Cecil wrote,

The Flat Earth Society just cannot accept the fact that there can be one
amp of current at one end of the coil and zero amps at the other end, just
like a piece of transmission line. Never mind that the coil is on top of
a mobile antenna and the current at the very top has no place to go.
--
73, Cecil http://www.qsl.net/w5dxp


What's that you said about ad hominem attacks, Cecil? I'm still waiting
for Yuri to make his far-out-outtasite-wow! mobile antenna based on the
results he gets from measuring coils with fish tank thermometers.
As for your ideas about current, they're just another example of someone
being led astray by the reification of abstract words and don't really account
for much.
You often use the
technique of telling other people what they believe, Cecil, in order, I
suppose,
to get them so embroiled in trying to explain what they do believe that the
original argument is obscured. This is what you've done in the above posting.
If you have to sink to misrepresenting other people's ideas in order to "win"
your argument, you've actually admitted that you've lost.
73,
Tom Donaly, KA6RUH

Yuri Blanarovich wrote:

Jim Kelley proclaimed:

It began when you
claimed more current goes into one end of an inductor than comes out the
other end. That notion is utterly without merit.


Aaaah, Flat Earth Society demonstrating their "knowledge".
Look at www.K3BU.us at pictures of RF ammeters SHOWING reality.
Not good enough? Keep harping, the eggs on your faces are getting bigger and
bigger.

Yuri

Yuri,

I think you're missing the point - just as Cecil is. You seem to have
forgotten that I agree with the idea that there is a current gradient
across these inductors - just as there is a current gradient along any
quarter wavelength of transmission line with standing waves. That
doesn't mean there's more current "going in one end" than is "coming out
of the other end." It's a sophomoric notion. Do you wanna be a
simpleton? You're almost there with this nonsense. Why do you want to
screw up a valid idea by attaching a ridiculous one to it?

73, Jim AC6XG

Yuri,

I think you're missing the point - just as Cecil is. You seem to have
forgotten that I agree with the idea that there is a current gradient
across these inductors - just as there is a current gradient along any
quarter wavelength of transmission line with standing waves. That
doesn't mean there's more current "going in one end" than is "coming out
of the other end." It's a sophomoric notion. Do you wanna be a
simpleton? You're almost there with this nonsense. Why do you want to
screw up a valid idea by attaching a ridiculous one to it?

73, Jim AC6XG



OK, so it is more current "coming out in one end", than is "coming in at the
other end"?
Is this what IS is?
The argument was "virtually same" vs. "different" (gradient, more at one end
than the other, etc.)
Are we taking off on tangents to muddy the waters?
I am almost done with cleaning the "lab", wx is warming up, I will soon get
out, do more tests and finish the article.
More articles I see in publications, more perpetuation of the wrong picture and
idea that current is the same in loading coils. Even QEX and new Antenna Book
keep on misleading.


Yuri, K3BU/m

Cecil, W5DXP wrote:
"The Flat Earth Society just cannot accept the fact that there can be
one amp of current at one end of a coil and zero amps at the other end,
just like a piece of transmission line."

What causes one amp of current at one end of a coil and zero amps at the
other end of the coil?

It is reflection. When an incident wave meets a discontinuity which
can`t take all the voltage or current contained in the incident wave,
the surplus voltage or current is reflected back toward the source by
the mismatched load.

At a point we might call "P" somewhere along an antenna wire, the
incident wave required a period of time, we might express in electrical
degrees, to reach "P" from the generator.

At the same point "P", the reflected wave takes longer to arrive as it
traveled past "P" to reach the reflection point, then it traveled back
to "P".

Further, either the voltage or current associated with the reflected
wave is delayed by an additional 180-degrees.

If the load impedance is too low to accept all the voltage in the
incident wave, the current is reversed without additional delay, but
there is a reversal in the phase of the reflected voltage. This can be
recalled by the fact that with a complete short, equal but opposite
volts cancel making zero volts across a short.

If the load impedance is too high to accept all the current in the
incident wave, the voltage is reversed without additional delay but
there is a reversal in phase of the reflected current.

At a discontinuity there is a phase reversal of either reflected volts
or amps, but not a reversal of phase in both.

At the open-circuits at the ends of a simple dipole antenna, nearly all
the incident current runs out of wire and has nowhere to go except
toward the generator that it came from.

To go to zero, the reflected current must equal the incident current but
it is traveling in the reversed direction.

The cancellation of current requires H-field energy to momentarily
transfer to the E-field. This so-called Ferranti effect doubles the
incident voltage at the open-circuit.

The impedance of the near open circuit is the doubled voltage divided by
the near zero amps. At 1/4-wave back from the extremely high-voltage,
high-impedance points at the dipole tips, the picture is inverted. The
volts are minimum and the amps are maximum.

Every segment of wire in a simple dipole of overall length of 1/2-wave
or less has higher voltage and higher impedance on its end nearer the
the dipole tip than it does on its end nearer the center of the dipole.

If any part of the simple dipole, 1/2-wave or shorter, is made of a coil
instead of a straight piece of wire, the coil too has a higher impedance
on the end nearer the dipole tip and a lower impedance on the coil end
near the center of the dipole.

The difference in current at opposite ends of an antenna loading coil is
due to the interaction of incident and reflected waves just as in a
straight wire.

The above seems a clear as sailing west to reach the east, to me.

Best regards, Richard Harrison, KB5WZI

Yuri Blanarovich wrote:

Yuri,

I think you're missing the point - just as Cecil is. You seem to have
forgotten that I agree with the idea that there is a current gradient
across these inductors - just as there is a current gradient along any
quarter wavelength of transmission line with standing waves. That
doesn't mean there's more current "going in one end" than is "coming out
of the other end." It's a sophomoric notion. Do you wanna be a
simpleton? You're almost there with this nonsense. Why do you want to
screw up a valid idea by attaching a ridiculous one to it?

73, Jim AC6XG


OK, so it is more current "coming out in one end", than is "coming in at the
other end"?

Do you think that is how to best describe what is happening in antenna
circuits, Yuri?

You do understand what a standing wave pattern is, right?

73, Jim AC6XG

Jim Kelley wrote:
That
doesn't mean there's more current "going in one end" than is "coming out
of the other end." It's a sophomoric notion.

Nope, it's not, Jim. Current cannot stand still. The current at the bottom
of the coil is referenced to the source current which in EZNEC, is usually
one amp at zero degrees which, *by convention*, has the RMS value flowing
into the antenna. The same convention is used for circuit components.

EZNEC then tells us that the current at the bottom of the coil is 0.87a
at -1.23 deg and the current at the top of the coil is 0.67a at -1.57 deg.
All these currents are phasors. One amp at zero degrees is flowing into
the antenna. 0.87a at -1.23 degrees is flowing into the bottom of the coil,
by convention, because the cosine of the phase_angle is positive. 0.67a at
-1.57 degrees is flowing out the top of the coil, by convention, because the
cosine of the phase_angle is positive. All referenced to the source current
(you know, that little current arrow that you draw on a diagram to indicate
the RMS current flow).

What is a sophomoric notion is your notion that current doesn't flow when
it's associated with a coil. Does it just sorta vegetate around the ends
of the coil or what? If you were asked to draw RMS current arrows on a
diagram associated with a coil, would you say it can't be done? Why do
you think the RMS conventions were invented?

Incidentally, this concept of current into the coil and current out of the
coil was introduced by Tom, W8JI who said in the original argument: "If you
look at HOW an inductor works, the current flowing in one terminal ALWAYS
equals the current flowing out the other terminal." Even if Tom was wrong
about the equal currents, he clearly comprehends the AC current flow convention.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

Jim Kelley wrote:
That
doesn't mean there's more current "going in one end" than is "coming out
of the other end." It's a sophomoric notion.

Nope, it's not, Jim. Current cannot stand still.

You keep saying that as if it was relevant.

The current at the bottom
of the coil is referenced to the source current which in EZNEC, is usually
one amp at zero degrees which, *by convention*, has the RMS value flowing
into the antenna.

Both in to and out of. Not one or the other.

What is a sophomoric notion is your notion that current doesn't flow when
it's associated with a coil.

I have no such notion. It's another of the straw constructs you use to
try to win an argument by any means possible.

Incidentally, this concept of current into the coil and current out of the
coil was introduced by Tom, W8JI who said in the original argument: "If you
look at HOW an inductor works, the current flowing in one terminal ALWAYS
equals the current flowing out the other terminal." Even if Tom was wrong
about the equal currents, he clearly comprehends the AC current flow convention.

Then I observe that neither you nor Tom completely understands standing
waves.

73, Jim AC6XG

Richard Harrison wrote:
If any part of the simple dipole, 1/2-wave or shorter, is made of a coil
instead of a straight piece of wire, the coil too has a higher impedance
on the end nearer the dipole tip and a lower impedance on the coil end
near the center of the dipole.

Yep, and for the same power level, a higher impedance usually means
a lower current and vice versa.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

Richard Harrison wrote:
If any part of the simple dipole, 1/2-wave or shorter, is made of a coil
instead of a straight piece of wire, the coil too has a higher impedance
on the end nearer the dipole tip and a lower impedance on the coil end
near the center of the dipole.

Yep, and for the same power level, a higher impedance usually means
a lower current and vice versa.

But the impedance *at* such points does not affect the current *at*
those points?

73, Jim AC6XG

Jim Kelley wrote:
You do understand what a standing wave pattern is, right?

At any instant of time at a standing wave current maximum point
(loop, antinode), the charge carriers are either moving toward
the load (ends of the dipole) or toward the source (feedpoint).
By convention, if the charge carriers are moving away from the
source, the current, dQ/dt, is positive. If the charge carriers
are moving toward the source, by convention, the current dQ/dt
is negative. Even standing wave current cannot stand still and
there are only two directions available in a wire. If the
current is not zero, it changes directions every 1/2 cycle.

Standing wave current is the sum of the forward current and
reflected current both of which are flowing.
--
73, Cecil http://www.qsl.net/w5dxp



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