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Here above is the Errante's antenna
laboratory prototype in a quick fan-monopoles deployment for the 20, 30, 40,
60, 80 and 160 meter bands operation.
N.B. Shown without the ABS weatherproof outer enclosure.
Freq. range: from 1 to 30 MHz
RF Power: 2KW CW
Click on the thumbnails to view larger
ANTENNA : what it is, how it works and how it came to be
VIRTUAL GROUND ¼ of wavelength
MONOPOLE (HF) ANTENNA
by Francesco Errante
The Author, by means of a particular
radio-electric circuitry for the suppression of
anyone of the two branches of a ½ of wavelength open dipole, has previously
demonstrated that, indeed, it is possible to receive and above all, transmit
large radio-electric signals across the space by employing a single
radiating/captating element of a physical length equal to ¼ of wavelength,
without the necessity of the presence of its symmetric (see Hertzian
Dipole ) or the necessity of a natural ground plane (see Marconi's
Antenna ) or an artificial one made of radials or counterpoises as in
the Ground Plane Antenna. The need to have the Earth or another
artificial ground as an electric reference point to correctly polarize a
single resonant radiator/captator of a physical length equal to ¼ of a
wavelength, has been eliminated by generating a virtual ground node,
the existence of which is function of the precise balancing of the of a
broad-band RF transformer. ("virtual ground" is defined as a point in an
electrical circuit that appears to be at ground, but is not actually attached
to ground, it is therefore, a node having a 0 degree phase angle difference
with respect to ground and has the same electrical potential as the
This method, however, implied a 50% dissipation of the system energy.
The invention described hereby eliminates the need for sacrificing
any of the system energy by exploiting the very same physical principal of
the virtual ground node.
The solution to that problem is
given by the possibility of generating the virtual ground node by
recombining two radio-electric signals, identical but 180 degree out of phase
between them-selves. This can be achieved by employing a broad-band
flux-coupled balun transformer(9) built around a binocular type ferrite core,
having a center-tapped balanced primary winding(11) for the obtainment of the
said virtual ground node to be used as a zero-potential reference
point for the whole of the circuit, through the conductive chassis(10)
and having also a secondary winding(13) exhibiting an impedance value of 150 Ohm
for the direct coupling to a ¼ of a wavelength radiator/captator(1).
The transformer(9) and the radiator/captator(1) are the essential parts of
the VIRTUAL GROUND ¼ of wavelength MONOPOLE ANTENNA, they alone,
infact, constitute a ¼ of wavelength monopole antenna with balanced input.
However, in order for it to match the current transmission line standards, it
has been necessary to provide it with a second transformer(5) capable of
adapting the unbalanced coaxial antenna output of a conventional transceiver
to the balanced input of this antenna transformer(9). The virtual ground node(6),
obtained on the secondary winding of the transformer(5),
is made available to the circuit through the conductive chassis(4).
The RF energy transfer between the two transformers(5 & 9) is
accomplished by the twinned coaxial transmission
lines(7) which can be of any length but must be identical between
them-selves so not to alter the original phase-angle difference between the
RF signals they are meant to be carrying. Although, the value of impedance of
the intermedium circuit, which comprises the primary winding of the
transformer(9), the twinned coaxial lines(7)
and the secondary winding of the transformer(5) can be set to any value, it
turned out to be convenient adopting a standard value of 50 Ohm.
It is of a paramount importance that the impedance
of local transformer's(5) secondary winding, the impedance of the open wire
balanced transmission line(7b) and the impedance of the remote
transformer's(9) primary winding be exactly the same.
a. it demonstrates that a single electrically
conductive element of a physical length equal to ¼ of wavelength is
all it takes to accomplish natural resonance and full radiation.
b. thanks to its most elementary shape and bare simplicity of the
radiating element, it allows further investigation into the physics
of the radiowaves. (see here)
a. the VIRTUAL GROUND MONOPOLE HF ANTENNA
demonstrates that, indeed, it is possible and relatively inexpensive
to implement an highly efficient way to better radiate RF energy
while cutting by 50% the room needed to deploy a full-size HF
b. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
larger bandwidth compared to conventional full-size aerials.
c. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
stronger immunity to parasitic capacitive effects compared to
conventional full-size aerials.
d. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers high
resonance stability regardless of the level and inclination above the
e. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
stronger immunity to out-of-band emissions compared to conventional
f. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
stronger immunity to electrostatic charges and noises compared to
conventional full-size aerials.
g. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a sharper
radiation pattern than conventional full-size aerials.
h. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
faster deployment time compared to conventional full-size
i. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much
better E.M.I. compatibility with highly populated environments
compared to conventional full-size aerials.
a. SHORT WAVES FIXED & MOBILE RADIO STATION FOR
CIVIL & MILITARY PURPOSES
b. STEALTH, FAST & TACTICAL DEPLOYMENT PURPOSES
c. SEARCH & RESCUE SERVICES
d. SHIP to SHIP & SHIP to SHORE MARINE COMMUNICATIONS
e. AIRCRAFT COMMUNICATIONS RANGE EXTENDING ANTENNA
f. DX-ing and metropolitan HAM RADIO STATIONS
g. ELEMENT in ARRAYS of AERIALS
h. RADIO-PHYSICS LABORATORIES
most F.A.Q.: can I drive 2 or more
monopoles simultaneously, as in a fan dipole configuration, so
that I can cover several HF bands? ANSWER: Yes ! The present virtual ground RF feeding
system allows you to run all the ¼ of wavelength monopoles needed to
give you a general coverage of the HF spectrum, without the need for
switchings. The monopoles can be arranged on both vertical and
horizontal planes. Space is all you need to deploy them. Now, also available for the 225 OhmErrante's multiband HF
Euro 700,00 +V.A.T. and shipping costs.
For an useful currency converter click here
NB. Price DOES NOT INCLUDE the
cost of the twinned coaxial line, nor the radiators, which, however,
can be supplied on request.
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