This thread belongs back in the original place, so it flows in context.

Yuri Blanarovich wrote:
OK, I have been accused of being wrong, claiming that current across the
antenna loading coil is or can be different at its ends.

No one said that.

I and "my camp" say that we are seeing somewhere 40 to 60 % less current at
the top of the coil, than at the bottom, in other words, significant or
noticeable drop.

Quit trying to make it a gang war. It is antenna theory, not a bar
room brawl with a bunch of drunks.

W8JI and "his camp" are claiming it can't be so, current through the coil
has to be the same or almost the same, with no significant drop across the
loading coil.

I have no camp. You are lifting what I say out of context and deleting
important things.

What I say, over and over again, is I can build an inductor in a short
mobile antenna that has essentially equal currents at each end. A
compact loading coil of good design has this type of performance.

The current taper across the inductor is not tied to the number of
"electrical degrees" the inductor "replaces". It is tied to the
distributed capaciatnce of the coil to the outside world in comparison
to the termination impedance at the upper end of the coil.


wrote in message
Let's focus on one thing at a time.

You claim a bug cather coil has "an electrical length at 4MHz of ~60
degrees". That concept is easily proven false, just like the claim a
short loaded antenna is "90-degree resonant". Both can be shown to be
nonsense pictures of what is happening.

Assume I have a 30 degree long antenna. If the loading inductor is 60
electrical degrees long, I could move it anyplace in that antenna and
have a 90 degree long antenna.

We all know that won't happen, so what is it you are really trying to
say?

OK lets get me some educating here.
I understand that, say quarter wave resonant vertical (say 33 ft at 40m) has
90 electrical degrees.
Is that right or wrong?

Right.

The current distrubution on said (full size) vertical is one quarter of the
wave of 360 deg. which would make it 90 degrees. Max current is at the base
and then diminishes towards the tip in the cosine function down to zero.
Voltage distribution is just opposite, min at the base, feed point and max
at the tip. EZNEC modeling shows that to be the case too.
Is that right or wrong?

Right. Although the distributed capacitance can change the shape.

If we stick them end to end and turn horizontal, we get dipole, which then
would be 180 deg. "long" or "180 degrees resonant".
If not, what is the right way?

Right.

If I insert the coil, say about 2/3 up (at 5 ft. from the bottom) the
shortened vertical, I make the coil size, (inductance, phys. dimensions)
such that my vertical will shrink in size to 8 ft tall and will resonate at
7.87 MHz.
I learned from the good antenna books that this is still 90 electrical
"resonant" degrees.
Maximum of current is at the feed point, minimum or zero at the tip.

What "good book"? It would help to see the context.

None of my engineering books use electrical degrees except to describe
overall antenna height or length.

They might say "60 degree top loaded resonant radiator" but they don't
say "60 degree tall radiator 90 degree resonant".

There might be a correct context, but I can't think of one off hand. So
I need an example from a textbook.

If you stick those verticals (resonant) end to end and horizontal, you get
shortened dipole, with current distribution equal to 180 degrees or half
wave. Max current at the feed point, minima or zero at the tips. (RESONANT
radiator)

The current distribution would not be the same as a half wave, becuase
the antenna is not 1/2 wave long.

Can we describe "pieces" or segments of the radiator as having proportional
amount of degrees corresponding to their physical length, when excited with
particular frequency?

Yes. It works fine for length. It does NOT work for loading inductors,
it does not work for short antennas which have anything form a uniform
distribution to triangular distribution, or any mix between including
curves of various slopes.

A 30 degree tall antenna with base loading simply has power factor
correction at the base, provided the inductor is not a significant
fraction of a wavelength long. It is a 30 degree base loaded radiator,
not a 90 degree antenna. And the inductor is not 60 degrees long.

73 Tom