Radio masts and towers
A transmission tower is usually a guyed at backstays construction of steel truss or tubular steel with a over the entire height of constant cross -section (see also Mast ). It is designed to accommodate antennas for broadcasting purposes, or for direct use as a transmitting antenna (mast antenna, even radiant transmission tower ).
Compared to free-standing radio towers made of steel or concrete towers are to be constructed cheaply. They vary in wind usually more than free-standing constructions same amount. Because of Pardunenfundamente they have a higher footprint as freestanding structures.
One problem with radio masts is the danger of wind-related vibrations. This is very large especially in tubular steel poles. One can reduce this tendency to oscillate in which incorporating cylindrical vibration in the structure. You find such vibration that look like cylindrical thickening, for example, the masts of DHO38 in Saterland.
There are also constructions (usually from reinforced concrete ) consist of a freestanding tower, on top of which a guyed radio mast is mounted on the ground. The best known such construction is the Gerbrandytoren in Lopik (Netherlands). Further towers of this design are available at Smilde (Netherlands) and to 2009 in Waldenburg (Baden- Württemberg, Germany ).
As a self- radiating transmission tower but they are usually superior to an isolated erected tower of high- frequency technical point of view, because they have a lower Fußpunktkapazität and a constant cross section, which can be made thinner than a free-standing structure, which gives better radiation properties. However, there can be problems with parasitic currents, which flow through the backstays, so they must be divided in most cases with insulators or on foot via a choke coil (or trap) must be grounded. When divided by insulators backstays can occur when thunderstorms static discharge, and surge arresters are parallel to the insulators needed, which require regular maintenance, which is associated with high costs because of their inaccessibility.
Inductors and capacitors of the resonant transformer and lightning protection devices are often housed in a separate Abstimmhaus. This is either immediately adjacent to the transmission tower or acts in some constructions as a stand for the transmission tower.
To allow access to the components of the transmission tower, which require specific maintenance, such as flight safety lamps, transmitting antennas, equipment or Pardunenabspannungen, a ladder is always provided. These can be mounted inside or outside the structure. For steel tubular poles it is mounted of weather protection reasons, mostly inside. In some transmission towers for shrinkage -reducing transmit antennas with multiple feeding the ladder from the mast structure in the lower part is isolated and acts as a feeder for convenient above the separating insulator mast part. In such constructions ascents of the mast in the current transmission mode is not possible. and it is to be used for maintaining the transmission mode during maintenance work on a different transmit antenna mast or adjust the transmit mode. Some towers also have an elevator, which is almost always implemented as a self-propelled climbing elevator static reasons and is driven by an electric motor or an internal combustion engine. Such a device is very useful in transmission towers with extremely high height or with many facilities that require maintenance. There are also some insulated from earth itself radiating transmission towers, where a lift is installed.
Some very high masts for FM radio and TV in the U.S.
The license terms in the U.S. allow you to send in most of the country from a maximum height of 2000 ft ( = 610 m) above ground. In shallow regions masts were erected for sending actually, which are so high. In the U.S. there are (as of 2008 ) a total of around 100 masts with heights of over 550 m. Especially many of them - 20 - are in North Carolina.
The KTVE Transmission Tower is a 609.6 meter high guyed mast for the distribution of FM and TV programs in Bolding, Arkansas, USA ( Geographical coordinates: 33 ° 4 ' 41 "N, 92 ° 13' 41 " W33.078055555556 - 92.228055555556 ). The KTVE transmission tower was completed in 1987 and is the property of Grapevine Communications.
The WTVZ Transmission Tower is a 381 meter high guyed mast for the distribution of FM and TV programs in Suffolk, Virginia, USA ( Geographical coordinates: 36 ° 48 '32 "N, 76 ° 30 ' 11 " W36.808888888889 - 76.503055555556 ). It was completed in 2002 and is owned by American Tower.
The KTUL transmission tower is a 581.86 meter high guyed mast for the distribution of FM and TV programs in Coweta, Oklahoma, USA ( Geographical coordinates: 35 ° 58 '8 " N, 95 ° 36' 56 " W35.968888888889 - 95.615555555556 ). The KTUL transmission tower was completed in 1988 and is the property of KTUL, LLC.
The KDLT Transmission Tower is a 609.3 meter high guyed steel lattice mast near Rowena, South Dakota, USA ( Geographical coordinates: 43 ° 30 ' 18 "N, 96 ° 33' 23" W43.505 - 96.556388888889 ). It was completed in 1998 and is used for distribution of television programs and radio programs on the FM band, and is the property of Red River Broadcast LLC.
The KBIM transmission tower is a 559.92 meter high guyed mast for the distribution of FM and TV programs in the vicinity of Roswell, New Mexico, USA ( Geographical coordinates: 33 ° 3 ' 20 " N, 103 ° 49' 14" W33 .055555555556-103.82055555556 ). It was completed in 1965 and is owned by Emmis Television.
The KLKN Transmission Tower is a 565.1 meter high guyed mast for the distribution of FM and TV programs in Genoa, Nebraska, USA ( Geographical coordinates: 41 ° 32 ' 28 " N, 97 ° 40 ' 46 " W41.541111111111 - 97.679444444444 ). It was completed in 1969 and is owned by Citadel Communications.
The KLDE transmission tower is a 615.1 -meter-high radio mast for FM radio and TV near Angelton in Texas, USA ( Geographical coordinates: 29 ° 17 ' 17 "N, 95 ° 13' 54" W29.288055555556 - 95.231666666667 ). This completed 1986 transmission tower is currently the fourth tallest building in the world and owned by Clear Channel Broadcasting.
The KPXM transmission tower is a 458.72 meter high guyed mast for the distribution of FM and TV programs in Big Lake, Minnesota, USA ( Geographical coordinates: 45 ° 23 '0 "N, 93 ° 42' 31" W45.383333333333 - 93.708611111111 ). It was completed in 1997 and is owned by Paxson Minneapolis / KXLI.
The KVLY mast is a 629 meter high radio mast in North Dakota and was from 1963 to 1974 and from 1991 to 2008, the tallest man-made structure.