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-   -   Lumped Load Models v. Distributed Coils (https://www.radiobanter.com/antenna/1140-lumped-load-models-v-distributed-coils.html)

Richard Clark February 2nd 04 08:48 PM

On Mon, 02 Feb 2004 14:12:54 -0600, Cecil Moore
wrote:

doesn't even come close to answering the original
question.


It was a ****-ant question in the first place.

Jim Kelley February 2nd 04 08:55 PM



Art Unwin KB9MZ wrote:

Jim What is electrically smal and compared to what ?.


I'm using the term in the same way one would use it to describe the
length of an antenna - i.e. its physical length as opposed to its
electrical length.

As for the rest: I don't know about Cecil's underpinnings. ;-)

73, Jim AC6XG

If one can make a small loop containing a small variable inductance as one
would make a variable capacitive form
which is what, 1/10 of a wave length and is inserted in Cecils drawing which
is more than a wavelength long I would consider that relatively small. Since
the circuit generated is purely from the constituents of the original
inductance then the relatively small loop can be inserted.
Knowing that the radiating surface is the inductance before it was reduced
what is to stop inserting the small loop in a black box that has dimensions
such that ports can be directly compared.? Cecil has stated that he is is
confident that he is correctin his assertions ( and he may well be) he is
not interested in counter proposals.
Sort of reminds me that Bush also comes from Texas !
We therefore must accept what Cecil says as unreservidly correct.and there
is nothing more to be said regarding the technical underpinnings. Either
that or attack the man himself which cannot provide resolution.
Regards
Art

"Jim Kelley" wrote in message
...


Cecil Moore wrote:

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.


It's certainly true that such a coil is not 'electrically' small.

73, Jim AC6XG


Cecil Moore February 2nd 04 09:29 PM

Art Unwin KB9MZ wrote:
Cecil has stated that he is is
confident that he is correct in his assertions ( and he may well be) he is
not interested in counter proposals.


Art, I'm not interested in counter proposals to reality. Reality is just
fine the way it is. What I would really be interested in is an explanation
of how a physically large coil, like a helical antenna, can cause a phase
reversal in the absence of any ground reference, i.e. in free space.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore February 2nd 04 09:38 PM

Jim Kelley wrote:
Do you mean physically small coils that are, naturally, also
electrically small. Or do you mean physically small coils that are
somehow electrically large?


A grain of sand is physically large when it is in your eye
but physically small under your foot. :-) Likewise, physically/
electrically small depends upon wavelength.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore February 2nd 04 09:40 PM

Richard Clark wrote:

wrote:
doesn't even come close to answering the original
question.


It was a ****-ant question in the first place.


Let's see - that's either sour grapes or sweet lemons -
I can't remember which.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore February 2nd 04 09:44 PM

Jim Kelley wrote:

Art Unwin KB9MZ wrote:
Jim What is electrically small and compared to what ?.


I'm using the term in the same way one would use it to describe the
length of an antenna - i.e. its physical length as opposed to its
electrical length.

As for the rest: I don't know about Cecil's underpinnings. ;-)


All I know is that every time there's a calculated or measured
current taper through a coil, according to some experts, it's
because the coil is not "physically small". :-) So where's the
model for "physically large" coils?
--
73, Cecil http://www.qsl.net/w5dxp



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Jim Kelley February 2nd 04 09:49 PM



Cecil Moore wrote:

Jim Kelley wrote:
Do you mean physically small coils that are, naturally, also
electrically small. Or do you mean physically small coils that are
somehow electrically large?


A grain of sand is physically large when it is in your eye
but physically small under your foot. :-) Likewise, physically/
electrically small depends upon wavelength.


Actually, that's not quite correct. In this context we are discussing
whether something's size is small or large compared to a wavelength.
Whether the wavelength is small or large compared to a grain of sand or
your eye is irrelevant. :-)

73, Jim AC6XG

Richard Clark February 2nd 04 09:52 PM

On Mon, 02 Feb 2004 15:40:40 -0600, Cecil Moore
wrote:

Richard Clark wrote:

wrote:
doesn't even come close to answering the original
question.


It was a ****-ant question in the first place.


Let's see - that's either sour grapes or sweet lemons -
I can't remember which.


See? Even you can't tell the difference.

Art Unwin KB9MZ February 2nd 04 10:15 PM

Well we will have to be patient
Richard has a way to show it by virtue of the use of Eznec.
I might add he is an expert with Eznec Having studied Meterology and
microwaves. Tho I am not sure he has
recognition of this by an acredited college and may well have got it on E
bay, they have advanced degrees on most things on the net these days
probably some for Shakespeare Olde English also..
Anyway there is really nothing more to be said on this subject until Richard
comes up with the real goods on Eznec and use it where all others have
failed..
Facts, all thereal facts.
Still the thread had a good run as far as threads go as some one said and
probably akin to sweeping up the streets in Pampalona to clean the bull****
left after the exciting run thru town. Yes some casualties among those that
run with the bulls but exciting to watch.
Best regards
Art

"Cecil Moore" wrote in message
...
Art Unwin KB9MZ wrote:
Cecil has stated that he is is
confident that he is correct in his assertions ( and he may well be) he

is
not interested in counter proposals.


Art, I'm not interested in counter proposals to reality. Reality is just
fine the way it is. What I would really be interested in is an explanation
of how a physically large coil, like a helical antenna, can cause a phase
reversal in the absence of any ground reference, i.e. in free space.
--
73, Cecil http://www.qsl.net/w5dxp



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Jim Kelley February 2nd 04 11:14 PM



Cecil Moore wrote:
All I know is that every time there's a calculated or measured
current taper through a coil, according to some experts, it's
because the coil is not "physically small". :-) So where's the
model for "physically large" coils?


I've also noted the use of that qualifier on several occasions in the
discussion. There are apparently effects which become measureable as
the inductors physical size begins to approach significant fractions of
a wavelength. These affects appear to relate more to the impedance and
radiation pattern of the antenna - first order affects as far as most
here are concerned to be sure. On the other hand, if the coil is not
physically small, then its probably not electrically small either. In
other words it may comprise a significant fraction of the electrical
length of the antenna. For a given inductance, a longer coil will
require more turns than a shorter coil. The more turns, the greater the
length of wire, and the greater the phase delay through the coil. A
coil with shorter physical length, would require less wire and fewer
turns to give the same inductance, and would give a shorter phase delay.

73, Jim AC6XG


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