Targeting tower
Encyclopedia
Targeting towers use a special device to ensure an antenna
's stability when strong wind blows.
This system is based on the geometrical properties of the parallelogram
. 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
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.
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 website http://map3.net/mappp/english/video.html.
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
's stability when strong wind blows.
This system is based on the geometrical properties of the parallelogram
Parallelogram
In Euclidean geometry, a parallelogram is a convex 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 equal measure...
. Three vertical rods are used to maintain the top platform horizontal when the tower bends under the wind effect
Structural load
Structural loads or actions are forces, deformations or accelerations applied to a structure or its components.Loads cause stresses, deformations and displacements in structures. Assessment of their effects is carried out by the methods of structural analysis...
. 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
Tower
A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....
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.
Specific tests have been led on a tower-test platform in Livorno
Livorno
Livorno , traditionally Leghorn , is a port city on the Tyrrhenian Sea on the western edge of Tuscany, Italy. It is the capital of the Province of Livorno, having a population of approximately 160,000 residents in 2009.- History :...
(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 website http://map3.net/mappp/english/video.html.