Topolna transmitter
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Topolna transmitter (Czech: RKS Topolna) is the central longwave broadcasting facility of Czech situated westward of the village Topolna at Morava river.
Topolna transmitter, which was established in 1951, was in the Communist era often mentioned as "Ceskoslevensko 1", in order to keep the location of the transmitter secret. It uses as antenna a directional antenna, whose maxima pointed in East-West direction. By this radiation pattern, it is assured that Topolna transmitter can be received well in each parts of Czech and Slovakia.
For the realization of this directional antenna pattern two 257 metre tall guyed lattice steel masts are used. These masts were until the mid of the 1970s, used as ground-fed mast radiators and are therefore insulated against ground. In the mid-1970s the transmission power was increased to 1500 kW, making Topolna transmitter to one of the most powerful transmitters in Europe.
By this measure, both masts were equipped with cage wire antennas, which made their electrical insulation against ground obsolete. After inauguration of these cage antennas the basement insulators were bridged, but remained in place.
As in other high power transmission facilities in Eastern Europe Topolna transmitter uses special overhead lines for transmitting the RF-power from the transmitter building to the masts.
After the end of communist era the transmission power of Topolna transmitter was reduced to 650 kW. Although it was several times announced to shut down Topolna transmitter it is still in use for transmitting the program of "CRo 1 - Radiožurnál", which can be received by the circumstance, that there is nearly no other transmitter working on the frequency of Topolna transmitter (270 kHz), well in whole Europe, especially at night times.
