Current across the antenna loading coil - from scratch
 

"Roy Lewallen" wrote in message
...
Mike Coslo wrote:
Yuri Blanarovich wrote:
Check my article that describes the controversy, shows some proof of
reality and then efforts of the "gurus" to deny it and "reason" why
it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is
that back in 1953 in QST article there was erroneous
conclusion/statement made, which propagated through the books, until
W9UCW measured the current across the loading coils and found that
there is significant drop from one end to the other, and the rest is
(ongoing) history

Hmm, certainly it would seem to make sense that:

The current in a typical loading coil in the shortened antennas drops
across the coil roughly corresponding to the segment of the radiator
it replaces.

Quote from your page.

I would not expect anything else. If the loading coil is making the
antenna act like a physically longer antenna, other "qualities" of that
simulation are likely to be similar.

Is there a reason why the coil would *not* do this?

Yes, many, and they've been discussed here at length. That this concept is
wrong can and has been shown by theory, modeling, and measurement. I made
and posted measurements on this newsgroup in November 2003 which
demonstrated clearly that the presumption is false.

The loading coil isn't making the antenna act like a physically longer
antenna. In the extreme case of a physically short inductor at the
feedpoint, it's simply modifying the feedpoint impedance and has no effect
whatever on the antenna's radiation. As the inductor gets longer, it does
become some part of the antenna, but adding an inductor which resonates,
say, a 45 degree physical radiator doesn't make the antenna act like a 90
degree physical radiator.

Roy Lewallen, W7EL

Oooops, carefull here.
As far as I know, nobody has claimed that inserted loading coil replaces the
"missing" degrees of the radiator in terms of providing magical properties
that would look like that "replaced" portion of the antenna, or make the
antenna act like 90 degree full size physical radiator.
What we are saying that the loading coil appears to replace "missing"
electrical degrees of the radiator in order to make it resonant, that is
back to 90 electrical degrees (has to be in order to resonant), which rest
of the existing "straight" radiator forces it to do (+/-). Radiation
properties and efficiency of the loaded antenna is proportional to the area
under the current curve. It is obvious to anyone comparing the area under
the current curve of full size quarter wave radiator vs. loaded radiator
that there is huge difference in area under the curve and performance,
efficiency, which is known and been verified by numerous measurements.
HOW the current curve is modified by different loadings and position along
the radiator is important in knowing how the current distribution curve
along the radiator is modified.
The whole controversy is that "gurus" claim current doesn't drop across the
coil, while we say that it does, therefore making the area under current
curve above the coil smaller and effciency of loaded antenna worse than they
believe and insist on.
Again, when applied in modeling programs, wrong assumption will produce
erroneous results, which will be magnified in multielement antenna designs.
So the "gurus" basically ignore behavior of coil in the standing wave
environment along the loaded radiator, where the current drops from max at
base to zero at the tip, but coil would magicaly resist that, because, bla,
bla, bla.... (see their "reasons")
So while everyone knows (?) that standing wave current drops acros (along)
the wire (all the antenna books show that), but it is "impossible" to drop
along the coiled wire (real inductance - coil, loading stub). Reality and
measurments prove that, but according to them "it can't be so".

I am already gathering necessary hardware to do more experiments,
measurements to show what is really happening, and will prepare articles how
to model and apply it to antenna design.
I would challenge the "unbelievers" to join me and repeat the tests, to see
wasaaaap.

73 Yuri, K3BU

Current across the antenna loading coil - from scratch
 

Yuri Blanarovich wrote:
What we are saying that the loading coil appears to replace "missing"
electrical degrees of the radiator in order to make it resonant, ...

W8JI says we are correcting the power factor. Every EE knows that
correcting the power factor involves shifting the phase, i.e.
the coil cannot correct the power factor without providing a phase
shift.

The whole controversy is that "gurus" claim current doesn't drop across the
coil, while we say that it does, ...

That context is specifically inductively loaded mobile antennas
where the current decreases from source to tip of the antenna,
true for all electrical 1/4WL monopoles.

For other antennas, the current may DROP, the current may RISE,
or the current may STAY THE SAME magnitude depending upon where
the coil is installed in the standing wave system. In particular,
none of the "gurus" has even attempted to explain the RISE IN
CURRENT through the coil in the right hand system at:

http://www.qsl.net/w5dxp/test316.GIF

There have been about 10 examples proving the "gurus" wrong and
they simply chose to ignore those examples. They complain that
those examples are biased toward technical correctness. I say,
YES, THEY ARE. AREN'T THEY SUPPOSED TO BE TECHNICALLY CORRECT?
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

chuck wrote:
Ian White GM3SEK wrote:
[SNIP]
The disagreement is entirely about the interpretation - in other
words, it's about the theory about standing and travelling waves.
Richard habitually misses out this step, which makes it look as if
the Bird wattmeter "proves" the physical existence of forward and
reverse travelling waves of power.
It doesn't. Everything that you see printed on the Bird's meter
scale, and in the Bird literature, represents that company's
particular interpretation of theory about waves on transmission lines.
details of that theory are *not* agreed within this newsgroup, which
means that - to some people - the two halves of Richard's claim do
not join up.


Ian, I've not detected this particular disagreement about waves on
transmission lines in the group. I would be most grateful to see a
brief statement of where and how Bird's interpretation of theory is
found infirm.

The Bird 43 has only one scale calibration: power. Readings on that
scale represent the power delivered to a 50-ohm load when the sensor is
turned to the forward direction. However, the instrument internally
senses only the voltage and current on the line. The "power" reading is
only a calibration, and is only completely meaningful when you use the
instrument in the same circumstances as when it was calibrated.

Now what happens if the load is not exactly 50 ohms? What happens when
you turn the sensor around? You then get some new and different readings
which have to be called "forward power" and "reflected power" - because
"power" is the only thing the Bird's meter scale is calibrated to
indicate.

The Bird Corporation's Application Note "Straight Talk About
Directivity" discusses the meaning of "forward and reflected power"
indications with a mismatched load. That document does not directly
address your question, Chuck, but takes the subject to a further level
of detail about the accuracy of the real-life instrument, and its
limited ability to discriminate between forward and reflected waves.
http://www.bird-electronic.com/app_n...irectivity.pdf

One notable thing about "Straight Talk" is how all the calculations
begin by taking the square root of the power indications. In other
words, all the relative RF power indications from the meter scale are
converted into relative RF voltages, and all the real calculations are
done on the voltages.

Another interesting observation is that if you have a mismatched load,
such that the meter indicates say 93W with the arrow on the sensor
pointing forward and say 23W with the sensor rotated 180deg, then you
would find that 70W is being delivered into the resistive part of the
mismatched load impedance (assuming perfect directivity and no errors of
any other kind).

There are two schools of thought about the physical meaning of all this.

One is that if the meter scale says "power", then there genuinely are
forward and reflected traveling waves of power on the line. In the "93 -
23 = 70W" example, the belief is that there genuinely is a power flow of
93W towards the load, only 70W of which is accepted and 23W is returned.

The other school of thought is that that's not true. The meter may
*read* more "forward power" than is actually being delivered to the
load, but that is a false indication because the instrument is not being
used in the situation for which the power scale was calibrated.
Therefore it is not to be taken at face value - and above all, the
letter "W" on the meter scale does not prove the physical existence of
forward and reflected waves of power.

Every detail about a Bird 43 or similar "directional wattmeter" can be
explained quite simply in terms of travelling waves of voltage and
current. And I do mean every detail - including why a meter that happens
to have been calibrated in "power" will read as it does.

The classic explanation was by Warren Bruene, W5OLY, of the Collins
company. He invented the familiar "Bruene bridge" directional coupler
which samples current through a toroidal transformer, and voltage by a
voltage divider. The principle of the Bird 43 is the same, but the two
separate sampling functions are easier to see in the Bruene bridge.

After a previous incarnation of this debate in 2002, I wrote a 2-page
article which summarised Bruene's original article (from QST, April
1959) and explained the crossover to the Bird sampling technique:
http://www.ifwtech.co.uk/g3sek/in-pr...-of.htm#bruene

An equally good explanation of those same meter readings can be
constructed by regarding the Bruene "bridge" literally as an impedance
bridge. There is no inconsistency between the two approaches - they are
just two different viewpoints looking at the same reality.

On the other hand, we have yet to see an explanation in equivalent
physical detail that is based entirely and exclusively on the viewpoint
of travelling waves of power (with no borrowing from explanations based
on voltage and current).

I am not blaming the Bird Corporation for any of these
misunderstandings. They are simply telling users how to work with the
available "power" markings on the meter scale. The problem is when some
users take them too literally.



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

Current across the antenna loading coil - from scratch
 

Thank you, Ian, for the quick and thorough reply! I look forward to
reading both papers.

73,

Chuck NT3G

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 16:32:22 +0100, Ian White GM3SEK
wrote:

On the other hand, we have yet to see an explanation in equivalent
physical detail that is based entirely and exclusively on the viewpoint
of travelling waves of power (with no borrowing from explanations based
on voltage and current).

Now Ian,

That is like asking us to explain a speedometer without recourse to
the units for distance and time.

73's
Richard Clark, KB7QHC

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 16:32:22 +0100, Ian White GM3SEK
wrote:

One is that if the meter scale says "power", then there genuinely are
forward and reflected traveling waves of power on the line. In the "93 -
23 = 70W" example, the belief is that there genuinely is a power flow of
93W towards the load, only 70W of which is accepted and 23W is returned.

The other school of thought is that that's not true. The meter may
*read* more "forward power" than is actually being delivered to the
load, but that is a false indication because the instrument is not being
used in the situation for which the power scale was calibrated.
Therefore it is not to be taken at face value - and above all, the
letter "W" on the meter scale does not prove the physical existence of
forward and reflected waves of power.

Hi Ian,

This argument sets up the first school for failure that is already
admitted to. Your statement from the second school that:
*read* more "forward power" than is actually being delivered to the
load, but that is a false indication
is already admitted to explicitly from the first school:
93W towards the load, only 70W of which is accepted and 23W is returned.
in that the 70W NOT 93W is the correct indication.

The "second" school has nothing to offer on the subject. The
"because" that attends their "discovery" of this error is specious
logic.

The fact remains that when you subtract 23W from the 93W you do find
70W in the load. The second school would have us believe none of the
numbers correlate to power, and yet the results bear out just the
opposite every day.

The second school needs to stay after class.

73's
Richard Clark, KB7QHC

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
(snip)
W8JI says we are correcting the power factor. Every EE knows that
correcting the power factor involves shifting the phase, i.e.
the coil cannot correct the power factor without providing a phase
shift.

Power factor correction shifts the relative phase of current with
respect to voltage. When talking about a phase shift, you have to be
careful to say what is being shifted relative to what else. There are
lots of possibilities.

A series inductor (a non real, ideal one) with absolutely no phase
shift or magnitude change in the current from one end to the other,
still produces a phase shift of input voltage to output voltage, so
the relative phase of voltage to current at the input is different
compared to the relative phase of voltage to current at the output. I
think this is the power factor correction effect W8JI is referring to.

Any real inductor does this, and also does some other things.

Current across the antenna loading coil - from scratch
 

Ian White GM3SEK wrote:
Now what happens if the load is not exactly 50 ohms?

If the feedline is 50 ohms, what happens is reflected
energy that is easily visible using a TDR, time domain
reflectometer.

One is that if the meter scale says "power", then there genuinely are
forward and reflected traveling waves of power on the line. In the "93 -
23 = 70W" example, the belief is that there genuinely is a power flow of
93W towards the load, only 70W of which is accepted and 23W is returned.

One correction. The Bird wattmeter is installed at a point
on the transmission line and it measures the power at that
point. What is traveling is the energy. Power is the number
of joules per second passing a fixed point. "Power flow" is
somewhat of a misnomer.

The other school of thought is that that's not true. The meter may
*read* more "forward power" than is actually being delivered to the
load, but that is a false indication because the instrument is not being
used in the situation for which the power scale was calibrated.

It certainly is being used in the situation for which it was
calibrated if the Z0 of the transmission line is 50 ohms.

On the other hand, we have yet to see an explanation in equivalent
physical detail that is based entirely and exclusively on the viewpoint
of travelling waves of power ...

Please give up on your misconception. Those are traveling waves
of *ENERGY*. Power is what is measured when traveling energy passes
a fixed point. Perhaps that is your whole point of confusion.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Cecil, W5DXP wrote:
"Any power engineering handbook will tell you what happens to the phase
when the power factor is corrected."

Most industrial loads have a lagging power factor. They represent an
inductive reactance in addition to their resistive loads. Extra energy
must be generated and transmitted just to charge this inductance which
does no work but demands current. Extra loss comes from this reactive
load. This is eliminated by tuning the inductance out with a capacitive
reactance at the load. This is often an overexcited synchronous motor.
When the motor has no mechanical load it is often called a "synchronous
capacitor".

An antenna needs zero reactance too if it is to accept maximum energy
and not make standing waves. Reactance impedes energy to the antenna.
Reactive current also increases loss in the transmission line as it does
in the case of the power utility frequency. So j0 is a goal in many
instances.

Best regards, Richard Harrison, KB5WZI

Current across the antenna loading coil - from scratch
 

Richard Harrison wrote:

Cecil, W5DXP wrote:
"Any power engineering handbook will tell you what happens to the phase
when the power factor is corrected."

Most industrial loads have a lagging power factor. They represent an
inductive reactance in addition to their resistive loads. Extra energy
must be generated and transmitted just to charge this inductance which
does no work but demands current. Extra loss comes from this reactive
load. This is eliminated by tuning the inductance out with a capacitive
reactance at the load.

Yet W8JI would have us believe that power factor correcting capacitor
functions faster than the speed of light, making an instantaneous
phase correction. Sorry, the real world doesn't work that way.

The bottom line is that we cannot shift phase without delaying
something, either voltage or current. Contrary to the presuppositions
of the lumped-circuit model, neither voltage nor current can travel
faster than the speed of light. That means that any phase shifting
of the relative phase angle difference down to zero results in a
delay.

I have seen it explained as "apparently" traveling faster than
light. That's just one more patch on an already flawed mode.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Yes, well, thank you _very_ much indeed, Cecil, for this further
insight into the workings of your mind.

Cheers,
Tom

(In the event that your newsreader is unable to follow threads
directly, please see the header of this message for references to the
message(s) to which it replies.)

Current across the antenna loading coil - from scratch
 

John Popelish wrote:
A series inductor (a non real, ideal one) with absolutely no phase shift
or magnitude change in the current from one end to the other, still
produces a phase shift of input voltage to output voltage, ...

If the voltage is leading the current, and the current
experiences no phase shift through the coil, doesn't that
imply that the voltage must travel faster than light and
indeed jump forward in time to catch up with the phase
of the current?

What does it mean to the E-fields and H-fields to say
the voltage is leading the current?
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 13:39:20 GMT, Cecil Moore
wrote:

What I am officially asking you to do is to cease and desist

Is that you Herr Doktor?

Current across the antenna loading coil - from scratch
 

K7ITM wrote:
Yes, well, thank you _very_ much indeed, Cecil, for this further
insight into the workings of your mind.

If you consider a request for you to honor the netnews
guidelines for attributions a problem, then it's your
problem, not mine. No ethical person would attribute one
person's postings to someone else.

If you don't like that attitude, I suggest you cease and
desist from violating the netnews guidelines for attributions.
I'm going to point it out every time you attribute a posting
from someone else to me or when you attribute one of my
postings to someone else.

When trimming one line attributes the posting to a completely
different person, that is a clear violation.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:

Cecil Moore wrote:
What I am officially asking you to do is to cease and desist

Is that you Herr Doktor?

That's a legal term under Texas law.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 17:49:31 GMT, Cecil Moore
wrote:

Richard Clark wrote:

Cecil Moore wrote:
What I am officially asking you to do is to cease and desist

Is that you Herr Doktor?

That's a legal term under Texas law.

Oh, must be Phil then, Herr Doktor never explains anything.

So, Phil, did you get your JD? Or do you just dress like one?

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 17:43:55 GMT, Cecil Moore
wrote:

When trimming one line attributes the posting to a completely
different person, that is a clear violation.
Is that an RMS Net violation of the superposition of all violations
considererd? If we back up the thread half a wavelength would the
violation be repeated, or would there be a phase issue? What is the
Vf of a violation in your religion?

Current across the antenna loading coil - from scratch
 

Yuri Blanarovich wrote:

Oooops, carefull here.
As far as I know, nobody has claimed that inserted loading coil replaces the
"missing" degrees of the radiator in terms of providing magical properties
that would look like that "replaced" portion of the antenna, or make the
antenna act like 90 degree full size physical radiator.

Agreed, it's not quite stated as such. Here are some statements which
were made:

From your web page http://www.k3bu.us/loadingcoils.htm, in bold type:

"In summary:
The current in a typical loading coil in the shortened antennas drops
across the coil roughly corresponding to the segment of the radiator it
replaces."

By Cecil, on March 5, on this newsgroup:

"A loading coil thread is climaxing over on qrz.com. I have
used EZNEC to generate a graphic which shows a 3/4WL vertical
and a similar 1/2WL vertical with a ~1/4WL loading coil. The
loading coil is a wire helical coil containing (surprise)
roughly 1/4WL of wire. The coil does a good (not perfect)
job of replacing 1/4WL of wire. Many things can be gathered
from observation of the current reported by EZNEC for the
two antennas. The coil occupies roughly the same number
of degrees of the antenna as the wire it replaces. The
current at the top and bottom of the coil is roughly the
same as the current at the two ends of the wire it replaces.
Is the coil an exact replacement? Of course not."

What we are saying that the loading coil appears to replace "missing"
electrical degrees of the radiator in order to make it resonant, that is
back to 90 electrical degrees (has to be in order to resonant), which rest
of the existing "straight" radiator forces it to do (+/-).

It's getting muddier and muddier just what you mean by "replace". Nobody
has questioned that a loading coil makes the antenna resonant; that's
its purpose. But that's simply an impedance transformation property
which can be accomplished well away from the antenna by many different
methods.

Radiation
properties and efficiency of the loaded antenna is proportional to the area
under the current curve. It is obvious to anyone comparing the area under
the current curve of full size quarter wave radiator vs. loaded radiator
that there is huge difference in area under the curve and performance,
efficiency, which is known and been verified by numerous measurements.
HOW the current curve is modified by different loadings and position along
the radiator is important in knowing how the current distribution curve
along the radiator is modified.

I agree with all this. I'm glad you've clarified this for the benefit of
posters like the one to whom my recent posting was directed.

The whole controversy is that "gurus" claim current doesn't drop across the
coil, while we say that it does, therefore making the area under current
curve above the coil smaller and effciency of loaded antenna worse than they
believe and insist on.

I don't think you'll have any trouble winning your arguments against
your imaginary "gurus", whomever and whatever they might be. Over two
years ago I made careful measurements which showed a current difference
between the top and bottom of a loading coil. Cecil posted an EZNEC
model on his web site showing a substantial difference. I've commented
on it several times, explaining the reason for the difference, and
modifying the model to illustrate the explanation.

The controversy is in the explanation of the difference. It simply
doesn't require Cecil's theories. I've never been able to tell exactly
what your theory is, if you indeed have one.

Again, when applied in modeling programs, wrong assumption will produce
erroneous results, which will be magnified in multielement antenna designs.
So the "gurus" basically ignore behavior of coil in the standing wave
environment along the loaded radiator, where the current drops from max at
base to zero at the tip, but coil would magicaly resist that, because, bla,
bla, bla.... (see their "reasons")

Would you name these "gurus" so we can read their postings and see what
you're talking about?

So while everyone knows (?) that standing wave current drops acros (along)
the wire (all the antenna books show that), but it is "impossible" to drop
along the coiled wire (real inductance - coil, loading stub). Reality and
measurments prove that, but according to them "it can't be so".

I am already gathering necessary hardware to do more experiments,
measurements to show what is really happening, and will prepare articles how
to model and apply it to antenna design.
I would challenge the "unbelievers" to join me and repeat the tests, to see
wasaaaap.

You'll be surprised when everyone agrees that there's a current
difference between the top and bottom of the coil. Unless your "gurus"
show up, whomever they are.

I've already made a test and posted the results, over a year ago. When
it failed to show a current difference anywhere near the number of
degrees it "replaced", your complaint was that I was using an inductor
which was too small physically. So obviously your theory works only on
certain size inductors. Once you or Cecil has the theory fully worked
out, it should be able to not only tell us what the current difference
between top and bottom should be, but also how physically large an
inductor must be before the theory works. And why it doesn't work for
physically small inductors.

Those of us stuck with old fashioned conventional theory can explain the
drop for small as well as large coils, so you folks have a bit of
catching up to do.

I think a lot of the experimental work can be done by modeling. I'd be
interested in hearing of any cases where measured results differ
significantly from EZNEC results. Incidentally, your web page is a bit
outdated in that respect, apparently being written before EZNEC v. 4.0
was available with its automated helix creation feature.

Roy Lewallen, W7EL

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:

Cecil Moore wrote:
That's a legal term under Texas law.

Oh, must be Phil then, Herr Doktor never explains anything.

I thought the explanation was obvious. If I am going to
get sued because of false attributions, I need a paper
trail and proof that I objected to those false attributions.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:

Cecil Moore wrote:
When trimming one line attributes the posting to a completely
different person, that is a clear violation.

Is that an RMS Net violation of the superposition of all violations
considererd?

Tsk, tsk, Richard, are you defending false attributions?
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 19:04:18 GMT, Cecil Moore
wrote:

Richard Clark wrote:

Cecil Moore wrote:
When trimming one line attributes the posting to a completely
different person, that is a clear violation.

Is that an RMS Net violation of the superposition of all violations
considererd?

Tsk, tsk, Richard, are you defending false attributions?

Tsk Tsk? to what accuracy ±59%?

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 19:02:56 GMT, Cecil Moore
wrote:

Richard Clark wrote:

Cecil Moore wrote:
That's a legal term under Texas law.

Oh, must be Phil then, Herr Doktor never explains anything.

I thought the explanation was obvious. If I am going to
get sued because of false attributions, I need a paper
trail and proof that I objected to those false attributions.

Paper trail? Phil, push over those stacks of "research" and fire up
the Xerox!

Current across the antenna loading coil - from scratch
 

Roy Lewallen wrote:
Agreed, it's not quite stated as such. Here are some statements which
were made:

From your web page http://www.k3bu.us/loadingcoils.htm, in bold type:

"In summary:
The current in a typical loading coil in the shortened antennas drops
across the coil roughly corresponding to the segment of the radiator it
replaces."

By Cecil, on March 5, on this newsgroup:
The coil occupies roughly the same number
of degrees of the antenna as the wire it replaces.

Roy, maybe you need to learn the definition of "roughly".
It is certainly not "exactly" as you are clutching at straws
to imply. Why you need to change the definitions of words
is obvious from your flawed arguments. Exactly what is
it about "roughly" that you don't understand?

It's getting muddier and muddier just what you mean by "replace".

That meaning has never been in doubt. "Replace" has always
meant bringing the necessary signals back into phase so the
feedpoint impedance is purely resistive. You know perfectly
well that it has never been about physical length or radiation.
Those are just another two of your straw men. Your attempt
to muddy those waters has been going on for years including
your attempt to discredit the distributed network model in
favor of the lumped circuit model. Hint: The distributed
network model is a superset of the lumped circuit model.
If you succeed in discrediting the distributed network
model, you have automatically succeeded in discrediting
the lumped circuit model. It's a lose-lose proposition
for you.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:
Paper trail? Phil, push over those stacks of "research" and fire up
the Xerox!

I am indeed printing out the postings just in case the false
attributions result in a lawsuit against me. I can't afford
not to be careful.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 19:24:27 GMT, Cecil Moore
wrote:

Richard Clark wrote:
Paper trail? Phil, push over those stacks of "research" and fire up
the Xerox!

I am indeed printing out the postings just in case the false
attributions result in a lawsuit against me. I can't afford
not to be careful.

But you CAN afford to be paranoid? What a WUSS!

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:
But you CAN afford to be paranoid? What a WUSS!

It doesn't cost anything to be paranoid. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:


Roy, maybe you need to learn the definition of "roughly".
It is certainly not "exactly" as you are clutching at straws
to imply. Why you need to change the definitions of words
is obvious from your flawed arguments. Exactly what is
it about "roughly" that you don't understand?

Cecil,

Is 10 degrees of phase shift "roughly" equal to 75 degrees of phase
shift? I don't think anyone is trying to nit-pick the numbers to a
precision of several significant figures. A multiple of greater than 7
would seem to be just a bit outside the scope of "roughly".

73,
Gene
W4SZ

Current across the antenna loading coil - from scratch
 

Ian White GM3SEK wrote:

Ian, I am leaving on a 6 state motorcycle trip and won't be
back until Monday. I would like for you to answer this
question while I am gone.

I've heard that, while operating portable, if I attach
a wire to my 75m mobile whip and run it up a tree, I
will be able to make more contacts. So I attach a 1/4WL
wire to the whip of my 75m mobile bugcatcher system.

I decide to measure the current "into" the bottom of the
coil and "out" of the top of the coil. To my utter amazement
I measure 1.3 amps flowing "into" the bottom of the coil and
2.1 amps flowing "out" of the top of the coil.

How does your lumped circuit theory explain that? Where is
that extra 0.8 amps of current coming from?

Please don't insult our intelligence by saying it cannot
happen. It does happen. I suspect you are at a loss to
explain it.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Gene Fuller wrote:
Is 10 degrees of phase shift "roughly" equal to 75 degrees of phase
shift?

Of course not. The 10 degrees of phase shift has already been
proven to be wrong because of reflections within the coil.
Why do you insist on bringing up old invalid data?

Please note that *nobody* is alleging that the phase shift
through a 75m bugcatcher coil is 75 degrees. That is just
another one of your straw men.

Now why don't you become a rational, ethical person and
suggest a valid way of measuring the phase shift through
a coil? Can you improve on my suggestion of yesterday?
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
Ian White GM3SEK wrote:
Now what happens if the load is not exactly 50 ohms?

If the feedline is 50 ohms, what happens is reflected
energy that is easily visible using a TDR, time domain
reflectometer.

One is that if the meter scale says "power", then there genuinely
are forward and reflected traveling waves of power on the line. In the
"93 - 23 = 70W" example, the belief is that there genuinely is a
power flow of 93W towards the load, only 70W of which is accepted and
23W is returned.

One correction. The Bird wattmeter is installed at a point
on the transmission line and it measures the power at that
point. What is traveling is the energy. Power is the number
of joules per second passing a fixed point. "Power flow" is
somewhat of a misnomer.

Sorry, you're right about "power flow". What I meant was a forward
travelling wave carrying 93W towards the load.


The other school of thought is that that's not true. The meter may
*read* more "forward power" than is actually being delivered to the
load, but that is a false indication because the instrument is not
being used in the situation for which the power scale was calibrated.

It certainly is being used in the situation for which it was
calibrated if the Z0 of the transmission line is 50 ohms.

I'm not sure which "transmission line" you meant here, but I don't think
it matters anyway.

The inserts are individually calibrated with a 50 ohm load impedance
connected to the "Antenna" socket. The internal pot is adjusted to give
the correct power reading (at one point on a meter scale that is
pre-printed), and then the insert is reversed and a tab is bent to
adjust the capacitive coupling to give the lowest possible reading.
There may be some interaction requiring the two adjustments to be
repeated, I don't know.

If you meant the transmission line outside of the instrument, the
calibration load may or may not include a length of matched 50 ohm
transmission line - it doesn't matter. Inside the instrument, the
characteristic impedance of the internal line is 50 ohms in order to
avoid introducing an impedance bump into a system that is already
matched, but even with say a 57 ohm internal line, the Bird insert could
be set up to indicate power correctly into a 50 ohm load. The only
difference is that the performance would become frequency-sensitive.


On the other hand, we have yet to see an explanation in equivalent
physical detail that is based entirely and exclusively on the
viewpoint of travelling waves of power ...

Please give up on your misconception. Those are traveling waves
of *ENERGY*. Power is what is measured when traveling energy passes
a fixed point. Perhaps that is your whole point of confusion.

You're right, they would indeed be travelling waves of energy rather
than power. But otherwise the same challenge is still out the if
forward and reflected travelling waves of energy exist, we would expect
to see a detailed explanation of how the Bird or any similar instrument
interacts with such waves as distinct from the explanations that we
already have for travelling waves of voltage and current.


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

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
Ian White GM3SEK wrote:

Ian, I am leaving on a 6 state motorcycle trip and won't be
back until Monday. I would like for you to answer this
question while I am gone.

I've heard that, while operating portable, if I attach
a wire to my 75m mobile whip and run it up a tree, I
will be able to make more contacts. So I attach a 1/4WL
wire to the whip of my 75m mobile bugcatcher system.

I decide to measure the current "into" the bottom of the
coil and "out" of the top of the coil. To my utter amazement
I measure 1.3 amps flowing "into" the bottom of the coil and
2.1 amps flowing "out" of the top of the coil.

How does your lumped circuit theory explain that? Where is
that extra 0.8 amps of current coming from?

Please don't insult our intelligence by saying it cannot
happen. It does happen. I suspect you are at a loss to
explain it.

I do not expect equal currents at the top and bottom of any real-life
coil. That is a strawman argument, based on what *you* claim other
people are saying.

But you can make coils that come quite close to behaving like an ideal
lumped inductance. And the closer they are, the closer to equal I expect
the currents at the two ends to become, and the closer to zero I expect
the phase shift in current to be... because that is how pure inductance
behaves, with no exceptions due to "special situations".


Cecil, in all sincerity, have a good trip and please drive safely. I'd
have been much safer on the roads last weekend if I hadn't been thinking
about this stuff as well.



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

Current across the antenna loading coil - from scratch
 

On Wed, 12 Apr 2006 19:55:08 GMT, Cecil Moore
wrote:

Richard Clark wrote:
But you CAN afford to be paranoid? What a WUSS!

It doesn't cost anything to be paranoid. :-)

You must have a Xerox bulk copy rate.

Current across the antenna loading coil - from scratch
 

Cecil,

I will retain the entire message below, so that I am not accused of
misattribution.

Where did you get this idea that the velocity factor is constant?
Specifically, why is the velocity factor of a resonant coil the same as
the velocity factor of a significantly shorter coil? It is pretty well
accepted that the inductance of coils does not scale linearly with the
length of the coil. Therefore any arguments about based on direct
calculation of Vf from L and C would seem to fail to support your model.

I can think of two possibilities.

The first is that you treat this entire problem as a transmission line.
Most people would accept that the velocity factor for 200 feet of RG8 is
indeed the same as the velocity factor for 100 feet of the same cable.

However, the velocity factor appears to be the crux of your latest
argument about the behavior of a loading coil. It is not exactly
acceptable technique to include the desired answer as part of the proof.


The other possibility is that you are taking the lead from one of the
Corum papers. In particular, I am referring to the paper labeled:

"TELSIKS 2001, University of Nis, Yugoslavia (September 19-21, 2001) and
MICROWAVE REVIEW"

If so, I suggest you go back and reread what was written. He
specifically says (page 4, left column) that the equations for velocity
factor that show Vf as a function of diameter, spacing, and wavelength
apply only at resonance. The exact words a

" . . . an approximation for M has been determined by Kandoian and
Sichak which is appropriate **for quarter-wave resonance** and is valid
for helices . . ."

The emphasis on quarter-wave resonance was in the original; I did not
change a thing. The remainder of the paper clearly indicates that he is
talking about coils near or at resonance. There is no extension of the
Vf equations to short non-resonant coils. Indeed, he comments several
times that his model smoothly joins with the lumped circuit model for
smaller coils. That would require a non-constant Vf.

You attempt at decomposition of a resonant coil into smaller
subcomponents simply fails.

This is not an "ignorant diversion". If you have a third method of
supporting your claim of constant Vf, let's hear it.

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

Cecil Moore wrote:

Gene Fuller wrote:

So you think adding turns to a coil is a nice linear process that
allows you to then subdivide the resonance effects according the
number of turns in each subsection?


That appears to me to be the most valid measurement that we
can make of the delay through a coil. If you have a better
way, please present it.


C'mon, you know as well as anybody that inductance of a coil tends to
increase as n-squared. Yes, there are all kinds of special cases and
correction factors.


Increasing the length of a coil or transmission line doesn't
change its velocity factor at a fixed frequency.

Adding turns and then pretending everything is nice and linear,
thereby allowing decomposition into subcomponents, is just plain silly.


Velocity factor is *nice* and linear, i.e. it is constant.

Please stop these diversions. I'm sure you are not that ignorant.

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
Richard Clark wrote:

Paper trail? Phil, push over those stacks of "research" and fire up
the Xerox!


I am indeed printing out the postings just in case the false
attributions result in a lawsuit against me. I can't afford
not to be careful.

Cecil, no one but a madman would ever sue you for anything.
Your presence alone would wreck any legal proceeding even
in a state as idiosyncratic as Texas.
73,
Tom Donaly, KA6RUH

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
John Popelish wrote:

A series inductor (a non real, ideal one) with absolutely no phase
shift or magnitude change in the current from one end to the other,
still produces a phase shift of input voltage to output voltage, ...


If the voltage is leading the current, and the current
experiences no phase shift through the coil, doesn't that
imply that the voltage must travel faster than light and
indeed jump forward in time to catch up with the phase
of the current?

What does it mean to the E-fields and H-fields to say
the voltage is leading the current?

It means that the current at both ends of the coil was delayed
(relative to its phase if the coil had not been there). It means that
there was a voltage difference across the ends of the coil that drove
that current through the coil.

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
Gene Fuller wrote:

Is 10 degrees of phase shift "roughly" equal to 75 degrees of phase
shift?


Of course not. The 10 degrees of phase shift has already been
proven to be wrong because of reflections within the coil.
Why do you insist on bringing up old invalid data?

Please note that *nobody* is alleging that the phase shift
through a 75m bugcatcher coil is 75 degrees. That is just
another one of your straw men.

Now why don't you become a rational, ethical person and
suggest a valid way of measuring the phase shift through
a coil? Can you improve on my suggestion of yesterday?

Cecil,

You spent a lot of time developing the "10 degree" model for the
bugcatcher coil. When and how did it get proven wrong? The only thing I
can recall is that you said it did not make sense technically, and
therefore it must be wrong. Recently you launched into this business
about adding turns to make the coil resonant. As I just explained, I
believe that approach is total nonsense.

You keep referring everyone to the now famous gif image on your web
page. The question becomes why is EZNEC correct in supporting your
position at some times and incorrect when it does not support your
position at other times?

73,
Gene
W4SZ

Current across the antenna loading coil - from scratch
 

Ian White GM3SEK wrote:
Cecil, in all sincerity, have a good trip and please drive safely. I'd
have been much safer on the roads last weekend if I hadn't been thinking
about this stuff as well.

Sincerely, Ian, how do you explain one amp on the source side of
a coil and two amps on the whip side of a coil? Nothing in your
response even came close to answering that question.

If you are dedicated to technical correctness, your evasion
of this technically simple question is perplexing.

How is it possible to have one amp "flowing into" the bottom
of a coil and two amps "flowing out" of the top of the coil?
If you really believe that one amp is flowing from the earth
ground to the coil through displacement current, please just
say so.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:

Cecil Moore wrote:
It doesn't cost anything to be paranoid. :-)

You must have a Xerox bulk copy rate.

I got a free printer with my new Dell computer.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Like I posted earlier today, Tom, all of this provides an interesting
window into Cecil's mind.

Imagine my reaction when I read today's (2006-04-12) edition of the
Lola comic strip: http://www.comics.com/comics/lola/index.html

Cheers,
Tom

Current across the antenna loading coil - from scratch
 

Gene Fuller wrote:
I will retain the entire message below, so that I am not accused of
misattribution.

Gene, to the best of my knowledge, you have never
misattributed anything.

Where did you get this idea that the velocity factor is constant?

The equation for velocity factor includes coil diameter,
turns per inch, and wavelength. Keeping the coil diameter
constant, the turns per inch constant, and the wavelength
constant should ensure that the velocity factor is constant.

Specifically, why is the velocity factor of a resonant coil the same as
the velocity factor of a significantly shorter coil? It is pretty well
accepted that the inductance of coils does not scale linearly with the
length of the coil. Therefore any arguments about based on direct
calculation of Vf from L and C would seem to fail to support your model.

You are obviously mistaken. If you increase the L by lengthening
the coil, you have also increased the C by the same percentage.
The L and C for any unit length are the same no matter how long
the coil or transmission line is.

" . . . an approximation for M has been determined by Kandoian and
Sichak which is appropriate **for quarter-wave resonance** and is valid
for helices . . ."

Yes, but if one doesn't change the frequency or the diameter or
the turns per inch, the approximation should hold since nothing
in the VF equation changes by shortening the coil. One should be
able to shorten or lengthen the coil andmaintain the same VF.

Seems it is up to you to prove what you are saying. Please prove
that the ratio of L to C ratio of a coil changes with length. That
should be an interesting proof.
--
73, Cecil http://www.qsl.net/w5dxp