Frankly speaking no standing waves. Waves always travel. In air travel the
pressure pulse. When the two waves travel in opposite directions they
interfere. See: http://en.wikipedia.org/wiki/Kundt's_tube
"The sound generator is turned on and the piston is adjusted until the sound
from the tube suddenly gets much louder. This indicates that the tube is at
resonance, which means its length is a multiple of the wavelength of the
sound wave. At this point the sound waves in the tube are in the form of
standing waves, and the amplitude of vibrations of air are zero at equally
spaced intervals along the tube, called the nodes."

Between the nodes are places where the amplitude is doubled. So the places
with doubled amplitude are standing. Pressure pulse travel.
In antennas is electron gas. The first place where the doubled amplitude
(amplitude means voltage or electron density) appear is end of the radials.
The next is halve wave apart from the end. Such places radiate strong
electric waves. They are the source of radiation.
Of course the next source is weaker because some part of energy is radiated.
But such is stronger than the trawled source (normal voltage pulse)

If antenna has only one source it is omnidirectional. If two or more is
directional because the waves from different sources interfere.

The halve wave dipole has the two sources. The next two appear than a
dipole is longer than the wave length.
So that what R. Clark wrote is obvious: "[* What is this proportional and
proportionate mean? For a dipole of
0.05 WL to a dipole of 0.5WL, the far field change for that 10:1
variation is negligible. However, for a dipole of 0.5WL to a dipole
of 1.25WL, the far field change for that 2.5:1 (a smaller proportion)
variation is very noticeable.]

The above is the antenna with the Helmholtz' pressure wave.
Could anybody describe the antenna with the Heavisde's TEM waves?
In a few words. Do not send mi to library.
S*

On Thu, 17 Sep 2009 19:15:56 +0200, Szczepan Bia?ek
wrote:

If antenna has only one source it is omnidirectional. If two or more is
directional because the waves from different sources interfere.

The halve wave dipole has the two sources. The next two appear than a
dipole is longer than the wave length.
So that what R. Clark wrote is obvious: "[* What is this proportional and
proportionate mean? For a dipole of
0.05 WL to a dipole of 0.5WL, the far field change for that 10:1
variation is negligible. However, for a dipole of 0.5WL to a dipole
of 1.25WL, the far field change for that 2.5:1 (a smaller proportion)
variation is very noticeable.]

In the space of two sentences you contradict yourself. You don't get
it, do you?

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
...
On Thu, 17 Sep 2009 19:15:56 +0200, Szczepan Bia?ek
wrote:

If antenna has only one source it is omnidirectional. If two or more is
directional because the waves from different sources interfere.

The halve wave dipole has the two sources. The next two appear than a
dipole is longer than the wave length.
So that what R. Clark wrote is obvious: "[* What is this proportional and
proportionate mean? For a dipole of
0.05 WL to a dipole of 0.5WL, the far field change for that 10:1
variation is negligible. However, for a dipole of 0.5WL to a dipole
of 1.25WL, the far field change for that 2.5:1 (a smaller proportion)
variation is very noticeable.]

In the space of two sentences you contradict yourself. You don't get
it, do you?

"If antenna has only one source" means the monopole antena (the second
source is "graved")
"The halve wave dipole has the two sources" means "dipole has visible the
both ends".
O.K now?
S*

Szczepan Bia³ek wrote:
"The halve wave dipole has the two sources" means "dipole has visible
the both ends".

A 1/2WL dipole is a standing wave antenna.
Are you saying that the forward energy is one source
and the energy reflected from the ends is a second
source?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

"Cecil Moore"
...
Szczepan Bia³ek wrote:
"The halve wave dipole has the two sources" means "dipole has visible
the both ends".

A 1/2WL dipole is a standing wave antenna.
Are you saying that the forward energy is one source
and the energy reflected from the ends is a second
source?

Each dipole has visible the two radials (sometimes end parts of the
transmitting line). Each radials has the one strong source at the end like
the Kundt's tube. See: http://en.wikipedia.org/wiki/Kundt's_tube
A dipole has the two radials so it has at least the two strong sources.
Only the two if it is shorter then WL. If it is longer than WL then appear
the next sources on the both radials at each 1/2WL from the end.

I will be absent till Monday evening.
S*

On Fri, 18 Sep 2009 08:51:04 +0200, Szczepan Bia?ek
wrote:

In the space of two sentences you contradict yourself. You don't get
it, do you?

"If antenna has only one source"

Thank you for confirming that in spite of quoting me, you just don't
get it.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
...
On Fri, 18 Sep 2009 08:51:04 +0200, Szczepan Bia?ek
wrote:

In the space of two sentences you contradict yourself. You don't get
it, do you?

"If antenna has only one source"

Thank you for confirming that in spite of quoting me, you just don't
get it.

You go into details.
In the Gas Analogy the monopole antena is exactly like the Kundt's tube.
See: http://en.wikipedia.org/wiki/Kundt's_tube
A dipole has the two Kundt's tubes.
S*

On Fri, 18 Sep 2009 18:33:00 +0200, Szczepan Bia?ek
wrote:

You go into details.

Yes, I do go into the details.

In the Gas Analogy the monopole antena is exactly like the Kundt's tube.

Analogy is a false arguement. In the car-seen-at-a-distance analogy,
this proves that only midgets or pygmies drive cars because we are too
big to fit into such small things seen in the distance.

73's
Richard Clark, KB7QHC

On Sep 17, 10:15*am, Szczepan Bia³ek wrote:
Frankly speaking no standing waves. Waves always travel. In air travel the
pressure pulse. When the two waves travel in opposite directions they
interfere. See:http://en.wikipedia.org/wiki/Kundt's_tube
"The sound generator is turned on and the piston is adjusted until the sound
from the tube suddenly gets much louder. This indicates that the tube is at
resonance, which means its length is a multiple of the wavelength of the
sound wave. At this point the sound waves in the tube are in the form of
standing waves, and the amplitude of vibrations of air are zero at equally
spaced intervals along the tube, called the nodes."

Between the nodes are places where the amplitude is doubled. So the places
with doubled amplitude are standing. Pressure pulse travel.
In antennas is electron gas. The first place where the doubled amplitude
(amplitude means voltage or electron density) appear is end of the radials.
The next is halve wave apart from the end. Such places radiate strong
electric waves. They are the source of radiation.

The problem I immediately see here is that you're probably interested
in electromagnetic radiation, not just the electric field. The
result, as I see it, is that the rest of your discussion is based on a
completely false premise. But see below.
....
The above is the antenna with the Helmholtz' pressure wave.
Could anybody describe the antenna with the Heavisde's TEM waves?
In a few words. Do not send mi to library.
S*

Others have tried to describe radiation from linear antennas in
reasonably simple terms. One of the best I know is Joseph Boyer's
pair of articles from May and June, I think it was, 1978 "Ham Radio"
magazine: "The Antenna-Transmission Line Analog." It's a non-
mathematical work; it will leave you with answers with not a lot to
back them up, but they do match what we observe, as far as I
understand it. I have these as a PDF, along with a fairly important
section from a book referenced by the articles.

Cheers,
Tom

K7ITM wrote:
"The Antenna-Transmission Line Analog."

It's a good analog. For instance a 1/4WL open-wire
open-circuit stub made with resistance wire with
a resistivity of 0.0000021 ohms-m has a feedpoint
impedance of 35 ohms according to EZNEC.

The current distribution is a close approximation
to a 1/4WL monopole. The additional resistance
over copper approximates the energy lost to
radiation in a 1/4WL monopole.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com