Current through coils
 

Food for thought.

At this moment in time it seems Cecil is claiming an inductor acts like
so many electrical degrees, but of course at any moment another waffle
might pops out of the Texas toaster and change everything.

Let's assume we have a mobile antenna that is 25 electrical degrees
tall. Now following the logic a loading coil acts like a transmission
line, we have a 65-degree loading coil.

Following the same twisted logic, since the loading inductor is
65-degrees long, we should be able the move it anywhere in the antenna
without changing antenna tuning.

Our 75 meter antenna should also work on 25 meters as a 3/4 wave
antenna, and on 37.5 meters as a half-wave.

Of course we all know it doesn't behave anything close to this way.

Wouldn't it be nice if Cecil could show us all how to predict the
resoances of an antenna based on his idea that loading inductor acts
like a transmission line? Where are the design equations we can all
use?

73 Tom

Current through coils
 

Gene Fuller wrote:
Indeed, it is clear from the quotes that the two treatments
are equivalent.

And indeed, the two treatments are equivalent for anyone who
understands both of them. The two treatments are obviously
not equivalent for someone who understands one and not the
other. It is an individual ignorance problem, not a problem
with the models.

If the standing wave analysis results are reported by an
individual to be different from the traveling wave analysis
results, what can we assume? If they are equivalent, why would
the results ever be different except for the ignorance
of the reporter?

Here is a 'yes' or 'no' technical question for everyone.
Is it possible to measure a phase shift through a wire
or coil using a signal (standing wave current) that
doesn't ever change phase?

The answer to that question is the entire crux of the
argument. If anyone answers 'yes' to that question, please
explain in detail how to accomplish that measurement feat.

Of course these authors were disadvantaged by a lack of understanding of
your "hidden mathematical concepts." 8-)

I thought we had agreed to stop using inuendo to try to
influence a technical argument. The mathematical concepts
are certainly NOT hidden. They are there for all to
understand and accept but are being ignored by certain
individuals.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

wrote:
That just shows how poorly we sometimes understand the workings of an
inductor.

There you go again, implying through inuendo that that 'we'
includes me but not you. This discussion is not about you
and me so I will make a few generalized statements.

An individual can understand perfectly how an inductor
works within the presuppositions of the lumped-circuit
model yet be completely ignorant of how an inductor
actually works in the real world in a distributed-network
environment.

The presuppositions of the lumped-circuit model cannot
be used to prove the validity of the lumped-circuit
model. The presuppositions of the lumped-circuit model
are invalid for many distributed-network environments.

This is a technical subject so I will ask a technical
question:

How is it possible to use a signal (standing wave current)
that is known not to change phase, to measure the phase delay
through a wire or coil?

Kraus provides a graph of that unchanging phase in Figure
14-2 of "Antennas for All Applications", 3rd edition.

The fact an inductor has self-resonance at one frequency (16MHz) does
not mean we can assume it is 90 degrees at that frequency and 45
degrees at half of that frequency!!

It certainly means we can make those assumptions within some
estimated degree of accuracy because they agree with the laws
of physics which don't change just because some individual
rejects them. Helicals, in general, obey the transmission line
laws of physics. They have relatively constant values of L, C,
R, and G over a certain range of frequencies. They exhibit the
characteristics of Z0 and VF. They do NOT exhibit the
presuppositions of the lumped-circuit model.

This business of treating an inductor like a transmission line is
destined to produce theories that crash and burn.

Inductors have been treated like transmission lines for the
better part of a century by engineers using the distributed
network model. Since the distributed network model is a
superset of the lumped-circuit model, why would they ever
crash and burn?
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Here is a 'yes' or 'no' technical question for everyone.
Is it possible to measure a phase shift through a wire
or coil using a signal (standing wave current) that
doesn't ever change phase?

There is no "standing wave current". There is only current.
Current can't stand.

Phase difference can be measured in a system that has standing waves,
just as it can in one without standing waves.

The answer to that question is the entire crux of the
argument. If anyone answers 'yes' to that question, please
explain in detail how to accomplish that measurement feat.

Any number of ways, if we disallow the impossible situiation where you
seem to think we can have current "standing still". Direct measurement
methods abound.

First Cecil says:
I thought we had agreed to stop using inuendo to try to
influence a technical argument. The mathematical concepts
are certainly NOT hidden.

Then Cecil does the opposite of what he asks Gene to do:
They are there for all to
understand and accept but are being ignored by certain
individuals.

Cecil first asks Gene to stop using inuendo.
One sentence later, Cecil uses inuendo. :-)

73 Tom

Current through coils
 

On 15 Mar 2006 10:10:35 -0800, wrote:

Let's assume we have a

Tom,

One coil has him stumbling to do his own math with his own references.
There is no reason to fill the road with intellectual boulders when he
trips over gravel.

73's
Richard Clark, KB7QHC

Current through coils
 

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.

Hmmm, dare I plunge into the next, obvious question?

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

Tom Donaly wrote:
What's the formula, Cecil?

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf equation (32)

The velocity factor can also be measured from the self-
resonant frequency at 1/4WL. VF = 0.25(1/f)

I suppose you also
have something that will tell us how to find your coil's characteristic
impedance; o.k., out with it.

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf equation (43)

and we can then achieve closure by comparing the same results with
Reggie's formulas.

Current through coils
 

wrote:

Food for thought.

At this moment in time it seems Cecil is claiming an inductor acts like
so many electrical degrees, but of course at any moment another waffle
might pops out of the Texas toaster and change everything.

That's not food for thought. That's emotional gut feelings. I
thought we agreed to cease and desist from ad hominem attacks?

Let's assume we have a mobile antenna that is 25 electrical degrees
tall. Now following the logic a loading coil acts like a transmission
line, we have a 65-degree loading coil.

*False assumption!* The phase delay through the coil is what it
is and we don't know exactly what it is. We do know it is not what
has been measured and reported using a signal source (standing wave
current) that doesn't ever change phase.

Our present choice is between a reported measurement that is
100% flawed, in the absolute sense of the word, and an estimate
with unknown accuracy based on the laws of physics. Given those
two, and only two, present choices, which choice should one make?

Please see the end of this posting for a description of the
logical diversion that is taking place here.

The phase delay through the coil is what it is and we don't know
exactly what it is. We do know it is not zero as the standing wave
current phase shift measurement would predict.

Let me focus the subject of the argument back upon the actual
subject of the argument and try to avoid diversions into the
unknown, like the above.

How does one measure the phase delay through a coil or wire
using a signal with forever unchanging phase? All of the phase
delay experiments so far have used the above flawed method.
So far, we only have experimental measurements that are flawed
except for the self-resonant experiments.

Which is preferred? The results from experiments known to
be 100% flawed or estimates with unknown accuracy based on
the laws of physics? Those are presently our only two choices.

Following the same twisted logic, since the loading inductor is
65-degrees long, we should be able the move it anywhere in the antenna
without changing antenna tuning.

*False assumption!* The superposition of all four of the
forward and reflected waves is much more complicated than that.

Our 75 meter antenna should also work on 25 meters as a 3/4 wave
antenna, and on 37.5 meters as a half-wave.

It's not as simple as that but I have the EZNEC current
distribution patterns that indicate something akin to
that indeed does develop. Give me a few hours and I
will post those results.

Where are the design equations we can all use?

Asked and answered but not sure of the accuracy applied
to 75m bugcatcher loading coils. Someone is working on
that. Please stand by.

The logical diversion that is happening here goes like this:

Person A says: "The moon is 10,000 miles from the earth.

Person B says: "That can't be true."

Person A says: "How far do you say the moon is from the earth?"

Person B says: "I don't know, but I do know it is not 10,000
miles."

Person A says: "Well, if you don't know and can't give me the
correct answer, I am right and you are wrong. The moon is
10,000 miles from the earth."

Does an absolutely false answer beat ignorance?
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Cecil Moore wrote:
Tom Donaly wrote:

Tell me a couple of things, Cecil: 1. the diameter of your bugcatcher
coil, and 2. the turn to turn wire spacing. I'd like to use the
information, using the formulae in your reference, to see just how
long your bugcatcher coil is electrically.


Please note that when my 75m bugcatcher coil is mounted
just above my GMC pickup ground plane, it is electrically
almost four times longer than it is laying on a stack of
books in my hamshack. The coil capacitance to ground is
obviously a lot higher when mounted over a ground plane.
The ground plane reduces the VF to approximately 1/4
the value obtained in isolation.

1. The measured self-resonant frequency of the coil
mounted on my pickup is ~6.6 MHz.

2. The measured self-resonant frequency of the coil
on a mag mount on my all-metal desk is ~6.6 MHz.

3. The measured self-resonant frequency of the coil
isolated from any ground is ~24.5 MHz.

The self-resonant frequency needs to be measured in
the environment in which it is installed. That means
one needs to model the coil 3 inches above a perfect
ground plane before calculating the self-resonant
frequency, Z0, or VF. I doubt that Dr. Corum's equations
take that into account since it would seem self defeating
to operate a Tesla coil over a physically close ground
plane. But I could be wrong on that point.

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

Thanks, Cecil.
73,
Tom Donaly, KA6RUH

Current through coils
 

wrote:
There is no "standing wave current". There is only current.
Current can't stand.

Addressed and proven to be a false statement. cos(kz)*cos(wt)
proves it is standing and not flowing.

Phase difference can be measured in a system that has standing waves,
just as it can in one without standing waves.

Addressed and proven to be a false statement. A signal
with unchanging phase cannot be used to measure the
phase delay through a wire or coil.

Any number of ways, if we disallow the impossible situiation where you
seem to think we can have current "standing still".

Please take a look at the equation for standing wave
current. It proves that the standing wave current is
standing still, just oscillating in place at any point
on the wire.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

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