Science Fair Project Encyclopedia
Warsaw radio mast
The Warsaw radio mast was the tallest structure ever built; however, it only existed from 1974 to 1991. Designed by Jan Polak, it was 646 meters (2,120 feet) tall and weighed 420 short tons (380 t). Construction was finished on May 18, 1973 and broadcasts were officially launched on July 30, 1974. The mast was located in Konstantynów, Poland at 19°48'23" E longitude and at 52°22'14" N latitude(), and was used by Warsaw Radio-Television (Centrum Radiowo-Telewizyjne) for long wave radio broadcast on the frequency 227 kHz (before February 1st, 1988) and 225 kHz (after February 1st, 1988). The mast was insulated against ground for a voltage of 120 kV and stood therefore on a 2 metre high insulator. It served as an aerial of half wavelength for the used frequency 225 kHz. The signals from its 2 megawatt transmitters could be received across all of Europe, North Africa and even in North America.
The Warsaw radio mast was a frame steelwork construction of steel tube. It had a cross section in form of a triangle. All three sides of this triangle had a length of 4.8 metres. The diameter of the steel tubes forming the edges of the construction had a diameter of 245 millimetres, the thickness of the walls of these tubes varied depending from the height between 8 and 34 millimetres. The mast construction consisted of 86 elements. Each element had a length of 7.5 metres. The mast was guyed in 5 levels with guys of 50 millimetres diameter, which were divided into multiple sections by special insulators. The weight of guys and insulators used for anchoring the mast was 80 metric tons. For better access to the flight safety lamps and other components of the mast, there was an elevator installed in the interior of the mast. The elevator had a maximum speed of 0.35 m/s and required 30 minutes for a trip from the bottom to the top of the construction.
The transmission building, which had a volume of 17000 cubic metres, was approximately 600 metres away from Warsaw radio mast. It contained the transmitter consisting of two 1000 kilowatt units built by Brown Boveri and Cie with a power of 1000 kilowatts. To the radio station, which had an area of 65 hectares, also belonged a mast for directional radio service for the radio-link to the studio.
The official name of the facility was Radiofoniczny Oorodek Nadawczy w Konstantynów, Radiowe Centrum Nadawcze w Konstantynowie or Warszawska Radiostacja Centralna (WRC) w Gabinie.
On August 8, 1991, the mast collapsed during renovation work. Three people were killed and 12 injured when it fell. As early as April 1992 the Polish government proposed rebuilding the tower, but this was successfully opposed by local residents.
After the collapse of the radio mast at Konstantynow, the Polish broadcasting company used the old transmitter of Raszyn with its 335 metre high mast near Warszawa, which is used since 1978 during daytime for the transmission of a second programme of the Polish broadcasting service in the longwave range on the frequency 198 kHz, for transmissions on 225 kHz with a power of 500 kilowatts. It is not possible to transmit from Raszyn on 198 kHz and 225 kHz simultanously, so the transmissions on the second longwave frequency 198 kHz had to be discontinued until either a second longwave broadcasting transmitting facility was built in Poland or a special frequency switch, which would allow transmissions on both frequencies would be installed at the transmitter Raszyn. The latter, more simple sounding solution would have decreased the effecitivity and reliability of both transmitters and was therefore inacceptable.
Because the Polish longwave transmitters are especially for the Polish people abroad from big importance, it was soon planned to rebuild the mast at Konstantynow. Unfortunately this was not possible due to protests by local residents, so a new transmitter site had to be found for the second Polish longwave transmission facility. This was found in form of an old military area near Solec Kujawski. On this site a new longwave transmitter facility with a transmitter of 1000 kW HF-power for the frequency 225 kHz was built from 1998 to 1999, the Longwave-transmitter Solec Kujawski. The new transmitter uses as aerials two grounded masts 330 metres apart from each other with heights of 330 and 289 metres and went in service on September 4, 1999. After the inaugauration of the transmitter Solec Kujawski the transmitter Raszyn was again used for transmissions on the frequency 198 kHz for the programme Radio Parlament .
The current use of the former transmission building is unknown.
Since the collapse of the Warsaw radio mast, the tallest construction in Poland is the transmission mast for FM-radio and TV at Olsztyn-Pieczewo with a height of 360 metres (coordinates: 53° 45′ 13″ N 20° 30′ 57″ E).
With its collapse, the KVLY-TV mast outside of Fargo, North Dakota, USA, became again the world's tallest structure, standing at 628.8 meters (2,063 feet) tall. This may be eclipsed during the next decade as plans are afoot to build a solar chimney in Australia that measures 1000 m (3280 ft) in height, or by the Burj Dubai, slated for completion in 2008.
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