Swisscom-Sendeturm St. Chrischona

Swisscom-Sendeturm St. Chrischona is a communications tower built in 1980-1984 near Basel, Switzerland. It is located at coord|47|34|18|N|7|41|13|E|region:CH-BS_type:landmark|display=inline,title near the St. Chrischona peak, on the territory of the municipality Bettingen, Basel-Stadt.

It was built as replacement for a 136 metre tall lattice tower, which was erected at the site in 1962. This lattice tower was once a part of famous Beromünster transmitter.

The tower is 250 m (820 ft) tall - a 98 m steel antenna on a 152 m concrete base - and not generally accessible for the public, although guided visits can be booked. Apart from television, FM Radio and DAB transmitters, and microwave relays, the tower also contains meteorological instruments, two 100 m³ drinking water reservoirs, and a meeting/conference room near the top of the concrete structure.

Architecture

The television tower Saint Chrischona shows some architecturally specific features. It is remarkable that it is carried by a striking "3-leg-construction," in contrast to most other television towers nearby. It has an aerodynamic shape; with a round shaft, the wind from both sides splits and causes at the rear an effect that keeps the tower from swaying too strongly. The lower part is built star-like, the tower at the apex sways even with strong winds only just up to 30 cm. The “Anntennenspitze” (round construction method), can sway up to 2.5 meters. The microwave radio relay antenna are of a height between 98 meters and 131 meters. VHF antennas are 152 meters high.

On the north side is a construction similar to “backpack” which has a height of 103 meters; two drinking water tanks that are 100 meters high that contain water supplies for the municipality of Bettingen. During the construction, the weight of the water had to be included in the tension of the tower, which is why it stood southwardly inclined before the completion.

The tower stands on a base construction which includes three basements which accommodate company / technical equipment. Because the location of the tower lies in the seismic zone of Basel – Erdbebengebiet in the Upper Rhine district, this has been built especially securely about the base. The tower should remain stable in an earthquake up to 8 on the Richter scale.

The television tower was in construction from July 1980 until December 1983, was put into operation on 2 August 1984. It replaced a 136 meter high steel radio tower that was built in 1962. This tower that was built in 1962 in Beromünster where it carried an antenna together with the today's reserve final tower for middle wave transmission. Saint Chrischona was already in use since 1954, a broadcasting tower that was 30 meters high at that time which transferred the Swiss television program to his time. Today's tower of Saint Chrischona carries broadcasting antennas for the “Southwest Broadcasting Company.” Because of this unique construction, it is said that the tower could remain standing during the high winds of a hurricane, where wind speeds appear up to 220 km/h, with an oscillation of only 40 centimeters.

Technical Data

*The entire height of 250 meters is divided into a 152 m high shaft with a tower basket and a 98 m high antenna
*Architects: Aegerter & Bosshardt
*Civil Engineer work: Vischer & Weber
*Building cost: 50 million Swiss francs
*Concrete volume: 10,000 cubic meters
*Total weight: 23,000 metric tons, of that; 13,500 metric tons in the foundation and 9,500 metric tons in the tower:*Armouring weight; 1,300 metric tons, steel pipe tower, 135 metric tons:*Steel for the antenna terraces: 120 metric tons, introduction steel: 90 metric tons
*Uses:*Transmitter, for the among other things, television programs SF 1 and SF two, the radioprograms DRS 1, DRS 2, DRS 3, Baden-Wurttemberg SWR1, SWR2, SWR 3, Baden-Wurttemberg SWR4, radio Basel 1 and radio basilisk.:*In addition, the tower serves for the radio and phone transference and for the water supply communications. Measuring instruments are, in addition, used for weather forecasting and aerial coordination. In an emergency the tower can be likewise used as a transmitter.

Broadcast television channels

* for the programs on: SF1, SF2, TSI1, TSR1

Broadcast radio stations

External links

*
* [http://www.biennophone.ch/sendestationen.htm#St.Chrischona pictures from the tower]
* [http://www.swisscom.com/SBC/content/Geschfe/Besichtigungen/Inspections.htm (pdf)]