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.

Contents

Band propagation characteristics

Historical significance

Broadcasting

ITU Region 2 note

List of longwave broadcasting transmitters

See also

External links

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 .

Historical significance

Essentially all radio transmitters before 1924 were longwave transmitters . 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) 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.

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 . 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.

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		Donebach	Directional aerial, two guyed steel lattice masts, 363 m high, fed at the top	500 kW	Night: 250 kW
	Radio Romania		Braşov	T-aerial on 2 guyed steel lattice masts with a height of 250 metres	1200 kW
	NRK Finnmark		Ingoy	Omnidirectional aerial, guyed steel lattice mast of 362 m height	100 kW
162 kHz	France Inter		Allouis	Two guyed steel lattice masts, height 350 m, fed on the top	2000 kW
171 kHz	Radio Medi		Nador	Directional aerial consisting of three guyed steel lattice masts, 380 metres tall	2000 kW
	Radio Rossii		Bolshakovo near Kaliningrad		150/75 kW
177 kHz	Deutschlandradio Kultur		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		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		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		Caltanissetta	Omnidirectional aerial, guyed steel lattice mast, height 282 m	10 kW	Inactive since August 2004
198 kHz	BBC Radio 4		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		Burghead	Guyed steel lattice mast	50 kW
	BBC Radio 4		Westerglen	Guyed steel lattice mast, height 152 m	50 kW
	Polskie Program 1		Raszyn	Guyed insulated mast, 335 m high	500 kW	Only active during the daytime
207 kHz	RÚV		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		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		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		Solec Kujawski	2 guyed radio masts fed on the top, heights 330 m and 289 m	1000 kW	Earlier transmitter site Konstantynow
234 kHz	RTL		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		Kalundborg	Alexanderson aerial, carried from 2 118 Meter high free-standing steel lattice towers	300 kW	Stop 15 february 2007
252 kHz	RTA Algier		Tipaza		1500 kW	French programme; during night-time half transmitter-power
	RTÉ Radio 1		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		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 Rossii		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		Vakarel	One of the few Blaw-Knox Towers in Europe, 215m high	75 kW
270 kHz	ČRO 1 - Radiožurnál		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		± 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
	Belaruskaje Radyjo 1 (BR1)		Sasnovy		500 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

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