Quadrant antenna
A quadrant antenna is a transmission antenna used in the shortwave range (KW) for high transmission powers with horizontal omnidirectional characteristics and is used, among other things, for the transmission of radio programs on shortwave. The quadrant antenna was developed by N. Wells in 1944.
The quadrant antenna consists of a whole-wave dipole stretched horizontally a few meters above the ground on masts , which is constructed as an angular dipole with an angle of 90 ° and is also referred to as an L-dipole . At an angle of 90 °, there is an almost uniform omnidirectional pattern in the horizontal plane. At the vertical angle , the main beam direction is in the range from 30 ° to 40 °. The antenna gain is approx. 6 dBi with good ground reflection .
Quadrant antennas are used for transmission powers in the order of magnitude of 100 kW up to 500 kW, they achieve ranges of up to 1,500 km due to the omnidirectional characteristics. The antenna is fed at the bend of the angular dipole. Due to the high transmission power and the resulting high voltage of a few kilovolts , the conductors of the antenna are designed as bundled conductors with a large outer diameter. In this way, disruptive corona discharges on the antenna lines can be avoided.
literature
- Alois Krischke (DJ0TR): Rothammels Antennenbuch . founded by Karl Rothammel. 13th edition. DARC Verlag, Baunatal 2014, ISBN 978-3-88692-065-5 , p. 1167 .
Individual evidence
- ↑ a b Quadrant Antenna for Shortwave Radio Broadcasting. Retrieved May 31, 2015 .
- ^ N. Wells: The quadrant aerial: an omni-directional wide-band horizontal aerial for short waves (= Electrical Engineers - Part III: Communication Engineering . Band 91 , no. 16 ). IEEE, 1944, pp. 182-193 , doi : 10.1049 / ji-3-1.1944.0040 .