Longwave
From Wikipedia, the free encyclopedia
Longwave can also refer to the economics concept of Kondratiev waves, also called cycles, surges, or K-waves, or to the rock band Longwave or to the tidal bore surfing film called Longwave
The Longwave radio broadcasting band is the range of frequencies between 148.5 - 283.5 kHz, which correspond to wavelengths longer than 600 meters. This range is included within the low frequency band (but the low frequency band extends above and below longwave signals). Longwave signals 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 interference-caused fadeouts. Instead, the D-layer of the ionosphere and the surface of the earth serve as a waveguide directing the signal.
The earliest radio transmitters were all longwave transmitters, because propagation of radio waves of higher frequency was not yet understood. Radio alternator or spark-gap transmitters were commonly used to generate the radio frequency carrier wave.
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[edit] Broadcasting
In Europe, North Africa and Asia, longwave radio frequencies in the band 148.5 to 283.5 kHz are used for domestic and international broadcasting.
Carrier frequencies are multiples of 9 kHz ranging from 153 to 279 kHz. There are two exceptions in Germany, where two stations are offset by 3 kHz either side of 180 kHz.
Historically LW stations operated on frequencies as high as 413 KHz (although the highest carrier frequency currently in use for LW broadcasting is 279 KHz) several countries transmitted radio programming over power lines or telephone lines using LW frequencies. These systems were known variously as Linjesender, Telefonrundspruch or Wire Broadcasting
Some stations derive the value of their carrier from an atomic clock. It can be therefore used as frequency standard.
In North America during the 1970's the longwave frequencies 167, 179 and 191KHz were used for a short lived network of Civil defence emergency broadcsting stations with stations at Ault, Colorado and Cambridge, Kansas. Nowadays the 160-190KHz range is used there for Amateur radio.
[edit] Radio navigation
In the Americas, frequencies between 200 and 430 kHz are used for non-directional beacons (NDBs), and do not necessarily follow the same 9 kHz spacing that other areas do.
[edit] 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 | Kind of aerial | Power | Remarks |
|---|---|---|---|---|---|---|
| 153 kHz | Deutschlandfunk | Image:Flag of Germany.svg Germany | Donebach | directional aerial, two guyed steel lattice masts, 363 m high, fed at the top | 500 kW | night 250 kW |
| Radio Romania |  Romania
| Braşov | T-aerial on 2 guyed steel lattice masts with a height of 250 metres | 1200 kW | ||
| NRK Finnmark | Image:Flag of Norway.svg Norway | Ingoy | omnidirectional aerial, guyed steel lattice mast of 362 m height | 100 kW | ||
| 162 kHz | France Inter | Image:Flag of France.svg France | Allouis | two guyed steel lattice masts, height 350 m, fed on the top | 2000 kW | |
| 171 kHz | Radio Medi | Image:Flag of Morocco.svg Morocco | Nador | directional aerial consisting of at least two guyed steel lattice masts, 380 metres high | 2000 kW | |
| Radio Rossiya | Image:Flag of Russia (bordered).svg Russia | Kaliningrad | 1200 kW | |||
| 177 kHz | Deutschlandradio Kultur | Image:Flag of Germany.svg Germany | Zehlendorf near Oranienburg | cage aerial mounted on 359.7 m high guyed mast, triangle aerial on 3 150 m high guyed steel lattice masts | 500 kW | since August 29th, 2005 in DRM-Mode |
| 183 kHz | Europe 1 | Image:Flag of Germany.svg Germany | Felsberg | directional aerial, 4 insulated guyed steel lattice masts, heights: 282 m, 280 m, 276 m and 270 m, 2 234 metre tall guyed steel lattice masts, which are insulated against ground as backup antenna | 2000 kW | French Program |
| 189 kHz | RÚV | Image:Flag of Iceland.svg Iceland | Gufuskalar near Hellissandur | slight oval bi-directivity aerial, top loaded parallel connected triangular loops, mast as a common member, all guys insulated except two radiating diametrically opposed grounded top guys, loops closed by copper straps in the ground from two conducting guy grounding points to base of the guyed steel lattice mast insulated against ground, height 412m | 300 kW | RÚV national programs 1 and 2 Rás 1 and Rás 2 |
| RAI | Image:Flag of Italy.svg Italy | Caltanissetta | omnidirectional aerial, guyed steel lattice mast, height 282 m | 10 kW | inactive since August 2004 | |
| 198 kHz | BBC Radio 4 | Image:Flag of the United Kingdom.svg United Kingdom | Droitwich | T-aerial on 2 guyed steel lattice masts insulated against ground with a height of 213 metres | 500 kW | Relays BBC World Service after the end of its own programmes. |
| BBC Radio 4 | Image:Flag of the United Kingdom.svg United Kingdom | Burghead | Guyed steel lattice mast | 50 kW | ||
| BBC Radio 4 | Image:Flag of the United Kingdom.svg United Kingdom | Westerglen | Guyed steel lattice mast, height 152 m | 50 kW | ||
| Polish Radio 1 | Image:Flag of Poland (bordered).svg Poland | Raszyn | Guyed insulated mast, 335 m high | 500 kW | only active at daytime | |
| 207 kHz | RÚV | Image:Flag of Iceland.svg Iceland | Eiðar near Egilsstaðir | omnidirectional aerial, steel lattice mast insulated against ground, height 220m | 100 kW | RÚV national programs 1 and 2 Rás 1 and Rás 2 |
| Deutschlandfunk | Image:Flag of Germany.svg Germany | Aholming | directional aerial, two guyed steel lattice masts, 265 m high, fed at the top | 500 kW | night 250 kW | |
| 216 kHz | Radio Monte Carlo | Image:Flag of Monaco (bordered).svg Monaco | Roumoules | directional aerial, 3 300 metre high guyed steel lattice masts, 330 metre high guyed steel lattice mast as backup aerial | 1200 kW | Transmitter site exterritorial, exclave of Monaco |
| 225 kHz | Polish Radio 1 | Image:Flag of Poland (bordered).svg Poland | Solec Kujawski | 2 guyed radio masts fed on the top, heights 330 m and 289 m | 1000 kW | Earlier tranmitter site Konstantynow |
| 234 kHz | RTL | Image:Flag of Luxembourg.svg Luxembourg | Beidweiler | directional aerial, 3 guyed grounded steel lattice masts, 290 m high, with vertical cage aerials | 2000 kW | Spare transmitter site Junglinster |
| 243 kHz | Danmarks Radio | Image:Flag of Denmark.svg Denmark | Kalundborg | Alexanderson aerial, carried from 2 118 Meter high freestanding steel lattice towers | 300 kW | |
| 252 kHz | RTA Algier | Image:Flag of Algeria.svg Algeria | Tipaza | 1500 kW | French programme; during nighttime half transmitter-power | |
| RTÉ Radio 1 | Image:Flag of Ireland.svg Ireland | Clarkestown | Guyed steel lattice mast, insulated against ground, height 248 m | 500 kW | Earlier used by Atlantic 252 and TeamTalk 252, decreases power at night | |
| 261 kHz | Transmitter Burg | Image:Flag of Germany.svg Germany | Burg | Cage aerial on 324 m high guyed steel lattice mast, 210 m high steel tube mast, insulated against ground, omnidirectional radiation | 200 kW | inactive at the moment, formerly used by Radio Wolga and Radioropa Info |
| Radio Rossiya | Image:Flag of Russia (bordered).svg Russia | Taldom | 2500 kW | Most powerful transmitter in the world | ||
| Radio Horizont | Image:Flag of Bulgaria (bordered).svg Bulgaria | Vakarel | 60 kW | |||
| 270 kHz | ČRO 1 - Radiožurnál | Image:Flag of the Czech Republic (bordered).svg Czech Republic | Topolna | two grounded guyed steel lattice mast with cage aerials, height 257 m, directional radiation with maximum of radiation in East-West direction | 500 kW | |
| 279 kHz | Musicmann279 | Image:Flag of the Isle of Man.svg Isle of Man | ± 5 km off Ramsey | Crossed field antenna | 500 kW | Tests originally planned to begin in early 2005 pending a summer 2005 launch; as of 2006, considerable uncertainty as to actual launch date |
| BR1 | Image:Flag of Belarus.svg Belarus | Minsk | 500 kW |
[edit] See also
- Electromagnetic spectrum: Shortwave, Low frequency, Groundwave, Skywave
- Lists: List of wave topics
- Other: 1 E3 m, National Institute of Standards and Technology, Fail-Safe
[edit] External links
- Tomislav Stimac, "Definition of frequency bands (VLF, ELF... etc.)". IK1QFK Home Page (vlf.it).
- The Medium Wave Circle - The premier club for MW/LW enthusiasts
- Medium Wave News - Published regularly since 1954
- Euro-African Medium Wave Guide
- "Longwave Club of America".
- [1] - LF activity of British radio amateur G3XDV
| Radio spectrum | ||||||||||
| ELF | SLF | ULF | VLF | LF | MF | HF | VHF | UHF | SHF | EHF |
| 3 Hz | 30 Hz | 300 Hz | 3 kHz | 30 kHz | 300 kHz | 3 MHz | 30 MHz | 300 MHz | 3 GHz | 30 GHz |
| 30 Hz | 300 Hz | 3 kHz | 30 kHz | 300 kHz | 3 MHz | 30 MHz | 300 MHz | 3 GHz | 30 GHz | 300 GHz |
da:Langbølgebåndet
de:Langwelle es:LF fr:Basse fréquence nl:LF (radiospectrum) ja:長波 pl:Fale długie sv:Långvåg link title
