David, leaving you out as one of the possibilities responsible
for throwing out this august group Give me one instance with
names of that which you are complaining about.

Actually some of those very same names have shamed other
people to leave this newsgroup and you will notice that
some of the language on this thread has already become
harsh and vindictive. So give me a name David, since
you are the first to come forward with the proverbial stone.
I.e. one without personal sin
Art
By the way what makes you think that these people are so
brittle that they will not return ?




Cecil Moore wrote in message ...
David J. Windisch wrote:
Speaking of pirhanas in the tank, this humble lurker and scribe takes this
opportunity to thank and congratulate you pirhanas posting here for driving
the likes of ... et al., right off this reflector with your feeding frenzies
over triviae, minutiae, and inconsequential stuff.

A larger question might be: Why do some (not all) of those guys stake their
reputations and egos on that very "triviae, minutiae, and inconsequential stuff"?

Some of those guys on your list disagree loud and long with each other, both
sides determined never to admit a mistake of any kind. Many list their degrees
and accomplishments as if those things are a vaccination against mistakes.

Driving a person off a public unmoderated newsgroup is impossible. What causes
people to leave this newsgroup under pressure is pride plus the heat in the kitchen.

Do you think we really need a newsgroup guru upper class whose assertions are
immune from other questioning minds?

Art, KB9MZ wrote:
"Are you suggesting using a capacitive coupling instead of an inductor?"

The dipole is about the simplest standing wave antenna. Its system must
be resonant to allow full current in the antenna.

The best arrangement for a dipole is a centerfed balanced pair of wires
in a straight line that is self-resonant but this is only possible at
discrete frequencies.

If an antenna is too short to be resonant, it may be resonated by adding
to its inductance or its capacitance, or both, if the antenna can`t be
lengthened.

My remark was only a reiteration of common knowledge. Coils are lossy
and capacitors tend to be nearly lossless.

Cecil has shown how an all-wave system with small losses can be made
that doesn`t even require a tuner. He uses a variety of selected ladder
line lengths to maximize antenna current.

Another option is to use a balanced dipole with a balanced line
connected with the transmitter through a tuner.

Bill Orr, W6SAI has a suggestion for reducing the range of impedances
the tuner must handle. It is to make the sum of the dipole length and
the feedline length into preferred sums. These are 110, 133, 177, or 212
feet. He shows how to make the dipole, balanced line, and tuner in his
book "Wire Antennas". He calls the dipole, line, and tuner: "A Universal
H-F Antenna System", to cover 3.5 to 29.7 MHz with one antenna.

Best regards, Richard Harrison, KB5WZI

I suppose it depends on how much the inductor radiates like an antenna.
There is no perfect coil out there.
-Mike KC0IOC

Roy Lewallen wrote:
Can I conclude from this that if I were to make a coil with more or less
inductance, then I would see a current difference between the ends of
the coil?

So tell you what. If you'll pull out your equations and calculate the
expected current difference, I'll replace the coil with one of 100 ohms
reactance and remeasure. How much current difference (magnitude andd
phase, of course) between the ends of a 100 ohm inductor at the base of
that same antenna?

Roy Lewallen, W7EL

Cecil Moore wrote:

Yuri Blanarovich wrote:

Judging by description, I would guess that there wasn't much difference.



The feedpoint of the radiator alone is 35-j185. The impedance of the
loading
toroid is 0.6+j193. Assuming perfect predictability, that gives the
antenna
system a feedpoint impedance of 35.6+j8, i.e. it is *longer* than
resonant.
That moves the current maximum point inside the toroid making the current
in and out even closer to equal. If a coil is installed at a current
maximum
point or a current minimum point, the current in and out will be the
same.
If a coil is installed at a place where the slope of the current envelope
is positive, the current will actually increase through the coil.

Roy, W7EL wrote:
"So tell you what. If you`ll pull out your equations and calculate the
expected current difference, I`ll replace the coil with one of 100 ohms
reactance and remeasure."

The challenge was directed to Cecil, but anyone can respond. The current
is a function of position along the antenna. Distribution is
cosinusoidal as Yuri said.

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.

Current into the bottom of the coil is 0.924A and into the top of the
coil it is 0.383A. These are related to the cosines of 22.5-degrees and
67.5-degrees, 0,924 and 0.383.

The expected current difference in ON4UN`s example is 0.54A.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Roy, W7EL wrote:
"So tell you what. If you`ll pull out your equations and calculate the
expected current difference, I`ll replace the coil with one of 100 ohms
reactance and remeasure."

The challenge was directed to Cecil, but anyone can respond. The current
is a function of position along the antenna. Distribution is
cosinusoidal as Yuri said.

That's right. The distribution is the result of the superposition of
the forward and reflected currents. It's basically just one quarter of
a cycle of the standing wave pattern. When the electrical length of a
loading coil represents any significant fraction of the length of the
antenna, the superposition of forward and reverse currents at each end
of the inductor will result in different values. The difference is due
to the phase delay through the loading coil, as Cecil has explained.
Delay is an unavoidable artifact of propagation through wire - whether
it happens to be wrapped into a coil, or not.

73, Jim AC6XG

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

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