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Transmitting radio programmes
Sometimes PLC was and is used for transmitting radio programmes over powerlines
or over telephone lines. Such devices were in use in Germany, where it was
called "Drahtfunk" and in Switzerland, where it was called "Telefonrundspruch"
and used telephone lines. In the USSR PLC was very common for broadcasting,
because PLC listeners cannot receive foreign transmissions. In Norway the
radiation of PLC systems from powerlines was sometimes used for radio supply.
These facilities were called Linjesender. In all cases the radio programme was
fed by special transformers into the lines. In order to prevent uncontrolled
propagation, filters for the carrier frequencies of the PLC systems were
installed in substations and at line branches.
An example of the programmes carried by "wire broadcasting" in Switzerland:
175 kHz Swiss Radio International
208 kHz RSR1 “la première” (French)
241 kHz “classical music”
274 kHz RSI1 “rete UN” (Italian)
307 kHz DRS1 (German)
340 kHz “easy music”
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