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Yuri Blanarovich wrote:
W8JI and other unbelievers that antenna and loading coils can not be
expressed in electrical degrees, can find another example in ON4UN's Low
Band DXing book, 4th edition, page 9-47, Fig 9-58, showing loaded
vertical
with mast being 40 deg. 59.6 ft. long, loading coil of 144 uH taking
(replacing radiator of) 40 deg and whip of 10 deg and 14.9 ft long, for
overall 90 deg electrical and quarter wave resonant system.
Soooo, to anyone outside of "equal current worshippers" it is obvious
that
coil is replacing 40 deg worth of radiator and it would drop equivalent
amount of current across the coil that corresponds to the length of
radiator
that coil replaces, because rest of the "straight" radiator FORCES IT TO
DO - because of standing wave and current.


That is not correct Yuri.

Anything from a pure inductance to a very poor distributed inductor
(like a linear loading or stub) can be used and all would have
different characteristics.

"Pure inductance" - get me one, never subject of discussion here, about real
antennas and real loading coils!

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.

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.

73 Tom


Another big WRONGO Tom!
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.

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. 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.

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.
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.

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.

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.
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. So if the antenna is 50 degrees long and we
want to maintain the resonance, the coil will replace (has to) the same 40
degrees regardless where it is placed, but its inductance and impedance will
vary, depending on the impedance of the insertion point at the radiator.
(Makes also sense - more turns - more current drop, RF choke effect. We are
still talking RF current in standing wave antenna, not DC.)
So the drop of RF current across the coil, depending on its position in the
resonant quarter wave radiator can be from little at the base, to
significant closer to the top, dependent on the position, insertion point,
impedance of the radiator. This is much more significant cause of current
drop across the coil that any "radiation or capacitance to the environment"
(Tom's trying to "twist out of it") as is demonstrated by our arguments.
So if we look at the fixed length of radiator and try to bring it to
resonance with coils, placed at different locations along the radiator, we
are replacing the SAME amount of electrical degrees, but depending on the
required impedance, then the number of turns, or inductance has to be
adjusted to conform. That jives what you and everybody knows and keep
saying.
So it is not the fixed inductance, (missing) length of wire in the coil, or
same number of turns that replaces degrees of "missing" radiator, but the
REQUIRED INDUCTANCE/IMPEDANCE and corresponding number of turns.

I hope this makes it little bit more clear and shuts down another WRONGOOO
that keeps popping up. Just measure it, stick it (properly defined) in
EZNEC - IT IS ALL THERE, for everyone to see.

So then if the standing wave causes drop of the RF current across the solid
wire of the antenna, it also causes the drop of current across the loading
coil, proportional to the amount of electrical degrees of radiator that coil
"replaces", magnitude being dependent on the impedance and inductance
required by the insertion point impedance along the radiator. (Almost sounds
like "Yuri's Law" :-)

I would like to thank NM5K for bringing it up and making me to understand
what the "problem" and proof is. It made me realize what role impedance of
the inductor plays in the STANDING WAVE antenna/circuit.
Sooo! The coil can and have RF current variation, drop across it, just like
piece of wire can, when in standing wave (antenna) environment. It is the
major cause and not the whatever capacitance etc. You wanna call it K3BU's
theory, I would be honored, but I do not claim any "ownership", many others
before me showed that, directly or indirectly, including John Kraus, W8JK.

I promise to do that article and series of experiments showing close
correlation between measurements and proper modeling in EZNEC, just give me
couple of weeks. I hope it will show and educate those willing to open their
minds, and those "flat Earthers" can do what they choose to (look silly).
I hope I made it more clear. I don't know how else I (we) can get it
through!

Soooo, but, but, but.... what?


Yuri Blanarovich, K3BU.us

I apologize to technical language purists for any clumsy wordiness' I may be
guilty of.