The Allouis longwave transmitter has been

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

's central

longwave In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the e ...

broadcast

transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...

since 1939. It is located near the village of

Allouis Allouis () is a commune in the Cher department of the Centre-Val de Loire region of France. Geography An area of lakes, woods and farming comprising the village and several hamlets, situated in the valley of the river Yèvre, some northwest ...

It broadcast the

France Inter France Inter () is a major French public radio channel and part of Radio France. It is a " generalist" station, aiming to provide a wide national audience with a full service of news and spoken-word programming, both serious and entertaining, li ...

public radio station from October 1952 until 31 December 2016. Since 2017, it broadcasts only the TDF time signal, which has been renamed ALS162 since 2017. The first transmitter, built in 1939 during the

Phoney War The Phoney War (french: Drôle de guerre; german: Sitzkrieg) was an eight-month period at the start of World War II, during which there was only one limited military land operation on the Western Front, when French troops invaded Germa ...

, used an aerial with four masts and a transmitter rated at 500 kilowatts.Chronologie des radios françaises en ondes longues 1921–2000
("Chronology of french long-wave transmitters 1921–2000") It was destroyed in 1944 during the scorched earth retreat by German forces. On 19 October 1952 a new 250 kW transmitter came into service. This used a special cage aerial, mounted on a high earthed mast. In 1957 the transmission power was increased to 600 kW, in 1974 to 1,000 kW, and in 1981 to 2,000 kW. Transmission power was reduced to 1,000 kW during the hours of darkness. In 2011 the transmission power was reduced to 1,500 kW for cost savings. For the same reason the transmission power was reduced to 1,100 kW in 2017 and subsequently in February 2020 to 800 kW.ANFR website (in French)
/ref> In 1974 the aerial was renewed. The cage aerials were removed and the mast height was increased to . A second mast of the same height was constructed at the same time. In 1977, the current

phase modulated Phase modulation (PM) is a modulation pattern for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Phase modulation is one of the two principal forms ...

time signal was added to the transmissions. The broadcast frequency, formerly 164 kHz, was changed to 163.840 kHz (the 5th harmonic of the common 32,768 Hz timekeeping frequency used by most

quartz clock Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least a ...

s) to be a more convenient frequency standard. In 1980, the first

atomic clock An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betwe ...

was installed to regulate the

carrier frequency In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a ...

.Les ré-orientations
/ref> On 1 February 1986, the frequency was changed to its current value of 162 kHz (still an accurately controlled frequency standard) to bring it to a multiple of 9 kHz in accordance with the

Geneva Frequency Plan of 1975 The Geneva Frequency Plan of 1975 (Aka "The Final Acts of the Regional Administrative LF/MF Broadcasting Conference (Regions 1 and 3) Geneva, 1975" or simply "GE75") is the internationally agreed frequency plan which was drawn up to implement th ...

. The radio channel

announced during 2016 that the channel would discontinue transmitting on the 162 kHz frequency on 31 December 2016, seeking cost savings of approximately 6 million Euros per year. The transmission of the ALS162 time signal was and will be continued after this date, as this time signal is critical for over 300,000 devices, which are deployed within French enterprises and state entities, like the French railways SNCF, the electricity distributor ENEDIS, airports, hospitals, municipalities, et cetera. The transmitter is owned by

TéléDiffusion de France TDF (which stands for ''Télédiffusion de France'' officially renamed ''TDF'' in 2004) is a French company which provides radio and television transmission services, services for telecommunications operators, and other multimedia services � ...

and the dissemination of the Metropolitan French national legal time to the public is a joint responsibility of ANFR (state body for radio frequencies), the trade body France Horlogerie and the LNE-SYRTE and LNE-LTFB time laboratories.Provision of the legal time by ALS162 signal
/ref>

References

External links

* * http://perso.wanadoo.fr/tvignaud/am/allouis/fr-allouis.htm * http://www.skyscraperpage.com/diagrams/?b44247 * http://skyscraperpage.com/diagrams/?b58020 {{Time measurement and standards Radio masts and towers in Europe Buildings and structures in Cher (department) Transmitter sites in France Time signal radio stations 1939 establishments in France