G5RV antenna

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G5RV Antenna

The G5RV antenna is a dipole with a symmetric resonant[1] feeder line, which serves as impedance matcher for a 50 Ohm coax cable to the transceiver.[2][3] Louis Varney (G5RV) invented this antenna in 1946.[4] It is very popular in the United States.[5] The antenna can be erected as horizontal dipole, as sloper or an inverted-v antenna. It can operate on all amateur radio bands within 3.5 through 30 MHz.[5][6] While the widely used 50 Ohm coax cable is often used to directly feed this symmetric antenna,[7] this is not good practice and should be avoided as it can result in RF interference due to high current flow on the outer surface of the coax braid. A 1:1 current balun should be used between coax and ladder line.[8]  The balun not only prevents RF interference but reduces receive noise and of course increases performance [9]

The dipole elements are 15.55 metres (51.0 ft) and the impedance-matching symmetric feedline (ladder-line) can be either 300 ohm (8.84 metres or 29.0 feet) or 450 ohm (10.36 metres or 34.0 feet).[10] As for all antennas in general the height of the G5RV above the ground shall be at least half of the longest wavelength to be used.[1] The ends of the symmetric feedline are directly soldered to a 50-Ohm coax cable to the transceiver.[2] A length of at least 20 metres (66 ft) 50 Ohm cable is recommended.[11] An antenna tuner is necessary for this antenna.[10]

There are many variants of the G5RV antenna.[12]

References[edit]

  1. ^ a b HF Antennas for all locations (L. Moxon, G6XN)
  2. ^ a b G5RV multi-band antenna (Louis Varney, G5RV) http://www.astrosurf.com/luxorion/qsl-g5rv.htm
  3. ^ The G5RV Multiband Antenna ... Up-to-Date (L. Varney, G5RV in The ARRL Antenna Compendium Vol. 1)
  4. ^ Practical Wire Antennas - Effective HF Designs for the Radio Amateur (J. Heys, G3BDQ)
  5. ^ a b ARRL Antenna Book 21st Edition – Chapter 7
  6. ^ Novice Antenna Notbook (D. DeMaw, W1FB)
  7. ^ Rund um die Antenne (M. Rüegger, HB9ACC) http://www.wreiner.at/2008/05/24/rund-um-die-antenne-von-hb9acc/
  8. ^ Maxwell, W. (2010). Reflections III Transmission Lines & Antennas
  9. ^ What I learned from building my own G5RV / ZS6BKW Antenna (VK4MDX) http://vk4mdx.wordpress.com/2009/02/15/what-i-learned-from-building-my-own-g5rv-zs6bkw-antenna-part-1/
  10. ^ a b Practical Antenna Handbook (4th Edition, J. Carr)
  11. ^ HF Antenna Systems: The Easy Way (J. M. Haerle)
  12. ^ The ZS6BKW Multiband HF Antenna Revisited (M. Vincent, G3UKV) http://www.ab4oj.com/dl/sprat_zs6bkw.pdf