Online Encyclopedia
Longwave
Longwave radio frequencies are those below 500 kHz, which correspond to wavelengths longer than 600 meters. They have the property of following the curvature of the earth, making them ideal for continuous, continental communications. Unlike shortwave radio, longwave signals do not reflect or refract using the ionosphere, so there are fewer phase-caused fadeouts.
The earliest radio transmitters, including the Alexanderson alternator , were all longwave transmitters.
In Europe, North Africa and Asia, longwave radio frequencies between 153 and 281 kHz are used for domestic and international broadcasting. In the Americas, frequencies between 200 and 430 kHz are used for non-directional radio beacons, and do not necessarily follow the same 9 kHz spacing that other areas do.
The frequency of 60 kHz is used by several nations, such as the United States, England, and Japan, for extremely accurate time and precision frequency signals. (77.5 kHz is used in Germany.) Many commercial appliances (such as self-setting clocks) sold since approximately 2000 have a VLF receiver capable of receiving these signals, which penetrate indoors more effectively than mediumwave or shortwave signals.
Radio signals below 50 kHz are capable of penetrating ocean depths to approximately 200 meters. The United States, Russian, British, Swedish, and Indian navies communicate with submarines on these frequencies.
In addition, Royal Navy nuclear submarines carrying ballistic missiles are allegedly under standing orders to monitor the BBC Radio 4 transmission on 198 kHz in waters near the U.K. It is rumoured that they are to construe a sudden halt in transmission as an indicator that the U.K. is under attack, whereafter their sealed orders go into place.
Longwave transmitting antennas take up large amounts of space, and have been the cause of controversy in the United States and Europe due to fears over proximity to high-power radio waves.
List of longwave broadcasting transmitters
List of the most important longwave broadcasting transmitters (Source: http://de.wikipedia.org/wiki/Langwelle).
Frequency | Name of transmitter | Country | Location | Power | Remarks |
---|---|---|---|---|---|
153 kHz | Deutschlandfunk | Germany | Donebach | 500 kW | night 250 kW |
Radio Romania | Romania | Brasov | 1200 kW | ||
NRK Finnmark | Norway | Ingoy | 100 kW | ||
162 kHz | France Inter | France | Allouis | 2000 kW | |
171 kHz | Radio Medi | Morocco | Nador | 1200 kW | |
Radio Rossia | Russia | Kaliningrad | 1200 kW | ||
177 kHz | DeutschlandRadio Berlin | Germany | Zehlendorf (Oranienburg) | 500 kW | |
183 kHz | Europe 1 | Germany | Felsberg | 2000 kW | French Program |
189 kHz | RAI | Italia | Caltanissetta | 10 kW | inactive since August 2004 |
198 kHz | BBC Radio 4 | Great Britain | Droitwich | 500 kW | BBC World Service |
BBC Radio 4 | Great Britain | Burghead | 50 kW | ||
BBC Radio 4 | Great Britain | Westerglen | 50 kW | ||
Radio Polonia | Poland | Raszyn | 500 kW | only active at daytime | |
207 kHz | Deutschlandfunk | Germany | Aholming | 500 kW | night 250 kW |
216 kHz | Radio Monte Carlo | France | Roumoules | 1200 kW | Transmitter site exterritorial, exclave of Monaco |
225 kHz | Radio Polonia | Poland | Solec Kujawski | 1000 kW | Earlier tranmitter site Konstantynow |
234 kHz | RTL | Luxemburg | Beidweiler | 2000 kW | Spare transmitter site Junglinster |
243 kHz | Danmarks Radio | Danmark | Kalundborg | 300 kW | |
252 kHz | RTA Algier | Algeria | Tipaza | 1500 kW | French programme; during nighttime half transmitter-power |
RTÉ Radio 1 | Ireland | Clarkestown | 500 kW | Earlier used by "Atlantic 252" and "TeamTalk 252" | |
261 kHz | Transmitter Burg | Germany | Burg | 200 kW | inactive at the moment |
Radio Rossia | Russia | Taldom | 2500 kW | Most powerful transmitter in the world | |
270 kHz | Radiozournal | Czech Republic | Topolna | 500 kW | |
279 kHz | Musicmann279 | Isle of Man | Location: coast | 500 kW | |
Belarus, Radio 1 | Belorussia | Minsk | 500 kW |
See also
- Electromagnetic spectrum: Shortwave, Low frequency, Groundwave, Skywave
- Lists: List of music videos by year, List of wave topics
- Other: 1 E3 m, National Institute of Standards and Technology, Fail-Safe
External links
Radio spectrum |