The G5RV antenna is a

dipole In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways: *An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system ...

with a

symmetric Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definiti ...

resonantHF Antennas for all locations (L. Moxon, G6XN) feeder line, which serves as impedance matcher for a 50 Ω coax cable to the

transceiver In radio communication, a transceiver is an electronic device which is a combination of a radio ''trans''mitter and a re''ceiver'', hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. Thes ...

.G5RV multi-band antenna (Louis Varney, G5RV) http://www.astrosurf.com/luxorion/qsl-g5rv.htm

Origin

Louis Varney (G5RV) invented this antenna in 1946. (Heys, J. (G3BDQ). Practical Wire Antennas - Effective HF Designs for the Radio Amateur It is very popular in the United States.American Radio Relay League. ''ARRL Antenna Book'', 21st ed. Chapter 7 The antenna can be erected as horizontal dipole, as sloper, or an inverted-V antenna. With a transmatch, it can operate on all HF amateur radio bands (3.5–30 MHz).

Impedance

The dipole elements are and the impedance-matching symmetric feedline (ladder-line or twin-lead) can be either 300 Ω () or 450 Ω ().Carr, J. ''Practical Antenna Handbook'', 4th Edition. As is in general the case for all electric antennas, the height of the G5RV above the ground should be at least half of the longest wavelength to be used. The ends of the symmetric feedline can be soldered directly onto a 50 Ω coax cable to the transceiver, however this is not good practice and should be avoided: It can result in high current flow on the outer surface of the coax braid, causing RF interference and degrading the polarization and gain of the antenna. A 1:1 current

balun A balun (from "balanced to unbalanced", originally, but now dated from "balancing unit") is an electrical device that allows balanced and unbalanced lines to be interfaced without disturbing the impedance arrangement of either line. A balun ...

should be used between coax and

ladder line Twin-lead cable is a two-conductor flat cable used as a balanced transmission line to carry radio frequency (RF) signals. It is constructed of two stranded or solid copper or copper-clad steel wires, held a precise distance apart by a plastic ...

. Including a balun not only prevents RF interference but reduces receive noise and increases performance A length of at least of 50 Ω cable is recommended for operation without a balun. A transmatch (antenna tuner) is not required to use this antenna near its nominal design frequency of 14 MHz, and judicious length adjustments can sometimes include one other frequency band. All other frequencies require a transmatch. There are many variants of the G5RV antenna. Two variations of the G5RV design, called ZS6BKW and W0BTU, can match several more amateur bands between 3.5–28 MHz without a transmatch.Vincent, M. (G3UKV). The ZS6BKW Multiband HF Antenna Revisited.
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References

Antennas {{radio-comm-stub