Current through coils
 

Cecil Moore wrote:
Richard Clark wrote:

Provide the Velocity Factor and Characteristic Impedance per the
formulas you offered:


Tom Donaly has graciously volunteered to provide those values.
Please stand by.

Actually, I just wanted to calculate the values for my own personal
edification. You'll have to do the arithmetic yourself, Cecil, and
then it won't mean much, because, as far as I know, no one has ever
done any experimental work to see if these equations have any meaning.
If a coil can slow down an electromagnetic wave as much as these
equations say it can, though, it qualifies as a very interesting device.
73
Tom Donaly, KA6RUH

Current through coils
 

Tom Donaly wrote:
If a coil can slow down an electromagnetic wave as much as these
equations say it can, though, it qualifies as a very interesting device.

Tom,

Here's another way to think about it.

If an inductor by itself delayed phase as much as Cecil claims, we
could build a phase or time delay system with only a large inductor. As
it is, we must always use a network of capacitors and inductors to
obtain phase delays or a transmission line of any substantial delay.

To construct a delay line, either a small parallel wire line is used or
a spiral around a metal core. The metal core acts like a shorted turn
and reduces flux coupling, and adds distributed capacitance to ground.

73 Tom

Current through coils
 

On 15 Mar 2006 16:36:51 -0800, wrote:

If an inductor by itself delayed phase as much as Cecil claims, we
could build a phase or time delay system with only a large inductor.

There is another explanation.

A lumped circuit has only one resonance. A transmission line has an
infinite number. It certainly isn't necessary to impose a strict test
of this. Finding second, third, and fourth harmonics for an inductor,
in situ, would certainly be compelling evidence of transmission line
behavior. Otherwise, any delay obtained through pencil whipping the
various formulas (and Reggie's equations veer far from the references
offered) is strictly what occurs AT RESONANCE, and any interpolation
of that delay to other frequencies is a presumption not yet proven.

73's
Richard Clark, KB7QHC

Current through coils
 

On Wed, 15 Mar 2006 15:38:32 -0800, Roy Lewallen
wrote:
Many analog scopes aren't capable of producing a meaningful Lissajous
figure at HF because of the limited bandwidth of the horizontal channel.

This is certainly true for poor scopes. If we are limited to HF, then
those with bandwidths above 100MHz might squeak by. However, there
are alternatives that were part and parcel to many older scopes: you
simply drive the plates directly like they did in the old days (1930s)
before the plates were driven by dedicated amplifier chains.

I have calibrated such old (very old) scopes that operated well out
into the 100s of MHz, but were often accompanied by a necessary
accessory, a microscope.

73's
Richard Clark, KB7QHC

Current through coils
 

On Wed, 15 Mar 2006 22:42:55 GMT, Cecil Moore wrote:
The VF of my 75m bugcatcher coil calculates out to be
VF = 0.0175 at 6.6 MHz

On Fri, 10 Mar 2006 13:35:14 GMT, Cecil Moore wrote:

I'm willing to bet that my 75m
bugcatcher coil has at least a 40 nanosecond delay on 4 MHz
which is a 60 degree current phase shift.

On Wed, 15 Mar 2006 18:03:28 GMT, Cecil Moore wrote:

The coil data is: ~6" dia, ~6.7" long, 26.5 T, seems
very close to 4 TPI. Looks to be #14 solid wire.

Total turns 26.5
Through total turns, total wire appears to be 505"

With nothing offered in the way of inductance, from calculations it
appears to be 72.9 µH

With nothing offered in the way of distributed capacitance, from
calculations it appears to be 8pF

On Tue, 14 Mar 2006 04:09:08 +0000 (UTC), "Reg Edwards"
wrote:
V = 1 / Sqrt( L * C ) metres per second,
where L and C are henrys and farads per metre respectively. The
formula for L and C can be found in your Bibles from coil dimensions,
numbers of turns, etc.

V = 1 / Sqrt (5.88 * 72.9* 10^-6 * 8 * 10^-12) meters per second

where the 5.88 is to correct for per meter computations

it follows that V must then be 17.1 million meters per second


The velocity factor = V / c
Vf = 0.057
and Zo = Sqr( L / C ).
Zo = Sqrt (72.9* 10^-6 / 8 * 10^-12)

3 KOhms

It appears your reference source leads you to an answer that is off by
325%

OR

Reggies' hints of a solution are in error

OR

I've pencil whipped this to death due to the tedious collection of
data spread through 300 postings and the chain of computation. I will
leave that to other, less lazy individuals to ponder.

OR

This is simply proof of an exercise in futility through the
misapplication of the theory of transmission lines to lumped
components.

It is quite apparent something's broke, but if the correspondence
descends into theory, it will be that theory is broke. There's enough
quantifiables to come to terms with before any theory is proven.

Current through coils
 

Richard Clark wrote:
On Wed, 15 Mar 2006 15:38:32 -0800, Roy Lewallen
wrote:
Many analog scopes aren't capable of producing a meaningful Lissajous
figure at HF because of the limited bandwidth of the horizontal channel.

This is certainly true for poor scopes. If we are limited to HF, then
those with bandwidths above 100MHz might squeak by. . .

Either you missed my point, or we differ on what constitutes a "poor"
scope. The Tektronix 465, for example, is a 100 MHz scope. Although it's
very long in the tooth now, it's not a "poor" scope by most measures.
But the specifications for X-Y display are as follows:

------

5 mV/div to 5 V/div, accurate ± 4%. Bandwidth is dc to at least 4 MHz.
Phase difference between amplifiers is 3° or less from dc to 50 kHz.

------

This wouldn't produce a meaningful Lissajous figure at HF.

Roy Lewallen, W7EL

Current through coils
 

Richard Clark wrote:
On Wed, 15 Mar 2006 22:42:55 GMT, Cecil Moore wrote:
The VF of my 75m bugcatcher coil calculates out to be
VF = 0.0175 at 6.6 MHz

On Fri, 10 Mar 2006 13:35:14 GMT, Cecil Moore wrote:

I'm willing to bet that my 75m
bugcatcher coil has at least a 40 nanosecond delay on 4 MHz
which is a 60 degree current phase shift.

On Wed, 15 Mar 2006 18:03:28 GMT, Cecil Moore wrote:

The coil data is: ~6" dia, ~6.7" long, 26.5 T, seems
very close to 4 TPI. Looks to be #14 solid wire.

Total turns 26.5
Through total turns, total wire appears to be 505"

With nothing offered in the way of inductance, from calculations it
appears to be 72.9 µH

With nothing offered in the way of distributed capacitance, from
calculations it appears to be 8pF

On Tue, 14 Mar 2006 04:09:08 +0000 (UTC), "Reg Edwards"
wrote:
V = 1 / Sqrt( L * C ) metres per second,
where L and C are henrys and farads per metre respectively. The
formula for L and C can be found in your Bibles from coil dimensions,
numbers of turns, etc.

V = 1 / Sqrt (5.88 * 72.9* 10^-6 * 8 * 10^-12) meters per second

where the 5.88 is to correct for per meter computations

it follows that V must then be 17.1 million meters per second

The velocity factor = V / c
Vf = 0.057
and Zo = Sqr( L / C ).
Zo = Sqrt (72.9* 10^-6 / 8 * 10^-12)

3 KOhms
. . .

This is a misapplication of transmission line formulas. The "C" in those
formulas is the shunt capacitance per unit length between the
conductors, not a series or longitudinal capacitance as used here. In
order to use the transmission line formulas, you have to have a second
conductor and determine the C per unit length between the two
conductors. Otherwise, you (or Cecil) have to come up with some other
equations. Some of the more picky of us readers will of course then ask
for the source and/or derivation of those other equations.

Roy Lewallen, W7EL

Current through coils
 

Tom Donaly wrote:
Actually, I just wanted to calculate the values for my own personal
edification. You'll have to do the arithmetic yourself, Cecil, and
then it won't mean much, because, as far as I know, no one has ever
done any experimental work to see if these equations have any meaning.

There are references for it in the Dr. Corum IEEE paper.
Kandoian and Sichak, "Wide Frequency Range Tuned Helical
Antennas and Circuits," Electrical Communications, Vol 30,
1953, pp. 294-299. It was published while I was in high
school.

If a coil can slow down an electromagnetic wave as much as these
equations say it can, though, it qualifies as a very interesting device.

I studied such 50 years ago at Texas A&M from papers
such as the above. The parameters for a transmission line
or a coil are the same just with different values.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

wrote:
If an inductor by itself delayed phase as much as Cecil claims, we
could build a phase or time delay system with only a large inductor.

We can build a time delay system with only a large inductor.
That's what large inductors do. How does a large inductor
cause a large arc on a Smith Chart without shifting the phase
of the signal?

One cannot use the presuppositions of the lumped-circuit
model to prove that there is no time delay through a
coil. The lumped-circuit presupposes zero time delay
through a coil with propagation times exceeding the
speed of light.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Clark wrote:
A lumped circuit has only one resonance. A transmission line has an
infinite number. It certainly isn't necessary to impose a strict test
of this. Finding second, third, and fourth harmonics for an inductor,
in situ, would certainly be compelling evidence of transmission line
behavior.

Using the same coil stock as W8JI's 100uH coil, I just set up
a 50 uH coil on a mag mount sitting on my metal desk. Its
first solid resonance was 9 MHz (1/4WL), its second solid
resonance was 27 MHz (3/4WL), and its third solid resonance
was 45 MHz (5/4WL). In addition to those, there other soft
spots and double dips along the frequency line.

W8JI reported something happening at 24 MHz as well as self-
resonance at 16 MHz. He was apparently not testing it over
a ground plane like an automobile body. That automobile
ground plane drops the VF much lower than an isolated
coil's VF.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Clark wrote:
This is simply proof of an exercise in futility through the
misapplication of the theory of transmission lines to lumped
components.

One certainly has to be careful. But Dr. Corum's formulas
matched my measurements closer than I expected.

One thing is for sure. One cannot use the presuppositions
of the lumped-circuit model to prove the validity of the
lumped-circuit model and that is what has happened so
far. One also cannot use a signal with unchanging phase
to measure the phase shift through a wire or coil.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Harrison wrote:
Tom, W8JI wrote:
"If an inductor by itself delayed phase as much as Cecil claims, we
could build a phase or time delay system with only a large inductor."

Recall that another name for the inductor is a "retardation coil", and
that the time constant of an inductor having an L in henrys and a
resistance in ohms is equal to L/R.

Yes, it's been known for over a century that the phase of the current
through an inductor lags the voltage across it, resulting in retardation
of the current relative to the voltage. And the time constant you refer
to is of course the time constant of the rise or decay of the current
through an inductor to which a voltage step is applied.

I don't see the connection between these and the contention that the
current into and out of an inductor are unequal. If there is one,
perhaps you can explain it. My texts all show a single equation relating
the voltage across an inductor to the current through it, as follows:

v = L * di/dt

This holds at all frequencies, i.e., all rates of change of current, and
it's from this that the above mentioned characteristics follow. If the
currents at the two inductor terminals are to be different, we'll need
two equations, one for the input current and one for the output current.
That is, v = f1(di1/dt) and v = f2(di2/dt), where f1 and f2 are
different functions. Have you come across such a set of equations in
your searches through your textbooks, or are the authors unaware of
Cecil's theories?

Roy Lewallen, W7EL

Current through coils
 

Roy Lewallen wrote:
Have you come across such a set of equations in
your searches through your textbooks, or are the authors unaware of
Cecil's theories?

I can't take credit for them, Roy, since I studied them at
Texas A&M in the 50's. Much of it appears in Ramo and
Whinnery's "Fields and Waves" and Johnson's "Transmission
Lines and Networks". They are just the rules of the
distributed network model of which the lumped-circuit
model is a subset. In any situation where the lumped-
circuit model yields different results than the
distributed-network model, the lumped-circuit model
is wrong.

The lumped-circuit model presupposes the conclusions
that some people are presenting as fact. Obviously,
the lumped-circuit cannot be presented as evidence
of proof of its presuppositions. But it appears that
is exactly what has happened. The lumped-circuit
model presupposes faster than light propagation
of signals. That alone should be enough to raise
a red flag. Can someone prove faster than light
speed by quoting the presuppositions of the
lumped-circuit model?

Quoting Dr. Corum again: "Lumped circuit theory
isn't absolute truth, it's only an analytical
theory ... The engineer must either use Maxwell's
equations or distributed elements to model reality."

My 75m bugcatcher meets his criteria for situations
where his VF equations work. It yields a VF of
0.0175 for the bugcatcher coil. That VF works
just like the 0.66 VF works for RG-213. On a coil
physically like the W8JI test coil but with 50 uH
inductance, I see coil resonances at 9 MHz, 27 MHz,
and 45 MHz, just as if it were 1/4WL of transmission
line. It appears that the calculated VF works over
a wide frequency range.

To prove the presuppositions of the lumped-
circuit model, a standing wave current is
used to measure phase. We already know the phase
of a standing wave current is unchanging all
along a 1/2WL dipole, per Kraus, yet some people
keep using standing wave current with its unchanging
phase to try to measure phase shift as if it were a
valid thing to do. One cannot measure a phase shift
in 45 degrees of dipole using standing wave current.
Why is it surprising that one cannot measure a
phase shift in 45 degrees of coil? There's no
current phase shift from the top of the coil
to the tip of the antenna either.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On Wed, 15 Mar 2006 18:19:21 -0800, Roy Lewallen
wrote:

This is a misapplication of transmission line formulas. The "C" in those
formulas is the shunt capacitance per unit length between the
conductors, not a series or longitudinal capacitance as used here. In
order to use the transmission line formulas, you have to have a second
conductor and determine the C per unit length between the two
conductors. Otherwise, you (or Cecil) have to come up with some other
equations. Some of the more picky of us readers will of course then ask
for the source and/or derivation of those other equations.

Hi Roy,

Well, it (the misapplication) certainly is that. That no two numbers
agree to the same problem misses more compelling evidence that hardly
demands strict accuracy in results obtained from any formula.

In short, no "other" equations are going to prove what cannot be
generally demonstrated.

Barring startling results demonstrating how either of the two coils
offered here in evidence reveal multiple resonances, that is enough to
kill the thread without needing tedious computations.¹

Another is the howler that this is all based upon the "coil's
characteristics," and Cecileo proved the Sun orbits the moon by
employing the bed of his truck in the exact solution.² This is called
new-age math with an harmonic convergence. It was convenient of all
his reference sources to include this truck factor as a hidden
variable - accessible to only those who know the secret handshake.

Just kidding, of course.

In fact, the authors tread very lightly in the context of a ground,
mentioning it only once as a necessity for
"characterizing the impedance of a structure
at a pair of terminals" [your point]

When the speculation is that the coil presents a 1:1 replacement for
the delay of the "missing" segment of the resonant antenna, then this
premise stumbles at the starting blocks. If I shorten the whip, then
the shorthand of:
On Tue, 14 Mar 2006 21:45:06 GMT, Cecil Moore wrote:
The velocity factor can also be measured from the self-
resonant frequency at 1/4WL. VF = 0.25(1/f)
offers this promise:
Make a smaller inductance (reducing turns will do)
to present a higher self-resonant frequency.

VF will fall.

From this, the delay climbs
to replace the shortened whip's missing angular contribution.

The reductio-ad-absurdum is that we repeat the trimming of the whip
until the inductance disappears.³ Ironically this leaves us with a
very short mast that now resonates! If we closed our eyes really,
really hard, and wished for a coil with a very high self resonance, it
could replace the mast too.

I see new marketing possibilities for 80 and 160 Meters.

¹ ² ³ Let's see, without any deep computations I count three thread
busters here. Offering the same proviso of probable computation
errors committed here, I would point out that only one thread buster
need survive to present the obvious fate to this theory.

73's
Richard Clark, KB7QHC

Current through coils
 

On Thu, 16 Mar 2006 03:30:36 GMT, Cecil Moore wrote:
One also cannot use a signal with unchanging phase
to measure the phase shift through a wire or coil.
Ah, Zen poetry disguised as erudition. I can top that!
One cannot cook a one minute egg using a compass.

Current through coils
 

On Thu, 16 Mar 2006 03:20:38 GMT, Cecil Moore wrote:
In addition to those, there other soft
spots and double dips along the frequency line.
not a very good transmission line model then, is it?

Current through coils
 

On Thu, 16 Mar 2006 03:20:38 GMT, Cecil Moore wrote:

Its first solid resonance was 9 MHz (1/4WL), its second solid
resonance was 27 MHz (3/4WL), and its third solid resonance
was 45 MHz (5/4WL).

What are they when you raise the assembly (I distinctly note that this
is NOT the resonance of the COIL you are speaking of) two feet higher?

Current through coils
 

Roy, W7EL wrote:
"I don`t see the connection between these and the contention that the
current into and out of an inductor are unequal."

Nor do I. Tom was not making a case for inequality of current in and out
of a coil either. He was just making an inaccurate statement.

Cecil has a good case. Straight wire and coiled wire have the same
properties, only more or less of them. When they are in the path of a
traveling wave and a reflection of that wave comes back from the
opposite direction, they respond similarly. An interference pattern
exists on the coil as it does on straight wire if the distance is
comparable to a wavelength. Superpositon makes both volts and amps vary
along the route.

So, indeed the current at one end of a coil in that situation can be
different at from that at the other end, the same as it would along a
wire.

Distributed network theory is newer than lumped network theory but both
have been around plenty long enough to be well established. I don`t
think Cecil is breaking any new ground.

Best regards, Richard Harrison, KB5WZI

Current through coils
 

Richard Harrison wrote:
Roy, W7EL wrote:
"I don`t see the connection between these and the contention that the
current into and out of an inductor are unequal."

Nor do I. Tom was not making a case for inequality of current in and out
of a coil either. He was just making an inaccurate statement.

What was the inaccurate statement he made? I've found Tom very willing
to correct errors, so I'm sure he'll correct it if we point it out to him.

Cecil has a good case. Straight wire and coiled wire have the same
properties, only more or less of them. When they are in the path of a
traveling wave and a reflection of that wave comes back from the
opposite direction, they respond similarly. An interference pattern
exists on the coil as it does on straight wire if the distance is
comparable to a wavelength.

Which distance do you mean -- the length of the coil or the length of
the wire?

Superpositon makes both volts and amps vary
along the route.

So, indeed the current at one end of a coil in that situation can be
different at from that at the other end, the same as it would along a
wire.

Yes, indeed. As I explained in several earlier postings, if you begin
with a coil and slowly stretch it out, the current distribution will go
from something resembling that of a lumped inductor (equal currents in
and out) to that of a straight wire (sinusoidal distribution). So "a
coil" can have any current distribution along that continuum, allowing
us to "prove" just about anything we wish as long as we don't say what
kind of coil we're talking about. In between the extremes, a third
distribution can occur, as King described in his book: when the coil
length is much less than a wavelength but the turns are loosely coupled,
you get a current that's highest in the middle and lower at both ends.
The disagreement regards the currents in what would qualify as a lumped
inductor -- one with very good coupling between turns, coil length very
short in terms of wavelength, and no significant coupling to other
conductors, but regardless of the length of wire it's made of. For that
case, it's been theoretically and demonstratively shown to be equal at
both ends.

Distributed network theory is newer than lumped network theory but both
have been around plenty long enough to be well established. I don`t
think Cecil is breaking any new ground.

His conclusions are sure new and different, and unlike established
theory, his theories don't seem to be subject to equations which
describe them quantitatively.

Roy Lewallen, W7EL

Current through coils
 

Richard Clark wrote:
Barring startling results demonstrating how either of the two coils
offered here in evidence reveal multiple resonances, that is enough to
kill the thread without needing tedious computations.¹

Last night I posted 1/4WL, 3/4WL, and 5/4WL measured resonant
points using the same coil stock as W8JI but with a shorter
50 uH coil. This coil 2" dia, 8 tpi, 8.5" long. It was
sitting on a mag mount on my metal desk.

When the speculation is that the coil presents a 1:1 replacement for
the delay of the "missing" segment of the resonant antenna, then this
premise stumbles at the starting blocks.

Nobody said anything about a 1:1 replacement. That was just
somebody's strawman.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Clark wrote:
What are they when you raise the assembly (I distinctly note that this
is NOT the resonance of the COIL you are speaking of) two feet higher?

Isolating the magmount would be disconnecting the
ground plane from a 1/4WL antenna and would contribute
nothing of value to the discussion.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Harrison wrote:
Distributed network theory is newer than lumped network theory but both
have been around plenty long enough to be well established.

Neumann didn't prove that the current through a coil is uniform.
He *assumed* it to be true as a simplification, so he could factor
out the current term from under the integral sign in one of Maxwell's
equations. Now Neumann's mathematical shortcut is being reported
here as a fact of physics. That's how well established it is.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Roy Lewallen wrote:
For that case, it's been theoretically and demonstratively shown to be
equal at both ends.

Only one of the reported measurements showed the magnitudes of
the currents to be equal and that was a small toroidal coil
quite unlike a 75m bugcatcher coil. Wes's web page shows the
currents to be unequal at the ends of the coil. Figure 3 shows
1.03 amps at the bottom of the coil and 0.66 amps at the top
of the coil. That's not equal.

http://www.k6mhe.com/n7ws/Loaded%20antennas.htm

--

Here's an example from EZNEC where the currents are not
only unequal, but if one considers to standing wave current
to be flowing, more current is flowing into the bottom of
the coil than out the top. What does the lumped-circuit model
have to say about that? This technical question goes unanswered.

http://www.qsl.net/w5dxp/qrzgif35.gif

--

As for phase shift using standing wave current, consider the
following half of a dipole:

FP----------x----------y----------

'x' is at the 30 degree point and 'y' is at the 60 degree
point. What is the standing wave phase shift between point
'x' and point 'y'? We can see from Figure 14-4 in Kraus'
"Antennas for All Applications", 3rd edition, that the
measured phase shift would be zero between 'x' and 'y'.
So why is it a surprise that if the wire between 'x' and
'y' is replaced by a coil, the phase shift remains zero?
The measured phase shift in the wire and the coil are the
same. This technical question goes unanswered.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Cecil Moore wrote:
Last night I posted 1/4WL, 3/4WL, and 5/4WL measured resonant
points using the same coil stock as W8JI but with a shorter
50 uH coil. This coil 2" dia, 8 tpi, 8.5" long. It was
sitting on a mag mount on my metal desk.

I think what we have here is Cecil has bought into the idea that
radically different behavior on one or more self-resonant frequencies
means we can apply an analogy of that behavior to all other
frequencies.

Most of us probably want a theory that works all the time, and we
probably think only one situation that proves the theory wrong is
required to dismiss the theory as being incorrect.

What Cecil is asking us all to do is is agree to a theory that only
works in special cases and ignore the times it does not.

73 Tom

Current through coils
 

Cecil Moore wrote:
Richard Harrison wrote:
Distributed network theory is newer than lumped network theory but both
have been around plenty long enough to be well established.

Neumann didn't prove that the current through a coil is uniform.
He *assumed* it to be true as a simplification, so he could factor
out the current term from under the integral sign in one of Maxwell's
equations. Now Neumann's mathematical shortcut is being reported
here as a fact of physics. That's how well established it is.

At the most basic level, Cecil does not understand what scientific
theories are all about.

That was not a "shortcut" or approximation. It was a rigorous test for
the limiting case where the coil has no other properties except pure
inductance, so no electromagnetic radiation is taking place. In that
limiting case, Maxwell's equations MUST join up with conventional
circuit theory... and indeed they DO.

In that limiting case, the current at the two terminals of a pure
inductance must be the same in both magnitude and phase. By "current" we
mean the simple, straightforward movement of charge. If you count the
electrons in and out at the two terminals, there can be no difference in
either magnitude or phase because that would require electrons to be
stored or lost from somewhere - which inductance cannot do. Kirchhoff's
current law recognises the logic of this.

This is how inductance always works in every type of non-radiating
circuit, both in theory and in real life.


When developing a new theory, it is normal, standard required practice
to test it for simplified, limiting cases that we already understand.
The new theory MUST work for all these test cases; it MUST connect
seamlessly with everything we already know.

At his point, some heckler pipes up: "Ah, but what about Einstein?"
Thank you, sir - the perfect example to prove my point! If Einstein's
equations of relativity are tested for the limiting case where
velocities are very low, they connect seamlessly into Newton's laws of
motion. If they hadn't, Einstein would have thrown them out and gone
back to think again.

Another point: antennas are the home territory of classical physics,
where everything is consistent with everything else. Classical physics
is plain physical reality, verified every day, a billion times over.
All of our validated knowledge joins together completely seamlessly -
and that's how we test anything new. In the home territory of classical
physics, reality is hard, sharp and clear. It allows no gaps and no
excuses. "What don't fit, ain't true."

Trained scientists accept the discipline of that, and turn it into a
useful tool. Engineers aren't always trained to think that way, but the
best are of a mind to do it anyway. They're creating new ideas all the
time, and the ones that "don't fit" or "don't make sense" are simply
abandoned (sometimes they're abandoned before they even make it into
fully conscious thought). One way or another, lots of ideas get thrown
away; no big deal, it's just part of the process of *having* ideas.

So...

When Cecil's theory is tested for the simple limiting case of pure
inductance, it MUST join up seamlessly with conventional circuit theory.
If it requires anything that "don't fit", such as a phase shift in
current through a pure inductance, or special kinds of "current" that
are different from the simple, straightforward movement of charge
(electrons), then the theory fails.



--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Current through coils
 

Cecil Moore wrote:
I think what we have here is Cecil has bought into the idea that
radically different behavior on one or more self-resonant frequencies
means we can apply an analogy of that behavior to all other
frequencies.

False. Nobody has said anything about "all other frequencies".

OK. I'm not sure what you are trying to say. It sounds like we all know
and agree a reasonable physial size lumped inductor with good flux
coupling between ends and stray C to the outside world that is small
compared to termination impedance works like a lumped inductor below
self-resonance of the inductor. There is only a tiny transmission line
effect and that effect has more to do with spatial size than conductor
length.

So...

What are you trying to say? Can you give an example in you own words
explaining what you are trying to say and why it is meaningful or
useful to others?

Surely you can put it all into a few words.

73 Tom

Current through coils
 

On Thu, 09 Mar 2006 21:40:40 GMT, "Cecil Moore"
wrote:

Your 100uH coil above exhibits 60 degrees of phase shift
even for the voltage and that's 1/6 wavelength

On Thu, 16 Mar 2006 08:56:19 GMT, Cecil Moore wrote:

When the speculation is that the coil presents a 1:1 replacement for
the delay of the "missing" segment of the resonant antenna, then this
premise stumbles at the starting blocks.

Nobody said anything about a 1:1 replacement. That was just
somebody's strawman.

We all know who "somebody" is. [threadbuster #4]

But if this is news to you, it must have been one of your other
personalities (Hokum's Razor?) at the keyboard who posted the message
at the top.

Current through coils
 

On Thu, 16 Mar 2006 09:08:37 GMT, Cecil Moore wrote:

Richard Clark wrote:
What are they when you raise the assembly (I distinctly note that this
is NOT the resonance of the COIL you are speaking of) two feet higher?

Isolating the magmount would be disconnecting the
ground plane from a 1/4WL antenna and would contribute
nothing of value to the discussion.

Certainly not for you, that is apparent. It would only more closely
conform to your reference material's isolated coils, and that would
jeopardize your "confirmations" n'est pas?

No matter, this thread has been put to bed anyway. It is coasting in
entertainment gear now.

Current through coils
 

I've been following this mind-numbing discussion for days now and still
don't have the answer to the original question:

Is the current the same at both ends of a mobile whip's loading coil?

Bill, W6WRT

Current through coils
 

wrote:
OK. I'm not sure what you are trying to say. It sounds like we all know
and agree a reasonable physial size lumped inductor with good flux
coupling between ends and stray C to the outside world that is small
compared to termination impedance works like a lumped inductor below
self-resonance of the inductor.

I absolutely agree about the characteristics of an inductor presupposed
by the lumped-circuit model. But one cannot use the presuppositions
of the model to prove the model is valid for all cases. The dissagreement
here is one of degree. I would have stated the assertion above, it behaves
"... like a lumped inductor *far* below self-resonance of the inductor." Dr.
Corum sets the "far below" range at 15 degrees or 1/6 the self-resonant
frequency.I previously showed that 15 degrees of 450 ohm transmission
line will change a load of 50+j0 into a load of 54+j100 ohms. That may
be accurate enough for Dr. Corum to start using the lumped-circuit model,
but not for me. I would be more inclined to set the limit at 5 degrees.

What are you trying to say? Can you give an example in you own words
explaining what you are trying to say and why it is meaningful or
useful to others?

What I am trying to say can best be illustrated by an example task that
I need to perform. I have a 180 foot dipole that I need to shorten so I
am going to install loading coils. I want the length of the loaded antenna
to be 90 feet. I'm pretty naive at this, so I am just going to build the
coil
out of the wire I remove from the antenna. My neighboring ham friend
says that will work just fine. And in the process of reducing the size of
my antenna, I want to learn something about antennas so I have borrowed
two toroidal current pickups to measure the current.

Note that at the frequency where the dipole is 1/2WL and resonant,
it is 180 feet long and 180 degrees long so the number of feet of
wire is also the number of degrees of antenna. Here is my 1/2WL
dipole with current pickup coils installed at points 'x' and 'y' and
FP is the feedpoint,the impedance of which is 60 ohms.

------------------------------FP-------x---------------y-------

Total length is 180 feet. The distance between 'x' and 'y' is 45 feet.
Since feet = degrees in this case, the number of degrees between
'x' and 'y' is known to be 45 degrees from antenna theory. Those
45 degrees are what I am going to attempt to replace with a coil.

So I adjust the feedpoint current to one amp at a reference phase
angle of zero degrees and measure the current at 'x' and the current
at 'y'. The current at 'x' is 0.92 amp at 0 deg. The current at 'y' is
0.38 amp at 0 deg. Already I am not understanding my measurements.
The electrical length between 'x' and 'y' is obviously 45 deg. Why is
there no phase shift at all in the measured current between 'x' and
'y' and the feedpoint current? But I want to complete this task so
I will wait until later for an explanation to that apparent paradox.

I take the 45 feet of wire from each side of the dipole, wind it
into two coils, and install them in each side. Now the 90 foot
long dipole looks like this.

-------//////-------FP------x-//////-y------

I make some more measurements with the feedpoint current set
to one amp at zero degrees. The resonant frequency of the dipole
has changed from the earlier resonant frequency. I have to adjust
the number of turns on the coil to return to the original frequency.
I discover that the feedpoint impedance has dropped to 45 ohms.
I measure the current at each end of the coil and at one end it is
1.1 amp at 0 deg and at the other end it is 0.6 amp at 0 deg

These are not the results predicted by my neighboring ham friend.
I'm confused but here are the things I know for sure.

1. The resonant frequency changed when I installed the coil so
the coil is not a perfect replacement for the wire.

2. The feedpoint impedance decreased from 60 ohms to 45
ohms. Since 45 ohms is closer to 50 ohms than is 60 ohms,
I'm not too interested in knowing why..

3. The current at 'x' increased from 0.92 amp at 0 deg in the
wire dipole to 1.1 amp at 0 deg in the loaded dipole. The phase
didn't change.

4.The current at 'y' increased from 0.38 amps at 0 deg in the
wire dipole to 0.6 amp at 0 deg in the loaded dipole. The phase
didn't change.

5. No matter where I measure the current in either system, the
phase always comes up zero degrees between any two points
from tip to tip anywhere on either dipole no matter how far
apart are the measurement points. My neighboring ham friend said the number
of degrees in the coil had to be the number of degrees in the
wire and indeed, both are measured to be zero degrees, but
I wonder if that's really what he had in mind when he said
the delay would be equal. Zero equals zero, but what does
that mean for me?

The change in feedpoint impedance and the different current
magnitudes don't much bother me but I am really bothered
by those phase measurements. The dipole is 180 degrees long
and the current should be changing phase, at least on the wire
if not through the coil. I need some expert to explain how those
phase measurements on the wire are possible on both antennas.
I know my phase measurements are correct but why are they
always zero degrees? And since they are always zero degrees,
what information are they providing?
--
73, Cecil, W5DXP

Current through coils
 

On Thu, 16 Mar 2006 09:09:40 -0800, Richard Clark
wrote:

On Thu, 09 Mar 2006 21:40:40 GMT, "Cecil Moore"
wrote:

Your 100uH coil above exhibits 60 degrees of phase shift
even for the voltage and that's 1/6 wavelength

On Thu, 16 Mar 2006 08:56:19 GMT, Cecil Moore wrote:

When the speculation is that the coil presents a 1:1 replacement for
the delay of the "missing" segment of the resonant antenna, then this
premise stumbles at the starting blocks.

Nobody said anything about a 1:1 replacement. That was just
somebody's strawman.

We all know who "somebody" is. [threadbuster #4]

But if this is news to you, it must have been one of your other
personalities (Hokum's Razor?) at the keyboard who posted the message
at the top.


:-) :-) :-) :-) :-)

It just occurred to me that those two posts were a week apart (more or
less) and denote a phase change (the one cancels the other if they
were to vectorally combined).

Thus and forever more, this proves that newsgroups (when heavily fed
from a source of confusion, linearly loaded with nonsense, and
terminated with a embarrassing revelation) exhibit transmission line
properties and can transform a stupid idea (at the top) into a
brilliant one (at the bottom) - or versa vice.

In conformance to transmission line properties, this cycle of phase
reversals is repeated every
1 / [1 + tan (c · Vf / posts)]² Years

Current through coils
 

On 16 Mar 2006 12:19:20 -0500, "Bill Turner" wrote:

Is the current the same at both ends of a mobile whip's loading coil?

Sorry Bill,

Depends....

Yes, of course not. The clear and compelling lesson to be learned is
that you CANNOT apply Kirchhoff's laws to networks that are large in
relation to wavelength. This single caveat was drilled into me in
sophomore EE.

Any variance in current measured, that is larger than errors that may
be attributed to is measurement PROVES that the size in relation to
wavelength necessarily invalidates Kirchhoff solutions. This single
truth has been observed by me at the calibration bench.

As Roy noted, it demands another set of equations. In the Metrology
field, that is what we were paid to use, or to derive. Suffice it to
say that modeling programs replace the tedium of scribbling out that
math, and just getting on with the next act.

73's
Richard Clark, KB7QHC

Current through coils
 

"Ian White GM3SEK" wrote:
That was not a "shortcut" or approximation.

It really doesn't matter if it is or it isn't. I was quoting another pretty
smart guy who seems to know the history of these models. He said
Maxwell's equations matured first, then the distributed network model
matured as a simplified subset of Maxwell's equations, then the lumped-
circuit model matured as a subset of the distributed network model.
But a chicken/egg argument is meaningless except for historical
accuracy. We are in the present looking at those models.

In that limiting case, the current at the two terminals of a pure
inductance must be the same in both magnitude and phase.

There's that catch word, "pure". Pure inductances do not exist
in the real world. They are a construct of the lumped-circuit
model and are presupposed to have the characteristice that
you mention. One cannot prove the validity of that model by
quoting the presuppositions. A 75m bugcatcher coil is NOT
a pure inductance.

By "current" we
mean the simple, straightforward movement of charge. If you count the
electrons in and out at the two terminals, there can be no difference in
either magnitude or phase because that would require electrons to be
stored or lost from somewhere - which inductance cannot do. Kirchhoff's
current law recognises the logic of this.

Standing wave current with its cos(kz)*cos(wt) equation is not constrained
by those rules since the phase of the standing wave is everywhere zero deg
for a 1/2WL thin-wire dipole.

This is how inductance always works in every type of non-radiating
circuit, both in theory and in real life.

A pure inductance cannot work that way in real life because it doesn't
exist in real life. If the forward current is in phase with the reflected
current at one end of the coil, the current will be a maximum (loop)
at that point. If the forward current is 180 degrees out of phase with
the reflected current at the other end of the coil, the current will be a
minimum (node) at that point. Please take a look at:

http://www.qsl.net/w5dxp/3freq.gif

How does one explain the current reported by EZNEC at two times
the resonant frequency?

When developing a new theory, it is normal, standard required practice
to test it for simplified, limiting cases that we already understand.
The new theory MUST work for all these test cases; it MUST connect
seamlessly with everything we already know.

The distributed network model predates my birth by decades and is not
new. It is known to work in situations where the lumped-circuit model
fails. It has never been known to fail in a situation where the lumped-
circuit model works.

At his point, some heckler pipes up: "Ah, but what about Einstein?"
Thank you, sir - the perfect example to prove my point! If Einstein's
equations of relativity are tested for the limiting case where
velocities are very low, they connect seamlessly into Newton's laws of
motion. If they hadn't, Einstein would have thrown them out and gone
back to think again.

The distributed network model is to relativity as the lumped-circuit model
is to Newtonian physics. Newtonian physics is a subset of relativity.
The lumped-circuit model is a subset of the distributed-network model.

When Cecil's theory is tested for the simple limiting case of pure
inductance, it MUST join up seamlessly with conventional circuit theory.

It's not my theory and it does indeed join up seamlessly. It is the lumped-
circuit model that does not join up seamlessly with Maxwell's equations.
How could it since it assumes faster than light speed of current flow?
The presuppositions of the lumped-circuit model even violate the
theory of relativity.

If it requires anything that "don't fit", such as a phase shift in
current through a pure inductance, or special kinds of "current" that
are different from the simple, straightforward movement of charge
(electrons), then the theory fails.

It doesn't require anything of pure inductances since pure inductances
don't exist in reality. It requires that real world inductances obey the
laws of physics.

If one doesn't understand the implications of the equation for standing
wave current, one needs to crack open that old dusty math book.
--
73, Cecil, W5DXP

Current through coils
 

Richard Clark" wrote:
On Thu, 09 Mar 2006 21:40:40 GMT, "Cecil Moore"
wrote:

Your 100uH coil above exhibits 60 degrees of phase shift
even for the voltage and that's 1/6 wavelength.

That does NOT say the coil replaces 60 degrees of wire in the antenna.
One who thinks such is mistaken. The phase shift in the coil is what it
is. It usually does NOT correspond to the phase shift of the wire it
replaces.
The point of that statement was that real world phase shift is never zero.
The one-way phase shift is known to be 90 degrees at the self-resonant
frequency.

On Thu, 16 Mar 2006 08:56:19 GMT, Cecil Moore wrote:

When the speculation is that the coil presents a 1:1 replacement for
the delay of the "missing" segment of the resonant antenna, then this
premise stumbles at the starting blocks.

Nobody said anything about a 1:1 replacement. That was just
somebody's strawman.

We all know who "somebody" is. [threadbuster #4]

But if this is news to you, it must have been one of your other
personalities (Hokum's Razor?) at the keyboard who posted the message
at the top.

Some people have misunderstood the meaning of that statement. See above.
So many jumping to conclusions - so few trying to understand.
--
73, Cecil, W5DXP

Current through coils
 

"Richard Clark" wrote in message
...
Cecil Moore wrote:
Isolating the magmount would be disconnecting the
ground plane from a 1/4WL antenna and would contribute
nothing of value to the discussion.

Certainly not for you, that is apparent. It would only more closely
conform to your reference material's isolated coils, and that would
jeopardize your "confirmations" n'est pas?

On the contrary, Tesla coils are operated over a large ground plane.
The sphere at the top functions like a top hat. Everyone really should
read the referenced Corum papers to avoid misconceptions like this
one.
--
73, Cecil, W5DXP

Current through coils
 

On Thu, 16 Mar 2006 18:20:19 GMT, "Cecil Moore"
wrote:
On Thu, 09 Mar 2006 21:40:40 GMT, "Cecil Moore"
wrote:
Your 100uH coil above exhibits 60 degrees of phase shift
even for the voltage and that's 1/6 wavelength.
That does NOT say the coil replaces 60 degrees of wire in the antenna.
Of course not. 1/6 wavelength of wire doesn't exhibit 60 degrees
phase shift - does it?
One who thinks such is mistaken.
Less than a week to this new phase shift in the non-linear dynamics of
Newsgroups-as-transmissionline. ;-)

The phase shift in the coil is what it is.

More Zen from the edge of Nirvana. Let me try mine:
The soup spoon in a magnetron is what Campbell's is to Andy Warhol.

Give us another!

Current through coils
 

On Thu, 16 Mar 2006 18:23:24 GMT, "Cecil Moore"
wrote:
Everyone really should read the referenced Corum papers
to avoid misconceptions like this one.

This is coasting with the brakes set on self-referentially.
Still amusing however.

Current through coils
 

"Bill Turner" wrote in message
...
I've been following this mind-numbing discussion for days now and still
don't have the answer to the original question:

Bill, I posted an example of me, as a naive ham, reducing the size of my
dipole from 180 feet to 90 feet by adding loading coils. Please follow
that experimental excursion to find out what the discussion is all about.

Is the current the same at both ends of a mobile whip's loading coil?

The mobile antenna is a standing wave antenna. It has a forward current
and a reflected current, both traveling waves, flowing through it.

1. The forward current flowing through the coil is close to the same
magnitude at both ends of the coil.

2. The forward current phase shift through the coil is difficult to measure
but it is NOT zero. It is more in the neighborhood of tens of degrees.

3. The reflected current flowing back through the coil is close to the
same magnitude at both ends of the coil.

4. The reflected current phase shift is close to the same as the
forward current phase shift, i.e. tens of degrees..

5. The standing wave current, the only one measured so far, is the
phasor sum of the forward current phasor and the reflected current
phasor. The magnitude of the standing wave current depends upon
the relative phase between the forward current and reflected current.

To see some variations please visit: http://www.qsl.net/w5dxp/3freq.gif

When one realized that the standing wave current at the bottom of
the coil is 0.1 amp while the standing wave current at the top of
the coil is 2 amps, one comprehends why he must abandon the
concept that standing wave current flows.

From the equation for the standing wave current, cos(kz)*cos(wt),
one can be see that the standing wave current is not a normal current.
This is explained in terms of light waves in "Optics", by Hecht.

6. Since the forward current phasor and reflected current phasor are
rotating in opposite directions, the phase of the standing wave current
is fixed and close to zero degrees all up and down the antenna, from
feedpoint to tip top. Since the phase of the standing wave is unchanging,
it cannot be used to measure the phase delay through a coil. All of the
delay measurements, except the self-resonant frequency measurements,
have used standing waves which are incapable of phase transitions in
the average loaded mobile antenna.

The phase of the standing-wave current is fixed close to zero degrees
until the antenna gets electrically longer than 90 degrees. Then it shifts
abruptly by 180 degrees and remains fixed at that new value for another
90 degrees. This is illustrated in Kraus', "Antennas for All Applications",
3rd edition, Figures 14-4 - 14.6.
--
73, Cecil, W5DXP

Current through coils
 

Cecil Moore wrote:
Note that at the frequency where the dipole is 1/2WL and resonant,
it is 180 feet long and 180 degrees long so the number of feet of
wire is also the number of degrees of antenna. Here is my 1/2WL
dipole with current pickup coils installed at points 'x' and 'y' and
FP is the feedpoint,the impedance of which is 60 ohms.

------------------------------FP-------x---------------y-------

Total length is 180 feet. The distance between 'x' and 'y' is 45 feet.
Since feet = degrees in this case, the number of degrees between
'x' and 'y' is known to be 45 degrees from antenna theory. Those
45 degrees are what I am going to attempt to replace with a coil.

So I adjust the feedpoint current to one amp at a reference phase
angle of zero degrees and measure the current at 'x' and the current
at 'y'. The current at 'x' is 0.92 amp at 0 deg. The current at 'y' is
0.38 amp at 0 deg. Already I am not understanding my measurements.

Your measurements are probably wrong.

When did you measure that? After we resolve the error in current, we
can move on.

73 Tom

Current through coils
 

Bill Turner wrote:
I've been following this mind-numbing discussion for days now and still
don't have the answer to the original question:

Is the current the same at both ends of a mobile whip's loading coil?

Bill, W6WRT

Bill,

Did you read this? Actual measurements!!

http://www.w8ji.com/mobile_antenna_c...ts_at_w8ji.htm

As Richard Clark said, it all depends on the physical size and
constrution of the inductor and the antenna above the inductor. In a
reasonably well-constructed antenna the difference is small.

Anyone who says otherwise is just guessing.

73 Tom