Allouis longwave transmitter
Encyclopedia
The Allouis longwave transmitter first entered service, as France
's central longwave
transmitter
, in 1939. It is located near the village of Allouis
.
Prior to its destruction in 1944 by German forces, it used an aerial with four masts and a transmitter rated at 500 kilowatts.
On 19 October 1952 a new 250 kW transmitter came into service. This used a special cage aerial
, mounted on a 308-metre high earthed mast. In 1957 the transmission power was increased to 600 kW, in 1974 to 1000 kW, and in 1981 to 2000 kW. Transmission power is reduced to 1000 kW during the hours of darkness.
In 1974 the aerial was renewed. The cage aerials were removed and the mast height was increased to 350 m. A second mast of the same height was constructed at the same time. Since 1977 the Allouis transmitter in Allouis has been used to transmit not only the France Inter
radio channel, but also AMDS-mode time signal
s.
The transmitter initially operated on 164 kHz, but this was changed to 163.840 kHz (the 5th harmonic of the common 32768 Hz timekeeping frequency) in 1977 to be a more convenient frequency standard.
In 1980, the first atomic clock
was installed to regulate the carrier frequency.
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.
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
's central longwave
Longwave
In radio, longwave refers to parts of 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...
transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
, in 1939. It is located near the village of Allouis
Allouis
Allouis is a commune in the Cher department of the Centre 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 of Bourges at the junction of the D20, D79 and the D122...
.
Prior to its destruction in 1944 by German forces, it used an aerial with four masts and a transmitter rated at 500 kilowatts.
On 19 October 1952 a new 250 kW transmitter came into service. This used a special cage aerial
Cage aerial
A Cage aerial is a radio antenna, which consists of the top portion of a tower or mast and of several parallel wires, which are radially arranged around the lower part of the mast. one advantage of the cage aerial is that the supporting tower can be grounded, allowing it to be used for other radio...
, mounted on a 308-metre high earthed mast. In 1957 the transmission power was increased to 600 kW, in 1974 to 1000 kW, and in 1981 to 2000 kW. Transmission power is reduced to 1000 kW during the hours of darkness.
In 1974 the aerial was renewed. The cage aerials were removed and the mast height was increased to 350 m. A second mast of the same height was constructed at the same time. Since 1977 the Allouis transmitter in Allouis has been used to transmit not only the France Inter
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 intelligent spoken-word programming, both serious and entertaining, liberally punctuated with an eclectic mix of...
radio channel, but also AMDS-mode time signal
Time signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...
s.
The transmitter initially operated on 164 kHz, but this was changed to 163.840 kHz (the 5th harmonic of the common 32768 Hz timekeeping frequency) in 1977 to be a more convenient frequency standard.
In 1980, the first atomic clock
Atomic clock
An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...
was installed to regulate the carrier frequency.
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.
External links
http://perso.wanadoo.fr/tvignaud/am/allouis/fr-allouis.htm- http://www.skyscraperpage.com/diagrams/?b44247
- http://skyscraperpage.com/diagrams/?b58020