"Richard Clark" wrote
...

As I stand on the corner waving goodbye to that bus, I fondly recall
how the logic stood that no current could be found on the tips of
radiators, thus trim them off to no loss of radiation. It took very
few decades before Art had then recognized that his new antenna's tips
had no more current than the full-length one, and he trimmed that one
once again! New and improved (as the saying goes). Another decade
passed into the new millennium and he observed that he could extend
this logic once again to the point where his last design encompassed a
160M full sized antenna in the space of two shoe boxes. The TRIUMPH
OF TITANIC PROPORTIONS.

Is any simillarity between Art and Tesla?
Bill Miller wrote: "*But* Tesla's "antennas" were similar physically to the
well-known "Tesla
Coil." These antennas, in spite of their enormous size, were electrically
"small" when compared with a wavelength. They were essentially a metallic
ball that was fed from the secondary of a resonant transformer. But they
appear to have had fairly large effective bandwidths in spite of their
electrically small size,"
S*

"Szczepan Bia³ek" wrote in message
...

"Richard Fry" wrote
...
On Sep 14, 12:41 pm, Szczepan Bia³ek wrote:

In which parts of antenna the charges acclerate?

Parts with r-f-current flow, the greatest radiation occurring from
locations along the radiator where current is greatest.

Your words: "Only the change in current and charge, over time, produces
EM
radiation."
At oscillations the current start from zero, accelerate to max speed and
deccelerate to zero.
At the max speed no acceleration at all.

Current flow is near zero at the ends of any unloaded dipole, and at
the top of any unloaded vertical monopole (even those in directional
arrays).

At the ends are the max accelerations and the max radiation.
S*


No, you have it wrong again - the current must be zero at the ends, there is
nowhere for it to go, and there cannot be acceleration of charge is there's
no current. Please go away and read some books and the NEETS module to
which I provided the link.

Chris

"Szczepan Bia³ek" wrote in message
...

"Richard Clark" wrote
...

As I stand on the corner waving goodbye to that bus, I fondly recall
how the logic stood that no current could be found on the tips of
radiators, thus trim them off to no loss of radiation. It took very
few decades before Art had then recognized that his new antenna's tips
had no more current than the full-length one, and he trimmed that one
once again! New and improved (as the saying goes). Another decade
passed into the new millennium and he observed that he could extend
this logic once again to the point where his last design encompassed a
160M full sized antenna in the space of two shoe boxes. The TRIUMPH
OF TITANIC PROPORTIONS.

Is any simillarity between Art and Tesla?
Bill Miller wrote: "*But* Tesla's "antennas" were similar physically to
the well-known "Tesla
Coil." These antennas, in spite of their enormous size, were electrically
"small" when compared with a wavelength. They were essentially a metallic
ball that was fed from the secondary of a resonant transformer. But they
appear to have had fairly large effective bandwidths in spite of their
electrically small size,"
S*


Tesla created HF transformers. He didn't design them as antennas but,
because of their significant length at the operating wavelength, they did
act that way to some extent. The metallic ball (often a torus nowadays) is
a means of terminating the secondary in a way that reduces spurious
discharges - its radius of curvature is large. His ideas to distribute
electrical power using Tesla coils were crazy and dangerous, but some argue
he was the inspiration for AC distribution at much lower voltages, which is
a good thing.

There is very little apparent similarity between Nicola Tesla and that 'Art
Unwin' character. Tesla was an inventor who realised amazing feats of
hardware construction, some of which worked as intended. 'Professor Unwin'
doesn't appear to create anything in hardware - he just talks about his own,
paraphysical theories and expects others to believe what he says.

Again, don't believe what I write - go to a technical library and read the
stuff that made it into books. You can't rely on what people write on the
internet; there are too many 'Unwins' out there.

Chris

On Sep 15, 7:06*pm, "christofire" wrote:
"Szczepan Bia³ek" wrote in message

...





"Richard Clark" wrote
.. .

As I stand on the corner waving goodbye to that bus, I fondly recall
how the logic stood that no current could be found on the tips of
radiators, thus trim them off to no loss of radiation. *It took very
few decades before Art had then recognized that his new antenna's tips
had no more current than the full-length one, and he trimmed that one
once again! *New and improved (as the saying goes). *Another decade
passed into the new millennium and he observed that he could extend
this logic once again to the point where his last design encompassed a
160M full sized antenna in the space of two shoe boxes. *The TRIUMPH
OF TITANIC PROPORTIONS.

Is any simillarity between Art and Tesla?
Bill Miller wrote: "*But* Tesla's "antennas" were similar physically to
the well-known "Tesla
Coil." These antennas, in spite of their enormous size, were electrically
"small" when compared with a wavelength. They were essentially a metallic
ball that was fed from the secondary of a resonant transformer. But they
appear to have had fairly large effective bandwidths in spite of their
electrically small size,"
S*

Tesla created HF transformers. *He didn't design them as antennas but,
because of their significant length at the operating wavelength, they did
act that way to some extent. *The metallic ball (often a torus nowadays) is
a means of terminating the secondary in a way that reduces spurious
discharges - its radius of curvature is large. *His ideas to distribute
electrical power using Tesla coils were crazy and dangerous, but some argue
he was the inspiration for AC distribution at much lower voltages, which is
a good thing.

There is very little apparent similarity between Nicola Tesla and that 'Art
Unwin' character. *Tesla was an inventor who realised amazing feats of
hardware construction, some of which worked as intended. *'Professor Unwin'
doesn't appear to create anything in hardware - he just talks about his own,
paraphysical theories and expects others to believe what he says.

Again, don't believe what I write - go to a technical library and read the
stuff that made it into books. *You can't rely on what people write on the
internet; there are too many 'Unwins' out there.

Chr

joe wrote:
Look at the antenna current as an electron oscillating
back and forth between the ends.

At HF frequencies, the electrons move hardly at all, tending
to oscillate back and forth in place. The idea that electrons
race from end to end in an antenna is simply false.

http://c2.com/cgi/wiki?SpeedOfElectrons

"... for a copper wire of radius 1 mm carrying a steady
current of 10 Amps, the drift velocity is only about
0.024 cm/sec!"

For a 100w 10 MHz RF wave, you can divide that distance by
more than 10,000,000. Exactly how far can the electron travel
in 0.05 microsecond?

It is the photons emitted by the electrons that travel at
the speed of light in the medium. That's the fields surrounding
the antenna conductor, not the electrons in the conductor.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

On Sep 15, 7:06*pm, "christofire" wrote:


There is very little apparent similarity between Nicola Tesla and that 'Art
Unwin' character. *Tesla was an inventor who realised amazing feats of
hardware construction, some of which worked as intended. *'Professor Unwin'
doesn't appear to create anything in hardware - he just talks about his own,
paraphysical theories and expects others to believe what he says.

Again, don't believe what I write - go to a technical library and read the
stuff that made it into books. *You can't rely on what people write on the
internet; there are too many 'Unwins' out there.

Chris

Hi Chris
The question that goes to nub of Arts claim is
why is adding a time varying field to the Gaussian law of statics
illegal? or to state it another way,
How is it illegal to change a static field into a dynamic field?
can you, will you answer the question or are you just sitting on
Richards shirt tail.

Jaro

Szczepan Bia³ek wrote:
At the ends are the max accelerations and the max radiation.

How can an electron accelerate at at open-circuit?
The acceleration is maximum at the current zero-
crossing with the greatest slope. That's at the
center of a 1/2WL dipole.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Richard Clark wrote:
On Mon, 14 Sep 2009 21:35:28 -0500, tom wrote:

Years is a fallacy. You showed up with your fantasies quite recently,
not even 2 years ago, at least with the nonsense you currently spout.
If it's true, prove it.

Hi Tom,

Actually Art arrived back in the dark ages of the fin-de-siecle. He
had just had a patent issued for a new invented antenna and asked if
anyone could explain how it worked. (drum-roll)

Several were astonished (as I have already mentioned) to find that his
antenna design had reflector (the new and improved model had two)
elements that were shorter than the driven element, and the director
elements longer.

Well, when no one could fulfill that request, we've been sub-morons
ever since. It's a rare honour that he keeps coming back here for the
validation of cretins when the Nobel Committee is located in Sweden.

73's
Richard Clark, KB7QHC

So are his fantasies new? Or did he have them before and just got a
stump from the patent office?

I truthfully don't remember him being around until lately.

The amazing thing is that his story slowly morphs with time, although it
might be better to say he adds more layers of manure.

tom
K0TAR

On Sep 15, 8:20*pm, tom wrote:
Richard Clark wrote:
On Mon, 14 Sep 2009 21:35:28 -0500, tom wrote:

Years is a fallacy. *You showed up with your fantasies quite recently,
not even 2 years ago, at least with the nonsense you currently spout.
If it's true, prove it.

Hi Tom,

Actually Art arrived back in the dark ages of the fin-de-siecle. *He
had just had a patent issued for a new invented antenna and asked if
anyone could explain how it worked. *(drum-roll)

Several were astonished (as I have already mentioned) to find that his
antenna design had reflector (the new and improved model had two)
elements that were shorter than the driven element, and the director
elements longer.

Well, when no one could fulfill that request, we've been sub-morons
ever since. *It's a rare honour that he keeps coming back here for the
validation of cretins when the Nobel Committee is located in Sweden.

73's
Richard Clark, KB7QHC

So are his fantasies new? *Or did he have them before and just got a
stump from the patent office?

I truthfully don't remember him being around until lately.

The amazing thing is that his story slowly morphs with time, although it
might be better to say he adds more layers of manure.

tom
K0TAR

And you would know seeing as you are full of it,
Art has posed the question can you answer it or are you
going to duck it as you usually do by making demands
and no offerings.

Jaro

"jaroslav lipka" wrote in message
...
On Sep 15, 7:06 pm, "christofire" wrote:


There is very little apparent similarity between Nicola Tesla and that
'Art
Unwin' character. Tesla was an inventor who realised amazing feats of
hardware construction, some of which worked as intended. 'Professor Unwin'
doesn't appear to create anything in hardware - he just talks about his
own,
paraphysical theories and expects others to believe what he says.

Again, don't believe what I write - go to a technical library and read the
stuff that made it into books. You can't rely on what people write on the
internet; there are too many 'Unwins' out there.

Chris

Hi Chris
The question that goes to nub of Arts claim is
why is adding a time varying field to the Gaussian law of statics
illegal? or to state it another way,
How is it illegal to change a static field into a dynamic field?
can you, will you answer the question or are you just sitting on
Richards shirt tail.

Jaro


I certainly haven't arrived here by sitting on anyone's shirt tails. If
you'd care to read some of the history of this NG you'd see where I come
from.

Your question is not put clearly, although I have seen garbled sentences
like this before in this Usenet group. My first question is: have you
bothered to read any of the respected books on the subject, such as
'Electromagnetics with applications' by Krauss and Fleisch. I suspect if
you had you wouldn't be asking me such a question - it makes no sense! Do I
take it you are referring to Gauss's law for electric fields? Are you aware
that there is a counterpart Gauss's law for magnetic fields? I don't
believe there is such a thing as a single 'Gaussian law of statics' -
someone has made that up!

Gauss's law for electric fields states: the integral of the electric flux
density over a closed surface equals the charge enclosed. This is an
important part of the basis of electrostatics, that is the study of
electrical phenomena caused by static charges, but it applicable at a point
in time to any scenario that involves an enclosed charge - which means any
electrical conductor, whether it carries a non-moving charge, DC or AC.
Gauss's law for magnetic fields states: the integral of the magnetic flux
density over a closed surface is equal to zero, and this is an important
part of the basis of magnetics, again whether static or changing.

Both of Gauss's laws are embodied in Maxwell's equations and for the normal
RF case of sinusoidally-alternating variables a number of different
notations can be used, a popular one being phasor notation. As you will
know, phasors are vectors that rotate at the same angular frequency but have
arbitrary phase relationships and amplitudes - so phasor notation is a
compact way of expressing quite a lot. But, in this case, every one of the
phasors involved, D the displacement current density, rho the enclosed
charge, and B the magnetic flux density, is a variable that alternates with
the passage of time. 'Dynamic' variables if you want to call them that.

Neither of Gauss's laws applies directly to strength of an electric or
magnetic field but the linkage is the other two of Maxwell's equations based
on Ampere's law and Faraday's law, which are both applicable to time-varying
fields - 'dynamic fields' if you must.

So ... would you like to put your question more clearly? What do you
actually mean by 'to change a static field into a dynamic field' in respect
of antennas, where all the electrical and magnetic variables are changing
with time, especially the fields? Is this the result of a misunderstanding
of the meaning of the word 'electrostatic' - used to differentiate between
those phenomena caused by the presence of contained charge and those caused
by its movement?

Chris