21th June 2014
f (upd 21st Jan 2016)
Felix Meyer HB9ABX
The skim this
page without to see the links and to
this brings you nothing!
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NEW: 29th July 2014
recomend to read the
introduction to the new
antenna, to understand
the idea behind, who was
let me to the new
The text in the theory
contains little text,
and the formulas and the
are better if you read
before this theory!
Here to the INTRODUCTION
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First : Antennas
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Here are the physical fundamentals, where we
in what is the difference
classic wire antenna. See
first Link above.
The principle in a classic antenna is :
Current in wire
The principle in Roomcap antenna :
Current over planes
Theory of classic
flowing in a current creatings a magnetic
field, and this field is
I = current, r = distance from
wire. And: here
Units of H-field = A/m
H = I /
(2 . phi . r)
The voltage produces an E-field around the
wire. As higher the voltage,
as higher is the E-field.
Units of E-field = V/m
Look a half
wave dipole, we see the voltage and
Current in wire
Picture: Half wave dipole
green= voltage, red = current
We see the following:
- At both ends of dipole = maximum voltage,
there the current is zero.
- At the center = maximum current, and the
voltage has minimum.
Correspondingly, we have a strong H-field in
the center of the dipol,
and we have at both ends H-field zero. At
boths ends we have strong
E-fields, and in the center we have a minimum
This field at the antenna is called "near-field".
This near-field radiates NOTHING, as no power
is radiating, because the
product of E-field x H-field = (nearly) NONE.
The both fields at the dipole are dephased by
The two fields are now form a reactive near-field in this the power is
Then, in the "transition zone" in which within
a few longwaves the "far field"
In the "far field" the E-field and H-field are
in phase to each other.
You can more
information about near field and far
To radiate REAL POWER, the product of
only REAL, therefore the cos(phi) should be at
cos of 90 degr = 0, cos von
0 degr = 1
(table with cos
Therefore, my thought was to elimate the phase
displacement between E-field
When you take a short radiator, then the cos
however how one
can increase the efficiency of the short
(A short radiator
is shorter than 7% of the wave
With a long radiator there on "voltage
maximum" with E field and
See these remarks
at "current maximum" with H field, whereby
these both fields are shift by 90
degrees, and therefore form a "near field"
that does not radiate.
Only then at distance a radiating filed
emerges, where the E field and H field
are in phase, and then we have a "far field",
where we have action at a distance.
Thanks to the short radiator, where we have a
"far field" in the Roomcap!
to the MAXWELL's equations:
These equations describe the relation between
the electric an magnetic
properties. See here
Now, the understanding is different, and
nearly nobody is capable to
understand this fully. These equations are in
differential or integral
form, and one learn only how the mathematical
rules are used.
Who understandes what these equalitions mean ?
Here I will try to explain my thoughts:
You see in it the current I, which produces
the H-field, and you see,
between the two plates a field H, without
having a conducter there.
In the capacitor is the E-field between the
The AC voltage is connected to the capacitor,
and therefore a AC current flows
in the wires to the capacitor. Now a current
flows inside the capacitor, which
generates a H-field between the plates.
This current is called displacement
The current I in the wires and the current in
the capacitor are in phase,
because wires and capacitor are in serie.
The voltage U is dephased by 90 degrees to
current I in the capacitor.
The E-field can not escape, because the plates
are shielding the own field!
With the circuit above can not radiate real
power, because cos(phi) ist here 0.
In order to obtain real power, real resistors
have to added, either in serie to
the conductor, or in parallel to the
A classic antenna added a radiation
resistance, in order to radiate real power.
The real power is: U x I x
The antenna theory states:
P= I x I x Rs (Rs = serial
radiating resistor), there the Rs should be as
And the current
Read the remarks
In the picture MAXWELL should be the capacitance as possible high,
greater C, the greater
is the I.
Therefore, many tried to build a small
C-antenna (EH-Antenne, CFA, Isotron,
HB9AKN), and more others.
Success: They failed, because their
efficiency is so low, and hence unusable.
Why ?: The E-field is between the cap
plates, therefore the E-field is shielded.
Here a new idea:
What happens, if we open a capacitor?
Now, we will find out something very
interesting, as we see below:
Therefore introduction of : OPEN
Picture: "open capacitor" (on
capacitor the E-field can radiate
in the room.
described as capacitor, where two plates are
parallel position to each other.
Hence, the E-field is shielded from the
environment by the plates, and the E-fields
not leak the capacitor. However, you orient
the plates such, that shows above, the E-field
and the displacement
current can flow in to the room
(environment), and hence
Observation: A (parallel) radiation
resistance appears in the "open capacitor"
(in the free room), and this receives the
transmitter power and radiates the
power as wave in the room.
This is now the principle
of the ROOMCAP antenna.
closed capacitor has (ideally) a infinite
high parallel resistance).
The "open capacitor" comprised of plane
below (counter plane) and of the
vertical plane. The two planes should see
each other as few as possible.
The direct capacitance is nearly zero, the
capacitance to the room is great.
Here I say, when the current flows over
"CURRENT OVER PLANES"
Out from this planes
flows the current into the environment.
The electromagnetic wave flies in form
into the space. A wire antenna
photons in the near-field, and
then in the transition
photons emerge to radiate then from the
far-field in the space. A possible
is, why the high efficience of
this antenna, the virtual photons have
not to be
converted to photons.
dimension of plane here (radiator),
where the length is shorter than 7 % of
the wave length. When one spreak about aperture
antenna (horn, parabolic), then
the dimension the antenna is 0.5 length to
many times the length the wave length.
This is a complete different thing!
The formulars for antennas origin from Maxwell
equations, whereby in
always the basis was "current
When I apply the Maxwell Equations for
"current over planes",
new formulars result!
"Maxwell" exchange the
capacitor by "open capacitor")
AND: This a very interisting
observation: Roomcap has only far-field !!!
The far-field begins at the Roomcap antenna!
The Roomcap antenna has no near-field!
(The measurement has showed, that the
intensity of E und H reduces with 1/r,
his the property of the far-field!
- To understand this better, see the important
>>> Important points:
- separate the
"open capacitor" from the coax by a current
- use a (nearly) lossless
impedance transformer before the "open
- isolate of the counter plane from the
The efficiency of the Roomcap
was measured to be 87% on 40 m!
with measuring and calculating is here
measured by more than 25 automatic station in
in distance range between 140 km to 2500 km.
The comparison with stations using wire
antennas during long time.
- antenna in normal heigth
between 6 to 20m above ground
- my position within distance of 200m from
- both stations use the same power
- in CW
- at the same time
- automatic transmission
- 1 hours long automatic measuring, Roomcap in
auto on the street
RBN evaluting and
The RBN evaluating
with text and pictures is here
>>> The field
strengh documented 4 to 10dB stronger than
the comparison stations!
Info about RBN system here .
There is no better
prove of the function of a antenne than
the reports, which are measured by the
remote stations !
Please let me know your opinion about
this theory. I wanted to exclude
discussion, but we go more into details,
math becomes very important.
Read the "comments" to get more details
- Tell me know typing errors.
Thanks for your email here.
(Note: The construction
guide is available, that construction is
corrent, see here
To better understand the eletromagnetic wave generation:
Now follows a result from Gerd Janzen,
where he tried with a test with a short antenna.
He investigated, if a short antenna with "super large top
can compete with a good dipole.
A such antenna is 7.89 dB or 9 dB weaker
than a normal dipole.
On below I will explain, why his best version was
The ROOMCAP in real measuring with RBN
versus den G5RV,
FD-3, Titanex Vertical GP 40/10 ,CP-6, etc. was ever stronger
than the comparing antennas.
The full report from Gerd Janzer is here (only in German)
Below see pictures from the Gerd Janzen simulation, added my
This the definition of the "super top capacity"
antenna with 2m diameter, 1m long vertical
radiator, and 6 radials, each one 2m long. Using EZNEC
Radition diagram: Antenne above ground =
0.05 m, Frequency = 14 Mc
"Top capacity antenna" = -4.30 dbi at 30 deg
"Super-C-Antenna" = -5.44 dbi at 30
See the results of the invigation
obtained Gerd Janzen obtained with his best short