On Sep 17, 12:15*pm, Szczepan Bia³ek wrote:
If antenna has only one source it is omnidirectional. If two or more is
directional because the waves from different sources interfere.

More study is needed on your part, S*. Consult the textbooks of the
authors that already have been listed, and quoted here.

Your unproven, personal opinions are not sufficient to support some of
the statements you post-- which accounts for the "negative" comments
responding to them.

Every single real-world antenna in existence has more than one source
along its length that contributes to its radiation pattern, and
therefore has some directionality.

Your study and accurate understanding of the works of the authors
mentioned will prove this.

RF

"Richard Fry"
...
On Sep 17, 12:15 pm, Szczepan Bia³ek wrote:
If antenna has only one source it is omnidirectional. If two or more is
directional because the waves from different sources interfere.

More study is needed on your part, S*. Consult the textbooks of the
authors that already have been listed, and quoted here.

Your unproven, personal opinions are not sufficient to support some of
the statements you post-- which accounts for the "negative" comments
responding to them.

I wrote: "Do not send me to librery".

Every single real-world antenna in existence has more than one source
along its length that contributes to its radiation pattern, and
therefore has some directionality.

I wrote" "Pressure pulse travel" I means that in monopole antena is one
strong source on the and and traveling source "along its length" .

Your study and accurate understanding of the works of the authors
mentioned will prove this.

Tell me who is right: Helmholtz or Heaviside?
S*

On Sep 18, 2:08*am, Szczepan Bia³ek wrote:
I wrote" "Pressure pulse travel" I means that in monopole
antena is one strong source on the and and traveling
source "along its length" .

I assume from what you posted before that you meant to write
"in a monopole antenna there is one strong source on the END..."

Could you please post the reason(s) you think so?

Note that only the change in current and charge, over time,
produces EM radiation. At the top of a monopole, and at the ends
of a dipole the net current is almost zero -- so those locations
generate very little of the total EM radiation from these antennas.

RF

Richard Fry wrote:
At the top of a monopole, and at the ends
of a dipole the net current is almost zero -- so those locations
generate very little of the total EM radiation from these antennas.

Since the forward current and reflected current are equal
in magnitude and opposite in phase at the ends, they act
like transmission line currents and the magnetic fields
cancel at the ends. They are in phase at the feedpoint -
hence the maximum radiation at that point.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

"Cecil Moore" wrote
...
Richard Fry wrote:
At the top of a monopole, and at the ends
of a dipole the net current is almost zero -- so those locations
generate very little of the total EM radiation from these antennas.

Since the forward current and reflected current are equal
in magnitude and opposite in phase at the ends, they act
like transmission line currents and the magnetic fields
cancel at the ends. They are in phase at the feedpoint -
hence the maximum radiation at that point.

EM means elecro- magnetic. Radiation can start from any of them, See what
Richard Harrison wrote: "At the open circuited ends of a resonant antenna
there is almost double
the forward voltage but zero total current due to cancellation of the
dorward and reflected currents at the open circuit. At the open circuit
in the wire, all the energy in the wave is transferred to the electric
field."
S*

On Fri, 18 Sep 2009 03:47:19 -0700 (PDT), Richard Fry
wrote:

so those locations
generate very little of the total EM radiation from these antennas.

Hi Richard,

The entire radiator radiates, not just portions of it. The phase,
time, distance relationships along the length contribute to a myriad
of characteristics, but they are not separable from the complete
contribution.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
The entire radiator radiates, not just portions of it. The phase,
time, distance relationships along the length contribute to a myriad
of characteristics, but they are not separable from the complete
contribution.

Using the method of moments, each segment contributes
radiation proportional to the net current in the segment.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com