Yuri Blanarovich wrote:
Roy,
please see my other posting, otherwise, I really promise to do the step by
step article, which will try to explain, correlate real life measurements
and modeling and present the comprehensive case of current being different
across antenna loading coils. Will do that with cooperation of other
"defenders" that contributed to "our" cause. There is no point of going back
and forth on tangents. We will measure, show the reality and then apply some
theory, explanation and summary of what is going on.
I hope it will correct misconceptions, provide better understanding and
benefit in proper modeling and design of loaded antenna elements and
systems.
Otherwise, I think we have reached point, when it is pointless to go around
in circles and argue that what IS, CAN'T BE, because.....

Before you get too carried away, look back in this thread where Cecil
posted a URL to his web site where he had an EZNEC (helical wire) model
of a coil at the base of a short whip. It showed significant current
drop from the bottom to the top, although no significant phase shift. I
replaced the whip part of the antenna with a wire directly to ground
from the top of the coil which contained a lumped RC to substitute for
the whip's impedance. The drop across the coil remained the same. So in
the course of developing your theory, you should explain why this
happens, since there are no longer the traveling and standing waves
which were on the whip. This model was, and still is, posted on my web
site. Then, to illustrate that the current drop from bottom to top is
due to shunt C, I removed the ground in the model, converting the model
to free space. I connected the bottom of the coil to the bottom of the
new wire with a wire instead of via the ground connection. The current
drop from bottom to top of the coil disappeared. (There's still a minor
difference due to several factors I mentioned in my posting.)

The fact that the current drop is the same for an antenna and for a
lumped circuit with the same impedance was also verified by measurements
I made and posted over a year ago.

Those model results are consistent with what I, Tom, and others have
been saying, and consistent with classical, known, circuit theory. They
aren't consistent at all with all this standing wave - traveling wave -
antenna replacement business. I've looked very carefully at the models
and concluded that EZNEC is operating well within its capabilities, so
the results are valid.

So for starters, why don't you explain how your theory fits with the
existing model results? Why is the current drop the same with an antenna
and for a lumped circuit? Why does removing ground make the current drop
go away? Why is there no significant phase shift in current from bottom
to top? Conventional theory can explain this. Can yours?

As for your promise to write the article, I have to point out that
you've made this promise before without delivering. So I'm not exactly
holding my breath waiting for it. I'm sure it'll make interesting
reading, though, and it's a revolutionary enough theory that the IEEE,
or at the very least QEX, should be happy to publish it when it's
finally complete.

Roy Lewallen, W7EL

Roy Lewallen wrote:
Before you get too carried away, look back in this thread where Cecil
posted a URL to his web site where he had an EZNEC (helical wire) model
of a coil at the base of a short whip. It showed significant current
drop from the bottom to the top, although no significant phase shift.

It showed a 10 degree phase shift. I've always said the phase
shift is what it is but it is NOT zero. 10 degrees is definitely
NOT zero even though you measured zero degrees shift. Wonder what
was wrong with your measurements?

So in
the course of developing your theory, you should explain why this
happens, since there are no longer the traveling and standing waves
which were on the whip.

Oh my, Roy, are you saying that zero ohms doesn't cause a reflection?
If so, your misconceptions are worse than I thought. A short to ground
causes exactly the same total reflection as an open-circuit, just with
different phases. I would have expected you to realize that.

I've looked very carefully at the models
and concluded that EZNEC is operating well within its capabilities, so
the results are valid.

Yes, they are and they shoot down your argument. Please explain
the results posted at: http://www.qsl.net/w5dxp/travstnd.GIF

So for starters, why don't you explain how your theory fits with the
existing model results?

You first, Roy, since you disagree with EZNEC.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:

Please explain the results posted at: http://www.qsl.net/w5dxp/travstnd.GIF

Cecil,

You may believe it is obvious, but it is not quite clear what you are
trying to show in that figure. On the left side, traveling wave, it
appears that "magnitude" means Io. On the right side, standing wave, it
appears that "magnitude" means Io cos(kx).

The gist of your position seems to be that somehow the traveling wave is
more powerful, or at least different, since the area under the current
magnitude curve is larger. In reality, however, it is necessary to pick
a single time at which to compare the two cases. It is of little value
to look at some sort of overall envelope for the traveling wave. The
correct magnitude of the traveling wave never has the shape of the
overall envelope. Pick a single time, say when wt is equal to zero or
equal to pi. Then compare the curves. In fact, if you pick any single
time for the left side the resulting curve shape will look a lot like
the right side.

73,
Gene
W4SZ

Gene Fuller wrote:
You may believe it is obvious, but it is not quite clear what you are
trying to show in that figure. On the left side, traveling wave, it
appears that "magnitude" means Io. On the right side, standing wave, it
appears that "magnitude" means Io cos(kx).

No, both plots are for I(x,t). The magnitude of the traveling wave
current is constant while the phase changes with 'x'. The phase of
the standing wave current is constant while the magnitude changes
with 'x'. They are virtually opposites of each other.

It is of little value
to look at some sort of overall envelope for the traveling wave.

Both currents are phasor RMS values along with their phases.

I am reporting *exactly* what EZNEC reports. If you don't like
that, talk W7EL into reporting something different.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
Gene Fuller wrote:

You may believe it is obvious, but it is not quite clear what you are
trying to show in that figure. On the left side, traveling wave, it
appears that "magnitude" means Io. On the right side, standing wave,
it appears that "magnitude" means Io cos(kx).


No, both plots are for I(x,t). The magnitude of the traveling wave
current is constant while the phase changes with 'x'. The phase of
the standing wave current is constant while the magnitude changes
with 'x'. They are virtually opposites of each other.

It is of little value to look at some sort of overall envelope for the
traveling wave.


Both currents are phasor RMS values along with their phases.

I am reporting *exactly* what EZNEC reports. If you don't like
that, talk W7EL into reporting something different.

Cecil,

Perhaps I was not clear. I understand the plots, and I have no question
that they show what EZNEC provides.

My question is why you feel there is anything of significance or
anything for the "gurus" to ponder.

As I explained, the curves are mostly a comparison of apples to oranges.
One (standing wave) shows the peak current at when the cos(wt) factor is
at a maximum. The other (traveling wave) shows the envelope of all the
current shapes over time. They are really two different entities, and
they have virtually no application to the topic featured in the past
17,000 messages.

What you call the "magnitude" of the traveling wave never actually
represents the current over the length of wire at any point in time.

73,
Gene
W4SZ

Gene Fuller wrote:
My question is why you feel there is anything of significance or
anything for the "gurus" to ponder.

Hopefully, I answered that question in my other posting. If one
wants to measure phase shift using a traveling wave current, one
measures the phase shift between two points.

If one wants to measure the phase shift using a standing wave
current, one measures the amplitudes at two points and subtracts
the arc-cosines of the normalized amplitude values.

You said essentially the same thing in your earlier posting -
that there is no phase information in the standing wave current
phase and all the phase information is in the amplitude values.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
m...
You said essentially the same thing in your earlier posting -
that there is no phase information in the standing wave current
phase and all the phase information is in the amplitude values.

thats the basic problem in this whole discussion. you are all talking about
the same thing, just using different notation and incomplete statements so
that none of you understands exactly what the others are trying to talk
about... when really you are all saying the same thing. its kind of like
after i graduated from college with an ee degree and my sister graduated
from an air force basic electronics course, she tried to ask me something
about currents in a transistor and i saw it all backwards... well of course
she was talking electron flow and i was talking hole flow. we both got the
same result but the notation was all different.

so, now i will raise my voice...

STOP THIS PETTY BICKERING AND GET OUT THERE AND USE AN ANTENNA INSTEAD OF
ARGUING ABOUT WHY THEY DON"T WORK THEY WAY YOU THINK THEY SHOULD!

Gene Fuller wrote:
You may believe it is obvious, but it is not quite clear what you are
trying to show in that figure.

Gene, I previously responded in words that I thought you would
understand, based on your previous understanding. It occurred
to me during my walk that not every reader is an engineer, not
every engineer is a EE, and not every EE also has a math degree.

Here it is in easier to understand terms. Given the 1/4WL conductor
and the web page at:

http://www.qsl.net/w5dxp/travstnd.GIF

The way to measure phase shift through a wire carrying the
traveling wave current is to put a current probe at location
A and location B, and measure the phase shift between those
two equal magnitude sine waves. If a coil exists in the circuit,
that would also be the way to get a rough measure of the phase
shift across the coil.

Example: The phase shift from 30% to 60% in the traveling wave
antenna is taken from the tabular data as 54.2-27.6 = 26.6 degrees.

The phase information is in the *phase* in a traveling wave.

For the standing wave current, the situation is completely
different. The phase measured between any two current probes
will always be zero. The phase of a standing wave current is
useless for measuring phase shift. The way to extract the
phase information is to measure the *amplitude* at two points
and then calculate the phase shift by taking the arc-cos of
the normalized amplitude.

Example: The phase shift from 30% to 60% in the standing wave
antenna is arc-cos(0.8843) - arc-cos(0.5840) = 26.5 degrees.

The phase information is in the *amplitude* in a standing wave.

Thus in both antennas, the phase shift in 30 percent of the
wire is about 27 degrees. (90*.3 = 27) If we had a coil installed
in that 30 degrees of the antenna instead of a wire, the same
concepts would apply.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil,

I thought you denounced and denied this "concept" earlier today.

73,
Gene
W4SZ


Cecil Moore wrote:
If we had a coil installed
in that 30 degrees of the antenna instead of a wire, the same
concepts would apply.

Gene Fuller wrote:
I thought you denounced and denied this "concept" earlier today.

Guess you misunderstood. A coil can replace 30 degrees of
an antenna but it won't use the same amount of wire as
30 degrees of wire. What I said is that an inductor is
more efficient than linear loading.
--
73, Cecil http://www.qsl.net/w5dxp