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A tunnel transmitter allows wireless reception in tunnels. It consists of a receiving antenna which receives the signal to be radiated in the tunnel, and a transmitting antenna installed in the tunnel, which is either a Yagi antenna[1] or a line antenna. In principle, a tunnel transmitter can work purely passively, in which case the received signal is passed over a cable to the antenna in the tunnel. Active systems, however, are more often used. In some cases the radio frequency inside the tunnel is different from the one used by the broadcaster. More often the program inside is transmitted on the same frequency as outside, in which case the information signal should be demodulated or converted to an intermediate frequency in the outside receiver, and then modulated/shifted back in the transmitter. Otherwise feedback may occur.[citation needed]
Tunnel transmitters are used in Germany only for audio transmitters working in FM-range and for further radio services, such as mobile phone services which also work in this frequency range.[citation needed] Elsewhere, there are also tunnel transmitters for audio broadcast transmitters, which work in the long and medium wave bands. An example of this is in the Dartford Crossing tunnel near London, where the programme "Virgin 1215" in the medium-wave band and the BBC's Radio 4 on 198 kHz long wave are rebroadcast in the tunnel. Emergency information could also be relayed using this system, interrupting programming to relay warnings.
^Graf, Rudolf F. (1999). Modern Dictionary of Electronics (7 ed.). Newnes. p. 858. ISBN0080511988.
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January 01, 1970
tunnel, transmitter, this, article, relies, largely, entirely, single, source, relevant, discussion, found, talk, page, please, help, improve, this, article, introducing, citations, additional, sources, find, sources, news, newspapers, books, scholar, jstor, a. This article relies largely or entirely on a single source Relevant discussion may be found on the talk page Please help improve this article by introducing citations to additional sources Find sources Tunnel transmitter news newspapers books scholar JSTOR August 2007 A tunnel transmitter allows wireless reception in tunnels It consists of a receiving antenna which receives the signal to be radiated in the tunnel and a transmitting antenna installed in the tunnel which is either a Yagi antenna 1 or a line antenna In principle a tunnel transmitter can work purely passively in which case the received signal is passed over a cable to the antenna in the tunnel Active systems however are more often used In some cases the radio frequency inside the tunnel is different from the one used by the broadcaster More often the program inside is transmitted on the same frequency as outside in which case the information signal should be demodulated or converted to an intermediate frequency in the outside receiver and then modulated shifted back in the transmitter Otherwise feedback may occur citation needed Tunnel transmitters are used in Germany only for audio transmitters working in FM range and for further radio services such as mobile phone services which also work in this frequency range citation needed Elsewhere there are also tunnel transmitters for audio broadcast transmitters which work in the long and medium wave bands An example of this is in the Dartford Crossing tunnel near London where the programme Virgin 1215 in the medium wave band and the BBC s Radio 4 on 198 kHz long wave are rebroadcast in the tunnel Emergency information could also be relayed using this system interrupting programming to relay warnings See also editLeaky feeder Through the earth mine communicationsReferences edit Graf Rudolf F 1999 Modern Dictionary of Electronics 7 ed Newnes p 858 ISBN 0080511988 External links editDublin port tunnel radio interruption system Retrieved from https en wikipedia org w index php title Tunnel transmitter amp oldid 1173323593, wikipedia, wiki, book, books, library,
