Current across the antenna loading coil - from scratch
 

"Roy Lewallen" wrote:
I'm afraid that the proponents of the alternative theories aren't
subject to either modeling or measurement results. There's already ample
theoretical, modeling, and measurement evidence to show that the theory
is faulty; further efforts would be a waste of time.

Roy, it is you who are ignoring the results of EZNEC. EZNEC proves
that one cannot use standing wave current phase to measure the phase
shift through a wire, much less through a coil. To see why, take a look at:

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

The standing wave current is absolutely FLAT. It cannot be used for
any valid measurement.
--
73, Cecil, W5DXP

Current across the antenna loading coil - from scratch
 

"Yuri Blanarovich" wrote:
Otherwise, I think we have reached point, when it is pointless to go
around
in circles and argue that what IS, CAN'T BE, because.....

Yuri, I think it is obvious that some people are suffering from
misconceptions.

The misconception that the "experts" are suffering from has *nothing* to do
with coils. That's the reason the coil discussion has gone in circles. There
may not be anything wrong with the coil concepts.

The misconception is about standing wave current VS traveling wave current.
The "experts" have asserted that "current is current" and that standing wave
current is the same as traveling wave current even though they have
different
equations. Even EZNEC recognizes the difference between standing wave
current and traveling wave current. I took a quarter wavelength of wire and
drove it as a standing wave wire and as a traveling wave wire. The piece
of wire was identical in both cases. I've posted the EZNEC results a
number of times and none of the "experts" have responded. Here they are
again: The corresponding EZNEC files are available at:

http://www.qsl.net/w5dxp/TravWave.EZ I(x,t)=Io*cos(kx+wt)
http://www.qsl.net/w5dxp/StndWave.EZ I(x,t)==Io*cos(kx)*cos(wt)

% along current in current in
wire #2 TravWave.EZ StndWave.EZ

0.28% 0.9998 at -0.99 deg 0.9996 at 0 deg
9.72% 0.9983 at -9.39 deg 0.9843 at -0.03 deg
19.7% 0.9969 at -18.23 deg 0.9454 at -0.05 deg
30.3% 0.9957 at -27.59 deg 0.8843 at -0.06 deg
39.7% 0.9949 at -35.96 deg 0.8023 at -0.08 deg
49.7% 0.9945 at -44.84 deg 0.7014 at -0.09 deg
60.3% 0.9945 at -54.20 deg 0.5840 at -0.09 deg
69.7% 0.9949 at -62.58 deg 0.4528 at -0.10 deg
79.7% 0.9956 at -71.43 deg 0.3110 at -0.11 deg
89.7% 0.9965 at -80.27 deg 0.1616 at -0.11 deg
99.7% 0.9976 at -89.14 deg 0.0061 at -0.11 deg

These values reported by EZNEC are graphed at:

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

Their differences are obvious. One might even argue that they are
opposites. The traveling wave magnitude looks like the standing
wave phase. The traveling wave phase looks like the standing
wave magnitude. That fits perfectly with Gene Fuller's assertion
that there is no phase information in standing wave current phase.
The only phase information in the standing wave current is in the
magnitude. Once the "experts" realize that is the source of their
misconception, everything will fall into place.

Again, it is NOT about coils. It is all about misconceptions
involving standing wave current.
--
73, Cecil, W5DXP

Current across the antenna loading coil - from scratch
 

"Reg Edwards" wrote:
I fail to see what you are all arguing about.

Here's the argument in a nutshell, Reg.

Can standing wave current phase be used to determine the
phase shift through a coil (or through a wire)?

Some of us say, No. Some of the "experts" say, Yes, but
so far have failed to explain how or why that is a valid
measurement technique.
--
73, Cecil, W5DXP

Current across the antenna loading coil - from scratch
 

Yuri Blanarovich wrote:
A pure inductance would have no current difference at each end. A good
compact inductor would have negligible current difference at each end,
only a long straight wire would act like the "missing antenna".

More BS, insisting on non-reality.

No, it is factual. No need to call names or get angry.

It is the stray capacitance from the inductor to the outside world that
allows any difference in current. Not the standing waves, not the
missing area of antenna.

I can have a fixed antenna and with no change other than the style of
coil have anything from nearly immeasurable differences to large
differences.

For example if the coil is a very large area single turn, it will
behave almost like the "missing degrees" you talk about. If it is a
compact inductor and has low capacitance to the outside world compared
to the antenna above the coil, it will have very little current
difference.

One way to prove the coil does not replace missing length is to simply
move the coil to a new location in a fixed height antenna. If the coil
looked like 40 degrees, it would resonate the antenna no matter where
it was installed.

WRONG, read below, it's the required inductance/impedance and fixed
"missing" degrees that need replacement.

As we go deeper into the discussion and "arguments" from "unbelievers" and
thanks to NM5K posting, about how fixed coil acts different, replaces
different amount of degrees, it hit me that the reason is the impedance
presented by the antenna (the straight part) radiator at the coil insertion
point. Using just as example, radiator having 90 degrees at the resonance,
with 50 degrees of whip and coil "replacing" 40 degrees in the said example
from the book.

What NM5K posting is that?

A coil is a coil. It doesn't know where you are using it. You teminate
it with a certain impedance, it operates the same way.

You can call it "40 degrees" or anything you like, but you better not
think it acts like that missing antenna area so far as phase shift or
current difference between ends. It doesn't act that way.

If it DID act the way you seem to be saying, a base loaded antenna
would be a terrible antenna. Yet over a good groundplane with a
reasonable inductor design, they can be very good.

You agree that impedance along the radiator changes, being low at the
bottom, around tens of ohms, to being high at the top, around thousands of
ohms.

I never said that. What do you mean by reactance? The X can be very
high but radiation resistance very low even near the open end.

Now you place the loading coil along the radiator, one extreme being
at the bottom, low impedance point - we know in order to maintain the
resonance of say 13 ft high (long) radiator (90 electrical degrees at
RESONANCE) the coil has a fewer turns, it's impedance is lower (as required
by the lower impedance at the bottom end of the antenna), and current drop
would relatively be small as W7EL proved and everybody knows.

So you admit your "my coil replaces 40 degrees" doesn't work? Or what
are you saying?

Now you move that coil say half way up the must, to higher impedance point
at the antenna, and that coil now, in order to maintain the "match" has to
have higher impedance, more turns and will exhibit MORE current drop across
it, while replacing THE SAME NUMBER OF "missing" DEGREES AT THE RADIATOR.

So the " 40 degrees" is just a meaningless number. It doesn't mean
anything so far as the coil goes. I'll go along with that.

Assuming that our goal is to stay with the same physical length of the whip
(which we do) and maintaining 90 degrees of resonant radiator. So the
radiator stays 50 degrees ()+50, 10+40, 20+30, 30+20, 40 + 10) long and coil
replaces the same "missing" 40 degrees.

As long as we both agree it does not have anywhere near the same amount
of current difference from start to finish the same length of antenna
would have, I agree.

If you are claiming the current difference at each end of the coil
relates to electrical degrees it "replaces" and not capacitance from
the coil to the outside world, I disagree.

Same if you move the coil higher, higher antenna impedance point, more turns
(inductance) required, more current drop exhibited, coil "replacing" THE
SAME NUMBER OF 40 DEGREES. It needs more turns, but again, the coil's
behavior is dictated by the impedance of the RADIATOR (standing waves) at
the insertion point, dictating the inductance, number of turns of the coil
in order to maintain the number of degrees, in order to maintain the
resonance (90 degrees) of the radiator.

The only reason why the inductor could have more "current drop" (what a
concept! current doesn't drop.) is because displacement current from
capacitance can be a larger portion of load impedance. The coil, in
effect, it acting a bit like a tiny "hat" and robbingh the whip above
the coil of current. Some displacement current branches off to the
world around the coil, leaving less to travel upwards.

In order to "overturn" this "Yuri's Theory" you would have to deny that
resonant antenna has varying current across its radiator (wire) - to deny
that current drops from the base to the tip.

I'm not sure what you are saying there.

You would have to deny that coil in the RF circuit has varying impedance
dependant on the number of turns and inductance and frequency.
Deny that in order to maintain the resonant frequency of shortened radiator
of the same physical length, you need to use coils of varying amount of
turns depending on its insertion point along the radiator (less on the
bottom, more closer to the top).
That behavior of the coil is "FORCED" by the remaining "wires" in the
radiator, in standing wave environment as Cecil is trying to get through
with help of Kraus and others.

You are free to think what you like, but I don't think Kraus is helping
Cecil. While a properly done use of standing waves would work, my
opinion is Cecil just has a fixation on it and is trying to change the
behavior of the system to match his misapplication of standing waves to
the coil.

I can take the VERY SAME radiator, make no change in coil location at
all, and change the current ratio at the start of the inductor and end
of the inductor ONLY by changing inductor design. This is with the
antenna operated on one frequency, with one coil location, and with the
feedpoint at X=0 (resonance).

If your theory about standing waves or the "40 degree replacement"
theory is correct, I sould not be able to do that. Yet I can.

I can build a loading coil that has almost no current difference across
the length, change nothing else but the coil, and wind up with almost
anything I like for current difference.

The reason that happens is displacement current and the fields around
the coil. It is not a function of standing waves or the "missing area"
the coil replaces.

It takes a lot less than three years of name calling and arguing to
measure it, assuming people can channel their energy into doing
something besides running around talking about people or arguing.

73 Tom

Current across the antenna loading coil - from scratch
 

Yuri Blanarovich wrote:
A pure inductance would have no current difference at each end. A good
compact inductor would have negligible current difference at each end,
only a long straight wire would act like the "missing antenna".

More BS, insisting on non-reality.

No, it is factual. No need to call names or get angry.

It is the stray capacitance from the inductor to the outside world that
allows any difference in current. Not the standing waves, not the
missing area of antenna.

I can have a fixed antenna and with no change other than the style of
coil have anything from nearly immeasurable differences to large
differences.

For example if the coil is a very large area single turn, it will
behave almost like the "missing degrees" you talk about. If it is a
compact inductor and has low capacitance to the outside world compared
to the antenna above the coil, it will have very little current
difference.

One way to prove the coil does not replace missing length is to simply
move the coil to a new location in a fixed height antenna. If the coil
looked like 40 degrees, it would resonate the antenna no matter where
it was installed.

WRONG, read below, it's the required inductance/impedance and fixed
"missing" degrees that need replacement.

As we go deeper into the discussion and "arguments" from "unbelievers" and
thanks to NM5K posting, about how fixed coil acts different, replaces
different amount of degrees, it hit me that the reason is the impedance
presented by the antenna (the straight part) radiator at the coil insertion
point. Using just as example, radiator having 90 degrees at the resonance,
with 50 degrees of whip and coil "replacing" 40 degrees in the said example
from the book.

What NM5K posting is that?

A coil is a coil. It doesn't know where you are using it. You teminate
it with a certain impedance, it operates the same way.

You can call it "40 degrees" or anything you like, but you better not
think it acts like that missing antenna area so far as phase shift or
current difference between ends. It doesn't act that way.

If it DID act the way you seem to be saying, a base loaded antenna
would be a terrible antenna. Yet over a good groundplane with a
reasonable inductor design, they can be very good.

You agree that impedance along the radiator changes, being low at the
bottom, around tens of ohms, to being high at the top, around thousands of
ohms.

I never said that. What do you mean by reactance? The X can be very
high but radiation resistance very low even near the open end.

Now you place the loading coil along the radiator, one extreme being
at the bottom, low impedance point - we know in order to maintain the
resonance of say 13 ft high (long) radiator (90 electrical degrees at
RESONANCE) the coil has a fewer turns, it's impedance is lower (as required
by the lower impedance at the bottom end of the antenna), and current drop
would relatively be small as W7EL proved and everybody knows.

So you admit your "my coil replaces 40 degrees" doesn't work? Or what
are you saying?

Now you move that coil say half way up the must, to higher impedance point
at the antenna, and that coil now, in order to maintain the "match" has to
have higher impedance, more turns and will exhibit MORE current drop across
it, while replacing THE SAME NUMBER OF "missing" DEGREES AT THE RADIATOR.

So the " 40 degrees" is just a meaningless number. It doesn't mean
anything so far as the coil goes. I'll go along with that.

Assuming that our goal is to stay with the same physical length of the whip
(which we do) and maintaining 90 degrees of resonant radiator. So the
radiator stays 50 degrees ()+50, 10+40, 20+30, 30+20, 40 + 10) long and coil
replaces the same "missing" 40 degrees.

As long as we both agree it does not have anywhere near the same amount
of current difference from start to finish the same length of antenna
would have, I agree.

If you are claiming the current difference at each end of the coil
relates to electrical degrees it "replaces" and not capacitance from
the coil to the outside world, I disagree.

Same if you move the coil higher, higher antenna impedance point, more turns
(inductance) required, more current drop exhibited, coil "replacing" THE
SAME NUMBER OF 40 DEGREES. It needs more turns, but again, the coil's
behavior is dictated by the impedance of the RADIATOR (standing waves) at
the insertion point, dictating the inductance, number of turns of the coil
in order to maintain the number of degrees, in order to maintain the
resonance (90 degrees) of the radiator.

The only reason why the inductor could have more "current drop" (what a
concept! current doesn't drop.) is because displacement current from
capacitance can be a larger portion of load impedance. The coil, in
effect, it acting a bit like a tiny "hat" and robbingh the whip above
the coil of current. Some displacement current branches off to the
world around the coil, leaving less to travel upwards.

In order to "overturn" this "Yuri's Theory" you would have to deny that
resonant antenna has varying current across its radiator (wire) - to deny
that current drops from the base to the tip.

I'm not sure what you are saying there.

You would have to deny that coil in the RF circuit has varying impedance
dependant on the number of turns and inductance and frequency.
Deny that in order to maintain the resonant frequency of shortened radiator
of the same physical length, you need to use coils of varying amount of
turns depending on its insertion point along the radiator (less on the
bottom, more closer to the top).
That behavior of the coil is "FORCED" by the remaining "wires" in the
radiator, in standing wave environment as Cecil is trying to get through
with help of Kraus and others.

You are free to think what you like, but I don't think Kraus is helping
Cecil. While a properly done use of standing waves would work, my
opinion is Cecil just has a fixation on it and is trying to change the
behavior of the system to match his misapplication of standing waves to
the coil.

I can take the VERY SAME radiator, make no change in coil location at
all, and change the current ratio at the start of the inductor and end
of the inductor ONLY by changing inductor design. This is with the
antenna operated on one frequency, with one coil location, and with the
feedpoint at X=0 (resonance).

If your theory about standing waves or the "40 degree replacement"
theory is correct, I sould not be able to do that. Yet I can.

I can build a loading coil that has almost no current difference across
the length, change nothing else but the coil, and wind up with almost
anything I like for current difference.

The reason that happens is displacement current and the fields around
the coil. It is not a function of standing waves or the "missing area"
the coil replaces.

It takes a lot less than three years of name calling and arguing to
measure it, assuming people can channel their energy into doing
something besides running around talking about people or arguing.

73 Tom

Current across the antenna loading coil - from scratch
 

"Cecil Moore" wrote
Can standing wave current phase be used to determine the
phase shift through a coil (or through a wire)?

=======================================
Cec and Co.

I couldn't care two hoots about standing waves, whatever they are. As
described in this newsgroup it's all just just a load of nonsense.

KISS. And forget all about SWR.
----
Reg.

Current across the antenna loading coil - from scratch
 

"Reg Edwards" wrote:
I couldn't care two hoots about standing waves, whatever they are.

The "experts" have that same problem, Reg, yet they are using
standing wave current phase to try to measure phase shift
through a coil, a known invalid approach since standing wave
current phase doesn't contain any phase information.
--
73, Cecil, W5DXP

Current across the antenna loading coil - from scratch
 

wrote:
It is the stray capacitance from the inductor to the outside world that
allows any difference in current. Not the standing waves, not the
missing area of antenna.

You are using standing wave current to try to prove your concepts
are valid. If you don't take time to understand standing wave current,
you will never correct those misconceptions.

Standing wave current phase contains no phase information. Therefore,
standing wave current phase cannot be used to measure the phase shift
through a wire or a coil.

The only phase information in a standing wave current is in the
magnitude which roughly follows a cosine function distorted by
the fields in the loading coil.

If the current at the bottom of the coil is 1.0 amps and the current
at the top of the coil is 0.7 amps, the phase shift through the coil
is *roughly* arc-cos(0.7) = ~45 degrees. As Gene Fuller says,
there's no phase information in standing wave current phase.
All the phase information is embedded in the magnitude. That's
easy to see from the I(x,t) = Io*cos(kx)*cos(wt) equation for
standing wave current.

It's also easy to see from: http://www.qsl.net/w5dxp/travstnd.GIF
plotted from EZNEC data.
--
73, Cecil, W5DXP

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:
I've posted the EZNEC results a
number of times and none of the "experts" have responded.

Cecil,

I wonder why?

Fool me once, shame on you.

Fool me twice, shame on me.

Fool me thrice, what an idiot I must be.

73,
Gene
W4SZ

Current across the antenna loading coil - from scratch
 

Cecil Moore wrote:


The misconception is about standing wave current VS traveling wave current.
The "experts" have asserted that "current is current" and that standing wave
current is the same as traveling wave current even though they have
different equations.


Cecil,

So how is your study of the NEC documents going?

I learn something new every time I plow through the mathematical
discussion. I find current discussed on almost every page, but I am
still searching for the part that discusses standing waves and traveling
waves. If you could help me find that section it would be appreciated.

73,
Gene
W4SZ