Jack Smith wrote:
(1) Input current = output current
(2) No phase shift.

If you model the circuit using the lumped values for the antenna R and
jX components it's easy to see this.

Anyone not believing this can try modeling the base inductor as:
O----[0.3 ohms R']--[+j192 ohms]---[0.3 ohms R'']----0
Put current through it using your favorite SPICE simulator and compare
the current through the R' and the R''. The two plots coincide.

We know what the model says. The original argument was over whether a
75m bugcatcher coil, containing distributed resistance, inductance, and
capacitance, actually possesses those same characteristics in reality.
A statement by a ham over on eham.net triggered the argument:

"If you look at HOW an inductor works, the current flowing in one terminal
ALWAYS equals the current flowing out the other terminal. "

That is how a lumped inductor works in a model. That is not how a distributed
inductor works in reality.
--
73, Cecil http://www.qsl.net/w5dxp



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On Tue, 11 Nov 2003 10:31:35 -0600, Cecil Moore
wrote:

Jack Smith wrote:
(1) Input current = output current
(2) No phase shift.

If you model the circuit using the lumped values for the antenna R and
jX components it's easy to see this.

Anyone not believing this can try modeling the base inductor as:
O----[0.3 ohms R']--[+j192 ohms]---[0.3 ohms R'']----0
Put current through it using your favorite SPICE simulator and compare
the current through the R' and the R''. The two plots coincide.

We know what the model says. The original argument was over whether a
75m bugcatcher coil, containing distributed resistance, inductance, and
capacitance, actually possesses those same characteristics in reality.
A statement by a ham over on eham.net triggered the argument:

"If you look at HOW an inductor works, the current flowing in one terminal
ALWAYS equals the current flowing out the other terminal. "

That is how a lumped inductor works in a model. That is not how a distributed
inductor works in reality.


My understanding of the particular question being debated is that the
loading coil is physically small and at the frequency in question may
be safely treated as a lumped element, and that some have said that
current-in current-out.

The fact that the small coil is connected to an antenna which is not
physically small is immaterial.

I apologize if I've misunderstood where this topic is at; it's been
very difficult to follow as it drifts back and forth.


Jack

On Tue, 11 Nov 2003 13:14:56 -0500, Jack Smith
wrote:

On Tue, 11 Nov 2003 10:31:35 -0600, Cecil Moore
wrote:

The original argument was over whether a
75m bugcatcher coil, containing distributed resistance, inductance, and
capacitance, actually possesses those same characteristics in reality.

I apologize if I've misunderstood where this topic is at; it's been
very difficult to follow as it drifts back and forth.

Hi Jack,

No apology is required from you. This thread has a very specific
question from a single correspondent (Roy). The substituted topic
that you find confusion with is a common form of (Cecil's) not being
responsive to the topic by deflection to other issues. The comedy
consists of the "gentlemen's agreement" to not cut this short when
this occurs.

But such is the gamesmanship that is being conducted, from the start.
The withholding of data to embarrass correspondents is not uncommon.
Lord knows how many I've embarrassed with simpler topics (the current
crew being only a subset). However, I generally restrain my
participation such that those threads are smaller. Otherwise the
posting of:
On Tue, 11 Nov 2003 10:26:32 -0800, Roy Lewallen wrote:

Otherwise, the
thread would have been about two postings long.
which totals 75 (soon to be 76 with this), and for which Roy has
contributed very little new details, nor any data across the majority
of 27 of his own (appealing for inductor values to force the issue
would have made the thread three postings long, c'mon now) obviously
reveals that entertainment is being served. OK, OK, for the sake of
the mythical lurker, we can all give a wink and a nod that it is
"edutainment."

I hope none expect an Emmy for these sweeps. [I would like to thank
all my books and their authors; and especially the large supporting
cast, all the little people, for making this possible.]

73's
Richard Clark, KB7QHC

Richard Clark wrote:
This thread has a very specific
question from a single correspondent (Roy).

Huh? This thread is a direct result of W8JI's alleged assertion that
the current into a coil and out of a coil is always the same or else
Kirchhoff's law is violated. Here is the quote, allegedly from W8JI,
that started this whole discussion.

"If you look at HOW an inductor works, the current flowing in one terminal
ALWAYS equals the current flowing out the other terminal."

Have you been on vacation or what?
--
73, Cecil http://www.qsl.net/w5dxp



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I apologize if the reason for my delay in posting measurement results is
seen as being to embarrass people. That's not at all the purpose. The
intent is simply to force people to make numerical predictions based on
their theories, rather than explaining the results after the fact. As it
turns out, Yuri is the only one confident enough of his theory to make a
numerical prediction(*). I happen to believe it's wrong, but by making
it he's earned my respect. A theory can be tested only if it predicts
results which can be tested. Whether it turns out to be right or wrong,
we learn from it. Those who've waffled and dodged the issue aren't in my
opinion worthy of the respect Yuri is.

When all this is done, I hope that readers come away with some assurance
that circuit theory does work and can be applied to antenna problems --
provided that the assumptions made for the components are valid. If all
that's taken away is a feeling that I've been doing this to try and
embarrass people, then it's been worse even than a monumental waste of
time. I really did have other things I wanted to do today besides make
antenna measurements, and I spent the time doing it only in the hope
that it would open some eyes.

Roy Lewallen, W7EL

(*) I've really solicited predictions only from people who don't agree
with conventional circuit theory, and believe that there will be a
difference in current from input to output. So there are also a number
of people who agree with me that conventional circuit theory holds, but
haven't explicitly made a prediction.

Richard Clark wrote:
. . .
But such is the gamesmanship that is being conducted, from the start.
The withholding of data to embarrass correspondents is not uncommon.
Lord knows how many I've embarrassed with simpler topics (the current
crew being only a subset). However, I generally restrain my
participation such that those threads are smaller. Otherwise the
posting of:
. . .

Roy Lewallen wrote:
When all this is done, I hope that readers come away with some assurance
that circuit theory does work and can be applied to antenna problems --
provided that the assumptions made for the components are valid.

Roy, isn't everything moot after Kraus tells us that an antenna coil
can cause a 180 degree phase reversal? Plus his graph of current in
a loaded antenna that shows a step function in the current at the
loading coils? The entire purpose of this discussion was to determine
if the following statement, allegedly made by W8JI, is true or false.

"This is in any book, including the ARRL Handbook. If you look at HOW
an inductor works, the current flowing in one terminal ALWAYS equals
the current flowing out the other terminal."

That's the very clear statement that was questioned by Yuri. And you
have already proved it not to be true even with your toroidal coil.

Incidentally, given a 180 degree phase reversing coil, the current
is flowing into both ends at the same time.
--
73, Cecil http://www.qsl.net/w5dxp



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Roy, W7EL wrote:
"When all this is done, I hope that readers come away with some
assurance that circuit theory does work and can be applied to antenna
problems -- provided that the assumotions made for the components are
valid."

Yes. And, there is another proviso. The reflected energy must be
considered along with the incident energy. Antenna problems are
relatives of transmission line problems.

Terman wrote of impedance in a transmission line with a reflection:
"When a reflected wave is present, the impedance will be alternately
greater and lower than the characteristic impedance, as illustrated in
Fig. 4-10."

This is also true of standing-wave antennas but is complicated by r-f
radiation from the antenna.

Early in this thread, I gave the example of W5LIT`s mobile antenna which
was all coil. It was a bamboo pole wound end to end with wire. At the
feed end its impedance was low. Approximately 90-degrees away at the tip
end, impedance was very high as indicated by the corona often produced
by the high voltage.

The current at the tip end was much less than at the feed point. The
ARRL Antenna Book shows how this can happen in Fig 6 on page 16-4 of the
19th edition.

I admire and appreciate Roy`s experimental verification of antenna
speculations and predictions. Until demonstrated, theory is only theory
and all such explanations are not necessarily so.

Best regards, Richard Harrison, KB5WZI

Cecil, W5DXP wrote:
"---isn`t everything moot after Kraus tells us that the antenna coil can
cause a 180 degree phase reversal?"

Yes. The Kraus example is a resonant circuit of a coil which with its
inherent self capacitance which can produce a leading or lagging total
impedance, depending on frequency.

B. Whitfield Griffith, Jr. demonstrates this with a series LRC circuit
on page 108 of "Radio-Electronic Transmission Fundamentals".

Total impedance, Zt = R+jomegaL-J/omegaC.

Griffith tabulates ZL, ZC, and Zt for 2.4, 2.5, 2.6, 2.7, and 2.8 MHz.
R=30 ohms at all frequencies.

2.4 MHz, j226ZL, -265ZC, 30-j39Zt
2.5 MHz, j236ZL, -j255ZC, 30-j19Zt
2.6 MHz, j245ZL, -j245ZC, 30-j0Zt
2.7 MHz, j254ZL, -j236ZC, 30+j18Zt
2.8 MHz, j264ZL, -j227ZC, 30+j37Zt

Griffith also gives Zt in polar coordinates but I don`t need to copy
that to show that reactance can be either positive or negative in a
circuit with both inductance and capacitance.

Best regards, Richard Harrison, KB5WZI

Jack Smith wrote:
My understanding of the particular question being debated is that the
loading coil is physically small and at the frequency in question may
be safely treated as a lumped element, and that some have said that
current-in current-out.

A 200 cubic inch 75m bugcatcher coil is NOT physically small and should
NOT be treated as a lumped element if one desires real-world results.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote in message ...
Jack Smith wrote:
My understanding of the particular question being debated is that the
loading coil is physically small and at the frequency in question may
be safely treated as a lumped element, and that some have said that
current-in current-out.

A 200 cubic inch 75m bugcatcher coil is NOT physically small and should
NOT be treated as a lumped element if one desires real-world results.

Cecil
When I first started working on my antenna design I didn't look at a
coil
as representing degrees per se. What I did was to ascertain the
resonant
frequency and the Q of the coil and transpose this into a length
that resonated with the same Q at the original frequency. True, the
radiation per unit length is different and has to be accounted for (a
critical important factor when comparing toroids to air wound coils)
but this aproach is quite different from using the "degrees" aproach
which is not the same because of the radiation difference ( See Roy's
aproach).
This aproach was the one I took with my antenna design
and it worked very well in practice as well as being confirmed by a
"theoretical" computor programs.
This aproach then allows a tranditional aproach of viewing current
behavior as it moves thru a distributed resistance and its limited
radiation.
Is there a fallacy in this aproach ?
Appreciate any insights that you have on the above to further my
education
Best Regards
Art