Beverage antenna
A beverage antenna (also known as a wave antenna ), named after its developer Harold Henry Beverage , is a long-wire antenna at a relatively low height that is fed from one side and the end of which is grounded via a resistor. This shifts the symmetrical radiation pattern of the dipole in the direction of the grounded antenna end, reducing the backward radiation . In the diagram, the arrowhead marks the earthed side. With a length that is five to ten times as large as the wavelength, a backward attenuation of about 10 dB can be achieved. Due to the one-sided supply, the antenna has a high resistance and requires a transformer for impedance matching .
The beverage antenna is one of the so-called "aperiodic antennas". It is not in resonance with the operating wavelength.
The overall efficiency of a beverage antenna is just as bad at 1% as that of the symmetrical design . This disadvantage is offset by the independence of the operating wavelength, which makes tuning to this wavelength largely unnecessary. This is an advantage in the commercial sector. In addition to the rhombus antenna, the beverage antenna is also used here and there for broadcast purposes. Another advantage is the low installation height, which rarely exceeds a few meters.
For radio amateurs it is usually only used for reception purposes, with the 160 meter band being preferred. Due to its broadband, it is also very well suited for the 80-meter and 40-meter tape .
See also
literature
- Ulrich Freyer: Antenna technology for radio practitioners. 1st edition, Franzis-Verlag GmbH, Poing 2000, ISBN 3-7723-4693-6 .
- Karl Rothammel , Alois Krischke : Rothammels Antennenbuch. 12th edition, DARC Verlag Baunatal, ISBN 3-88692-033-X .