On Thu, 4 Dec 2003 11:08:21 -0600 (CST),
(Richard Harrison) wrote:
Yuri Blanarovich posted ON4UN`s Fig 9-22 from "Low-Band DXing".
45-degrees of the 90-degree total length of a center-loaded whip comes
from the loading coil. Current tapers cosinusoidally from 1A at the
drivepoint to 0A at the tip.

Hi Richard,

First, and unfortunately, the antenna offered was never anywhere close
to 45° tall. The one Yuri posted barely stood 20° tall.

Second, Yuri's complaint centered on the notion of Modeling, not
measuring. He was making a plea to improve the accuracy and
efficiency of Modelers (all of this is EZNEC implicit, or by extension
NEC generically). Yuri never demonstrated the so-called cosinusoidal
variation in either Models or in Measurement. In fact, Yuri never
demonstrated ANY variation in current along ANY radiator.

Third, the argument of lumped or distributed circuit properties had
been answered with a protocol BEFORE the argument started. The
protocol offered every bit of correlation to ON4UN's drawings.

Fourth, this correlation did not demonstrate a slavish equality to the
so-called cosinusoidal variation, but rather demonstrated a conceptual
agreement. In fact, the Model data shows a divergence from that
curve.

Fifth, no one has bothered to demonstrate anywhere, that with the
protocol, that it is or is not born out in measurement.

Six, the differences of Models employing the protocol and those not
employing it shows about 0.5dB difference. This responds to the
original complaint of Yuri, in that no remarkable efficiencies are
gained or lost by this debate. To make matters worse, no Measure of
differences has been made to accept or dismiss this Model either.
This of course returns us to methods and accuracies, and given the
forecast of 0.5dB, the prospects of that turning into a metaphysical
freak show are more prominent than field tests resolving it in the
noise.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Six, the differences of Models employing the protocol and those not
employing it shows about 0.5dB difference.

The point you straddled in that marvelous enumeration of trivia, is that
there can be significantly greater that ".5dB" of difference in the
attributed current profiles along an antenna, due to a much greater than
".5dB" difference in some attributes of real vs. ideal loading coils.

But there's no question that it's possible to build an airplane that
flies, without understanding why if flies.

73, Jim AC6XG

On Thu, 04 Dec 2003 11:56:28 -0800, Jim Kelley
wrote:
there can be significantly greater that ".5dB" of difference in the
attributed current profiles along an antenna, due to a much greater than
".5dB" difference in some attributes of real vs. ideal loading coils.

Hi Jim,

I suppose that would matter if you were putting your lips to the
radiator.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Hi Jim,

I suppose that would matter if you were putting your lips to the
radiator.

Right. But it wouldn't matter if you were putting your lips to it. At
least, not to me. ;-)

73, Jim AC6XG

Jim, AC6XG wrote:
"But there`s no question that it`s possible to build an airplane that
flies, without understanding why it flies."

True, but it`s often better to understand what you are doing, especially
when innovating. Sometimes mistakes can be avoided. The Wright Brothers
certainly understood aerodynamics and worked hard to develop their
design before it ever flew.

They built the world`s first wind tunnel to perfect their airfoils while
trying to avoid possible fatal cut and trys. Because they knew why it
flew, The Wrights were the first to sustain powered flights.

Heath`s kits were airplanes before they started producing electronic
kits.

Best regards, Richard Harrison, KB5WZI

(Richard Harrison) wrote in message ...
Jim, AC6XG wrote:
"But there`s no question that it`s possible to build an airplane that
flies, without understanding why it flies."

True, but it`s often better to understand what you are doing, especially
when innovating. Sometimes mistakes can be avoided. The Wright Brothers
certainly understood aerodynamics and worked hard to develop their
design before it ever flew.

They built the world`s first wind tunnel to perfect their airfoils while
trying to avoid possible fatal cut and trys. Because they knew why it
flew,





The Wrights were the first to sustain powered flights.

What do you mean by that Richard ? My understanding is that many had
conquered powered flight in Europe before the Wrights even got
off the ground. As far as powered flights was it not the French that
crossed the Atlantic first?

Regards
Art


Heath`s kits were airplanes before they started producing electronic
kits.

Best regards, Richard Harrison, KB5WZI

Art, KB9MZ wrote:
"What do you mean by that Richard?"

The Wrights were the first to sustain powered flight. That means the
first practical airplane.

It wasn`t really Ernest and Julio Gallo that first got Americans to fly.
It was the Wright Brothers. The Wrights were already accomplished
mechanical designers and bicycle manufacturers. They collected and
studied all the information on flight they could get from around the
world and analyzed it for flaws to avoid in their own work. They
designed a new aluminum engine from the ground up to avoid overloading
their new flying machine. These guys were serious and practical
scientists and engineers.

This all happened 100 years ago. After the prototype flew, the Wrights
went into production on air frames and engines. Many WW-2 aircraft were
powered by "Wright Cyclone Engines".

One of the original Wright engines was owned by a California collector.
When a replica of the original Wright Flyer was recently built from the
original plans and specifications, the nearly 100 year old engine was
obtained from the collector, bolted into the new-old airframe and the
engine worked very well in powered flight of the replica. The builders
of the replica tested it on the ground for thrust the same as the Wright
brothers had. When the plane flew it was just like old times.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Jim, AC6XG wrote:
"But there`s no question that it`s possible to build an airplane that
flies, without understanding why it flies."

True, but it`s often better to understand what you are doing, especially
when innovating.

It's probably true for antennas as well as airplanes.

73, Jim AC6XG

Richard Clark wrote:
Six, the differences of Models employing the protocol and those not
employing it shows about 0.5dB difference.

If you would like to see more difference, try to model a 180 degree
phase-shifting coil using EZNEC.
--
73, Cecil, W5DXP

On Thu, 04 Dec 2003 14:55:51 -0600, Cecil Moore
wrote:

Richard Clark wrote:
Six, the differences of Models employing the protocol and those not
employing it shows about 0.5dB difference.

If you would like to see more difference, try to model a 180 degree
phase-shifting coil using EZNEC.

Not worth the effort.