Ještěd Tower

The tower foundation consists of a circular reinforced concrete slab with a thickness of 1 meter and a diameter of 13.40 meters . The foundation is laid in the altitude of 1004.75 meters.[13][14] The load-bearing element of the structure consists of two concentric reinforced concrete rollers with inner diameters of 4.4 and 12.5 meters (and a wall thicknesses of 30 centimeters);[14][15] the narrower is 42.4 meters high, the wider (external) is 22.5 meters high.[16] On the tubes the individual floors are suspended on a steel structure, starting with the second floor.[4] The columns were manufactured by Průmstav Pardubice.[16] The supporting steel structures for the floors and for the tower structure were manufactured in the Mostárna plant in the then state-owned company Vítkovice Iron Works of Klement Gottwald. A steel shell with a length of 44 meters of a variable diameter (from 10.50 meters to 1.62 meters) is attached to the inner column [14] The laminate support roller (diameter of 1.90 meters and a wall thickness of 16 to 12 millimeters) attached to it, originally had a length of 17.52 meters which was extended another 3 meters during the 1997 reconstruction.[14][17]

Restaurant interior

In the basement of the building, there are engine rooms and warehouses. The first floor is shared by the administrative offices and the television transmission hall that is connected to the antenna systems on the ninth floor by means of an elevator and an emergency staircase built inside the central tube. The rest of the first floor is occupied by the restaurant kitchen. On the second floor there is an observation terrace, a buffet and the main entrance hall with the reception desk. The hall is dominated by a suspended staircase leading to an observation restaurant on third floor.[4]

On the fourth and fifth floor there are hotel rooms. On the fourth floor there are 12 double rooms and one apartment. Rooms on the fifth floor were originally used as flats for the hotel and transmitter employees but were later converted to hotel apartments. The sixth and seventh floors house the transmitting technology. There is a specially developed laminated cladding in the shape of a revolving hyperboloid[2] shielding against extreme weather conditions. On the eighth and ninth floors the architect placed drinking water tanks and a backup battery power supply. There is an elevator engine room on the tenth floor.[4] Above it a special pendulum is installed, movement of which absorb cross vibrations caused by the wind.[2]

Jiri Jiroutek Phenomenon Jested 01

At the third to the fifth floor levels (i.e. the restaurant and hotel floors) the outer shell takes on the shape of a conical rotating surface. It consists of 64 conically placed panels. The panel surface is made of anodized aluminium sheets. At the restaurant level, these panels are glazed over the entire width and complemented by a low window sill, while at the hotel level there are smaller windows with rounded corners.[4]

Parabolic antennas of microwave transmitters are located on the seventh and eighth floors. The building cover is made of trapezoid-shaped laminated panels, which are not joined by any metal elements, as these would prevent the passage of electromagnetic waves. The upper side of the elevator machine room on the tenth floor is fitted with a welded steel tube, which forms a 48 meter high antenna mast. Its surface is covered with metallized aluminum and a spiral staircase leads up inside the tube. An the top of the mast there is a self-supporting laminate extension of 18 meters attached. During the 1997 transmitter reconstruction it was extended by another 3 meters. The extension is there to protect the TV broadcast antennas against the elements. On top of the extension there is a steel lid, on which an annular pendulum weighing 800 kg is suspended by means of dampers.[4]

Glass emblems mounted on the concrete transmitter shaft

The interior design including its furniture comes from Otakar Binar. Cookware and some textile accessories were based on Karl Wünsch designs. Glass makers Stanislav Libenský and his partner Jaroslava Brychtová also participated in the interior furnishing. They originally planned inserting a tall glass pendulum in the publicly accessible space. The pendulum would consist of two lenses representing the eternal movement. Instead, they decided to drill eight glass emblems into the concrete transmitter shaft. According to the artists, the shaft and its modification suggested the tower was growing up from the rock. On the other hand, for Karel Hubáčekt the glass emblems embodied fallen meteorites. The author of the trellis located in the hotel corridor is Jaroslav Klápště. The staircase walls and the hotel corridors are lined with ceramic tiles designed by Děvana Mírová. The entrance doors and the hotel reception walls are covered with wrought sheets by Miloš Koška, the tapestry hanging on the lounge wall was created by Vladimír Křečan.[4]

On 1 May 1971, the transmitter (equipped with Tesla III-Zona) [18] began broadcasting television signal [4] from the new tower. In September 1973, broadcasting of the second Czechoslovak Television program was added.

After the Velvet Revolution, the transmitter (using a Tesla equipment) was spreading signals of Czech Television (ČT1 and ČT2), Nova and Prima and Czech Radio (Radiožurnál, Praha (today Dvojka) and Vltava) and of private operators ( Radio Proglas, Radio Contact Liberec and Europe 2).

In connection with the broadcasting digitization in the Czech Republic, in June 2009 the antenna systems in the laminate extension were updated.[18]

In addition to radio and television broadcasting, Jested is also an important node for radio relay and optical links.[18] Mobile operators T-Mobile, O2, Vodafone and Nordic Telecom have base stations (BTS) here.[19]