Current in antenna loading coils controversy
 

Howdy perpetual arguers!

Here is the good one for you on eHam.net

http://www.eham.net/articles/6512

between yours truly (right) and Tom, W8JI (wrong).

It centers around the argument that the RF current in the antenna loading coils
is (or not) equal. Classic case of "theory" (wrongly applied) to real life
measurements and facts. There is referenced previous article that started it
all and on my budding web site www.K3BU.us full text with pictures at
http://www.k3bu.us/loadingcoils.htm

It looks like this factor is not properly accommodated in modeling programs
using loading inductors in antenna elements. In view of the above, time
permitting, I will try to do some work and try to shed some more light on the
subject.

Any experiences out there, rather than more "reasons" why it ain't so?
Proper accommodation in modeling programs can give substantial improvement in
loaded elements modeling.

Let the games begin :-)

Yuri, K3BU

On 29 Oct 2003 18:58:40 GMT, oSaddam (Yuri Blanarovich)
set up a tar baby:


|
|Let the games begin :-)

You say (at least I think you said): "Roy Lewallen, W7EL, author of
EZNEC and Wes Stewart, N7WS recommend workarounds to replace the coil
with cylinder of similar size or breaking the coil to number of
physical segments with appropriate inductances."

I'll admit to forgetting more things as I get older but I'll be damned
if I remember making any such statement.

Can you post a link to this so I know what it is that you think I
said, or what I said that I don't remember saying?

Wes Stewart N7WS

. . loading coil current . . . is (or is not) equal to what
????????? ".

Please state unambiguously and explicitly what it is you wish to know.
---
Reg.

Look at the article(s), it refers to current being equal (or not) at both ends
of the loading coil in the antenna elemnt.

In a nutshell, I (and W9UCW, etc.) found that current diminishes accross the
coil. W8JI using Kirchoff and Ohm says it can't.

I am curious if anyone else made measurements (never mind "theory") and what
they found.

Yuri

Can you post a link to this so I know what it is that you think I
said, or what I said that I don't remember saying?

Wes Stewart N7WS



Without going the route of providing "evidence" I posted the question about the
modeling loading coils here, and Roy and you provided suggestions of the
described workaround (if my memory doesn't fail me :-)

Yuri

Another stiff dick contest between you and Tom?

"Yuri Blanarovich" wrote in message
...
Howdy perpetual arguers!

On 29 Oct 2003 20:40:11 GMT, oSaddam (Yuri Blanarovich)
wrote:

|
|Can you post a link to this so I know what it is that you think I
|said, or what I said that I don't remember saying?
|
|Wes Stewart N7WS
|
|
|
|Without going the route of providing "evidence" I posted the question about the
|modeling loading coils here, and Roy and you provided suggestions of the
|described workaround (if my memory doesn't fail me :-)

In other words, I didn't say it.

|
|Yuri

"Yuri Blanarovich" wrote

I (and W9UCW, etc.) found that current diminishes across the
coil. W8JI using Kirchoff and Ohm says it can't.

I am curious if anyone else made measurements (never mind "theory") and
what
they found.

=============================

If you mean the current distribution along the length of the coil was not
uniform but tapering then it is not surprising.

The important thing is by how much did it taper and in what direction? Up
or down?

Please describe clearly the type of instruments used and how you made your
measurements.

By how much did the current measuring instrument affect the strength of
current flowing, for example by detuning the antenna?

What was the length and diameter of the coil, and the number of turns?

What were the lengths of the antenna above and below the coil?

At what frequencies were the measurement made?

What was the current in amps in the coil wire at the bottom, at the centre
and at the top of the coil?

What does the current distribution in the coil affect, AND BY HOW MUCH?
----
Reg

Reg Edwards wrote:
If you mean the current distribution along the length of the coil was not
uniform but tapering then it is not surprising.

The important thing is by how much did it taper and in what direction? Up
or down?

Please describe clearly the type of instruments used and how you made your
measurements.

By how much did the current measuring instrument affect the strength of
current flowing, for example by detuning the antenna?

What was the length and diameter of the coil, and the number of turns?

What were the lengths of the antenna above and below the coil?

At what frequencies were the measurement made?

What was the current in amps in the coil wire at the bottom, at the centre
and at the top of the coil?

What does the current distribution in the coil affect, AND BY HOW MUCH?
----
Reg

Gee, Reg. Until now I've always gotten the impression that you already
learned everything there was to know about this stuff. :-)

73, AC6XG

Another stiff dick contest between you and Tom?


Yep,
I post fact of life, Tom pompously chimes in that it can't be so with some
added ridicule, and I won't budge to a bully that is barking up the wrong tree.
This is about 5th time. Watch him to become expert in few moths "he said it all
along" :-) and will become a guru.

All in the good spirit of learning :-)

Yuri

What does the current distribution in the coil affect, AND BY HOW MUCH?
----
Reg



Reg it is all there in my article and references I posted in my post. Can you
look up those links or is there a problem? I hate to go over the stuff again.
If you can't look up the links, perhaps I could post the text here, but article
has details, measurements, pictures of meters and facts of life.

Yuri
www.K3BU.us