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 Earth")
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.

Following the publication of the studies on the behaviour of a balanced transmission line in a progressive wave regime, a variant to the virtual ground monopole HF antenna is disclosed here below:

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.

Scientific relevance:

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)

Operational advantages:

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 antenna. 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 ground. e. the VIRTUAL GROUND MONOPOLE HF ANTENNA offers a much stronger immunity to out-of-band emissions compared to conventional full-size aerials. 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 aerials. 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.

Applications:

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 Ohm Errante's multiband HF antenna system

Price: 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. RADIONDISTICS' products carry an unconditional lifetime guarantee.