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