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Longwave





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.

Additional recommended knowledge

Contents

Band propagation characteristics

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 and less severe interference-caused fadeouts. Instead, the D-layer of the ionosphere and the surface of the earth serve as a waveguide directing the signal[citation needed].

Historical significance

Essentially all radio transmitters before 1924 were longwave transmitters[citation needed]. Propagation of shorter wavelengths was not understood until the shortwave experiments by amateur radio operators in 1923 and by Marconi in 1924. Spark-gap transmitters were used prior to World War I, until the development of powerful Radio alternators by General Electric just prior to the war. Vacuum tubes began to be used to generate radio frequencies in the mid-1920s.

After 1924, use of longwave radio for long distance communication began to decline, as much less expensive shortwave transmitters began to carry increasingly heavy volumes of long distance communication. A period of explosive growth of shortwave communications began in 1927, leading to rapid decline in longwave radio usage.

Broadcasting

In Europe, North Africa, Russia and Mongolia (ITU Region 1), 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). Some stations derive their carrier frequencies from an atomic clock. It can be therefore used as frequency standard.

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[citation needed].


ITU Region 2 note

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[citation needed]. Nowadays the 160-190 kHz range is used there for Part 15 Lowfers amateur and experimental stations. The 190-435 kHz bands is one of the bands used for navigational beacons.

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, fed at the top 100 kW  
Al Kasirha  Algeria Bechar Three guyed steel lattice masts 1000 kW  
162 kHz France Inter  France Allouis Two guyed steel lattice masts, height 350 m, fed on the top 2000 kW Time signal phase-modulated
171 kHz Medi 1  Morocco Nador Directional aerial consisting of three guyed steel lattice masts, 380 metres tall 2000 kW  
Radio Rossii  Russia Bolshakovo near Kaliningrad 150/75 kW  
Radio Rossii  Ukraine Krasne near Lwow 150/75 kW inactive at present
177 kHz Deutschlandradio Kultur  Germany Zehlendorf near Oranienburg Omnidirectional aerial, 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 between 2 and 5 a.m. CET DRM-Mode

Non-standard frequency (not divisible by 9)

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 Programme

Non-standard frequency (not divisible by 9)

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 Omnidirectional aerial, guyed steel lattice mast 50 kW  
BBC Radio 4  United Kingdom Westerglen Omnidirectional aerial, guyed steel lattice mast, height 152 m 50 kW  
Polskie Radio Parlament/Program 1  Poland Raszyn Omnidirectional aerial, guyed steel lattice mast insulated against ground, 335 m high 500 kW Only active during the daytime
Radio Majak  Russia Sankt Petersburg - Olgino Omnidirectional aerial, 205 m high guyed steel lattice mast 150 kW
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 Radio Program 1  Poland Solec Kujawski Directional aerial, 2 guyed radio masts fed on the top, heights 330 m and 289 m 1000 kW Earlier transmitter site Konstantynów
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
Radio 1  Russia Krasny Bor transmitter Omnidirectional aerial, 271.5 metres tall guyed mast with cage antenna 1200 kW May be inactive at present
243 kHz Danmarks Radio  Denmark Kalundborg Alexanderson aerial, carried from 2 118 Meter high free-standing steel lattice towers 300 kW Stop 15 February 2007
252 kHz RTA Algier  Algeria Tipaza Omnidirectional aerial, single guyed lattice steel mast 1500 kW French programme; during night-time half transmitter-power
RTÉ Radio 1  Ireland Clarkestown Omnidirectional aerial, 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 Omnidirectional aerial, cage aerial on 324 m high guyed, grounded steel lattice mast, 210 m high steel tube mast, insulated against ground 200 kW Inactive at the moment, formerly used by Radio Wolga and Radioropa Info
Radio Rossii  Russia Taldom Omnidirectional aerial, 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 One of the few Blaw-Knox Towers in Europe, 215m high 75 kW
270 kHz ČRO 1 - Radiožurnál  Czech Republic Topolna Directional aerial (maximum of radiation in East-West direction), two grounded 257 m high guyed steel lattice mast with cage aerials 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; as of 2007, key personnel have resigned and company's future is uncertain. In October 2007 the Company's web sites disappeared.
Belaruskaje Radyjo 1 (BR1)  Belarus Sasnovy 500 kW  
Radio Mayak (RUS)  Russia Yekaterinburg Omnidirectional aerial, guyed steel lattice mast of 256 m height, fed at the top 50 kW  

 

See also

  • Electromagnetic spectrum: Low frequency, Very low frequency, Shortwave, Groundwave, Skywave
    • Radio: AM radio, BBC Radio 4, BBC Light Programme, Radio clock, Office de Radiodiffusion Télévision Française, Warsaw radio mast, Digital Radio Mondiale, International broadcasting,
    • Shipping: Satellite navigation system, Navigation, Shipping Forecast
  • Lists: List of wave topics
  • Other: 1 E3 m, National Institute of Standards and Technology, Fail-Safe, WGU-20


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

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Longwave". A list of authors is available in Wikipedia.
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