Warsaw radio mast

The Warsaw radio mast in Konstantynów

View from a distance

The Warsaw radio mast was the tallest structure in existence until its collapse in 1991. Designed by Jan Polak, it was 646.38 meters (2,120 feet) tall. Construction started in July 1970 and was completed May 18, 1974, operation started on July 22 of the same year. 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 so stood on a 2 metre high insulator. Its height meant it served as an aerial of half wavelength for its broadcasting frequency. The signals from its 2-megawatt transmitters could be received across all of Europe, North Africa and even in North America. Its weight is debated: 380 tonnes, 420 tonnes, 550 tonnes and even 660 tonnes have been cited, probably the result of inaccurate conversion of units by translators. Polish sources claim 420 metric tonnes.

Construction

File:Warsaw Radio Mast Description.gif

Desription of transmitter Gabin and Warsaw Radio Mast in Polish language

The Warsaw radio mast was a frame steelwork construction of steel tubing. It had a cross section in the 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 of which had a length of 7.5 metres. The mast was guyed in 5 levels with 3 guy wires of 50 mm diameter. Each guy was fixed on a separate anchor block at the ground. In spite of the problems with static electrical charges described at guy-wire, that require huge overdimensioned backstage insulators, conventional guys divided by insulators seem to have been used, at least for the lower guy levels of the mast. Nevertheless, it cannot be ruled out that later the guys were grounded via coils (or directly) at the anchor basements. 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 as well.

Warsaw Radio Mast was an insulated, ground-fed mast radiator. It stood on three insulator columns each consisting of two 2 metre high insulators, which were arranged on top of each other. These columns insulated the construction of Warsaw Radio Mast for a voltage of 120 kV against ground. Later a tube, which was fixed with insulators to the mast construction was installed in it [1], [2], [3], [4]. This tube may have served as feeder for a middle-feeding of the radio frequency power in the mast. A middle-feeding of radio frequency power of the mast would have allowed grounding the mast at its base. This would make have its maintenance, the power supply to flight-safety lamps and the elevator and the possibly planned installations of antennas for radio services in the VHF/UHF-range on its top much easier.

The transmission of the radio frequency from the transmitter building to the mast was made by a special overhead radio frequency transmission line (German: Reusenleitung) with a length of approximately 600 metres.

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 1000 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 76 metre tall lattice tower with rectangular cross-section for directional radio service for the radio-link to the studio.

For the power supply of the station, a 110kV-substation, to which two lines run, was built. Although the power consumption of the station was enormous (approximately estimated 6000 kW), this power supply was quite overdimensioned, but installed, because of the great importance of the station as Poland's central transmitter.

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".

Warsaw Radio Mast in Culture

Warsaw Radio Mast was mentioned in Guinness Book as world's tallest structure. It was also shown on postal stamps [5].

Collapse

On August 8 1991 at 16:00 UTC, the mast collapsed because of a mistake in exchanging the guys on the highest stock of the mast. Officially, the workers had left the area well before the mast collapsed, so no one was killed or injured. Some unconfirmed sources claim there had been 3 fatalities and 12 people hurt.^[6]. However it is possible, that this is a confusion with the collapse of WLBT Tower on October 23rd, 1997, at which 3 people were killed.

The version of mistakes in the exchange of guys was confirmed by Jan Polak, the main constructor of the mast.^[7] The mast first bent and then snapped roughly at half of its height. The top went straight to the ground near the base, followed by the lower half which leaned and fell in an unconfirmed direction. At the collapse also a small mobile crane, which was property of Mostostal Zabrze was destroyed[8]. The helix building and the transmitter building (including the transmitter devices in it) were not damaged by the collapsing mast.

A special committee decided that blame lay with Mostostal Zabrze, which built and maintained the mast. The construction coordinator and chief of one of Mostostals divisions that built the mast were accused of causing the catastrophe; the former was sentenced to 2.5 years, the latter to 2 years.

It is sometimes claimed that this work was sabotaged by special Soviet forces; however, there is no evidence for this theory.

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.

Replacement

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. Although some preworks of it, as the refurbishments of the old besements, which should be reused, have already started, the rebuild of the mast had to be cancelled due to violent protests of people living in the surrounding, who claimed that the waves sent out by the mast were bad for their health. Although this statement could not be proved, a new site for the transmitter had to be sought. It was found in the form of an old military area near southeastly of Solec Kujawski, where from 1998 to 1999 a new longwave transmission facility with a transmitter of 1200 kW HF-outpower for the frequency 225 kHz was built. This facility, which was inaugaurated on September 4, 1999, uses as aerials two grounded, upfeed masts, which are 330 respectively 289 metres tall and which are 330 metres apart from each other.

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.

Current state

Except for the mast and the radio frequency transmission line which leads to it, nearly all components of the facility are still there. While the 110kV-substation and the directional radio tower are still in use, the present use of the buildings is unknown.

From the mast, the basement and the anchor blocks are also still there.

See also

• List of masts
• Gabin Tower Memorial Festival
• List of famous transmission sites

External links

• A gallery of photos related to the Warsaw radio mast
• http://jerzyjedrzejkiewicz.webpark.pl/str01/galerie/rcn/rcn_14.html

References

• Anti-mast page
• [9]
• Diagram
• http://radiopolska.pl/forum/viewtopic.php?t=2798
• http://www.skyscraperpage.com/diagrams/?b46244
• [10]
• Further information (in Polish)
• [11]
• Pictures for showing actual state of site