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. 3 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
towers, 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
[1].
antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. In other words, antennas convert radio frequency electrical currents into electromagnetic waves and vice versa.
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In geometry, a parallelogram is a quadrilateral with two sets of parallel sides. The opposite sides of a parallelogram are of equal length, and the opposite angles of a parallelogram are congruent. The three-dimensional counterpart of a parallelogram is a parallelepiped.
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Structural loads are forces applied to a component of a structure or to the structure as a unit.
In structural design, assumed loads are specified in national and local design codes for types of structures, geographic locations, and usage.
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tower blocks. In the United States, the now-destroyed World Trade Center had the nickname the Twin Towers, a name shared with the Petronas Twin Towers in Kuala Lumpur.
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In 2004, 9 Radar supporting poles have been installed in Italy for sea survey purpose. These poles are designed for extreme climatic conditions (222 km/h wind speed, with 24 square meter on the top). The tilt angle of the radar must not exceed 0.5° under a 160 km/h wind.
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Country Italy
Region Tuscany
Province Livorno (LI)
Mayor Alessandro Cosimi
Area km
Population
- Total (as of December 30, 2004)
- Density /km
Time zone CET, UTC+1
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