Ismaning radio transmitter

The Transmitter Ismaning is a large radio transmitting station near Ismaning, Bavaria, Germany. It was inaugurated in 1932. From 1932 to 1934 this transmitter (which replaced the Stadelheim Transmitter at Munich-Stadelheim) used a T-antenna as transmitting antenna, which was spun between two 115-metre-high free-standing wooden lattice towers, which were 240 metres apart. As this antenna had an unfavourable vertical radiation pattern, which produced much skywave resulting in a too small fading-free reception area at night, in 1934 a new antenna was installed. Therefore, one of the towers was dismantled and rebuilt on a 39 metres high wooden lattice base. While this work took place, an L-Antenna was used, which was spun between the other tower and a small auxiliary wooden tower.

After completion of the new wood tower, which was 156 metres high without the arms carrying the antenna 156 (with these arms its height amounted to 163 metres), the second wood tower was dismantled and rebuilt in 1935 at Nuremberg-Kleinreuth, where it served until 1961 as a transmission tower for medium wave. The wood tower at Ismaning carried a dipole antenna, whose point of feeding was at 120 metres height. From this point of feeding, several wires ran to the arms on the tower top and to fastening spots at a height of 80 metres. At this height a differential transformer was installed in a small housing inside the tower; its task was to prevent the drain of the radiated high frequency over the feeder. This antenna, developed by the company Lorenz, was called "Höhendipol". It was one for the transmitter frequency of 740 kHz, which was used from 1934 to 1950, optimized fading-reducing transmitting antenna. However, according to the wave plan of Copenhagen, which required directional radiation at night times, it could only be used during daylight hours after 1950. In 1969 this antenna was dismantled after a new medium wave transmitting mast was built. Between 1969 and 1977 the wood tower was used for carrying transmitting antennas for FM broadcasting. In 1977 a 100-metre-high guyed steel framework mast took over this function, so the wood tower became defunct in 1977. The state of the tower worsened more and more after 1977, and it seemed to be impossible to repair this tower, which was nicknamed "Bavarian Eiffel Tower," and which was already under protection as a monument. On March 16, 1983 it was blown up. Its concrete foundations and the tuning house, which once stood under the tower, can still be seen today.

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