Longwave

For other uses, see Longwave (disambiguation).

The tuning dial on a 1940s radio, showing longwave wavelengths between 800 and 2000 metres, corresponding to frequencies between 375 and 150 kHz

In radio, longwave refers to parts of the radio spectrum with relatively long wavelengths. 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. Most commonly it refers to radio wavelengths longer than 1000 meters (frequencies less than 300 kHz), including the ITU's low frequency (LF) (30–300 kHz) and very low frequency (VLF) (3–30 kHz) bands. Sometimes part of the medium frequency (MF) band (300–3000 kHz) is included.

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-broadcast use

Non-directional beacons

Main article: Non-directional beacon

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.

Time signals

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.
• 66.66 kHz in Taldom transmitter, Russia.
• BPC in Lintong, China 68.5 kHz.
• 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.

Military communication

The United Kingdom, Russian Federation, United States, Germany, and Sweden use frequencies below 50 kHz to communicate with their submarines.

LowFER

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 136 kHz and 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.

Historic

Swedish station SAQ, located at the Varberg Radio Station facility in Grimeton, is the last remaining operational Alexanderson alternator transmitter. Although the station ended regular service in 1996, it has been maintained as a World Heritage Site and makes at least two demonstration transmissions yearly, on 17.2 kHz.

Broadcasting

Longwave is used for broadcasting only within ITU Region 1. The longwave broadcasters are located in west, north, central and southeast Europe, the former Soviet Union, Mongolia, Algeria and Morocco.

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

Carrier frequencies are exact multiples of 9 kHz ranging from 153 to 279 kHz, except for a French language station Europe #1 in Germany. This station did keep to correctly spaced channels spacing for 4 months—only 7 years ago—and all Mongolian transmitters are spaced at 10 kHz.

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.

In January 2014 Russia closed all of its LW broadcast transmitters except for one in Caucasus, which was shut down in 2015.

Long distance reception

Because longwave signals can travel very long distances, some radio amateurs and shortwave listeners engage in an activity called DXing. DXers attempt to listen in to far away transmissions, and they often will send a reception report to the sending station to let them know where they were heard. After receiving a report, the sending station may mail the listener a QSL card to acknowledge this reception.

The longest distance over which a longwave signal has been received is 18,451 kilometres (11,465 mi). It occurred on July 27, 2015, when Mike Thayne of England, received Radio NL on 358 kHz from New Zealand.

List of longwave broadcasting transmitters

List of stations currently operating:

  Denotes non-standard frequency (not divisible by 9)

Freq. (kHz)	Station name	Language	Country	Location	Aerial type	Power (kW)	Coordinates	Remarks
153	Radio Antena Satelor	Romanian	Romania	Brașov	T-aerial on 2 guyed steel lattice masts, height: 250 metres.	200	;
	NRK P1	Norwegian	Norway	Ingøy	Omnidirectional aerial, guyed steel lattice mast 362 m tall, fed at the top, ex-Omega equipment.	100		The transmitter is important for the fishing fleet in the Barents Sea.
	Chaîne 1	Arabic	Algeria	Kenadsa	Three 357 metres tall guyed masts.	500		Active with very low modulation and power.
162	France Inter	French	France	Allouis	Two guyed lattice steel masts, height: 350 m, fed on the top.	1000/2000	;	Time signal phase-modulated.The transmitter is planned to go off air at the end of 2016.
164	MNB Radio 1	Mongolian	Mongolia	Ulan Bator	259 metres tall cable-stayed steel truss mast.	500		Broadcasts from 21:00 to 14:00 UTC.
171	Médi 1	Arabic and French	Morocco	Nador	Directional aerial consisting of three guyed steel lattice masts, 380 metres tall.	1600	;  ;
183	Europe 1	French	Germany	Felsberg-Berus	Directional aerial, four ground insulated steel lattice masts 270 m, 276 m, 280 m and 282 m tall. Spare aerial: two ground insulated steel lattice masts, height: 234 m.	2000	Main antenna:  ;  ;  ; , Spare antenna:  ;	DRM tests after 00:00 UTC.
189	RÚV Rás 1/RÚV Rás 2	Icelandic	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	English	United Kingdom	Droitwich (SFN)	T-aerial on 2 guyed steel lattice masts insulated against ground with a height of 213 metres.	500	;	All four transmitters carry Radio teleswitch PSK data. Droitwich relays BBC World Service from 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.
				Dartford Tunnel (SFN)		0.004
207	RÚV Rás 1/RÚV Rás 2	Icelandic	Iceland	Eiðar near Egilsstaðir	Omnidirectional aerial, steel lattice mast insulated against ground, height 221 m.	100
	SNRT Al Idaâ Al-Watania	Arabic	Morocco	Azilal Demnate	304.8 metres tall guyed mast	400
209	MNB Radio 1	Mongolian	Mongolia	Choibalsan	Cable-stayed steel truss mast, height: 275.84 metres	75		Broadcasts from 21:00 to 14:00 UTC.
				Dalanzadgad				Broadcasts from 21:00 to 14:00 UTC.
				Olgii	Omnidirectional antenna, 352.5 metres high guyed mast	30		Broadcasts from 21:00 to 14:00 UTC.
216	Radio Monte Carlo Info	French	Monaco	Roumoules	Directional aerial, 3 300 metre high guyed steel lattice masts, 330 metre high guyed steel lattice mast as backup aerial.	700/1400	; ; , Backup antenna:	Transmitter located in France. In operation from 5:30 to 23:00 CET.
225	Polskie Radio Jedynka	Polish	Poland	Solec Kujawski	Directional aerial, 2 guyed radio masts fed on the top, heights 330 m and 289 m.	1000		Earlier Konstantynów was used ( )
227	MNB Radio 1	Mongolian	Mongolia	Altai	Cable-stayed steel truss mast.	75		Broadcasts from 21:00 to 14:00 UTC.
234	RTL	French	Luxembourg	Beidweiler	Directional aerial, 3 guyed grounded steel lattice masts, 290 m high, with vertical cage aerials.	1500/2000	;  ;	Spare transmitter site Junglinster (  ;  ; )
243	DR Langbølge	Danish	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.
252	Chaîne 3	Arabic	Algeria	Tipaza	Omnidirectional aerial, single guyed lattice steel mast, height 355 m.	750/1500		Half transmitter power during night.
	RTÉ Radio 1	English	Ireland	Clarkstown	Omnidirectional aerial, guyed steel lattice mast, insulated against ground, height 248 m.	100/300		The only AM transmitter for RTÉ Radio 1. Power is decreased at night to 100 kW. It is tentatively scheduled to cease broadcasting on May 1, 2017.
270	ČRo Radiožurnál	Czech	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	;	Broadcasting from Monday to Friday 5:00-24:00 CET and 6:00-24:00 CET at weekends.
279	BR Pershy Kanal/BR Radyjo Stalitsa	Belarusian	Belarus	Sasnovy	353.5 metres tall guyed mast	500
	TR1 Watan Radio	Turkmen	Turkmenistan	Ashgabat	Cable-stayed steel truss mast	150

List of stations that have closed or are otherwise inactive:

  Closed

Freq. kHz	Station name	Country	Location	Aerial type	Power kW	Coordinates	Remarks
153
	Deutschlandfunk	Germany	Donebach	Directional aerial, two guyed steel lattice masts, 363 m high, fed at the top	500	;	closed
	Radio Mayak	Turkmenistan	Ashgabat		650		closed
	YuFM	Russia	Taldom transmitter	Omnidirectional aerial, guyed steel lattice mast of 257 m height	300		closed
	Radio Rossii		Popova near Komsomolsk-na-Amure		1200		closed
162	TRT Radyo 4	Turkey	Agri	Two guyed lattice steel masts, height 250 m	1000	;	inactive
	Radio Tashkent 1	Uzbekistan	Tashkent		150		closed
	Radio Rossii	Russia	Norilsk	Omnidirectional antenna, 205 m high antenna	150	?	closed
	Radio Yuldash, Radio Rossii		Ufa				closed
171
		Netherlands	Lopik		500		closed
	Voice of Russia	Russia	Oktyabrsky	257 m metres tall antenna.	1200		closed
	Radio Rossii	Russia	Bolshakovo near Kaliningrad	Omnidirectional antenna, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)	600		closed
	Radio Ukraine 1	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 Radyo 2	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
	Kazakh Radio 1	Kazakhstan	Alma-Ata		250		closed
	Radio Mayak	Kazakhstan	Aktyubinsk		150		closed
		Kazakhstan	Chimkent		50		closed
189
	Rai Radio 1	Italy	Caltanissetta	Omnidirectional aerial, guyed steel lattice mast, height 282 m	10		closed
	Sveriges Radio P1	Sweden	Orlunda		300		closed
	Radio Rossii	Russia	Kostantinogradovka near Blagoveshchensk	Omnidirectional aerial, 257 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)	1200		closed
	Sakartvelos Radio	Georgia	Dusheti		250		inactive
198
	Polskie Radio Parlament/Radio Polonia	Poland	Raszyn	Omnidirectional aerial, guyed steel lattice mast insulated against ground, 335 m high	200		closed
	Chaine 1	Algeria	Berkaoui		2000		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
	Radio Mayak	Russia	Ufa		150		closed
		Kyrgyzstan	Krasnaya Rechka near Bishkek		150		closed
207
	RNE Radio 5	Spain	Logroño	Directional antenna, 300 metres tall.	>100		closed
	Radio Ukraine 1	Ukraine	Brovary	Omnidirectional antenna, 259.6 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)	600		closed
	Jordan Radio	Jordan	Al Karanah		?	;	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
216
	NRK P1	Norway	Lambertseter near Oslo		200		closed
	Azerbaijan Radio	Azerbaijan	Baku		500		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	TRT GAP	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
234
	Radio Moldova	Moldova	Grigoriopol		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
	Radio Rossii	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	TRT Radyo 4	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
	Kazakh Radio 1	Kazakhstan	Karaganda	Omnidirectional aerial, guyed steel lattice mast of 254 m height	1000		closed
	Kazakh Radio 2	Kazakhstan	Alma-Ata		1000		closed
252
	Yle Radio 1	Finland	Lahti		200	,	closed
	Radio Tojikston	Tajikistan	Dushanbe		150		closed
	Radio Rossii	Russia	Kazan	Omnidirectional aerial, 152 m high guyed lattice steel mast with cage antenna ( ARRT-antenna)	100		closed
261	Radioropa Info	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
270
	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
279
	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

Height diagram of the antenna towers and antenna masts of longwave broadcasting stations

See also

• 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

External links

• 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
• (German)
• European and Asian Longwave Stations - Medium Wave Radio
• List of long- and mediumwave transmitters with GoogleMap-Links to transmission sites