Targeting towers use a special device to ensure an
antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
's stability when strong wind blows.
This system is based on the geometrical properties of the
parallelogram
In Euclidean geometry, a parallelogram is a simple (non- self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of eq ...
. Three vertical rods are used to maintain the top platform horizontal when the tower bends under the
wind effect. The top platform is pin connected to the mast, thanks to a special mechanical link based on universal joint system. The system allows to reduce the size and the weight of the towers, because contrary to standard poles, stiffness is not needed.
In standard
tower
A tower is a tall structure, taller than it is wide, often by a significant factor. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures.
Towers are specifi ...
s, the antenna beam's rotation must not exceed a certain angle (currently between 0.5° and 2°), otherwise the communication is cut. This design criterion is more severe than the resistance criteria and leads to use twice the steel quantity.
Targeting towers have been used for the first time in 2004 in Italy for high
radar supporting poles
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weat ...
.
Specific tests have been led on a tower-test platform in
Livorno (Italy). The test used 2 cameras filming simultaneously a target meanwhile the pole was submitted to dynamic oscillations. One being fixed on the pole and the other on the top platform. The results of this test are shown on an external websit
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Radio frequency antenna types
Antennas (radio)