Fact 1.

Any loading coil of finite length contributes towards to the total
radiation.

Fact 2.

The input and output currents of a loading coil of finite length are always
different from each other.

Fact 3.

The radiation pattern of a short vertical is fixed and remains independent
of the location/height of the loading coil.

Fact 4.

Computer programs do not tell gospel truths. They are at least as
unreliable as their human programmers.

----
Reg.

As posted in a previous thread go to www.carolyns-creations.com/ve6cb to
view the (modeled) current distribution on an 84" monopole at 21.3 MHz.

Frank


"Reg Edwards" wrote in message
...
Fact 1.

Any loading coil of finite length contributes towards to the total
radiation.

Fact 2.

The input and output currents of a loading coil of finite length are
always
different from each other.

Fact 3.

The radiation pattern of a short vertical is fixed and remains independent
of the location/height of the loading coil.

Fact 4.

Computer programs do not tell gospel truths. They are at least as
unreliable as their human programmers.

----
Reg.

"Frank" wrote
As posted in a previous thread go to www.carolyns-creations.com/ve6cb to
view the (modeled) current distribution on an 84" monopole at 21.3 MHz.

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

Frank, I don't know, and it doesn't matter, how you produced the amperes
versus height graph which beautifully displayed itself with a single
mouse-click on my computer screen.

It displays the curve-shape which any properly educated electrical engineer,
or amateur with any intuitive common sense, ought to expect. Thanks!

The many reams of heated arguments which have appeared on this newsgroup
have been a disgrace to the profession. Yes, I know its an amateur mewsgroup
but the (aggressive?) contestents are mostly so-called professionals.

Clearly you have chosen an adequate mathematical demonstration model with
the ability to use it. Most likely without any thoughts about Terman or
theorem-writers Thevenin and Kirchoff, etc., who personally I have hardly
ever heard of.

If you have not already done so, may I suggest you include radiation
resistance in the model for slightly greater accuracy. It may remove the
small kink in your curve which occurs immediately at the bottom end of the
coil. I don't think it should be there. But further elaboration is hardly
worth the effort.

I also think its a good idea to base demonstration models (like actual
experimental measurements) on the lower frequencies. Try the 160 metre band.
They are likely to be more accurate representations.

Frank, if you have the time to spare perhaps you should contribute to this
newsgroup more often. Improve its already good entertainment, even
educational if sometimes confusing, value!

By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight. French politics go
down very well with their excellent wine and British very mature Cheddar
cheese.

Hic!
----
Reg, G4FGQ

Reg Edwards wrote:
By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight.

I hear the French are pi$$ed at us for our small boycott of
French wine, French vacations, French Fries, etc. :-) Ever
notice that us and US mean the same thing for us?
--
73, Cecil http://www.qsl.net/w5dxp


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Cecil Moore wrote:

Reg Edwards wrote:

By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight.


I hear the French are pi$$ed at us for our small boycott of
French wine, French vacations, French Fries, etc. :-) Ever
notice that us and US mean the same thing for us?

I'm boycotting Texas. No Texas bugcatchers for me, they're
unamerican.
73,
Tom Donaly, KA6RUH

Tom Donaly wrote:
I'm boycotting Texas. No Texas bugcatchers for me, they're
unamerican.

I heard the Texas Bugcatcher guy is an SK so he probably
doesn't care.
--
73, Cecil http://www.qsl.net/w5dxp


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"Cecil Moore" wrote in message
...
Reg Edwards wrote:
By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight.

I hear the French are pi$$ed at us for our small boycott of
French wine, French vacations, French Fries, etc. :-) Ever
notice that us and US mean the same thing for us?
--
73, Cecil http://www.qsl.net/w5dxp


Don't know if it is true, but I heard that France had a problem that
wiped out one type or area of grapes and they imported some of the same type
from the U.S. True?

73,
--
Steve N, K,9;d, c. i My email has no u's.

Steve Nosko wrote:
"Cecil Moore" wrote in message
...

Reg Edwards wrote:

By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight.

I hear the French are pi$$ed at us for our small boycott of
French wine, French vacations, French Fries, etc. :-) Ever
notice that us and US mean the same thing for us?
--
73, Cecil http://www.qsl.net/w5dxp



Don't know if it is true, but I heard that France had a problem that
wiped out one type or area of grapes and they imported some of the same type
from the U.S. True?

73,

The French wine industry was decimated in the 19th century by
a phylloxera infestation from America. The problem was solved by
using native American root stock onto which French grape vines were
grafted. Most wine grapes in America have European ancestry.
I doubt whether there's a grape vine in the world that cares
who is president of the U.S.
73,
Tom Donaly, KA6RUH

Thanks for your comments Reg. The fact is my graph is produced in Excel
from data provided by a NEC 2 output file generated by few trivial lines of
NEC code. I cannot claim to have done anything requiring much thought. I
just considered, since so much discussion is centered on current
distribution, that some might be interested in the posted curves. So far
yours is the only response. I will probably delete the page in a day or so.
The loading inductor is 2.5" diameter, 6" long, with turns spaced at 0.5".
The NEC code is listed on the site, so anybody can copy to verify the
validity of my results -- or the validity of the code.

I have included a conductivity for copper (5.8001E7 S/m), and since the
ground is defined as perfect, this accounts for all losses within the model.
The program predicts the total radiated power as 95.918 W from 100 W input.
The input current is 2.3874 A RMS, and input impedance 17.545 Ohms. The
radiation resistance is therefore 16.829 Ohms. (Sorry for all the decimal
places, but they produce such nice round numbers). I was also puzzled by
the slight increase in current just under the loading coil, but suspect it
was caused by coupling between the lower conductor and the base of the coil.

I agree that some experimental data would be good. I have been planning for
some time to erect a 160 m vertical, so can see how the predicted results
compare. I have also used your software for modeling verticals, and it is
in very close to the results produced by NEC. The one problem with NEC 2
(Though not with NEC 4) is that it cannot model buried radials, but can get
very close to the ground.

I don't mind an occasional post on this news group, but not sure I can
contribute much. I do enjoy reading other people's posts though.

I sure could enjoy a glass of wine with cheese, but have nothing much in my
fridge -- except for some old Cheddar.

Regards,

Frank


"Reg Edwards" wrote in message
...

"Frank" wrote
As posted in a previous thread go to www.carolyns-creations.com/ve6cb to
view the (modeled) current distribution on an 84" monopole at 21.3 MHz.

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

Frank, I don't know, and it doesn't matter, how you produced the amperes
versus height graph which beautifully displayed itself with a single
mouse-click on my computer screen.

It displays the curve-shape which any properly educated electrical
engineer,
or amateur with any intuitive common sense, ought to expect. Thanks!

The many reams of heated arguments which have appeared on this newsgroup
have been a disgrace to the profession. Yes, I know its an amateur
mewsgroup
but the (aggressive?) contestents are mostly so-called professionals.

Clearly you have chosen an adequate mathematical demonstration model with
the ability to use it. Most likely without any thoughts about Terman or
theorem-writers Thevenin and Kirchoff, etc., who personally I have hardly
ever heard of.

If you have not already done so, may I suggest you include radiation
resistance in the model for slightly greater accuracy. It may remove the
small kink in your curve which occurs immediately at the bottom end of the
coil. I don't think it should be there. But further elaboration is hardly
worth the effort.

I also think its a good idea to base demonstration models (like actual
experimental measurements) on the lower frequencies. Try the 160 metre
band.
They are likely to be more accurate representations.

Frank, if you have the time to spare perhaps you should contribute to this
newsgroup more often. Improve its already good entertainment, even
educational if sometimes confusing, value!

By the way, I'm on Dourthe No.1, Bordeaux 2001, tonight. French politics
go
down very well with their excellent wine and British very mature Cheddar
cheese.

Hic!
----
Reg, G4FGQ

Frank wrote -
I have also used your software for modeling verticals, and it is
in very close to the results produced by NEC. The one problem with NEC 2
(Though not with NEC 4) is that it cannot model buried radials, but can
get
very close to the ground.

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

The only program I am reasonably familiar with is the several years old free
EZNEC. I don't know whether it has been updated or not and I make very
little use of it. Come to think of it, I don't make much use of my own
programs either.

Regarding shallow buried radials in conjunction with a vertical, have you
tried my recent program RADIALS2 ?

It is intended to demonstrate performance of the radials themselves in a
given ground rather than antenna performance. Which I suspect is the reverse
of NEC-4.

As you probably know, the effects of above-ground radials change very
rapidly as they get within a few inches of the ground surface. But once in
the ground they tend to remain static.

RADIALS2 uses an entirely different, unconventional form of performance
analysis. If other programs don't take soil permittivity into account at HF,
predictions must lose accuracy. Are the inputs and outputs of NEC-4 in a
form suitable for a direct comparison with my simple program?

But in view of the large uncertainties involving ground conditions, accuracy
is not worth making much of a song and dance about.
----
Reg, G4FGQ