Blaw-Knox tower

A Blaw- Knox Tower is a guyed, self- radiant transmission tower for medium wave in the form of a double pyramid. The Blaw -Knox transmission tower acts as insulated against ground even more radiant transmission tower, its length is usually equal to about half of the emitted wave.

History

The steel manufacturing company founded in 1917 Blaw -Knox in Blawnox at Pittsburgh, Pennsylvania in 1927 took masts into their product range and subsequently developed rapidly some innovative antenna variants, which tried to solve then existing technical problems.

On June 30, 1930, designed as a double pyramid transmission tower type has been filed for patent. The most important feature of the developers call in their patent that because of the solid construction of the mast must be anchored in only one plane, will thus avoided that will derived via the usual frequently guyed masts on the ropes too much transmission energy into the ground. Apparently, had the then usual backstays insulators, which have to withstand very high loads, even insufficient insulation effect.

The patented features also include a means of an electric motor, a retractable and extendable boom tip in order to allow an optimal adjustment to the transmitting frequency.

Subsequently, numerous masts of this type originated in the U.S. but also in Europe. The first plant in Europe using Blaw- Knox towers during the winter of 1932/33, on the Bisamberg in Vienna. A special feature of this system exhibited a similar passive reflector mast, which was 115 m from the transmitter mast removed. The two masts had a height of 130 m. The operation was admitted on May 28, 1933 April 13, 1945, the two towers were blown up by withdrawing SS troops.

Both in the U.S. and in Europe some Blaw -Knox transmission towers remain. The design of the TV tower Bratislava is very similar to that of a Blaw -Knox transmission tower.

Europe

  • Lisnagarvey, Northern Ireland (Year: 1936, height: 108 meters, upper part cut ( original height of 144.8 meters) )
  • Lakihegy, Hungary ( year: 1933, height: 314 meters)
  • Wakarel, Bulgaria ( Year: 1937, height: 215 meters)
  • Stara Zagora, Bulgaria ( year: 1936, height: 88 meters)
  • Ulbroka, Latvia ( year: 1947, height: 125 meters, 2010 Burst)

USA

  • WSM, Nashville, Tennessee - 246 m, built in 1932; originally 267 m; Tower stands in Brentwood, Tennessee.
  • WLW, Cincinnati, Ohio - 227 m, built in 1934; Tower stands in Mason, Ohio.
  • WBT, Charlotte, North Carolina - Three towers each 130 meters high, built in 1934 (West mast ) or 1945 (both other masts, Western and Ostmast after destruction in 1989 by Hurricane Hugo reconstructed )
  • WFEA, Manchester, New Hampshire - 121 m, built in 1931
  • WBNS, Columbus, Ohio - 116 m
Medium frequency Mast radiator Blaw-Knox Guy-wire Kamzík TV Tower Riga LVRTC Transmitter Mason (Ohio)
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