Longwave transmitter Orlunda
Encyclopedia
The Orlunda longwave transmitter was a longwave
broadcast facility in central Sweden
which broadcast Sveriges Radio
Programme 1 from 1962 to 1991. The facility is currently in use as a museum.
, had begun plans for an upgraded longwave transmitter to serve central Sweden as early as the 1940s. The original facility, located in central Motala
, was both antiquated and poorly situated; the transmitter was inefficient and staff were needed on site to operate it day and night, and signal fading occurred as close as 80 kilometres away. After numerous studies it was determined that a site east of the town of Vadstena
would provide a clear signal to the surrounding area. Construction began in 1958; engineer Folke Strandén designed a ring antenna system consisting of a central mast surrounded by five antennas, to be connected to two 300 kW Compagnie Français Thomson Houston
(CFTH) transmitters. The station itself was built underground in a windowless concrete bunker with 1.5 metre thick walls designed to survive a Soviet air attack
. The bunker would host the power supply, transmitters, transformers, and a V-12 diesel engine to be used as a backup generator. All cables leading to and from the facility were likewise buried underground.
The antenna system was designed to produce a ground wave intended to prevent interference with distant transmitters on the same frequency. Unfortunately, the transmitter also broadcast a signal at a 40° angle; this did not affect reception, but its effect on distant stations is unknown. Programs were sent to the facility by telephone cable and were amplified before transmission. The centre antenna, 250 metres in height, was located near the station and the secondary antennas, 200 metres each in height, were arranged in a ring surrounding the station; each secondary antenna was 630 metres from the centre antenna and 630 metres from its neighbours.
Construction was completed in 1961 and the station was officially inaugurated by HRH Prince Bertil in May of that year. The station began broadcasting in 1962, after the necessary tests and adjustments had been conducted.
Some Swedes complained that it was a mistake to build an expensive longwave facility financed by license fees when the more enjoyable FM radio was gaining in popularity. Critics pointed out that many FM stations could be built for the cost of one longwave station. Televerket responded by stating that the Orlunda station was required because many of its listeners did not yet own FM receivers. However, despite Televerket's insistence on the importance of AM broadcasting, it introduced an FM network only a few years later; the Orlunda facility was the last longwave transmitter and the second-last AM transmitter (Sölvesborg
was the last) built by Televerket.
On 12 July 1970 the station's central antenna was struck by lightning, cutting off a stay, setting an oil-filled stay isolator on fire, and crushing the base isolator. This caused the central antenna to collapse over the bunker, destroying the antenna but causing little damage to the sturdily-built bunker, only a crack in the ceiling visible from the inside entrance. Power was lowered to 150 kW while the feeders were reconnected to the five ring antennas. The central mast was never rebuilt. When the feeders were rebuilt the power was raised again to 300 kW, but lowered again in the 1970s to 100 kW after the 1973
and 1979
oil crises. This cut listenership as it increased maintenance costs; an attempt by Televerket to close down the station and replace it with a new longwave facility on the island of Gotland
met with protests and the idea was dropped.
Sveriges Radio later introduced processed sound to increase sound quality, but this had the effect of the modulation transformer almost reaching its alarm limit.
oscillator was installed to stabilize the carrier. In 1987 three of the five remaining antennas were demolished as part of a military anti-sabotage exercise. The transmitter beam was later changed on the two remaining antennas to improve reception in Copenhagen
and Helsinki
without decreasing reception in Oslo
.
Televerket conducted a survey in 1989 to gauge listenership, which revealed that only 200 people tuned in regularly. A request for 3 million Swedish krona
in additional funding for transmitter maintenance was denied by the Swedish government in 1991, and it was decided shortly thereafter that the station would be shut down on 30 November of that year. Listeners had six months advance notice of the closure. The last broadcast featured a special program ending with the Swedish national anthem.
In 1994 and 1995 the two remaining antennas were dismantled.
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...
broadcast facility in central Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
which broadcast Sveriges Radio
Sveriges Radio
Sveriges Radio AB – Swedish Radio Ltd – is Sweden's national publicly funded radio broadcaster. The Swedish public-broadcasting system is in many respects modelled after the one used in the United Kingdom, and Sveriges Radio - like Sveriges Television - shares many characteristics with...
Programme 1 from 1962 to 1991. The facility is currently in use as a museum.
Planning and construction
The Swedish Telecom Administration Board and its technical department, TeleverketTeleverket (Sweden)
Televerket was the public utility company responsible for telecommunications in Sweden between 1953-1993; however, it originated 100 years earlier....
, had begun plans for an upgraded longwave transmitter to serve central Sweden as early as the 1940s. The original facility, located in central Motala
Motala
Motala is a locality and the seat of Motala Municipality, Östergötland County, Sweden with 29,798 inhabitants in 2005. It is the third largest city of Östergötland, following Linköping and Norrköping...
, was both antiquated and poorly situated; the transmitter was inefficient and staff were needed on site to operate it day and night, and signal fading occurred as close as 80 kilometres away. After numerous studies it was determined that a site east of the town of Vadstena
Vadstena
Vadstena is a locality and the seat of Vadstena Municipality, Östergötland County, Sweden, with 5,612 inhabitants in 2005. From 1974 to 1979 Vadstena was administered as part of Motala Municipality....
would provide a clear signal to the surrounding area. Construction began in 1958; engineer Folke Strandén designed a ring antenna system consisting of a central mast surrounded by five antennas, to be connected to two 300 kW Compagnie Français Thomson Houston
Thomson SA
Technicolor SA , formerly Thomson SA and Thomson Multimedia, is a French international provider of solutions for the creation, management, post-production, delivery and access of video, for the Communication, Media and Entertainment industries. Technicolor’s headquarters are located in Issy les...
(CFTH) transmitters. The station itself was built underground in a windowless concrete bunker with 1.5 metre thick walls designed to survive a Soviet air attack
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
. The bunker would host the power supply, transmitters, transformers, and a V-12 diesel engine to be used as a backup generator. All cables leading to and from the facility were likewise buried underground.
Technical specifications
The two transmitters could be used either independently or together, and featured a CFTH specialty, steam-cooled tubes called "Vapotrones". They had a power efficiency of 66%.The antenna system was designed to produce a ground wave intended to prevent interference with distant transmitters on the same frequency. Unfortunately, the transmitter also broadcast a signal at a 40° angle; this did not affect reception, but its effect on distant stations is unknown. Programs were sent to the facility by telephone cable and were amplified before transmission. The centre antenna, 250 metres in height, was located near the station and the secondary antennas, 200 metres each in height, were arranged in a ring surrounding the station; each secondary antenna was 630 metres from the centre antenna and 630 metres from its neighbours.
Construction was completed in 1961 and the station was officially inaugurated by HRH Prince Bertil in May of that year. The station began broadcasting in 1962, after the necessary tests and adjustments had been conducted.
Operations
The station originally broadcast Programme 1 of Sveriges Radio, the Swedish national broadcaster, on 191 kHz. Its improved coverage and higher power provided a better signal to hundreds of thousands of listeners in central Sweden. The station was also audible in northern Sweden at night.Some Swedes complained that it was a mistake to build an expensive longwave facility financed by license fees when the more enjoyable FM radio was gaining in popularity. Critics pointed out that many FM stations could be built for the cost of one longwave station. Televerket responded by stating that the Orlunda station was required because many of its listeners did not yet own FM receivers. However, despite Televerket's insistence on the importance of AM broadcasting, it introduced an FM network only a few years later; the Orlunda facility was the last longwave transmitter and the second-last AM transmitter (Sölvesborg
Sölvesborg medium wave transmitter
The Sölvesborg mediumwave transmitter is a radio station at Björkenabben on the peninsula Listerlandet, inaugurated 30 May 1985.The station most recently transmitted on 1179 kHz, used by Radio Sweden International , and is owned by Teracom.-Technical specifications:The station is situated outside...
was the last) built by Televerket.
Problems
Soon after the station entered service, the East German international station Stimme der DDR commenced broadcasting on 185 kHz, interfering with reception at longer distances. After several complaints, the East German government closed the station.On 12 July 1970 the station's central antenna was struck by lightning, cutting off a stay, setting an oil-filled stay isolator on fire, and crushing the base isolator. This caused the central antenna to collapse over the bunker, destroying the antenna but causing little damage to the sturdily-built bunker, only a crack in the ceiling visible from the inside entrance. Power was lowered to 150 kW while the feeders were reconnected to the five ring antennas. The central mast was never rebuilt. When the feeders were rebuilt the power was raised again to 300 kW, but lowered again in the 1970s to 100 kW after the 1973
1973 oil crisis
The 1973 oil crisis started in October 1973, when the members of Organization of Arab Petroleum Exporting Countries or the OAPEC proclaimed an oil embargo. This was "in response to the U.S. decision to re-supply the Israeli military" during the Yom Kippur war. It lasted until March 1974. With the...
and 1979
1979 energy crisis
The 1979 oil crisis in the United States occurred in the wake of the Iranian Revolution. Amid massive protests, the Shah of Iran, Mohammad Reza Pahlavi, fled his country in early 1979 and the Ayatollah Khomeini soon became the new leader of Iran. Protests severely disrupted the Iranian oil...
oil crises. This cut listenership as it increased maintenance costs; an attempt by Televerket to close down the station and replace it with a new longwave facility on the island of Gotland
Gotland
Gotland is a county, province, municipality and diocese of Sweden; it is Sweden's largest island and the largest island in the Baltic Sea. At 3,140 square kilometers in area, the region makes up less than one percent of Sweden's total land area...
met with protests and the idea was dropped.
Sveriges Radio later introduced processed sound to increase sound quality, but this had the effect of the modulation transformer almost reaching its alarm limit.
The end
In 1986 the station's frequency was changed to 189 kHz to meet international standards proposed at the 1979 Geneva World Administrative Radio Conference. A rubidiumRubidium
Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...
oscillator was installed to stabilize the carrier. In 1987 three of the five remaining antennas were demolished as part of a military anti-sabotage exercise. The transmitter beam was later changed on the two remaining antennas to improve reception in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
and Helsinki
Helsinki
Helsinki is the capital and largest city in Finland. It is in the region of Uusimaa, located in southern Finland, on the shore of the Gulf of Finland, an arm of the Baltic Sea. The population of the city of Helsinki is , making it by far the most populous municipality in Finland. Helsinki is...
without decreasing reception in Oslo
Oslo
Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...
.
Televerket conducted a survey in 1989 to gauge listenership, which revealed that only 200 people tuned in regularly. A request for 3 million Swedish krona
Swedish krona
The krona has been the currency of Sweden since 1873. Both the ISO code "SEK" and currency sign "kr" are in common use; the former precedes or follows the value, the latter usually follows it, but especially in the past, it sometimes preceded the value...
in additional funding for transmitter maintenance was denied by the Swedish government in 1991, and it was decided shortly thereafter that the station would be shut down on 30 November of that year. Listeners had six months advance notice of the closure. The last broadcast featured a special program ending with the Swedish national anthem.
In 1994 and 1995 the two remaining antennas were dismantled.
Today
Everything remains at the station today except for the antennas and the V12 diesel engine. It is currently operated as a private museum which may be visited by prior appointment. The lands surrounding the station were sold back to their original owners.External links
- http://www.skyscraperpage.com/diagrams/?b46230
- http://www.skyscraperpage.com/diagrams/?b46231
- http://www.skyscraperpage.com/diagrams/?b46232
- http://www.skyscraperpage.com/diagrams/?b46233
- http://www.skyscraperpage.com/diagrams/?b46234
- http://www.skyscraperpage.com/diagrams/?b46236
- http://hem.passagen.se/longwave/ (Swedish language only)