Transmitter of television

The transmitting television or radio-FM are vertical structures (metal or out of concrete) of self-supporting type, stayed, tripod, whose site was particularly studied. They are generally placed to close-cropped-countryside, on high points or in the center of a vast plain to profit from the best release. The importance of the terrestrial Curve and the local Géomorphologie has a decisive influence on the range of a transmitter, also depending on the Fréquence or spectrum of work.

Constructions

The majority highest and important pylons of transmission (TV, radio, telecom etc) are stayed, but in urban area because of the lack of place for the side anchoring of the stays on the ground, the pylons (known as then " autostables") are built on the basis of quadripode or tripod (Mulhouse, RTL-Dudelange, Anlier etc), such as for example the Eiffel Tower: it is a broadcast transmitting station of TV, radio and telecommunications strategic important.

The transmitter highest of France is located at the Aiguille of the South in the Solid mass of the Mont Blanc.

The two higher stayed pylons of France are: - the transmitter long waves of France Inter with Allouis close to Bourges a 354 m height (Source TDF Allouis). It is the highest construction of France. - the transmitter TV and MF of Mans-Mayet (72) with 342 Mr. (Source TDF).

The most powerful transmitter of analogical television in France east that of the Rock Trédudon in Finistere with 703 kw BY in UHF (BY being Apparent Power Radiated which takes account of the profit of the antennas).

In other countries, in particular in Germany, the transmitters are often placed on lathes supporting at the same time the equipment of power of the transmitters, the antennas and panoramic restaurant turning as to Cologne, Hamburg or Berlin.

Operation

The transmitters are today mainly controlled (fed in programs) by the satellite S, received on professional Parabole S. One still uses point-to-point connections called radio-relay systems which use frequencies of about 3 GHz with 8 GHz to transmit, by jumps of approximately 50 km, the signals since the primary source or the centers secondary towards the network of transmitters. The signals are then converted into VHF or UHF, presenting some polarization. They can be returned towards the local relay transmitters, i.e. points of secondary réémission with more low power. The latter is expressed in radiated P.A.R or apparent power, which corresponds to the power of the source amplified by the profit of sending antenna.

The majority of the transmitters are of omnidirectional type, i.e. they radiate on 360° according to the importance and of the particularism of the zone to be served. However, as private individuals for the installation of the TNT and in order to limit the covering of the frequencies by close transmitters, several transmitters use one-way antennas. It is for example the case of transmitter TNT of the Mount-Ventoux whose diagram of radiation is directed south-western (towards Avignon), elsewhere it will be thus impossible to receive the TNT even if the Mount-Ventoux is seen.

The French transmitters and relay transmitters diffuse the 6 national chains secam and some to 18 chains in numerical quality within the framework of TNT, like sometimes of the TV local met in the greatest agglomerations. The broadcast transmitting stations can also accommodate the telephone services mobile. They accommodate also directional parabolas intended for the routing of the signals of the reports TV or radio. Today, of the satellite connections are also used for this purpose.

With the Congo-Brazzaville, for example, there exists the center transmitting CCT located at Tangombo, a northern district of Brazzaville. This center thus allows the diffusion of the emissions in all the town of Brazzaville like in its surroundings.

See too

the pylon of Mans - Mayet as well as many others are the property of TDF
the reception antennas for the TNT
Qualité of reception in terrestrial television
Coverage area, definition, Exemple: Transmitting French collected in French-speaking Switzerland

Photographs

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