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Longwave

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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 nor 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).

Name of transmitter Frequency Country Location Power Remarks
Deutschlandfunk 153 kHz Germany Donebach 500kW (day)/250kW (night)
Radio Romania 153 kHz Romania Brasov 1200kW
NRK Finnmark 153 kHz Norway Ingoy 100kW
France Inter 162 kHz France Allouis 2000kW
Radio Medi 171 kHz Marocco Nador 1200kW
Radio Russia 171 kHz Russia Kaliningrad 1200kW
DeutschlandRadio Berlin 177 kHz Germany Berlin-Zehlendorf 500kW
Europe 1 183 kHz Germany Felsberg-Berus 2000kW Program in French language
RAI 189 kHz Italia Caltanissetta 10kW
BBC Radio 4 198 kHz Great Britain Droitwich 500kW
BBC Radio 4 198 kHz Great Britain Burghead 50kW
BBC Radio 4 198 kHz Great Britain Westerglen 50kW
Radio Polonia 198 kHz Poland Raszyn 500kW only active at daytime
Deutschlandfunk 207 kHz Germany Aholming 500kW (day)/250kW (night)
Radio Monte Carlo 216 kHz France Roumoules 1200kW Transmitter site exterritorial, exclave of Monaco
Radio Polonia 225 kHz Poland Solec Kujawski 1000kW Earlier transmitter site Konstantynow
RTL (French Program) 234 kHz Luxemburg Beidweiler 2000kW Spare transmitter site Junglinster
Danmarks Radio 243 kHz Denmark Kalundborg 300kW
Algeria (French Program) 252 kHz Algeria Tipaza 1500kW
Irland 252 kHz Ireland Clarkestown 500kW Earlier used by "Atlantic 252"
Transmitter Burg 261 kHz Germany Burg 200kW inactive at the moment
Radio Rossia 261 kHz Russia Taldom 2500kW Most powerful transmitter of the world
Radiozournal 270 kHz Czech Republic Topolna 500kW
Musicmann279 279 kHz Isle of Man Location: coast 500kW (planned)
Belorussia 279 kHz Belorussia Minsk 500kW

See also

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