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An axonometric view of the balun balun for our multibanda antenna system balun for our multibanda antenna system balun for turnstile antennas

HF Turnstile antennas broadband driver, NOW available as standard! Find out more here.

Errante's 2x225 Ohm virtual ground balun for the dipole-like center-fed folded monopoles multiband HF antenna system Find out more here.

 

ERRANTE's BALUN

Virtual ground balun for dipole & loop

A state-of-the-art high power broadband HF balun

 

Patent n.0001347484 (ITAPA20030019) and
Patent n.0001347486 (ITAPA20030021)
Visit www.uibm.gov.it and enter Francesco Errante in the search box to see all of my patents, or verify it directly from the European Patent Office archive HERE

External view of the balun enclosure held up in the air, without the dipole's branches connected to it

Errante's 50/70 Ohm virtual ground balun
Freq. range: from 1 to 30 MHz
RF Power: 2KW CW

Click on the thumbnails to view larger pictures
Virtual ground balun seen from the socket compartment access side An axonometric view of the balun enclosure Particular of the coaxial socket compartment Side view of the balun weatherproof enclosure


N.B. The balun pictured above is available as standard for the following impedance values:

NEW! unbalanced 50 Ohm input to a 225+225 Ohm balanced output to suit the Errante's 225 Ohm, multiband HF antenna system ;

unbalanced 50 Ohm input to a 70 Ohm balanced output to suit an ˝ wavelength open dipole antenna;

unbalanced 50 Ohm input to a 300 Ohm balanced output to suit an ˝ wavelength folded dipole antenna;

unbalanced 50 Ohm input to a 50 Ohm balanced output to suit an ˝ wavelength inverted Vee dipole antenna;

unbalanced 50 Ohm input to a 200 Ohm balanced output to suit a full wavelength, single turn, Deltaloop antenna.

Any other impedance values combination to be manufactured upon special order.

 

ERRANTE's BALUN : what it is, how it works and how it came to be made.

by Francesco Errante

The virtual ground balun presented hereby is the practical application in the field of the short wave radio communications of what the Author has previously created for scientific purposes. It, infact, along with the virtual ground balun for doubling the ˝ wavelength folded dipole antenna, descends from the radio-electric circuitry for the suppression of anyone of the two branches of a ˝ of wavelength open dipole.

Errante's balun is, essentially, a pure electrical transformer which, in its most elementary layout, has a minimum of 3 tuned circuits: a primary circuit (primary winding LC network) and 2 secondary circuits (secondary windings LC networks).
Generally, the Errante's balun secondary circuits are identical to each other in order to feed symmetrical balanced antennas. When necessary, the secondary windings can be formed to have impedance values different between each other, while maintaining the phase angle difference of the balanced terminations to a constant ±90 degree with respect to the virtual ground node. Moreover, as all the pure electrical transformers, Errante's balun can be made to have more than a couple of secondary windings.

Errante's balun is characterized for NON allowing any impedance transformation to take place unless its terminations impedance values are matched (NON-fluctuating impedance).
Errante's balun terminations impedance values are set by design, hence the impedance transformation ratio is a function of them and not viceversa, unlike it happens with any other balun arrangement.
See for example the Guanella's or the Ruthroff's transformers which are instead characterized by having a fluctuating terminations impedance values, as they are nothing else than an arrangement of auto-transformers, their input and output circuits are unseparable and, therefore, any change made to their primary circuits will inevitably affect their secondary circuits.
In practice, a balun having a fluctuating termination impedance value carries out its impedance transformation duty within a very ample range of impedance values, changing its input termination impedance according to the one of its load and viceversa. Therefore, supposed we have a Guanella's type balun with a transformation ratio of 4:1, it will show an input impedance of 75 Ohm if its load impedance is of 300 Ohm, or it will show an input impedance of 50 Ohm if its load impedance is of 200 Ohm. This cannot happen if an Errante's type of balun is employed, because each termination impedance value is a fixed property of the relevant termination and does not vary even if there is a change in the values of the impedance of the circuits (antennas or transmission lines) connected to them.
By limiting the line-load system impedance to the imposed values only, it is possible to inhibit both lines and loads (antennas) from giving origins to unwanted resonances, which are, generally, harmonic resonances, very often deriving from the presence of more than a load on the same feed-point, which generates alternative paths for the RF.
(for example: multiple dipoles o monopoles, fan antennas and so on). This is something not to be underestimated, not only with regard to the transmitting phase but and above all, to the receiving phase as well. Employing a NON-fluctuating impedance balun, infact, introduces a very high rejection to interfering radio signals from sources outside the bands of the radio spectrum for which an antenna is ment. This translates in an excellent stability and selectivity of the transmission line or antenna systems which employ Errante's baluns.

A virtual ground balun represents the ideal device for the correct feeding of dipole and loop antennas. The virtual ground balun carries out many functions at once allowing to:
1) match the RF source impedance to the chosen load while introducing neglectable insertion loss of power;
2) transform the RF signal fed to it into two identical portions with the correct phase angle difference for the natural feeding of open or folded dipoles and loop antennas;
3) obtain a virtual ground node for the correct polarization of its unbalanced port;
4) obtain a common ground path for the dissipation of the charges induced by the electrostatic phenomena;
5) obtain an high de-coupling between its two balanced ports.

The generic virtual ground balun's schematic diagram is shown here below.

VIRTUAL GROUND BALUN - Errante's balun

The virtual ground balun is housed inside a weatherproof rugged metal enclosure having two separate compartments: one hosts the balun circuitry while the other one protects the coaxial connectors. The said metal enclosure not only ensures an high mechanical robustness and a total stability against the weather agents, it also works as the general electric conductor for all the references to the virtual ground node. Such an enclosure ensures also a full electrostatic shielding of the RF balun transformer circuitry.

Radiondistics claims the originality of the balun's unique electromechanical layout, as well as the balun radio-electric circuitry.

Operational advantages:

a. the virtual ground balun allows the feeding of dipole and loop antennas with much less loss than conventional baluns

b. the virtual ground balun allows an aerial to exhibit a much larger bandwidth compared to when the same antenna is fed by a conventional balun.

c. the virtual ground balun allows an antenna to exhibit a much stronger immunity to parasitic capacitive effects compared to when the same antenna is fed by conventional baluns.

d. the virtual ground balun allows an antenna to exhibit a strong resonance stability, regardless of the level and inclination of it above the ground.

e. the virtual ground balun allows an antenna to exhibit a much stronger immunity to out-of-band emissions compared to when the same aerial is fed by a conventional balun.

f. the virtual ground balun allows an antenna to exhibit a much stronger immunity to electrostatic charges and noises compared to when it is fed by a conventional balun.

g. the virtual ground balun, owing to the constructive and destructive interference phenomena taking place in the transformer allows the dipole antenna to exhibit a sharper radiation/reception pattern (off the beam axis signal rejection) compared to the same aerial when fed by a conventional balun.

h. the virtual ground balun allows a much faster antenna deployment time compared to conventional baluns.

i. the virtual ground balun allows an antenna to exhibit a much better compatibility with highly populated environments (EMC TVI) compared to when it is fed by a conventional baluns.

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. DX-ing and metropolitan HAM RADIO STATIONS

f. ELEMENT in ARRAYS of AERIALS

g. RADIO-PHYSICS LABORATORIES

see also SWR-metered balun

 

Unconditional Lifetime Guarantee

Prices:
Euro 250,00 +V.A.T. and shipping costs.
N.B. The price of the new 50/225+225 is Euro 500,00 +V.A.T. and shipping costs.
For an useful currency converter click here








RADIONDISTICS' products carry an unconditional lifetime guarantee.

Schematic diagram of Guanella's and Ruthroff's baluns

Schematic diagrams of the Guanella's and the Ruthroff baluns

 

 

All the concepts, methods, designs and devices presented on this web site
are the original novelty works of FRANCESCO ERRANTE.
Patents & Copyright © 2003- of FRANCESCO ERRANTE.

Material is governed by the Copyright, Designs and Patent Act.
No reproduction, in whole or in part, without written permission.
Copies of these documents made by electronic or mechanical means, including information storage and retrieval systems, may only be employed for personal use.
All rights reserved.


All rights reserved. Copyright © 2003- Francesco Errante
www.Radiondistics.com - Tel.(+39) 339.180.1313