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G3TXQ Broadband Hexagonal Beam Sketches

G3TXQ Broadband Hexagonal Beam Sketches

The G3TXQ broad band hexagonal beam for 6 – 20 meters is constructed of six fiberglass arms and 14 or 16 gauge stranded copper wire. The center post is made of PVC water pipe. The beam is fed at the top of the center post with 50 ohm coax and weighs about 25 pounds. The hexagonal beam consists of two elements for each band. The driven element is in the shape of an “M” and the reflector element is wrapped around the four spreaders to the rear of the driver wires. The elements are made of wire instead of tubes used by most yagi antennas. Therefore there is a need for a supporting structure. The supporting structure consists of six flexible fiberglass arms attached to a base. The arms are as shown and thus the name hexagonal beam.

The antenna elements are held in place by the base/tube structure, the wires and kevlar/dacron cords. All bands of the antenna are fed by a single coax cable.

To the right are sketches of how the G3TXQ broad band hexagonal beam is configured for a single band. A sketch of the wires of a five band hexagonal beam is also shown to the right.

In late 2007 Steve Hunt, G3TXQ, conducted extensive testing and modeling of many variations of the classic hexagonal beam seeking to overcome its narrow banded deficiency without sacrificing the simplicity and small size. The design featured in this G3TXQ broad band hexagonal beam is the result of his efforts in this regard. It has a turn radius of 11 ft but has a significantly broader frequency response than the original hex beam, is easier to build and easier to adjust and tune. A full explanation of the design is available on Steve’s web site. An overall comparison of the new broad band design and the classic design is also available there.

The guidelines presented here are based on my own construction of the G3TXQ broad band hexagonal beam in several iterations beginning with the version documented in my QST article of March 2009. We began offering the hexagonal beam for sale in 2009 and it has been improved substantially over the QST version. These guidelines reflect some of those improvements.