In radio, longwave refers to parts of the radio spectrum with relatively long wavelengths – typically kilometer-sized or greater. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.
In contemporary usage, the term longwave is not defined precisely and its meaning varies across the world. The most common definition is the radio band with wavelengths greater than 1000 meters (frequencies less than 300 kHz), which would include the ITUs low frequency (LF) (30–300 kHz) and very low frequency (VLF) (3–30 kHz) bands, but sometimes part of the medium frequency (MF) band (300–3000 kHz) is included. In all cases it includes the entire LF band.
In Europe, Africa and large parts of Asia (ITU Region 1), where a range of frequencies between 148.5 and 283.5 kHz is used for AM broadcasting (in addition to the medium wave band), the term longwave usually refers specifically to this broadcasting band.
The Region 1 longwave broadcast band falls wholly within the low frequency band of the radio spectrum (30–300 kHz). Broader definitions of longwave may extend below and/or above it. In the US, the Longwave Club of America is interested in "frequencies below the AM broadcast band", i.e., all frequencies below 535 kHz. (Lower frequencies correspond to longer wavelengths.)
Non-directional beacons transmit continuously for the benefit of radio direction finders in marine and aeronautical navigation. They identify themselves by a callsign in Morse Code. They can occupy any frequency in the range 190–1750 kHz. In North America they occupy 190–535 kHz. In ITU Region 1 the lower limit is 280 kHz.
There are stations in the range 40–80 kHz that transmit time signals to radio clocks. For example:
- WWVB in Colorado on 60 kHz.
- DCF77 in Frankfurt am Main, Germany on 77.5 kHz.
- JJY in Japan on 40 & 60 kHz.
- 66.6 kHz in Taldom transmitter, Russia.
- 50 kHz in Irkutsk, Russia.
- MSF time and 60 kHz frequency standard transmitted from Anthorn in the UK
Radio controlled clocks receive their time calibrations signal with built-in longwave receivers. They use longwave, rather than shortwave or mediumwave, because the accuracy of the clocks is not affected by changes in the time signal's travel from the transmitter to the ionosphere and to the receiver; as longwave travels by groundwave, rather than skywave, the propagation time does not vary.
In North America during the 1970s the frequencies 167, 179 and 191 kHz were assigned to the short-lived Public Emergency Radio of the United States. Nowadays the 160–190 kHz range is used in the United States for Part 15 LowFER amateur and experimental stations, and the 190–435 kHz band is used for navigational beacons.
Longwave is used for broadcasting only within ITU Region 1. Most of the longwave broadcasters are in Europe, the former Soviet Union and Mongolia. The rest are located in Turkey, Algeria and Morocco. Saudi Arabia, Qatar and the United Arab Emirates have vacant low powered broadcasting allocations.
Typically, a larger area can be covered by a longwave broadcast transmitter than a medium-wave one. This is because ground-wave propagation suffers less attenuation due to limited ground conductivity at lower frequencies.
Carrier frequencies are exact multiples of 9 kHz ranging from 153 to 279 kHz, except for a station in Germany on 183 kHz and five Mongolian transmitters.
Until the 1970s, some longwave stations in northern and eastern Europe and the Soviet Union operated on frequencies as high as 433 kHz.
Some stations, for instance Droitwich in the UK, derive their carrier frequencies from an atomic clock. They can be therefore used as frequency standards. Droitwich also broadcasts a low bit-rate data channel, using narrow-shift phase-shift keying of the carrier, for Radio Teleswitch Services.
List of longwave broadcasting transmitters
List of stations currently operating:
|Freq. kHz||Station name||Country||Location||Aerial type||Power kW||Coordinates||Remarks|
|153||Radio Antena Satelor||Romania||Brașov||T-aerial on 2 guyed steel lattice masts with a height of 250 metres||200||;|
|NRK P1 Finnmark||Norway||Ingoy||Omnidirectional aerial, guyed steel lattice mast of 362 m height, fed at the top, ex-Omega equipment||100||The transmitter is important especially for the fishing fleet in the Barents Sea.|
|Chaîne 1/Radio Algérie International||Algeria||Kenadsa / Bechar||Three guyed steel lattice masts, height 357 m.||2000||;|
|162||France Inter||France||Allouis||Two guyed lattice steel masts, height 350 m, fed on the top||2000||;||Time signal phase-modulated.|
|MTRK Radio Tashkent||Uzbekistan||near Tashkent||Omnidirectional antenna, 235 m high antenna||150|
|164||Voice of Mongolia||Mongolia||Ulan-Bator||500|
|171||Medi 1||Morocco||Nador||Directional aerial consisting of three guyed steel lattice masts, 380 metres tall||2000||; ;|
|Radio Kavkaz||Russia||Oktyabrskiy||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||1200|
|183||Europe 1||Germany||Felsberg-Berus||Directional aerial, four ground insulated steel lattice masts. Heights of 270 m, 276 m, 280 m and 282 m. Spare aerial: two ground insulated steel lattice masts of 234 m height.||2000||Main antenna:; ; ; , Spare antenna: ;||French language channel. The most powerful longwave transmitter in Germany; DRM Test after 00:00 UTC.|
|189||RÚV Rás 1 and RÚV Rás 2||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|
|198||BBC Radio 4||United Kingdom||Droitwich (SFN)||T-aerial on 2 guyed steel lattice masts insulated against ground with a height of 213 metres||500||;||All three transmitters carry Radio teleswitch PSK data. Droitwich relays BBC World Service after the end of Radio 4 schedule (01:00 to 05:20 UTC).|
|Burghead (SFN)||Omnidirectional aerial, guyed steel lattice mast, height 154 m||50|
|Westerglen (SFN)||Omnidirectional aerial, guyed steel lattice mast, height 152 m||50|
|Chaîne 1/Radio Algérie International||Algeria||Berkaoui / Ouargla||Three guyed steel lattice masts.||2000||; ;|
|207||RÚV Rás 1 and RÚV Rás 2||Iceland||Eiðar near Egilsstaðir||Omnidirectional aerial, steel lattice mast insulated against ground, height 221 m||100|
|209||Voice of Mongolia||Mongolia||Choibalsan||75|
|Voice of Mongolia||Mongolia||Dalanzadgad||75|
|Voice of Mongolia||Mongolia||Olgii||Omnidirectional antenna, 352.5 metres high guyed mast||30|
|216||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||; ; , Backup antenna:||Transmitter site is located in France. In operation from 5:30 to 23:00 CET.|
|225||Polskie Radio Program 1||Poland||Solec Kujawski||Directional aerial, 2 guyed radio masts fed on the top, heights 330 m and 289 m||1000||Earlier transmitter site was Konstantynów ( )|
|227||Voice of Mongolia||Mongolia||Altai||75|
|234||RTL||Luxembourg||Beidweiler||Directional aerial, 3 guyed grounded steel lattice masts, 290 m high, with vertical cage aerials||2000||; ;||Spare transmitter site Junglinster ( ; ; )|
|Radio 1||Armenia||Gavar||Omnidirectional aerial, 259.4 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||500|
|243||DR P1 and DR P2||Denmark||Kalundborg||Semi-directional Alexanderson antenna 153/333 degrees, two grounded 118 m steel lattice radiating towers with interconnecting top wire capacitance||50||;||Transmitting in time slots only; DRM test from 3 October 2008.|
|252||Chaîne 1, Chaîne 3 and Radio Algérie International||Algeria||Tipaza||Omnidirectional aerial, single guyed lattice steel mast, height 355 m||1500||French programme; during night-time half transmitter power.|
|RTÉ Radio 1 Extra||Ireland||Clarkstown||Omnidirectional aerial, guyed steel lattice mast, insulated against ground, height 248 m||500||The only AM transmitter for RTÉ Radio 1. Decreases power at night to 100 kW. On 23 September 2014 RTÉ announced the closure of Radio 1's longwave service on 27 October 2014. The proposed switch-off date of RTE Radio 1 on LW has now been postponed until 19 January 2015.|
|Radioi Tojikston 1||Tajikistan||Yangi-Yul||150||; ; ;|
|270||ČRo 1 - Radiožurnál||Czech Republic||Topolná||Directional aerial (maximum of radiation in East-West direction), two grounded 257 m high guyed steel lattice mast with cage aerials||50||;||Broadcast from Monday to Friday 5:00-24:00 CET and 6:00-24:00 CET at weekends. Was due to cease broadcasting on 28 February 2014 although is still transmitting at greatly reduced power|
|Radio Slovo||Russia||from Novosibirsk moved to Raduga||Omnidirectional aerial, 209 metres tall guyed mast with cage antenna||150|
|279||Belaruskaje Radyjo 1||Belarus||Sasnovy||500|
List of stations that have closed or are otherwise inactive:
|Freq. kHz||Station name||Country||Location||Aerial type||Power kW||Coordinates||Remarks|
|Deutschlandfunk||Germany||Donebach||Directional aerial, two guyed steel lattice masts, 363 m high, fed at the top||500||;||closed|
|YuFM||Russia||Taldom transmitter||Omnidirectional aerial, guyed steel lattice mast of 257 m height||300||inactive (reportedly closed)|
|Radio Rossii||Russia||Popova near Komsomolsk-na-Amure||Omnidirectional aerial, guyed steel lattice mast of 257 m height||1200||closed|
|162||TRT 4||Turkey||Agri||Two guyed lattice steel masts, height 250 m||1000||;||inactive|
|Radio Rossii||Russia||Norilsk||Omnidirectional antenna, 205 m high antenna||150||?||closed|
|Radio Yuldash, Radio Rossii||Russia||Ufa||150||closed|
|Radio Rossii||Russia||Bolshakovo near Kaliningrad||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||600||closed|
|Ukrainian Radio||Ukraine||Krasne near Lwów||Omnidirectional antenna, 259 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||150/75||inactive|
|Radio Rossii||Russia||Raduga||Omnidirectional antenna, 255 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||250||closed|
|Radio 1||Russia||Murmansk||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||150||closed|
|Radio 1||Russia||Noginsk||Omnidirectional antenna, 242 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||150||closed|
|Radio 1||Russia||Ezhva near Syktyvkar||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||150||closed|
|Radio Rossii||Russia||Tulagino near Yakutsk||Omnidirectional antenna, circle antenna with 1 central and 6 ring masts||150||; ; ; ; ; ;||closed|
|177||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||closed|
|180||TRT 4||Turkey||Polatli||Omnidirectional antenna, 250 m high guyed latice steel mast||1200||inactive|
|Radio Rossii||Russia||Yelizovo near Petropavlovsk-Kamchatskiy||Omnidirectional antenna, 255 m high guyed lattice steel mast||150||closed|
|Radio Mayak||Russia||Kruchina near Chita||Omnidirectional antenna, 200 m high guyed lattice steel mast||150||inactive|
|189||RAI||Italy||Caltanissetta||Omnidirectional aerial, guyed steel lattice mast, height 282 m||10||closed|
|Radio Rossii||Russia||Kostantinogradovka near Blagoveshchensk||Omnidirectional aerial, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||1200||closed|
|Polskie Radio Parlament/Radio Polonia||Poland||Raszyn||Omnidirectional aerial, guyed steel lattice mast insulated against ground, 335 m high||200||closed|
|Radio Mayak||Russia||Saint Petersburg - Olgino||Omnidirectional aerial, 205 m high guyed steel lattice mast||150||inactive|
|Radio Mayak||Russia||Angarsk||Before 2001: T-antenna spun between 2 205 m tall guyed steel lattice mast||250||, possibly||closed|
|Radio Mayak||Russia||Avsyunino||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||150||inactive|
|Kyrgyzstan||Krasnaya Rechka near Bishkek||150||closed|
|RNE Todo Noticias||Spain||Logroño||Directional antenna, 300 metres tall.||>100||closed|
|Ukrainian Radio||Ukraine||Brovary||Omnidirectional antenna, 259.6 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||600||closed|
|Radio Mayak||Russia||Tynda||Omnidirectional aerial, steel lattice mast insulated against ground, height 244 m||150||closed|
|Deutschlandfunk||Germany||Aholming||Directional aerial, two guyed steel lattice masts, 265 m high, fed at the top||500||;||closed|
|Norway||Lambertseter near Oslo||200||closed|
|Radio Rossii||Russia||Krasnoyarsk||Omnidirectional antenna, guyed lattice steel mast, 210 m tall||150||closed|
|Radio Rossii||Russia||Atamanovka||Directional antenna||150||closed|
|Radio Rossii||Russia||Birobidzhan||2 guyed masts, 260 m high||30||;||closed|
|225||Turkey||Van||Omnidirectional antenna, 250 m high guyed lattice steel mast||600||inactive|
|Radio Rossii||Russia||Surgut||Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||1000||closed|
|Libya||Yafran near Tripoli||1000||closed|
|Radio 1||Russia||Krasny Bor transmitter near Sankt-Peterburg||Omnidirectional aerial, 271.5 metres tall guyed mast with cage antenna||1200||closed|
|Russia||Koskovo near Murmansk||Omnidirectional aerial, 210 m tall guyed mast||250||inactive|
|Radio 1||Russia||Novosemeykino near Samara||Four 205 metres tall towers insulated against ground arranged in a square||2000||; ; ;||closed|
|Radio Rossii||Russia||Raduzhnyy near Magadan||Omnidirectional aerial, 259 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||1000||closed|
|Radio Rossii||Russia||Odinsk near Irkutsk||Omnidirectional aerial, 259 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||500||closed|
|Radio 1||Russia||Koskovo near Arkhangelsk||Omnidirectional aerial, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||500||closed|
|243||Turkey||Erzurum||Omnidirectional antenna, 185 m high guyed lattice steel mast||200||inactive|
|Radio Rossii||Russia||Razdolnoye near Ussuriysk||Omnidirectional antenna, 259 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||1000||closed|
|Kazakhstan||Karaganda||Omnidirectional aerial, guyed steel lattice mast of 254 m height||1000||closed|
|Radio Rossii||Russia||Kazan||Omnidirectional aerial, 152 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)||100||closed|
|261||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||inactive|
|Radio Rossii||Russia||Taldom||Omnidirectional antenna, circle antenna with 1 central and 5 ring masts, height of central mast 275 m||2500||; ; ; ; ;||closed|
|Radio Rossii||Russia||Kruchina near Chita||Omnidirectional antenna, guyed lattice steel mast, 260 m high||150||closed|
|Radio Rossii||Russia||Tyumen||Omnidirectional antenna, guyed lattice steel mast, 220 m high||150||closed|
|Radio Rossii||Russia||Vorkuta||Omnidirectional antenna, guyed lattice steel mast, 220 m high||50||closed|
|Radio Horizont||Bulgaria||Vakarel||One of the few Blaw-Knox Towers in Europe, 215 m high||75||closed|
|Radio Rossii||Russia||Orenburg||Omnidirectional aerial, guyed steel lattice mast of 137 m height||25||closed|
|Radio 1||Russia||Khabarovsk||2 guyed steel lattice masts, height: 164 m||150||;||closed|
|Radio Rossii||Russia||Gorno-Altaisk||Omnidirectional antenna, 143m high guyed lattice steel mast||50||closed|
|Radio Rossii||Russia||Selenginsk||Omnidirectional aerial, 260 m high guyed lattice steel mast with cage antenna (ARRT-antenna)||150||closed|
|Radio Rossii||Russia||Vestochka near Yuzhno-Sakhalinsk||Omnidirectional antenna, guyed lattice steel mast, 258 m high||1000||closed|
|Radio Rossii||Russia||Yekaterinburg||Omnidirectional aerial, guyed steel lattice mast of 256 m height, fed at the top||150||closed|
Notes and references
- "long wave". Cambridge Online Dictionary. Cambridge Univ. Press, UK. 2011. Retrieved December 29, 2012.
- "long wave". MacMillan Online Dictionary. MacMillan Publishers. 2009. Retrieved December 29, 2012.
- Graf, Rudolf F. Graf (1999). Modern Dictionary of Electronics, 7th Ed.. US: Newnes. p. 437. ISBN 0750698667.
- The World Book Dictionary. US: World Book, Inc. 2003. p. 1232. ISBN 0716602997.
- "About LWCA". Longwave Club of America. Retrieved 2010-01-05.
- Ground-wave propagation curves for frequencies between 10 kHz and 30 MHz. ITU-R Recommendation P.368-9
- Guide to Broadcasting Stations (17th ed.). Butterworth. 1973. p. 18. ISBN 0-592-00081-8.
- World Radio TV Handbook
- "RTÉ Radio 1 Moves from Longwave Transmission". RTÉ Commercial Enterprises. 2014. Retrieved 23 September 2014.
- "RTÉ postpones closure of long wave radio service". RTÉ Commercial Enterprises. 2014. Retrieved 15 October 2014.
- Low frequency: for other uses (military, commercial and amateur) of this part of the radio spectrum (30–300 kHz)
- Electromagnetic spectrum: Very low frequency, Shortwave, Ground wave, Skywave, Medium wave
- Radio broadcasting: AM broadcasting, BBC Radio 4, BBC Light Programme, Radio clock, Office de Radiodiffusion-Télévision Française, Warsaw radio mast, Digital Radio Mondiale, International broadcasting,
- Shipping: Global navigation satellite system, Navigation, Shipping Forecast
- Lists: Index of wave articles
- Other: 1 kilometre, National Institute of Standards and Technology, Fail-safe, WGU-20
- Tomislav Stimac, "Definition of frequency bands (VLF, ELF... etc.)". IK1QFK Home Page.
- 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
- How to receive DRM from Kalundborg longwave station
- Reception of long wave and very long wave with ferrite antennas 5-50 kHz
- Klawitter, G.; Oexner, M.; Herold, K. (2000). "8.2 Langwellenrundfunk". Langwelle und Längstwelle (in German). Meckenheim: Siebel Verlag GmbH. pp. 116–131. ISBN 3-89632-043-2.
- Busch, Heinrich (2001-11-14). "Luftschiff Graf Zeppelin LZ127". (German)
- European and Asian Longwave Stations - Medium Wave Radio
- List of long- and mediumwave transmitters with GoogleMap-Links to transmission sites