"Richard Fry" wrote
...
On Sep 21, 12:23 pm, Szczepan Bia³ek wrote:
You only do not realize that EM waves can start from the ELECRIC field.
The
electric field is radiated from the ends where is high voltage and no
current.

No, Szczepan, it is you that does not realize that voltage, alone,
cannot produce an

Let us assume that electromagnetic field is a proposition by Maxwell.
The electric field is more realistic.

Only the change in current and charge flowing along a conductor, over
time, produces far-field EM radiation. That radiation includes both
the magnetic and electric fields, at right angles to each other and to
the direction of travel.

It is untrue that one part of a conductor or antenna radiates the
magnetic field, and another part radiates the electric field, no
matter the claims of the proponents of the E-H antenna (which have not
been demonstrated).

But it is experimentally proved. Stationary charge - electric field, Moving
charge - magnetic field.
Probably the both fields are the same. Only instruments are different.

The fact that the ends of a dipole, and the top of a monopole have
very little net current flowing means that those locations cannot
contribute very much to the EM radiation from those antennas.

But there are the doubled voltage. Very strong pulses must appear in space.

You really should form your opinions from research in modern textbooks
on antennas, rather than using Wikipedia and inapplicable analogies to
sound waves. At a minimum you could recognize the quotes from them on
this subject that already have been posted here.

Up to now the acoustic analogy is fully applicable.
S*

RF

On Sep 22, 3:34*am, Szczepan Bia³ek wrote:

Up to now the acoustic analogy is fully applicable.

Not if one understands the physics of radiation.

But it is experimentally proved. Stationary charge - electric field,
Moving charge - magnetic field.

Untrue, and I challenge you to cite any credible experimental data
that you think proves your belief.

Far-field EM radiation is produced only by the current flow on the
antenna, and that radiation contains BOTH the electric and the
magnetic fields.

You may have missed the accurate description posted by Chris, and
pasted below.

"The acceleration of charge in an antenna results almost entirely from
the
applied potential difference at its terminals. The radiated fields
result
from the alternating current effectively passing through the radiation
resistance, and all the other, reactive, fields have no direct effect
on the
radiation resistance, or the component of the current that passes
through it
in phase with the voltage that is developed across it, which together,
of
course, represent the radiated power. The reactive fields affect the
terminal impedance and a large imaginary part can upset the device
trying to
send power into the antenna, but that is more of a system issue. The
alternating current that passes through the radiation resistance is
composed
of charge that moves in time with each RF cycle, accelerating and
decelerating accordingly. The electrostatic field developed between
the
ends of a half-wave dipole reaches its maximum value a quarter of a
cycle
later than the voltage at the drive point so any effect it has on the
charge
in the antenna elements during each cycle must be reactive, and it
doesn't
affect the radiation resistance or the radiated wave."

RF

"Richard Fry" wrote
...
On Sep 22, 3:34 am, Szczepan Bia³ek wrote:

Up to now the acoustic analogy is fully applicable.

Not if one understands the physics of radiation.

Physics of radiation is unknown. Antennas are the nice apparatus to analyse
it.

But it is experimentally proved. Stationary charge - electric field,
Moving charge - magnetic field.

Untrue, and I challenge you to cite any credible experimental data
that you think proves your belief.

Far-field EM radiation is produced only by the current flow on the
antenna, and that radiation contains BOTH the electric and the
magnetic fields.

For me the magnetic field is the illusion.

You may have missed the accurate description posted by Chris, and
pasted below.

"The acceleration of charge in an antenna results almost entirely from
the
applied potential difference at its terminals. The radiated fields
result
from the alternating current effectively passing through the radiation
resistance, and all the other, reactive, fields have no direct effect
on the
radiation resistance, or the component of the current that passes
through it
in phase with the voltage that is developed across it, which together,
of
course, represent the radiated power. The reactive fields affect the
terminal impedance and a large imaginary part can upset the device
trying to
send power into the antenna, but that is more of a system issue. The
alternating current that passes through the radiation resistance is
composed
of charge that moves in time with each RF cycle, accelerating and
decelerating accordingly. The electrostatic field developed between
the
ends of a half-wave dipole reaches its maximum value a quarter of a
cycle
later than the voltage at the drive point so any effect it has on the
charge
in the antenna elements during each cycle must be reactive, and it
doesn't
affect the radiation resistance or the radiated wave."

My description is shorter:
The supply unit sends the voltage pulses (in opposite phase) in the
transmissing line. If such pulses collide the voltage is doubled and the
strong radiation take place. In straight radiator the forward pulse collides
with the reflected. In folded dipoles with that from the other wire.
S*

On Sep 23, 5:46*am, Szczepan Bia³ek wrote:

Physics of radiation is unknown.

Perhaps to you at this point, but not to many others who read the
posts here and elsewhere.

RF

Szczepan Białek wrote:

Physics of radiation is unknown. Antennas are the nice apparatus to analyse
it.

The physics has been known for a very long time now.

You are a babbling idiot.

For me the magnetic field is the illusion.

Any semblance to reality of your "thinking" is an illusion.

snip

My description is shorter:
The supply unit sends the voltage pulses (in opposite phase) in the
transmissing line. If such pulses collide the voltage is doubled and the
strong radiation take place. In straight radiator the forward pulse collides
with the reflected. In folded dipoles with that from the other wire.
S*

Yet more babbling nonsense of an idiot kook.

Did you tire of being constantly spanked for being a babbling kook in
sci.physics and decide maybe your chances of being accepted are better
in an amateur group?

Guess what, a lot of amateurs are engineers and actually understand the
theory.

Hell, even those that are not engineers obviously understand it a hell of
a lot better than you do.


--
Jim Pennino

Remove .spam.sux to reply.