Oldest continuously operating radio transmitting installation in the world
Preserved Nauen transmitter building designed by Herman Muthesius, dating from 1920
Nauen Transmitter Station (German: Grossfunkstelle Nauen or Sender Nauen) in Nauen, Havelland district, Brandenburg, Germany, is the oldest continuously operating radio transmitting installation in the world. Germany's first high power radio transmitter, it was founded on 1 April 1906 by Telefunken corporation and operated as a longwaveradiotelegraphy station through World War II, and during World War I became Germany's main link with the outside world when its submarine communications cables were cut. Upgraded with shortwave transmitters in the 1920s it was Germany's most advanced long range radio station, continually upgraded with the latest equipment and serving as an experimental station for Telefunken to test new technology. At the end of World War II, invading Russian troops dismantled and removed the transmitting equipment. During the Cold War it served as the GDR's (East Germany's) international shortwave station Radio Berlin International (RBI), and was the East Bloc's second most powerful radio station, disseminating Communist propaganda to other countries. Since German Reunification in 1991 it has been operated by Deutsche Telekom, Germany's state telecommunication service. The original 1920 transmitter building designed by architect Herman Muthesius is still used; it is one of the many remaining buildings designed by that architect that is a protected cultural heritage site.
Original 25kW spark-gap transmitter built 1906, showing large 400μF Leyden jar capacitor bank (rear) and vertical spark gaps (right)
Umbrella antenna of transmitter
100kW quenched spark transmitter installed in 1913, said to be the most powerful transmitter in the world at the time.
1,037 metre wire inverted-L flattop antenna aimed at Africa, built in 1913.
During the early years of the 20th century after Marconi's 1901 transatlantic radio demonstration, industrial nations began building networks of powerful longwave transoceanic radiotelegraphy stations to communicate with other countries and keep in touch with their overseas colonies. These transmitted telegram traffic with Morse code at high speed using paper tape machines. During World War I long-distance radio communication became a strategic technology; not only was it necessary to keep in timely contact with distant armies and naval fleets, but a nation without it could be isolated by an enemy cutting its submarine telegraph cables, as happened to Germany during both world wars.
The Telefunken company, founded in 1903 by German radio pioneers Adolf Slaby, Georg von Arco, and Karl Ferdinand Braun, was (with its rival, Britain's Marconi Company) one of the two giant wireless firms of the age.[1] Built by Telefunken under the direction of engineer R. Hirsch on a 40-hectare property north of Nauen, leased from Fideikommissar Fritz Stotze,[2] the Nauen station was Germany's first high power radio transmitter. Trial service was initiated on 9 August 1906, and operational service began on 16 August 1906 using a 25kW spark gap transmitter designed by von Arco, which fed an umbrella antenna supported by a steel lattice mast 100 metres high, insulated from earth.[3][4] Since the station had no commercial power, a 35HP steam tractor was installed in the transmitter building, a light half timbered house, which powered a 50 Hz alternator producing 25kilowatts (kW) output power. The transmitter worked at frequencies of 75 – 100kHz with a radiated power of around 10kW, and the station could be received at a range of about 3,500 kilometres (2,200mi).[4]
The station was financed by Germany's Post Office, which wanted to develop it as a strategic link with Germany's overseas colonies, as well as handling commercial telegram traffic to the Americas.[5] In 1909 a post office official, Hans Bredow, became station director, who set about to achieve these goals by making Nauen a 'superpower' station.[1]
In 1911 the station changed from an experimental to a commercial station, with call sign POZ. The steam power plant was increased to 100kW and the transmitter was replaced with a new more efficient 35kW quenched-spark transmitter which increased the range to about 5,300 kilometres (3,300mi).[4] In the same year the antenna tower was increased to 200 metres in height; however, this tower was destroyed by a storm on 31 March 1912. A temporary replacement antenna was suspended between two 120 metres high masts.
In 1913 the station was upgraded to communicate with Germany's African colony Togoland.[4] The transmitter was replaced with a 100kW quenched-spark transmitter, the most powerful transmitter in the world at the time.[5] The omnidirectional umbrella antenna was replaced by a 1,037-meter (3,402ft) long directional flattop antenna consisting of 20 parallel horizontal wires supported by five 120-meter (390ft) towers, pointed at southwest Africa. These improvements gave the station a range of 9,000 kilometres (5,600mi), allowing communication with all of Europe, North America, the coast of South America, and at night with Togoland.[4]:294
In addition to the spark transmitter, in 1913 a 100kW Joly-Arco alternator transmitter was installed.[4] This was an early continuous wave radio transmitter technology invented by Georg von Arco similar to the Alexanderson alternator. It generated radio frequency current at 8kHz using a rotating generator turned by an electric motor, which was increased in frequency to 32kHz with two cascaded saturated core magnetic frequency doubler transformers before being applied to the antenna.[6] This transmitter was capable of daylight transatlantic communication with its sister station in Sayville, Long Island, New York,[6] while other transatlantic radio stations could only achieve transatlantic contact at night. Also an experimental 6kW radiotelephony transmitter was built, one of the earliest AM transmitters, which allowed voice communication with Vienna, 640 kilometres (400mi) distant.[4]:295
First World War and the interwar period
Station in 1931
Alternator radio transmitters. The two in center were the 100kW units from 1913. The two on the sides were the 400kW units installed 1916. At rear are the frequency doubler transformers and tank circuits
After the beginning of World War I in 1914, the station became very important because the transatlantic cables leading to Germany were cut by the British Navy. During the war, the station was run by the German Admiralty, which used it for military communication with its fleet as well as commercial radiotelegraphy traffic. The British Radio Intelligence Service devoted much effort into intercepting and decoding encrypted military communications from the station during the war.
In 1916, at the urging of Bredow, major additional development of the station took place. Two huge 400kW Joly-Arco alternator transmitters were installed, which could work in parallel giving an output power of 800kW;[7] making the station by far the most powerful radio transmitter in the world. These were some of the largest alternator transmitters ever built, and operated at the limit of this technology.[7] The alternator had a 1.65 meter diameter rotor weighing 7 tons, rotating at 1500 rpm.[6][7] The rotor's 240 teeth (magnetic poles) generated 1200 amps alternating current at 450 volts and a frequency of 6kHz. This was doubled twice by two cascaded frequency doubler transformers to give 24kHz, which was applied to the antenna.[8] The large doubler transformers, although 90% efficient, required a powerful forced-oil cooling system to remove the 40kW waste heat.[8][7] A system of switchable doubler and tripler transformers allowed the transmitter to operate on a range of frequencies: 12kHz, 18kHz, 24kHz, 36kHz, or 48kHz.[7] The antenna system was enormously increased in size. In 1920 the main flattop antenna, carried on two 260-metre (850ft) and four 125-metre (410ft) masts, was 2,484 metres (8,150ft) long. These transmitters gave the station a range of 11,000 kilometres (6,800mi), which was increased to 18,000 kilometres (11,000mi) by the end of the war, essentially covering most of the world.[9]
At a right angle to the large antenna was a smaller antenna, carried by three masts, which was used by the 100kW transmitter, so the station could transmit on two frequencies at the same time.
During the war the Nauen station was Germany's main communication link with the outside world.[1] Germany's Transocean news service broadcast overseas news summaries in English twice daily from Nauen, which could be received worldwide, to circumvent the censorship of Britain's cable network, to get their version of the news to the Americas and the Far East.[9] In 1918 in World War 1 US president Woodrow Wilson transmitted a request for surrender to Nauen from the alternator station at New Brunswick, New Jersey.
A new transmitter building designed by Hermann Muthesius was erected in 1920, an Art Deco style cathedral-like structure to give space for more high power transmitting equipment. The modernized station was inaugurated on September 29, 1920 by German president Friedrich Ebert.
In the 1920s long distance radio communication shifted from the longwave to the shortwave bands with the discovery of the skywave (skip) propagation mechanism. The last longwave transmitter was installed at Nauen in 1923 and vacuum tube shortwave transmitters were installed after 1924. On 1 January 1932 the German Reichspost took over the station. It was considerably expanded and by 1939 was one of the biggest and most powerful communication complexes in the world. Although vacuum tube transmitters had long been the state of the art in the 1930s, the high power alternator transmitters were again modernized in 1937 for use in WW2 to communicate with Germany's U-boat fleet.
Second World War and the post-war period
Long distance shortwave transmitting antenna at Nauen, 2004One of the four ALLISS antennas at Nauen, 2010
In World War II, the longwave transmitters were used by the military to transmit instructions to submerged submarines. Unlike higher frequency radio waves, the very low frequency (VLF) waves generated by the alternator transmitters could penetrate seawater and reach submerged submarines without the need for them to surface and become vulnerable to detection. The station survived World War II without damage, but after May 1945 was disassembled by Soviet occupation forces. All technical mechanisms were dismantled and the masts of the station were blown up. Whether and where the dismantled transmitters were used in the Soviet Union is unknown. The Muthesius building was also planned to be blown up, but this was prevented.
The building was used for potato storage up until 1955 when the communistGerman Democratic Republic (GDR, East Germany), in whose borders the station ended the war, began to use it as a radio station again. In 1959 it became the GDR's international shortwave broadcasting station, Radio DDR, which broadcast under the name Radio Berlin International (RBI). Between 1959 and 1989 21 transmitters with power up to 100kW and 45 antenna systems were installed for worldwide radio communication. Between 1971 and 1981 three 500kW superpower shortwave transmitters were installed, feeding 23 high gain curtain antennas positioned to broadcast to politically important countries. As the Eastern Bloc's second most powerful radio station after Moscow, it became important as a dissemination channel of Cold War propaganda to both Western and other East Bloc countries.
In 1964 two German companies built one of the first prototype rotating shortwave broadcast antennas nearby at the Dechtower dyke, which was used until the end of the Cold War.[2] It has been preserved as a historical structure. This consisted of a 70 metre tower supporting two reflective dipole arrays weighing 40 and 70 tons covering 5.8 to 18.8MHz that could be rotated 360° and tilted in elevation from horizontal to 30° to adjust to changing ionosphericskywave propagation conditions. It has a gain of 14.1 and 20.0dB and is fully automatic in operation.
German reunification and after
On 3 October 1990, the day the GDR reunified with the Federal Republic of Germany, all transmitters were switched off and the station was provisionally transferred to German international shortwave broadcaster Deutsche Welle.[1] In 1991 it was taken over by Deusche Bundespost Telecom, Germany's Federal telecommunications service. It was decided to upgrade the station with new transmitters and antennas. Four modular rotating ALLISS antennas and 500kW transmitters made by Thomcast Communications were installed between 1995 and 1997.
When the Deutsche Bundespost was privatized, all transmitters were transferred to Deutsche Telekom AG as its legal successor. From 2001 the broadcasting division belonged to the subsidiary T-Systems, where it was run as a separate division Media & Broadcast. In preparation for a sale, it was spun off on June 1, 2007 to T-Systems Media & Broadcast GmbH (M&B). In January 2008, the Media & Broadcast GmbH was merged with the French network operator Télédiffusion de France (TDF); since February 15, 2008 it has been operating as Media Broadcast GmbH.
The company operates its own transmitter location in Nauen for shortwave broadcasting.[10]
Current status
A new shortwave broadcasting system consisting of four rotating towers and four 500 kilowatt transmitters was built by Thomcast Communications between 1995 and 1997.
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz ; above the medium frequency band (MF), to the bottom of the VHF band.
International broadcasting, in a limited extent, began during World War I, when German and British stations broadcast press communiqués using Morse code. With the severing of Germany's undersea cables, the wireless telegraph station in Nauen was the country's sole means of long-distance communication.
AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave transmissions, but also on the longwave and shortwave radio bands.
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 early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.
Grimeton Radio Station in southern Sweden, close to Varberg in Halland, is an early longwave transatlantic wireless telegraphy station built in 1922–1924, that has been preserved as a historical site. From the 1920s through the 1940s it was used to transmit telegram traffic by Morse code to North America and other countries, and during World War II was Sweden's only telecommunication link with the rest of the world. It is the only remaining example of an early pre-electronic radio transmitter technology called an Alexanderson alternator. It was added to the UNESCO World Heritage List in 2004, with the statement: "Grimeton Radio Station, Varberg is an outstanding monument representing the process of development of communication technology in the period following the First World War." The radio station is also an anchor site for the European Route of Industrial Heritage. The transmitter is still in operational condition, and each year on a day called Alexanderson Day is started up and transmits brief Morse code test transmissions, which can be received all over Europe.
An Alexanderson alternator is a rotating machine invented by Ernst Alexanderson in 1904 for the generation of high-frequency alternating current for use as a radio transmitter. It was one of the first devices capable of generating the continuous radio waves needed for transmission of amplitude modulated signals by radio. It was used from about 1910 in a few "superpower" longwave radiotelegraphy stations to transmit transoceanic message traffic by Morse code to similar stations all over the world.
The Orfordness transmitting station was a major radio broadcasting facility at Orford Ness on the Suffolk coast in the United Kingdom able to broadcast to much of Europe. It closed in May 2012 after more than 30 years of service. In 2017 Radio Caroline started broadcasting from the site, though not with the same intended coverage of an audience in Europe as the original station.
Deutschlandfunk is a public-broadcasting radio station in Germany, concentrating on news and current affairs. It is one of the four national radio channels produced by Deutschlandradio.
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Radio Ukraine International, abbreviated RUI, is the official international broadcasting station of Ukraine, with foreign language news and programming being produced by Ukrainian Radio's main editorial department for broadcasting in EBU languages. RUI broadcasts in Belarusian, Bulgarian, English, German, Hungarian, Polish, Romanian and Slovak. The Ukrainian language programming aired on RUI is produced by the domestic First Channel.
An umbrella antenna is a capacitively top-loaded wire monopole antenna, consisting in most cases of a mast fed at the ground end, to which a number of radial wires are connected at the top, sloping downwards. One side of the feedline supplying power from the transmitter is connected to the mast, and the other side to a ground (Earthing) system of radial wires buried in the earth under the antenna. They are used as transmitting antennas below 1 MHz, in the MF, LF and particularly the VLF bands, at frequencies sufficiently low that it is impractical or infeasible to build a full size quarter-wave monopole antenna. The outer end of each radial wire, sloping down from the top of the antenna, is connected by an insulator to a supporting rope or cable anchored to the ground; the radial wires can also support the mast as guy wires. The radial wires make the antenna look like the wire frame of a giant umbrella hence the name.
The Wiederau transmitter is the oldest broadcasting facility in Saxony. It is located near Wiederau, a village which is part of the municipality of Pegau, and is used for medium-wave, FM and Television broadcasting.
Georg Wilhelm Alexander Hans Graf von Arco was a German physicist, radio pioneer, and one of the joint founders of the "Society for Wireless Telegraphy" which became the Telefunken company. He was an engineer and the technical director of Telefunken. He was crucial in the development of wireless technology in Europe.
Rás 1 is an Icelandic radio station belonging to and operated by Ríkisútvarpið (RÚV), Iceland's national public service broadcaster. Broadcast throughout Iceland on FM, via satellite, DVB and also 189 kHz longwave, it is currently among the country's most listened-to radio stations.
The Goldschmidt alternator or reflector alternator, invented in 1908 by German engineer Rudolph Goldschmidt, was a rotating machine which generated radio frequency alternating current and was used as a radio transmitter. Radio alternators like the Goldschmidt were some of the first continuous wave radio transmitters. Like the similar Alexanderson alternator, it was used briefly around World War I in a few high power longwave radio stations to transmit transoceanic radiotelegraphy traffic, until the 1920s when it was made obsolete by vacuum tube transmitters.
Berlin-Köpenick transmitter was a transmission facility for broadcasting on medium wave, short wave, and VHF in Berlin-Köpenick, Germany, near the suburb of Uhlenhorst, after which it was occasionally named.
The Wertachtal transmitter site in Bavaria, Germany, was from 1972 to 2013 the biggest shortwave broadcasting facility in Europe. It was located in the valley of the Wertach River near the village of Amberg (Swabia), and was originally operated by Deutsche Bundespost, and later by Media Broadcast GmbH. Before the site was closed, it included 14 500 kW radio transmitters and two 100 kW radio transmitters. It was built in 1969 and demolished in 2014.
The Sainte-Assise transmitter is a very low frequency (VLF) radio transmitter and military installation located on the grounds of the Château de Sainte-Assise in the communes of Seine-Port, Boissise-la-Bertrand, and Cesson in the Seine-et-Marne department of the Île-de-France region of France. The transmitter's original equipment was inaugurated on 9 January 1921, at the time being the most powerful radio transmitter on Earth. On 26 November 1921 the first French radio program was transmitted from Sainte-Assise. In 1965 the transmitter was used to send VLF signals to FR-1, the first French satellite. Since 1998 the French Navy has used the transmitter to communicate with submerged submarines.
1 2 3 von Arco, Georg; Dornig, W. High-frequency equipment at Nauen wireless station, Physikalische Zeitschrift, vol. 40, p. 665-667, 18 December 1919, abstracted in von Arco, Georg; Dornig, W. (1920). "High-frequency equipment at Nauen wireless station". Science Abstracts, Section B: Electrical Engineering. London: Institute of Electrical Engineers. 23: 215–217. Retrieved 18 February 2020.
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