Roomcap -THEORY                                                                             
21th June 2014 (upd 21st Jan 2016)                                                                                 
Felix Meyer HB9ABX                                                                                    

Theory of  Roomcap           

The skim this page without to see the links and to calculate,
this brings you nothing!

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>>> NEW: 29th July 2014
I recomend to read the introduction to the new antenna, to understand the
the idea behind, who was let me to the new construction.
The text in the theory contains little text, and the formulas and the pictures
are better if you read the introduction before this theory!


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First :  Antennas and Physics

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Here are the physical fundamentals, where we exply
in what is the difference to the
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 antenna here  and here
The current flowing in a current creatings a magnetic field, and this field is
called H-field.  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 strenght.
Principle: 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 E-field.         
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 90 degrees.
The two fields are now form a reactive near-field in this the power is stored.
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 field: here and here

To radiate REAL POWER, the product of
     should be
only REAL, therefore the cos(phi) should be at most 1.

cos of  90 degr = 0,   cos von  0 degr = 1               (table with cos values here)

Therefore, my thought was to elimate the phase displacement between E-field
and H-field.

When you take a short radiator, then the cos (phi) >0.95,
however how one can increase the efficiency of the short radiator ?
(A short radiator is shorter than 7% of the wave length)            see  PICTURE
Note: With a long radiator there on "voltage maximum" with E field and
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!        .

NEW          >>>>>>     See these remarks

Then 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:

Picture: MAXWELL

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 plates.
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 current.

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 capacitance.
A classic antenna added a radiation resistance, in order to radiate real power.
The real power is:  U x I x cos(phi). 
The antenna theory states:
P= I x I x Rs   (Rs = serial radiating resistor), there the Rs should be as high
as possible.
And the current ???         
NEW >>>>>>>>>   Read the  remarks 

In the picture MAXWELL should be the capacitance as possible high, because
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 CAPACITOR:

Picture: "open capacitor"  (on the right)

With open capacitor the E-field can radiate in the room.

This always 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 can
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
                                       emerges new properties.

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.

(A 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 the planes:
                        "CURRENT OVER PLANES"
Out from this planes flows the current into the environment.

The electromagnetic wave flies in form as photons into the space. A wire antenna
generates virtual photons in the near-field, and then in the transition zone (here) the
photons emerge to radiate then from the far-field in the space. A possible explanation
is, why the high efficience
of this antenna, the virtual photons have not to be
converted to photons.

Note: The 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 in wire".

When I apply the Maxwell Equations for "current over planes", then
new formulars result!
(In picture "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!   See here  and  here 
- To understand this better, see the important >>> remarks

>>>  Important points:

- separate the "open capacitor" from the coax by a current choke,
- use a
(nearly) lossless impedance transformer before the "open capacitor",
- isolate of the counter plane from the "ground".

efficiency of the Roomcap was measured to be 87% on 40 m!
The analyse with measuring and calculating is here availabe.
The signal measured by more than 25 automatic station in Europe,
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 comparison station
- 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
(with RBN evaluting and analysing).
The RBN evaluating with text and pictures is here

>>>  The field strengh documented 4 to 10dB stronger than the comparison stations!
(with QSB compensated )
             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 !

A request: Please let me know your opinion about this theory. I wanted to exclude mathematic
discussion, but we go more into details, math becomes very important.
Read the "comments" to get more details info.
- 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 capacity"
can compete with a good dipole.
His conclusion:
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 not successful.
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 comments:

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 program.

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 deg

See the results of the invigation obtained Gerd Janzen obtained with his best short version.