Yuri Blanarovich wrote:
Experiment #1:
I will drive DC current through the coil in order to generate heat and observe
the temperatures across the coil.
Any problems with that?

Of course there's a problem with that, Yuri. You absolutely must use
a "physically small" coil so the gurus will be right. :-)
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

While I normally can see your point, even if I disagree with your
conclusions.

In this case Cecil, your just plain wrong!

"Cecil Moore" wrote in message
Thanks for the tips, Wes, and it does work. The names of the .EZ files
are on the .gif graphic that I prepared which illustrates the current
magnitudes and phases for 3/2WL phased arrays.

http://www.qsl.net/w5dxp/phasesbw.gif
--
73, Cecil, W5DXP



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Art Unwin KB9MZ wrote:
Did you find something wrong with my suggestion above?

Nope, nothing "wrong". I just avoid making assertions when I'm
not 95% certain that I am correct. Thus, most of the time, I am
unresponsive. I am 95% certain that the average humongous mobile
loading coil is not "physically small" and is more like a
certain percentage of a helical antenna which indeed does
obviously demonstrate a net current gradient.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Wes Stewart wrote:

wrote:
|A quick scan of your article produces nothing new.

Fine. Then this thread is closed.

I apologize, Wes. After closer inspection, I have to disagree
with myself. Imax is the reference zero degree point for the
"cosine rule". If that point occurs inside the loading coil,
then the number of degrees occupied by the loading coil becomes
ArcCos(Iin/Imax) + ArcCos(Iout/Imax) This helps to resolve the
problem I was having with ArcCos(Iout/Iin). If, as you say, the
current maximum point occurs inside the coil, then the forward
current and reflected current are in-phase inside the coil and
the coil occupies much more of the antenna than ArcCos(Iout/Imax)
I do believe a "Thank you very much" is in order. For your antenna,
the calculated degrees that the coil occupies is within 1.5 degrees
of the estimated degrees.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

W4JLE wrote:
While I normally can see your point, even if I disagree with your
conclusions. In this case Cecil, your just plain wrong!

Would you mind telling me what I am wrong about? I presently
have no clue. I freely admit to being wrong about what the
stock market has done this year. Is that what you are talking
about?
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Richard Clark wrote,

On 31 Jan 2004 19:32:18 GMT, (Tdonaly) wrote:
I have to eschew
Gesundheit

Thank you.

Where do I begin...

To limit the universe, I disagree with the data referenced on your web page
purporting to show how EZNEC got it wrong. Your just plain wrong.


"Cecil Moore" wrote in message
...
W4JLE wrote:
While I normally can see your point, even if I disagree with your
conclusions. In this case Cecil, your just plain wrong!

Would you mind telling me what I am wrong about? I presently
have no clue. I freely admit to being wrong about what the
stock market has done this year. Is that what you are talking
about?
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

W4JLE wrote:
Where do I begin...
To limit the universe, I disagree with the data referenced on your web page
purporting to show how EZNEC got it wrong. Your just plain wrong.

I am not trying to be hardnosed about this. I am actually trying to be
gentle about challenging someone's religion. If an inductive stub is
properly modeled by EZNEC, why is an equivalent inductive coil not
properly modeled? By properly modeled, I mean in agreement with reality.

EZNEC assumes that the current travels through the lumped inductive
reactance at faster than the speed of light. Why is it surprising to
find out that doesn't match reality? What am I missing, besides religion
based on math models?
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Here's a post of mine from the thread titled 'colinear connundrum'
from a
few years ago. Perhaps it will shed some light on the subject :

Gray Frierson Haertig wrote:
"One of the classic implementations of the collinear uses parallel
resonant circuits as the phase inverting means between separate
elements---."

I`ve discussed the if and how a parallel resonant circuit can
replace a
short-circuit 1/4-wave stub as a phase inverter, and never been
satisfied either.

If considered as two terminal devices, a 1/4 wl stub, parallel
resonant
LC circuit and an insulator are equivalent, at least for steady state
AC. Understanding the difference requires a slightly more elaborate
model for the stub or LC circuit. The model must account for charge
accumulation, or common mode current on the device. Classic network
theory can be used if a third, or 'common mode center tap' is added to
the device model.

Consider the parallel resonant LC circuit with the center of the
inductor (or capacitor) grounded. The impedance between the two 'hot'
terminals will be very high as in the two terminal case. The ground
connection introduces a new constraint. The voltage on a 'hot'
terminal
is now constrained to be equal in magnitude and of opposite polarity
from the other 'hot' terminal. This is not the case for the two
terminal
device model.

The three terminal device (center tap grounded) can be used as a
polarity reversing 1:1 transformer by connecting one 'hot' terminal to
a
ground referenced source and driving a load with the other terminal.
Of
course the same effect could be accomplished without the capacitor if
the center tapped inductor (autotransformer) had suitable properties.

Note that if the two 'hot' terminals are shorted the impedance (common
mode) to ground is zero.

Observe:
The differential mode impedance between 'hot' terminals is very high
(ideally infinite).
The common mode impedance to ground is zero.
The voltage on the 'hot' terminals respect to ground is of equal
magnitude and opposite polarity.

But, as Gray noted, a perfect parallel resonant circuit is an
insulator.
So is the perfect short-circuit 1/4-wave stub.

Now look at a 1/4 wl shorted stub far removed from ground. Viewed as
a
two terminal device it behaves similar to a parallel resonant LC
circuit. If the two open 'hot' wires are shorted, the stub looks like
a
1/4 wl long wire. The impedance with respect to ground is
approximately
36 ohms, which is very small compared to the nearly infinite
differential impedance. Think of it as a single 1/4 wl counterpoise;
adding a second colinear 'radial' results in an even lower ( 36/2
ohms) 'virtual ground' impedance.

Thus the 1/4 wl stub behaves similar to the parallel resonant LC
circuit
with the grounded center tap. The common mode behavior of the
freespace
1/4 wl stub provides the low impedance 'virtual ground'. Of course
suppressing the common mode resonance by coiling the transmission line
or applying a common mode choke has the effect of inserting a high
impedance in series with the 'ground' connection.

In reality, the common mode impedance to ground of an isolated LC
circuit is not infinite. Both the inductor and capacitor have
capacitance to space which will provide some 'grounding' effect. At
MF
through VHF, the components would generally need to be physically very
large to have a usefully low common mode impedance to ground however.


The opposite terminals of the parallel resonant circuit and the
opposite
terminals of the short-circuit stub are out of phase, in either
case.
They are equivalent.

Coupling between the elements exists in an ordinary dipole, even
though
the elements are end-to-end. There must be enough coupling to
complete
the transmission circuit, else the antenna wouldn`t work.


Turns out the mutual impedance between two isolated colinear dipole
elements is of the wrong polarity for parasitic operation as a
broadside
array. As you might expect, the mutual impedance between elements is
dominated by end to end capacitance which is wrong for broadside gain.
The Yagi configuration has a natural tendency to provide broadside
gain,
while the colinear does not.


I think equivalence is the key. If one works, the other must work
too.


As long as they are truly equivalent for the case being considered.
Failing to consider common mode impedances is unfortunately a very
common practice and will often lead to incorrect conclusions. The
devil
is often in the details.

bart
wb6hqk

Bart
I am just not smart enough to follow all of your post.
But in between the lines I see a correlation to what I suggested that Cecil
does to modify his collinear dipoles in the center portion a replacement
circuit for a dimensionless inductance to a circuit that have dimensions in
every sense and is its equal.
However he has rejected this aproach.
I would also add that if he imposed a parallel circuit that over lapped the
dipole at each side
then he has achieved an increased radiation efficiency per unit length since
the parallel circuit radiation is additive to the dipole radiation.. That
would replace a large portion of the center of a extended zepp and also
eliminate the stub portion.which are basically inefficient.
( Cecil has also rejected this notion in the past prefering his multi stub
length arrangement as shown on his page.)
However, the idea of a combination loop dipole in this circle just apears to
bring gasps of horror.as does the replacement of inefficient parts ( low
efficiency portions or same that has counter phase radiation.)
Since your post is laced with technical stuff that I don't understand but
deals with the advantages of a loop over a stub, perhaps those that are more
enlightened than I of which their are many, will discuss further your
contribution so that education will replace the frustration that
unfortunately now abounds

Regards
Art


"Bart Rowlett" wrote in message
om...
Here's a post of mine from the thread titled 'colinear connundrum'
from a
few years ago. Perhaps it will shed some light on the subject :

Gray Frierson Haertig wrote:
"One of the classic implementations of the collinear uses parallel
resonant circuits as the phase inverting means between separate
elements---."

I`ve discussed the if and how a parallel resonant circuit can
replace a
short-circuit 1/4-wave stub as a phase inverter, and never been
satisfied either.

If considered as two terminal devices, a 1/4 wl stub, parallel
resonant
LC circuit and an insulator are equivalent, at least for steady state
AC. Understanding the difference requires a slightly more elaborate
model for the stub or LC circuit. The model must account for charge
accumulation, or common mode current on the device. Classic network
theory can be used if a third, or 'common mode center tap' is added to
the device model.

Consider the parallel resonant LC circuit with the center of the
inductor (or capacitor) grounded. The impedance between the two 'hot'
terminals will be very high as in the two terminal case. The ground
connection introduces a new constraint. The voltage on a 'hot'
terminal
is now constrained to be equal in magnitude and of opposite polarity
from the other 'hot' terminal. This is not the case for the two
terminal
device model.

The three terminal device (center tap grounded) can be used as a
polarity reversing 1:1 transformer by connecting one 'hot' terminal to
a
ground referenced source and driving a load with the other terminal.
Of
course the same effect could be accomplished without the capacitor if
the center tapped inductor (autotransformer) had suitable properties.

Note that if the two 'hot' terminals are shorted the impedance (common
mode) to ground is zero.

Observe:
The differential mode impedance between 'hot' terminals is very high
(ideally infinite).
The common mode impedance to ground is zero.
The voltage on the 'hot' terminals respect to ground is of equal
magnitude and opposite polarity.

But, as Gray noted, a perfect parallel resonant circuit is an
insulator.
So is the perfect short-circuit 1/4-wave stub.

Now look at a 1/4 wl shorted stub far removed from ground. Viewed as
a
two terminal device it behaves similar to a parallel resonant LC
circuit. If the two open 'hot' wires are shorted, the stub looks like
a
1/4 wl long wire. The impedance with respect to ground is
approximately
36 ohms, which is very small compared to the nearly infinite
differential impedance. Think of it as a single 1/4 wl counterpoise;
adding a second colinear 'radial' results in an even lower ( 36/2
ohms) 'virtual ground' impedance.

Thus the 1/4 wl stub behaves similar to the parallel resonant LC
circuit
with the grounded center tap. The common mode behavior of the
freespace
1/4 wl stub provides the low impedance 'virtual ground'. Of course
suppressing the common mode resonance by coiling the transmission line
or applying a common mode choke has the effect of inserting a high
impedance in series with the 'ground' connection.

In reality, the common mode impedance to ground of an isolated LC
circuit is not infinite. Both the inductor and capacitor have
capacitance to space which will provide some 'grounding' effect. At
MF
through VHF, the components would generally need to be physically very
large to have a usefully low common mode impedance to ground however.


The opposite terminals of the parallel resonant circuit and the
opposite
terminals of the short-circuit stub are out of phase, in either
case.
They are equivalent.

Coupling between the elements exists in an ordinary dipole, even
though
the elements are end-to-end. There must be enough coupling to
complete
the transmission circuit, else the antenna wouldn`t work.


Turns out the mutual impedance between two isolated colinear dipole
elements is of the wrong polarity for parasitic operation as a
broadside
array. As you might expect, the mutual impedance between elements is
dominated by end to end capacitance which is wrong for broadside gain.
The Yagi configuration has a natural tendency to provide broadside
gain,
while the colinear does not.


I think equivalence is the key. If one works, the other must work
too.


As long as they are truly equivalent for the case being considered.
Failing to consider common mode impedances is unfortunately a very
common practice and will often lead to incorrect conclusions. The
devil
is often in the details.

bart
wb6hqk