so finding any kl is trivial. Secondly, even if you're
right about the current in your antenna being a sine function, in order
to use that information, you have to measure the current input at the
current maximum - which you've already defined to be the center of the
antenna - in order to compare it with the current at the point of
interest in order to get your result. In short, you still have to
know the current at two points in order to get an answer. The
information isn't contained in just one measurement. So let me turn it
around and ask you to tell me again why you think you can get some
"phase" information from measuring a single point on an antenna
without knowing anything else about it.

I haven't read Kraus, but I expect he was talking about an idealized,
infinitely thin antenna. Add thickness to the wire, and a feedpoint gap,
and you may come up with something slightly more complicated.
73,
Tom Donaly, KA6RUH

Tom Donaly May 15th 06 06:12 PM

FIGHT! FIGHT! FIGHT!
 
Cecil Moore wrote:

Gene Fuller wrote:

Cecil Moore wrote:

Please answer this question. Does the amplitude of the
standing wave current contain any phase information?

You have previously asserted that it does. Roy says
it doesn't. Time to chose between technical fact
and agreeing with your friend (who is technically
incorrect).



Cecil, You win!
You have now set the new world record in misquoting. You might want to
give a call to the fine folks at Guinness.



It was a simple yes/no question, Gene. That you refuse to
answer speaks volumes so I will ask it once again, copying
from a previous posting that you ignored.

Just insert an 'X' for the one you agree with. If you don't
respond, I will add this to a long list of questions that
I have asked that the "experts" are afraid to answer.

_____ Standing wave current magnitude contains some phase
information.

_____ Standing wave current magnitude contains zero phase
information.


If a magnitude can, by itself, contain phase information, why
do we have to specify the angle in a phasor?
73,
Tom Donaly, KA6RUH

Cecil Moore May 15th 06 06:26 PM

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Tom Donaly wrote:
Cecil, you can always know something you already know. Knowing that your
antenna is 1/2 wavelength long gives you all the information you need
for your definition of phase.


Apparently that knowledge is not enough for W7EL who said
regarding the current distribution in a 1/2WL thin-wire
dipole:

W7EL wrote:
Of course I reject the notion that there's "phase information
in the standing wave current magnitude".


This in the face of technical evidence that the standing
wave current magnitude is a cosine function of the number
of degrees the referenced point is away from the feedpoint.

Also contradicting Gene Fuller who said:
The only "phase" remaining is the cos (kz) term, which is really
an amplitude description, not a phase.


By the way, where did you get that table, from EZNEC?


From page 464 of "Antennas for all Applications", 3rd Edition,
by Kraus and Marhefka. Where Kraus presents the independent
variable in fractions of a wavelength, I simply converted it
to degrees. Most knowledgeable people comprehend that there
are 360 degrees per sinusoidal cycle, i.e. per one wavelength.
--
73, Cecil http://www.qsl.net/w5dxp

Richard Clark May 15th 06 06:29 PM

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On Mon, 15 May 2006 17:12:58 GMT, "Tom Donaly"
wrote:

_____ Standing wave current magnitude contains some phase
information.

_____ Standing wave current magnitude contains zero phase
information.


If a magnitude can, by itself, contain phase information, why
do we have to specify the angle in a phasor?



Hi Tom,

Cecil probably doesn't understand that both options give both current
magnitude AND phase as choices. Rather makes the "question"
pointless, but nothing new in the correspondence from our Xerox
philosopher.

For the record:

____X____ Standing wave current magnitude contains NO phase
information.

73's
Richard Clark, KB7QHC

Cecil Moore May 15th 06 06:49 PM

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Tom Donaly wrote:
I didn't say that the value of the standing wave current on a
1/2 wavelength dipole doesn't vary with length. I did say that
just measuring the value at some point doesn't give you all the
information you need to calculate the phase.


The subject is a 1/2WL thin-wire dipole with a feedpoint current
of 1 amp at 0 degrees as illustrated by Kraus on page 464 of
"Antennas for All Applications", 3rd Edition. That's about the sixth
time I have stated those boundary conditions.

The information isn't contained in just one measurement.


For a 1/2WL thin-wire dipole with a feedpoint current of 1 amp
at 0 degrees, as illustrated by Kraus, all the phase information
one needs to know is indeed "contained in just one measurement".

I haven't read Kraus, but I expect he was talking about an idealized,
infinitely thin antenna.


I have been very careful about specifying Kraus' 1/2WL thin-wire
dipole as the subject of this discussion. It is easiest to
understand because it has the least number of variables.

What is the agenda in trying to divert the subject away from
something easy to understand to something that is difficult
to understand?
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 15th 06 07:07 PM

FIGHT! FIGHT! FIGHT!
 
Tom Donaly wrote:
If a magnitude can, by itself, contain phase information, why
do we have to specify the angle in a phasor?


The subject is the standing wave current phasor on a
1/2WL thin-wire dipole, not phasors in general.

The point is that we do *NOT* have to specify the angle
for the standing wave current phasor on a 1/2WL thin-wire
dipole. The standing wave current phase angle at any point
up and down the antenna is already known to be EXACTLY the
same as the angle of the source current at any particular
time. That's why W7EL's phase measurements were meaningless
and his conclusions false. Note he has refused to discuss
the subject with me here or over private email.

If the source current is 1 amp at 0 degrees, the standing
wave current magnitude equals cos(X) and the standing wave
current phase equals zero degrees. That you guys disagree
indicates ignorance of the assertions of Kraus, Balanis,
and others.

This is what the argument is all about. The phase angle
for the standing wave current is known to be zero degrees
and unchanging with respect to the source current phasor.
The standing wave magnitude is known to be the cosine of
the number of degrees away from the feedpoint. That same
number of degrees is the absolute value of the phase angle
of the forward current and reflected current phasors.

The magnitude of the standing wave current on a 1/2WL
thin-wire dipole, fed with 1 amp at 0 degrees as
illustrated by Kraus, indeed does contain all the phase
information that anyone could ever need or want.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 15th 06 07:18 PM

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Richard Clark wrote:
For the record:

____X____ Standing wave current magnitude contains NO phase
information.


Remember the context is the 1/2WL thin-wire dipole fed
by 1 amp at 0 degrees on page 464 in Kraus' "Antennas
For All Applications", 3rd Edition where the standing wave
current magnitude EQUALS cos(X) where X is the number of
degrees away from the feedpoint. The arc-cosine of the standing
wave current magnitude *IS* the phase.

One other point. At least one expert has said that nothing
is lost in the superposition process. We know that the
forward traveling wave has phase and the reverse traveling
wave has phase. If the superposed standing wave current
magnitude contains no phase information, then something was
lost in the superposition process because the standing wave
current phase certainly contains no phase information as
illustrated at:

http://www.qsl.net/w5dxp/travstnd.GIF
--
73, Cecil http://www.qsl.net/w5dxp

Richard Clark May 15th 06 07:30 PM

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On Mon, 15 May 2006 18:18:43 GMT, Cecil Moore
wrote:

Richard Clark wrote:
For the record:

____X____ Standing wave current magnitude contains NO phase
information.


Remember the context is the 1/2WL thin-wire dipole fed


Context schmomtext, Nothing said is nothing said.

This is the problem that comes of a Xerox education.

Tom Donaly May 15th 06 07:43 PM

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Richard Clark wrote:
On Mon, 15 May 2006 18:18:43 GMT, Cecil Moore
wrote:


Richard Clark wrote:

For the record:

____X____ Standing wave current magnitude contains NO phase
information.


Remember the context is the 1/2WL thin-wire dipole fed



Context schmomtext, Nothing said is nothing said.

This is the problem that comes of a Xerox education.


Hi Richard,
all Cecil's information is in the schmomtext.
73,
Tom Donaly, KA6RUH

Gene Fuller May 15th 06 08:27 PM

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Based on my reading, it appears that Kraus did not say anything closely
resembling Cecil's comments. Cecil is "interpreting" a very simple
picture in Kraus. All of the math appears to arise from Cecil's
imagination.

Cecil is so good at quoting that he should have no problem with
providing the exact unedited words from Kraus that support the
arc-cosine analysis.


73,
Gene
W4SZ

Roy Lewallen May 15th 06 08:40 PM

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Tom Donaly wrote:

If a magnitude can, by itself, contain phase information, why
do we have to specify the angle in a phasor?


It looks like Cecil is trying to use "phase" as a function of position,
of the envelope of a standing wave rather than the time phase of the
total voltage or current which brings about the standing wave. This
makes it possible to keep the simple topic suitably muddled and enhances
the opportunity to misquote.

As I pointed out some time ago, the envelope of a standing wave isn't in
general sinusoidally shaped. At the one extreme of a matched load, the
total current or voltage vs position function is a straight line, and
there is no standing wave. At the other extreme where there's a complete
reflection, the function is sinusoidally shaped. The current on an
antenna falls into neither category, although the distribution on a thin
antenna is nearly sinusoidal. In between the two extremes, the shape of
the total current or voltage vs position function (that is, the envelope
of the standing wave) is neither straight nor sinusoidal, but can be
described with hyperbolic trig functions.

You can of course divide the period of any periodic function into 360
degrees or two pi radians and call the point along it a "phase" relative
to some arbitrary reference. In the case of a standing wave's envelope,
doing so doesn't generally accomplish anything useful. But it seems to
be providing fodder for imagining great and wonderful insights about
physics. And it certainly is useful in keeping a meaningless argument
going by interpreting "phase" to mean either time phase or the
positional "phase" of a standing wave envelope as necessary to keep the
discussion from proceeding on a linear and logical track.

Roy Lewallen, W7EL

Dave May 15th 06 09:01 PM

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"Cecil Moore" wrote in message
. com...
Tom Donaly wrote:
I didn't say that the value of the standing wave current on a
1/2 wavelength dipole doesn't vary with length. I did say that
just measuring the value at some point doesn't give you all the
information you need to calculate the phase.


The subject is a 1/2WL thin-wire dipole with a feedpoint current
of 1 amp at 0 degrees as illustrated by Kraus on page 464 of
"Antennas for All Applications", 3rd Edition. That's about the sixth
time I have stated those boundary conditions.

The information isn't contained in just one measurement.


For a 1/2WL thin-wire dipole with a feedpoint current of 1 amp
at 0 degrees, as illustrated by Kraus, all the phase information
one needs to know is indeed "contained in just one measurement".

I haven't read Kraus, but I expect he was talking about an idealized,
infinitely thin antenna.


I have been very careful about specifying Kraus' 1/2WL thin-wire
dipole as the subject of this discussion. It is easiest to
understand because it has the least number of variables.

What is the agenda in trying to divert the subject away from
something easy to understand to something that is difficult
to understand?
--
73, Cecil http://www.qsl.net/w5dxp


The AGENDA is to get you guys fighting! boy, sure didn't take much, even in
a thread that was obviously a troll with no technical question to start it
of! you guys are just fighting over your own statements since there was no
initial technical question or statement that started this thread... i love
it, kept me amused through a whole rainy weekend and now on a rainy
monday... supposed to rain more this week, think you guys can keep going a
bit longer??



Tom Donaly May 15th 06 10:17 PM

FIGHT! FIGHT! FIGHT!
 
Dave wrote:
"Cecil Moore" wrote in message
. com...

Tom Donaly wrote:

I didn't say that the value of the standing wave current on a
1/2 wavelength dipole doesn't vary with length. I did say that
just measuring the value at some point doesn't give you all the
information you need to calculate the phase.


The subject is a 1/2WL thin-wire dipole with a feedpoint current
of 1 amp at 0 degrees as illustrated by Kraus on page 464 of
"Antennas for All Applications", 3rd Edition. That's about the sixth
time I have stated those boundary conditions.


The information isn't contained in just one measurement.


For a 1/2WL thin-wire dipole with a feedpoint current of 1 amp
at 0 degrees, as illustrated by Kraus, all the phase information
one needs to know is indeed "contained in just one measurement".


I haven't read Kraus, but I expect he was talking about an idealized,
infinitely thin antenna.


I have been very careful about specifying Kraus' 1/2WL thin-wire
dipole as the subject of this discussion. It is easiest to
understand because it has the least number of variables.

What is the agenda in trying to divert the subject away from
something easy to understand to something that is difficult
to understand?
--
73, Cecil http://www.qsl.net/w5dxp



The AGENDA is to get you guys fighting! boy, sure didn't take much, even in
a thread that was obviously a troll with no technical question to start it
of! you guys are just fighting over your own statements since there was no
initial technical question or statement that started this thread... i love
it, kept me amused through a whole rainy weekend and now on a rainy
monday... supposed to rain more this week, think you guys can keep going a
bit longer??



You're welcome, Dave. Glad to oblige.
73,
Tom Donaly, KA6RUH

Cecil Moore May 16th 06 06:34 AM

FIGHT! FIGHT! FIGHT!
 
Gene Fuller wrote:
Cecil is so good at quoting that he should have no problem with
providing the exact unedited words from Kraus that support the
arc-cosine analysis.


"It is generally assumed that the current distribution of an
infinitesimally thin antenna is sinusoidal, ..."

Simply look at Kraus' graph in Figure 14-2. A sinusoid with
current amplitude equal to 1.0 at the center and current
amplitude equal to zero at the end is obviously a cosine
wave. Since the magnitude varies from 1.0 at the center to
zero at the end, taking the arc-cosine of the magnitude
yields the distance from the center in degrees.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 16th 06 06:54 AM

FIGHT! FIGHT! FIGHT!
 
Roy Lewallen wrote:
It looks like Cecil is trying to use "phase" as a function of position,


Referenced to the source current, the phase of the forward traveling
wave current *IS* directly proportional to position along the dipole.
Any competent engineer knows that. So is the phase of the rearward
traveling wave current. That is obvious from the equations for those
two currents. Those are simply facts of physics that you probably
should try to comprehend instead of dismissing them.

Inet = Io*cos(X)*cos(wt) = Ifor*cos(-X+wt) + Iref*cos(X-wt)

Inet is the standing wave current. X is the distance in degrees from
the feedpoint. If the source current is 1.0 amps at 0 degrees, e.g.
from EZNEC, at t=0 Inet = Io*cos(X) = Ifor*cos(-X) + Iref*cos(X)

As I pointed out some time ago, the envelope of a standing wave isn't in
general sinusoidally shaped.


Balanis says: "If the diameter of each wire is very small (d lamda)
the ideal standing wave pattern of the current along the arms of
the dipole is sinusoidal with a null at the end."

Kraus says: "It is generally assumed that the current distribution
of an infinitesimally thin antenna is sinusoidal,..."

d lamda for an 80m dipole made out of #18 wire. I'm sorry to hear
that you disagree with both Balanis and Kraus.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 16th 06 06:57 AM

FIGHT! FIGHT! FIGHT!
 
Dave wrote:
you guys are just fighting over your own statements since there was no
initial technical question or statement that started this thread...


Doesn't have to be. This is a continuation of earlier threads.
And I'm not fighting - I'm simply stating the laws of physics
as asserted by Balanis, Kraus, and Hecht.
--
73, Cecil http://www.qsl.net/w5dxp

Tom Donaly May 16th 06 02:25 PM

FIGHT! FIGHT! FIGHT!
 
Cecil Moore wrote:
Gene Fuller wrote:

Cecil is so good at quoting that he should have no problem with
providing the exact unedited words from Kraus that support the
arc-cosine analysis.



"It is generally assumed that the current distribution of an
infinitesimally thin antenna is sinusoidal, ..."

Simply look at Kraus' graph in Figure 14-2. A sinusoid with
current amplitude equal to 1.0 at the center and current
amplitude equal to zero at the end is obviously a cosine
wave. Since the magnitude varies from 1.0 at the center to
zero at the end, taking the arc-cosine of the magnitude
yields the distance from the center in degrees.


The key words are "infinitesimally thin," and "generally assumed."
With you, Cecil those words become just "thin," and "dead certain."
I'm glad you clarified that for us. I was beginning to wonder about
Kraus. Now I know it's just Kraus' message suffering from Cecil distortion.
73,
Tom Donaly, KA6RUH

Gene Fuller May 16th 06 02:34 PM

FIGHT! FIGHT! FIGHT!
 
Cecil Moore wrote:
Gene Fuller wrote:

Cecil is so good at quoting that he should have no problem with
providing the exact unedited words from Kraus that support the
arc-cosine analysis.



"It is generally assumed that the current distribution of an
infinitesimally thin antenna is sinusoidal, ..."

Simply look at Kraus' graph in Figure 14-2. A sinusoid with
current amplitude equal to 1.0 at the center and current
amplitude equal to zero at the end is obviously a cosine
wave. Since the magnitude varies from 1.0 at the center to
zero at the end, taking the arc-cosine of the magnitude
yields the distance from the center in degrees.


Cecil,

Sorry, I missed the comments that Kraus made about the phase of a
standing wave. Is that the concept that is represented by the " ..." in
your quote above?

73,
Gene
W4SZ


Cecil Moore May 16th 06 03:04 PM

FIGHT! FIGHT! FIGHT!
 
Tom Donaly wrote:
The key words are "infinitesimally thin," and "generally assumed."
With you, Cecil those words become just "thin," and "dead certain."


Kraus is using author-speak as most technical authors do to
avoid nit-picking from people like you. Balanis uses the words,
"very small" for the wire diameter.

I'm glad you clarified that for us. I was beginning to wonder about
Kraus. Now I know it's just Kraus' message suffering from Cecil distortion.


It is true for infinitesimally thin wire *AND* anything close
to that condition, i.e. also true for d lamda, according
to Balanis who says: "If the diameter of each wire is very
small (d lamda), the ideal standing wave pattern of the
current along the arms of the dipole is sinusoidal with a null
at the end."

The diameter of #18 wire is certainly very small compared to
a wavelength at 80m (0.003' 246') ensuring that the standing
wave current distribution on the real world dipole is sinusoidal
within a certain degree of real world accuracy.

If you want to see the sinusoidal current waveform for yourself,
observe the current distribution reported by EZNEC for a G5RV
used on 20m. Anyone with EZNEC, presumably including W7EL,
can observe that sinusoidal standing wave current pattern.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 16th 06 03:29 PM

FIGHT! FIGHT! FIGHT!
 
Gene Fuller wrote:
Sorry, I missed the comments that Kraus made about the phase of a
standing wave.


Quoting: "Figure 14-2 Relative current amplitude AND
PHASE along a center-fed 1/2WL cylindrical antenna."
Emphasis mine so you can't miss it this time.

I thought you were knowledgable enough to convert
Kraus's independent variable of wavelength to degrees in
his graph on page 464 of the 3rd edition of "Antennas For
All Applications". Allow me to assist you in that task.

The 'X' axis is "Distance from center of antenna in WL"

X in X in
wavelength degrees
0.00 0
0.05 18
0.10 36
0.15 54
0.20 72
0.25 90

Hope that helps you to understand Kraus's graph better.
Using the degree column, the standing wave current,
Itot, on that graph equals cos(X). The standing wave
current also equals Ifor*cos(-X) + Iref*cos(X) where
'X' is the phase angle of the forward traveling current
wave and the rearward traveling current wave. A phasor
diagram at 0.02WL = 72 degrees would look something
like this:

/ Iref
/
/
+----- Itot = Ifor*cos(-X) + Iref*cos(X)
\
\
\ Ifor

Incidentally, from the above phasor diagram, it is easy
to see why the phase angle of the standing wave current
is always zero (or 180 deg) since Ifor and Iref are
rotating in opposite directions at the same phase
velocity.
--
73, Cecil http://www.qsl.net/w5dxp

Gary Schafer May 16th 06 04:26 PM

FIGHT! FIGHT! FIGHT!
 
On Tue, 16 May 2006 05:54:59 GMT, Cecil Moore
wrote:

Roy Lewallen wrote:
It looks like Cecil is trying to use "phase" as a function of position,


Referenced to the source current, the phase of the forward traveling
wave current *IS* directly proportional to position along the dipole.
Any competent engineer knows that. So is the phase of the rearward
traveling wave current. That is obvious from the equations for those
two currents. Those are simply facts of physics that you probably
should try to comprehend instead of dismissing them.

Inet = Io*cos(X)*cos(wt) = Ifor*cos(-X+wt) + Iref*cos(X-wt)

Inet is the standing wave current. X is the distance in degrees from
the feedpoint. If the source current is 1.0 amps at 0 degrees, e.g.
from EZNEC, at t=0 Inet = Io*cos(X) = Ifor*cos(-X) + Iref*cos(X)

As I pointed out some time ago, the envelope of a standing wave isn't in
general sinusoidally shaped.


Balanis says: "If the diameter of each wire is very small (d lamda)
the ideal standing wave pattern of the current along the arms of
the dipole is sinusoidal with a null at the end."

Kraus says: "It is generally assumed that the current distribution
of an infinitesimally thin antenna is sinusoidal,..."

d lamda for an 80m dipole made out of #18 wire. I'm sorry to hear
that you disagree with both Balanis and Kraus.


Could you explain how to build one of those antennas that has infinite
impedance at its ends?

73
Gary K4FMX

Tom Donaly May 16th 06 04:43 PM

FIGHT! FIGHT! FIGHT!
 
Cecil Moore wrote:
Tom Donaly wrote:

The key words are "infinitesimally thin," and "generally assumed."
With you, Cecil those words become just "thin," and "dead certain."



Kraus is using author-speak as most technical authors do to
avoid nit-picking from people like you. Balanis uses the words,
"very small" for the wire diameter.

I'm glad you clarified that for us. I was beginning to wonder about
Kraus. Now I know it's just Kraus' message suffering from Cecil
distortion.



It is true for infinitesimally thin wire *AND* anything close
to that condition, i.e. also true for d lamda, according
to Balanis who says: "If the diameter of each wire is very
small (d lamda), the ideal standing wave pattern of the
current along the arms of the dipole is sinusoidal with a null
at the end."

The diameter of #18 wire is certainly very small compared to
a wavelength at 80m (0.003' 246') ensuring that the standing
wave current distribution on the real world dipole is sinusoidal
within a certain degree of real world accuracy.

If you want to see the sinusoidal current waveform for yourself,
observe the current distribution reported by EZNEC for a G5RV
used on 20m. Anyone with EZNEC, presumably including W7EL,
can observe that sinusoidal standing wave current pattern.


Give it up, Cecil. You don't even have a coherent notion of the
meaning of the term "phase." Selectively quoting, and re-interpreting
Bibles in order to make it seem as if the Gods agree with you won't cut
it, either. All the simple-minded rural sophistry in the world won't
make you right, or the rest of us wrong.

73,
Tom Donaly, KA6RUH

Cecil Moore May 16th 06 06:42 PM

FIGHT! FIGHT! FIGHT!
 
Gary Schafer wrote:
Could you explain how to build one of those antennas that has infinite
impedance at its ends?


An open circuit is close enough to infinite to satisfy
almost anyone. In virtually every technical textbook,
ideal conditions are assumed until one understands the
concepts involved. Then the real world conditions are
introduced. That's all I am doing - presenting the
concepts involved in an ideal dipole as described by
Kraus and Balanis. Do secondary real world conditions
exist in reality. Of course they do and nobody is
saying that they don't. The difference between infinity
and ten megohms is often negligible for analysis purposes.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore May 16th 06 06:57 PM

FIGHT! FIGHT! FIGHT!
 
Tom Donaly wrote:
Give it up, Cecil. You don't even have a coherent notion of the
meaning of the term "phase." Selectively quoting, and re-interpreting
Bibles in order to make it seem as if the Gods agree with you won't cut
it, either. All the simple-minded rural sophistry in the world won't
make you right, or the rest of us wrong.


When you lose the technical argument, Tom, you always respond
with ad hominem attacks devoid of any technical content.

Fact is, the phase of the forward traveling current referenced
to the source current is equal to the distance from the source
expressed in degrees. The laws of physics will not stand for
anything else. That same number of degrees *IS* the phase
angle of the traveling wave(s). Every competent engineer knows
that as it is obvious from the equations in any good textbook.
--
73, Cecil http://www.qsl.net/w5dxp


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