Purpose of this article: This article describes the basics of the G5RV Antenna – a multi-band HF wire antenna

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Why a G5RV Antenna?

  • A multi-band antenna originally designed to fit a 30.5m (100ft) long UK suburban house block covering 80M to 6M
  • A G5RV Junior design is available (Best on 30M 15M & 10M)
  • A good antenna to experiment with and offer flexible deployment options
  • Fairly easy to build

 

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Parts

Stranded hard drawn copper wire is preferred, however copper wire will stretch. Some constructors use stainless steel wire.
 Ladderline 450Ω (TTS Systems)

1:1 Balun (See Text)
 Co-Ax Cable RG-58 or RG8X

Center and end insulators (See Text)

UV proof Rope.

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Construction or installation notes

 

Building a G5RV

  1. Cut the lengths of wire required. Total length around 31.09 meters.
    • The window line is used to mach the G5RV. Window line is also known as Ladder Line and Open feeder which is rated by its impedance at radio frequencies. If your window line is 300Ω (TV Ribbon) the length is 8.5M. Ladder line at 450Ω the length is 10.4M
    • Keep the Co-Ax run as short as practical. RG58 is fine at HF.
    • Decide what layout options will work for your QTH (Steer well clear of power lines, telephone lines, TV antennas)
    • Try to get the antenna as high as practically possible.
    • What options do you have to hold the dipole in the air? Mast? Trees? Buildings?
    • The G5RV will work as an inverted “V”.
    • What will you use as insulators for the centre feed-point and ends?
    • How will you weather-proof the open joins to the wire antenna elements?
    • According to some texts, the use of a balun is not essential, however this will ensure that RF is kept out of the shack and the antenna radiates the RF.

Things to consider when building a G5RV

  • Tet Emtron have a suitable centre insulator, just put the SO239 in your useful junk box. You could also make your own centre feed-point insulator by cutting/sawing an acrylic cutting board to size.  Drill and file holes for the wires, feedline and rope.
  • End insulators are available from many sources. A bag of Electric Fence insulators are exactly the same as amateur radio ones and may work out cheaper.
  • Whilst a bit messy, you can use silicon sealer and/or self-amalgamating tape to provide a level of weather proofing.  You could also build a small box to house the connectors
  • You could buy a commercial balun which will make you antenna system more efficient.   Tony VK3TZ from Rippletech provides a great local product, as does Mark VK6MOA from Tet Emtron.
  • Ask for help at your local club.  G5RV antennas make great club projects and learning opportunities. Buying in bulk reduces costs.
  • Performance of your G5RV will depend on your local site and may require tuning. Do not cut the wire – just fold back the excess against the antenna and only trim when satisfies with the VSWR.

MOUNTING CONSIDERATIONS

Your installation may not be textbook perfect. Try and make your antenna as high as practicable and keep the ladder line away from objects especially metal ones. You can make your antenna an inverted “V” if this fits your situation better.

Links to G5RV articles.

Louis Varney’s G5RV Antenna construction and analysis
Half-size G5RV – 80m conversion for a small garden (G5RV Jr) 

G5RV U-Shape Installation – G8ODE

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Images

 

 

 

 

 

 

 

 

An example of 1 to 1 Balun https://www.tetemtron.com.au/product-p/tb-11k.htm 

Tet Emtron TB-11K Kit

 

Examples of Centre Insulator