The longwaveradio band is the range of frequencies approximately lying between 12 and 1000 kHz[1] (corresponding to wavelengths between 20000 and 250 metres respectively), although the term also applies to subsets of this range (for example commercial longwave broadcasting is understood to range from 148.5 and 283.5 kHz, i.e. wavelengths between 2000 and 1000 metres).
This range encompasses the low-frequency (LF) band (30 kHz?300 kHz).
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 .
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 , as well as station WGU-20 in Chase, MD.
Nowadays the 160-190 kHz range is used there for Part 15Lowfers amateur and experimental stations. The 190-435 kHz band is used for navigational beacons.
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 kW
French progamme. The most Powerful Longwave transmitter in Germany.
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
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