Warsaw radio mast

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The Warsaw radio mast was the tallest structure ever built; however, it existed only from 1974 to 1991. Designed by Jan Polak, it was 646.38 meters (2,120 feet) tall. The weight is debated. There are numbers of 380 tonnes, 420 metric tonnes, 550 metric tonnes or even 660 tonnes. This is probably an effect of bad conversion of units applied by translators. Polish sources claim 420 metric tonnes. Construction started in July 1970, end of works on May 18, 1974. The operation started in July 22. The mast was located in Konstantynów, Poland ([52°22′14″N, 19°48′23″E]), and was used by Warsaw Radio-Television (Centrum Radiowo-Telewizyjne) for long wave radio broadcast on the frequency 227 kHz (before February 1 1988) and 225 kHz (after February 1 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.

Construction

The Warsaw radio mast was a frame steelwork construction of steel tubing. It had a cross section in form of a triangle. All three sides of this triangle had a length of 4.8 metres. 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 3 guy wires of 50 mm 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. There were protected interior ladders, too.

The transmission building, which had a volume of 17,000 cubic metres, was approximately 600 metres away from the Warsaw radio mast. It contained the transmitter consisting of two 1,000 kilowatt units built by Brown Boveri and Cie. For the generation of the transmission frequency, which was a standard frequency, an atomic clock was used. 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 Ośrodek Nadawczy w Konstantynowie, Radiowe Centrum Nadawcze w Konstantynowie or Warszawska Radiostacja Centralna (WRC) w Gąbinie. The radio program was called "Program Pierwszy Polskiego Radia", "Program I PR" or unofficially "Jedynka".

Collapse

On August 8 1991, the mast collapsed at 16:00 UTC because of a mistake in exchanging the guys on the highest stock of the mast. No one was killed or injured, though some unconfirmed sources claim there had been 3 killed and 12 injured ([link]). The workers had left the area well before the mast collapsed. It is sometimes claimed that this work was sabotaged by special Soviet forces. However there is no evidence for this theory. The version of mistake in the exchange of guys was confirmed by Jan Polak - the main constructor of the mast. [link] The mast first bent and after that it snapped roughly at the half of the height. Soon, the top leaned and went straight to the ground near the base, followed by the lower half which leaned and fell in unconfirmed direction. The transmitters apparently survived.

Special committee decided it was Mostostal Zabrze, which built, and maintained the mast. The construction coordinator and chief of one of Mostostals divisions that built the mast were accused for causing the catastrophe, the first of these was sentenced to 2.5 years, the other two for 2 years.

After the collapse of the radio mast at Konstantynów, the Polish broadcasting company used the old transmitter of Raszyn with its 335 metre high mast near Warsaw, which had been used since 1978 during the 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 simultaneously, 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 was installed at the transmitter Raszyn. The latter, simpler solution would have decreased the effectiveness and reliability of both transmitters and was therefore unacceptable.

Because the Polish longwave transmitters are of special importance to Polish people abroad, as early as April 1992 the Polish government planned to rebuild the mast at Konstantynów. In September 1995 the Polish government was set to rebuild the mast, but it was never rebuilt due to local protests, which claimed that the waves sent out by the mast were bad for their health, so a new transmitter site had to be found. An old military area near Solec Kujawski was eventually decided on as the new site and a new longwave transmitter facility with a transmitter of 1000 kW HF-power for the frequency 225 kHz was built there from 1998 to 1999 (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 entered service on September 4 1999.

After the inaugauration of the transmitter at Solec Kujawski, the transmitter at Raszyn was again used for transmitting 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]).

After the collapse, the KVLY-TV mast outside of Fargo, North Dakota, USA, regained the title of the world's tallest structure, standing at 628.8 meters (2,063 feet) tall. This may be superseded during the next decade as plans are afoot to build the Burj Dubai or a Solar updraft tower in Australia that will stand 1000 m (3280 ft) tall, but the financial viability of the latter project remains unclear.

See also

• List of masts
• Gabin Tower Memorial Festival

Gallery

Image:Foto_277_web.jpg|View up from the base Image:Foto_308_web.jpg|Collapsed mast Image:Foto_309_web.jpg|Worker near the base of a collapsed mast Image:WRM_enc1.jpg|Maintenance worker on the first floor Image:WRM_enc2.jpg|Panoramic view with additional data

External links

• [Anti-mast page]
• [link]
• [Diagram]
• [link]
• [link]
• [link]
• [link]
• [Further information (in Polish)]

 

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