Hexbeam
A Hexbeam , also Hexagonal-Beam or Upside-Down Umbrella , is a design of a directional antenna for shortwave and ultra- shortwave , which is used especially in the amateur radio sector. Since the antenna is hexagonal, it is called a hexbeam. It is also known as a W antenna because antenna elements are W-shaped. In simplified terms, the design looks like an umbrella turned up.
The antenna design is a modified form of the Yagi-Uda antenna . It consists of a W-shaped dipole and a reflector. As with the Moxon antenna , the directors are missing. Your antenna gain is between 5 dBi and 6 dBi , the forward / backward attenuation is up to 20 dB.
For shortwave, the Hexbeam is made with six arms made of non-conductive materials such as B. fiberglass - or plastic pipes are built, to which the metallic antenna elements are then insulated from wires. Originally two W-shaped antenna elements were attached here. This antenna is first introduced in 1996 by Mike Traffie, N1HXA. Steve Hunt, G3TXQ, investigated this Classic Hexbeam as there were conflicting experiences from users and do-it-yourselfers with antenna gain , bandwidth and forward / backward attenuation. Hunt published his improvements in December 2007 in the online magazine AntennaX as broadband Hexbeam. Hunt changed the dimensions and shape of the antenna elements. With the Broadband Hexbeam, for example, the emitter is still designed in a W shape, while the reflector is more U-shaped or semicircular.
Radio amateurs like to build the Hexbeam as a multi-band antenna to cover different frequency ranges. The combinations for 20 m , 15 m and 10 m (3-band) and the combination for 20 m, 17 m , 15 m, 12 m and 10 m are popular . m (5-band) amateur radio bands. Hexbeams are also built for the 40 m and 30 m tape. The antenna elements (wires) for the lowest frequency band are located outside. When building multi-band hexbeams, the vertical spacing of the individual elements is critical. The elements of a multi-band Hexbeam influence each other and if the elements do not run parallel, parameters of the antenna are changed undesirably.
literature
- Alois Krischke, Karl Rothammel: Rothammels Antennenbuch . 13th edition. DARC Verlag, 2013, ISBN 978-3-88692-065-5 , Chapter 17.2.5.10: Hexagonal Beams (17 .: Horizontal HF directional antennas).
Individual evidence
- ↑ http://www.swschwedt.de/kunden/dm2ble/Hexbeam-G3TXQ/hexbeam-g3txq-ab.txt ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Miniature Antennas, Communications Quarterly, Spring 1996, p. 99 ff.
- ↑ Archive link ( Memento of the original dated December 12, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
