The Konstantynów mast: 646 metres, 2 megawatts and the collapse of 8 August 1991

The radio mast at Konstantynów near Gąbin was a steel lattice structure with an equilateral triangular cross-section, 4.8 metres wide on each side. The site was chosen after long studies. What counted was the geometric centre of Poland after the border changes, the high conductivity of the ground, and the absence of industrial and residential buildings nearby.

Groundwork for the foundations began on 5 July 1969, and the state-owned company Mostostal Zabrze carried it out. Workers set the base of the mast in place on 18 October 1972, and construction finished on 18 May 1974. Installation of the transmitter began in October 1973, and the equipment entered regular service on 22 July 1974. Jan Polak designed it. The mast consisted of 86 sections of 7.5 metres each. Its vertical steel tubes had a diameter of 245 millimetres and a wall thickness of 8 to 34 millimetres, depending on height.

A long wave reaching Antarctica

The structure worked as a half-wave radiator, so its height matched half the wavelength of the broadcast. Until 1 February 1988 it transmitted at 227 kHz, and afterwards at 225 kHz, on a wave 1332 metres long. The signal from transmitters with a power of 2 megawatts could be picked up almost anywhere in the world, including Canada, the United States and Antarctica. The base of the mast lay 115.2 metres above sea level. In operation the structure carried a potential difference of 120 kilovolts, so it stood on a two-metre insulator.

Konstantynów was not Poland's first central transmitter. A mast went up at Raszyn as early as 1931, and after the Second World War the station was rebuilt in 1949 with a 200-kilowatt transmitter, soon increased to 500 kilowatts. That was still not enough for good reception across the country, so in the late sixties officials decided to build a new central facility. During storms, when the mast at Konstantynów could not work, the signal was temporarily switched to Raszyn. Direct telephone lines linking both centres and the power sector made that easier.

8 August 1991

The mast collapsed on 8 August 1991. After the disaster the title of tallest structure in the world returned to the KVLY-TV mast in Blanchard, North Dakota, which had lost it in 1974 and held it until 2009. The tallest structure in Poland today is the 358.7-metre FM and TV mast at Kosztowy. Konstantynów remains the third tallest building ever erected, with only the Burj Khalifa of 2009 and the Merdeka 118 tower of 2022 above it. The mass of the structure is disputed: some Polish sources give 420 tonnes.