Radome (antenna dome)

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A very large radome from the Fraunhofer Society (formerly FGAN ) in Wachtberg
Radome over the parabolic antennas for receiving satellite television on a private yacht
Radar station near Putgarten on the Baltic Sea

A radome ( Engl. Radome , a suitcase word from dome radar , plural: radome or radomes), also radome , a closed protective sheath antennas for measurements (eg. Radar antennas ) or (eg. For data transmissions directional antennas ) before protects against external mechanical and chemical influences such as wind or rain.

use

Nose of a CRJ as a radoma

Radoms can be found on permanently installed large radar systems (e.g. air traffic control radar ) and on ships . Smaller radomes are used for radio links , satellite antennas on vehicles or small ships, and also for meteorological measuring devices. They take the wind load from the antenna system (which is usually designed to be movable for the purpose of tracking) and protect the antennas on ships against the corrosive effects of seawater . The bow fairing of aircraft with a navigation or weather radar in the aircraft nose is also called a radome.

In particular, radomes keep weather influences (wind, precipitation) away from the antennas. In the case of aircraft, they have to withstand air resistance . On naval ships, they also protect against unwanted viewing. Radio astronomy antenna systems can be positioned more precisely if a radome prevents the influence of wind. In contrast, the additional attenuation by the radome cover (depending on the material about 1–2 dB) is accepted.

For the protective cover around a radar, materials must be used that are particularly permeable to radio waves (short-wave electromagnetic waves). They should reflect , absorb , break , scatter or change their polarization as little as possible . Materials for radomes that meet both the required mechanical and electrical properties are essentially glass fiber reinforced plastics (organic resins such as epoxy resins, polycarbonates or polyethylene terephthalates) for applications in the lower temperature range and ceramics ( aluminum oxide , beryllium oxide ) for high temperature stress. Foam-like materials are also used for sandwich core layers. On the floor, triangular to hexagonal elements made of glass fiber reinforced plastics are used, which are then joined together to form a self-supporting spherical shape, often a geodesic dome . The first radome was made in 1941 from Plexiglas for an experimental S-band radar of a Douglas B-18 A.

Air domes made of flexible materials are also well suited . They get their shape from a slight overpressure inside and can be entered through pressure locks. Their disadvantage is that these air domes deform in strong winds or storms and thus the shell gets into the area of ​​the rotating antenna. For safety reasons, antenna rotation must then be switched off from a given wind speed in order to avoid damage to the antenna.

A radome can also be used to hide the antenna system inside. Outside observers cannot then infer the technical equipment inside. Military facilities in particular are often optically protected by radomes (e.g. Großer Arber , the lower-lying radome for the former radio altimeter ).

The world's largest radome , that of the Fraunhofer-Gesellschaft (formerly FGAN ), is in the small village of Werthhoven in the municipality of Wachtberg .

Despite the mostly light color of the radome, solar radiation and the waste heat from the systems housed inside the radome cause temperatures that have to be reduced to a level that is tolerable for people and technology using forced ventilation or air conditioning .

Radomes in Europe

Radoms of the Bad Aibling Station used by the secret service

Germany

Radome as a weather radar station for the German Weather Service DWD in Dreieich-Offenthal
Radar station at Stockholm / Bromma Airport , also known as "the golf ball".

Austria

Sweden

Switzerland

France

The Pleumeur-Bodou radome and its facilities were built for the transmissions of the first “ Telstar ” satellites in 1961 (first transmission on July 11, 1962). The opposite station was in the USA in the city of Andover (Maine) .

The radome has a height of 50 m and consists of a 2 mm thick shell made of Dacron . The covered area is about 10,000 square meters (and would thus offer space for the triumphal arch in Paris ).

Inside the radome there is a rotatable and swiveling horn antenna (54 m long, 30 m high, mass 340 t) for the frequency of 137 MHz. Received signals were pre-amplified directly at the antenna with frozen amplifiers and fed to further stages.

Today there is a communication museum on the site. The radome can be visited and the antenna can be viewed. There are also film screenings in the Radom. The Radom is a listed building.

See also

Web links

Commons : Radoms  - Collection of Images
Wiktionary: Radom  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ Florian Pfeiffer: Analysis and optimization of radomes for automotive radar sensors . 1st edition Cuvillier, Göttingen 2010, ISBN 978-3-86955-333-7 .
  2. ↑ Erwin Baur: Introduction to Radar Technology . Springer-Verlag, 2013, ISBN 978-3-663-01400-3 , p. 43 ( limited preview in Google Book search).
  3. ↑ DJ Kozakoff: Analysis of radomes-enclosed antennas . Artech House, 2010, ISBN 978-1-59693-442-9 , pp. 3 ( limited preview in Google Book Search).
  4. ↑ Christian Magerl: Written question from Member of Parliament Dr. Christian Magerl wind turbines and radar. ( PDF ; 26 kB) p. 1 , accessed on June 16, 2011 .
  5. ↑ Erich Schmidt-Eenboom , Snoopers Without a Nose: The BND - the uncanny power in the state , Econ Verlag , 3rd edition, 1993, p. 227, Bundestag printed matter: BTD 11/7669 of August 13, 1990
  6. ↑ Patrik Müller: BND listening post in Rheinhausen allows insights for the first time , Badische Zeitung , February 11, 2015
  7. ↑ The Swiss weather radar network. Federal Office for Meteorology and Climatology , November 29, 2016, accessed on March 23, 2017 .

Visitor information of the "Parc du Râdome" Pleumeur-Bodou / Bretagne