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HB9ABX > ANTENN 11.04.08 19:00l 134 Lines 5748 Bytes #999 (0) @ WW
BID : JZ5ZKAHB9EAS
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Subj: Antennas and Physics
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Sent: 080411/1416z @:HB9EAS.CHE.EU [Basel JN37TM] DP6.00 $:JZ5ZKAHB9EAS
From: HB9ABX @ HB9EAS.CHE.EU (Felix)
To: ANTENN @ WW
Antennas and Physics / Felix Meyer, HB9ABX, April 11th 2008
Antennas are structures, which convert electrical oscillations of
a line into radio waves in space, and respectively convert radio
waves into electrical oscillations in a line.
In classical theory, an antenna is treated as a device, where an
oscillating current flowing in a conductor produces a (electro)
magnetic field (EM field), which converges into E and H field,
to an electromagnetic wave (EM wave) travelling in space.
The exact cause of the EM wave is said to be acceleration of
electric charge.
http://electron9.phys.utk.edu/optics421/modules/m1/production.htm
This theory, concentrated on the "current in the wire", was leading
to the development of the traditional antennas as: dipols, yagis,
LPSs, verticals, loops and so on.
This theory is correct, however it does not represent the full truth.
Only one half of the physics is considered here, because EM
waves are not only generated by time varying magnetic fields,
but also by dynamically varying electric fields.
This fact became clear to me by studying the Maxwell equations,
and by thoughts gained through quantum physics, especially
through the behaving and the properties of photons.
( http://en.wikipedia.org/wiki/Maxwell's_equations
http://en.wikipedia.org/wiki/Photon )
In the Maxwell equations you find the Gauss' law, the Maxwell-
Faradays law of induction, and the expanded AmpŠre's circuital
law. They describe the dynamic interaction of the curly electric
and magnetic field, and the current.
Technical handbooks treat EM waves throughout as waves,
generated by oscillating current in a conductor, where the
radiation begins. Accordingly the formulas are established.
The frequently used antenna simulation program NEC (EZNEC)
and its family does not (yet) allow to define and simulate my
new antenna construction.
As a consequence, special "antenna rules" were createt, based
on this one-side view.
As an example, a good antenna guide lists the following
golden rules for antenna design:
1. Much wire in the air will bring the best results
2. As high as possible (antenna at ground level is bad)
3. Current radiates (ARRL Handbook: current produces the
radiated signal)
Furthermore, most antenna books write, that antennas with the
higher radiation resistance radiate more, and that short
antennas generally have a very low efficiency.
All these rules are based on the experience gained during
many years of work with traditional wire antennas.
Now I don't want to say, that these rules are wrong, but I have
to limit applicability of them: They are only valid for antennas
based on the physical law of wave generation by oscillating
currents in a conductor.
Traditional antennas are based on this principle.
For antennas, based on the wave generation by dynamically
changing electric fields (E field antennas), these rules do
not apply.
The intention for my new antenna design was, to produce a
maximum dynamic E field in the space around the antenna.
During the last 3 years I built such antennas and conducted
many field tests, comparing this antenna with traditional wire
antennas. The result was, that an antenna with 150cm radiator
length (= 5 feet) at a wavelength of 40m produced constantly
the same signal strength, and many times a stronger signal at
the remote station by comparing with dipols, verticals, G5RV,
FD3, and longwires.
The transmit power and the location were identical, and during
the qso many switchovers between the test antenna and
comparing antenna were made.
The hight above ground of the base of the new antenna was
only 50cm to 150cm, while the comparing antenna was in
its original hight!
Hundreds of tests were made from 10m to 160m wavelength,
and always the same result was obtained. The length of the
radiator on 160m was just 3m!
I published many of these tests in the internet under
"New HF Antenna".
The following criterias apply for the "New HF Antenna":
- areas (planes) are used, which form in the space a capacity,
in which the E field is produced.
- these areas have to be arranged in a special manner, open
into space (a capacitor with two directly opposed plates
produces practically no radiation).
- the feedline may not be part of the antenna. The line is not
allowed to radiate.
- feeding of the antenna has to be floating, without reference
to ground.
- the impedance has to be adjusted such, that the SWR
is below 1.5
- the dimension of the areas has to be small in relation to the
wavelength. (Length of the radiator < 7% of the wavelength,
otherwise the phase difference of the E field is reducing the
radiation efficiency).
In my realisation, feeding is made by the "varylink". This is part
of the antenna structure and permits to obtain a SWR below 1.1
on each band.
This has the advantage, that the antenna does not require an
antenna tuner.
Other realisations:
Others have also developed antenna types, which are using the
principle of E field wave generation. E.g. Isotron, Microvert,
EH-Antenna (Crossfield antenna CFA) and similars.
All these realisations do not fulfill all criterias listed above, and
therefore their efficiency is 8 db to 18 db less than the
"New HF Antenna".
Future:
Development of additional versions of this antenna continues.
The significance of this antenna will be important, due to many
restrictions in available space, and regulations to errect traditional
antennas with their large physical dimensions.
COPYRIGHT: This article may be copied and used, provided this
is done in its entirety. No editing or change of any kind is permitted.
Felix HB9ABX
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