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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

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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?

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

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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

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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.

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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

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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

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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

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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??

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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

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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