RadioBanter - Lumped Load Models v. Distributed Coils

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- Antenna (https://www.radiobanter.com/antenna/)

- - Lumped Load Models v. Distributed Coils (https://www.radiobanter.com/antenna/1140-lumped-load-models-v-distributed-coils.html)

had a girl friend like that once...

" Art Unwin KB9MZ" wrote in message
news:PT8Ub.174501$5V2.875722@attbi_s53...
Sorry about that, missed the period before co

http://web.ukonline.co.uk/g3ldo

Art

Mark Keith wrote:
"----so far I don`t recollect anyone actually measuring a real world
coil, and finding max current at the top of the coil."

It could be done but it isn`t the ordinary function of loading coils to
work with low current in and high current out.

One could reason that 1/4-wave back from the open-circuit end of an
antenna element a low-impedance high-current point is created. Since the
function of a loading coil is usually to supply the missing part of a
1/4-wave in a shortened element, one would expect to find the
high-current terminal of the coil facing the transmitter and the low
current end of the coil facing the open-circuit end of the element.

Best regards, Richard Harrison, KB5WZI

Art Unwin KB9MZ wrote:
Now when I come to your drawing of a vertical I become confused because the
top end is clearly zero current flow
which presumably is a requirement for resonance
but the inductance suddenly becomes dimension less ...

The coil in sqcoil.gif has dimensions, Art, but the drawing is in two
dimensions, x & z. The y dimension exists normal to the plane of the
drawing. The coil is a square coil in three dimensions. It is 2 feet
wide in the x dimension and 2 feet wide in the y dimension. The coils
are 0.5 feet apart.
--
73, Cecil http://www.qsl.net/w5dxp

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Richard Harrison wrote:
One could reason that 1/4-wave back from the open-circuit end of an
antenna element a low-impedance high-current point is created. Since the
function of a loading coil is usually to supply the missing part of a
1/4-wave in a shortened element, one would expect to find the
high-current terminal of the coil facing the transmitter and the low
current end of the coil facing the open-circuit end of the element.

I've posted the 'sqcoil.ez' file to my web site that shows low current into
the bottom of the coil and high current out of the top of the coil. The
radiation pattern shows why that configuration is unpopular - mostly
a cloud warmer with a take-off-angle of 48 degrees at 14.7 MHz.

However, when 'sqcoil.ez' is run at 29.4 MHz, it turns into a phased array
with close to 180 degrees of phase-reversal in the coil and an omni-
directional gain of 3+ dBi at a take-off-angle of 12 degrees.
--
73, Cecil http://www.qsl.net/w5dxp/sqcoil.ez

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Thanks for the reply Cecil
It is obvious to me that you are refering to a drawing or GIF as you call it
that I cannot retrieve to review thus I cannot continue this discussion as
it would resemble a chess game where I could not see opposing positions to
ascertain whether a rook was allowed to move as a pawn to thwart any moves I
made.
I like that analogy Cecil but it does resemble a discussion
that cannot progress with clarity or resolve. We are all playing on our home
fields where each is not sure how a touchdown was scored, if it was scored
and in whose favor..
No wonder this thread has more trails than a fishbone
with each poster crunching different parts of the bone
on the assumption that all are chewing on the same part.
Presumably my posting is now so unclear that it will fit neatly into and
conform to the overall thread.
Cecil we have severe weather here that it requires a real snow job from me
to emerge back into this particular thread !!!!!
Regards
Art

"Cecil Moore" wrote in message
...
Art Unwin KB9MZ wrote:
Now when I come to your drawing of a vertical I become confused because
the
top end is clearly zero current flow
which presumably is a requirement for resonance
but the inductance suddenly becomes dimension less ...

The coil in sqcoil.gif has dimensions, Art, but the drawing is in two
dimensions, x & z. The y dimension exists normal to the plane of the
drawing. The coil is a square coil in three dimensions. It is 2 feet
wide in the x dimension and 2 feet wide in the y dimension. The coils
are 0.5 feet apart.
--
73, Cecil http://www.qsl.net/w5dxp

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square coils will not work, the current goes so fast, it can't turn the
corners and it all shoots out the end.

This causes the current at the top of the coil to be less than that at the
bottom.

All clearly covered in the Kraus Cliff Notes.

"Cecil Moore" wrote in message
...
Art Unwin KB9MZ wrote:
Now when I come to your drawing of a vertical I become confused because
the
top end is clearly zero current flow
which presumably is a requirement for resonance
but the inductance suddenly becomes dimension less ...

The coil in sqcoil.gif has dimensions, Art, but the drawing is in two
dimensions, x & z. The y dimension exists normal to the plane of the
drawing. The coil is a square coil in three dimensions. It is 2 feet
wide in the x dimension and 2 feet wide in the y dimension. The coils
are 0.5 feet apart.
--
73, Cecil http://www.qsl.net/w5dxp

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W4JLE wrote:
square coils will not work, the current goes so fast, it can't turn the
corners and it all shoots out the end.

:-) That's why I have developed an octal coil. I'll post the results this
weekend. The coil is 4.5 turns, 12 inches in diameter, and 22 inches long.
--
73, Cecil http://www.qsl.net/w5dxp

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Cecil Moore wrote:
I've posted the 'sqcoil.ez' file to my web site that shows low current into
the bottom of the coil and high current out of the top of the coil.

So according to "convention", standing wave current flows away from the
source. Is that your claim?

73, Jim AC6XG

Jim wrote,

Cecil Moore wrote:
I've posted the 'sqcoil.ez' file to my web site that shows low current into
the bottom of the coil and high current out of the top of the coil.

So according to "convention", standing wave current flows away from the
source. Is that your claim?

73, Jim AC6XG

If it "flows" anywhere it isn't a standing wave. If there were more of
something going out of the coil than going in, the coil would have to
be manufacturing that something. Cecil's ideas on waves are well
known and lead to some pretty unbelievable results.
73,
Tom Donaly, KA6RUH