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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, descends from the
radio-electric circuitry for the
suppression of anyone of the two branches of a ˝ of wavelength open dipole
and from the virtual ground balun for
doubling the ˝ wavelength folded dipole antenna.
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.
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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:
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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 allows an antenna to exhibit a sharper radiation
pattern 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.
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Applications:
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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
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