Longwave
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The longwave radio broadcasting band is the range of frequencies lying between 148.5 and 283.5 kHz (corresponding to wavelengths between 1000 and 2000 metres). This range is included within the low-frequency (LF) band, although the LF band covers a wider range than that used for longwave transmissions. 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 Russia, (ITU Regions 1 and 3) 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 however these systems were phased out with the introduction of ISDN and later ADSL and it is believed that there are no longer any in operation.
Some stations derive their carrier frequencies from an atomic clock. It can be therefore used as frequency standard.
In the Americas (ITU Region 2), there is no longwave broadcast band. In North America during the 1970s the longwave frequencies 167, 179 and 191 KHz were used for a short-lived network of civil defence emergency broadcasting stations with stations at Ault, Colorado and Cambridge, Kansas. Nowadays the 160-190 kHz range is used there for Part 15 Lowfers. The 190-435 kHz and 510-530 kHz bands are used for navigational beacons, and 500 kHz is the maritime distress (emergency) frequency.
[edit] List of longwave broadcasting transmitters
List of the most important longwave broadcasting transmitters (Source: http://de.wikipedia.org/wiki/Langwelle).
| Frequency | Station name | Country | Location | Aerial type | Power | Remarks |
|---|---|---|---|---|---|---|
| 153 kHz | Deutschlandfunk |  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 |  Norway |
Ingoy | Omnidirectional aerial, guyed steel lattice mast of 362 m height | 100 kW | ||
| 162 kHz | France Inter |  France |
Allouis | Two guyed steel lattice masts, height 350 m, fed on the top | 2000 kW | |
| 171 kHz | Radio Medi |  Morocco |
Nador | Directional aerial consisting of three guyed steel lattice masts, 380 metres tall | 2000 kW | |
| Radio Rossiya |  Russia |
Kaliningrad | 1200 kW | |||
| 177 kHz | Deutschlandradio Kultur | 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 | 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 |  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 |  Italy |
Caltanissetta | Omnidirectional aerial, guyed steel lattice mast, height 282 m | 10 kW | Inactive since August 2004 | |
| 198 kHz | BBC Radio 4 |  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 | United Kingdom |
Burghead | Guyed steel lattice mast | 50 kW | ||
| BBC Radio 4 | United Kingdom |
Westerglen | Guyed steel lattice mast, height 152 m | 50 kW | ||
| Polskie Program 1 |  Poland |
Raszyn | Guyed insulated mast, 335 m high | 500 kW | Only active during the daytime | |
| 207 kHz | RÚV | 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 | 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 |  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 | Polskie Program 1 | 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 |  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 |  Denmark |
Kalundborg | Alexanderson aerial, carried from 2 118 Meter high freestanding steel lattice towers | 300 kW | Stop 15 february 2007 |
| 252 kHz | RTA Algier |  Algeria |
Tipaza | 1500 kW | French programme; during nighttime half transmitter-power | |
| RTÉ Radio 1 |  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 to 100kW, one website reported the callsign of this station to be EIRE | |
| 261 kHz | Transmitter Burg | 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 | Russia |
Taldom | Central mast, 275 metre tall, surrounded by 5 guyed masts on a circle around | 2500 kW | Most powerful transmitter in the world | |
| Radio Horizont |  Bulgaria |
Vakarel | 60 kW | |||
| 270 kHz | ČRO 1 - Radiožurnál |  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 |  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 |
| Belaruskye Radio 1 (BR1) |  Belarus |
Minsk | 500 kW |
[edit] See also
- Electromagnetic spectrum: Low frequency, Very low frequency, Shortwave, Groundwave, Skywave
- Lists: List of wave topics
- Other: 1 E3 m, National Institute of Standards and Technology, Fail-Safe, WGU-20
[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
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| 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 |
