History
In 1977, The United States and Australian governments agreed to establish an OMEGA navigation system in south-eastern Australia. [1] [2] The agreement was extended in 1995, to 30 September 1997. [3]
Station G was an Omega transmitter that used an umbrella antenna carried by a 432 metres (1,417 ft) tall grounded lattice steel guyed mast. Unlike many of the other Omega Transmitters, Woodside was not a "hot tower," that is, one which is insulated from a ground connection by large ceramic insulators that support the entire weight of the structure. Rather, the tower was electrically insulated from the topmost guys which served as the radiators, similar to the metal radials of an umbrella without cloth covering. The mast simply supported the downward sloping guy wires which are the active elements. The guy wires were also used to hold the tower itself in place. [4] This mast was the tallest structure in the southern hemisphere. [5] Construction of this station was originally planned to be built in New Zealand but after protests from anti-war protestors it was built in Australia, [6] although not without controversy. [7] The tower was officially opened in October 1982, [8] but had been operating for 3 months prior to that, with the first broadcast at 10am on the 16th of August, having taken 3.5 years to construct, [9] however the tower itself having taken only 30 days to be constructed. [10]
After the shutdown of the OMEGA navigation system on 30 September 1997, the station was used as a transmitter for uni-directional communications to submarines on 13 kHz under the callsign VL3DEF until 2004. Until December 2008, it had been transmitting a 100 baud MSK modulated signal on 18.6 kHz. [11]
Naval Communication Station Harold E. Holt is a joint Australian and United States naval communication station located on the north-west coast of Australia, 6 kilometres (4 mi) north of the town of Exmouth, Western Australia. The station is operated and maintained by the Australian Department of Defence on behalf of Australia and the United States and provides very low frequency (VLF) radio transmission to United States Navy, Royal Australian Navy and allied ships and submarines in the western Pacific Ocean and eastern Indian Ocean. The frequency is 19.8 kHz. With a transmission power of 1 megawatt, it is claimed to be the most powerful transmission station in the Southern Hemisphere.
OMEGA was the first global-range radio navigation system, operated by the United States in cooperation with six partner nations. It was a hyperbolic navigation system, enabling ships and aircraft to determine their position by receiving very low frequency (VLF) radio signals in the range 10 to 14 kHz, transmitted by a global network of eight fixed terrestrial radio beacons, using a navigation receiver unit. It became operational around 1971 and was shut down in 1997 in favour of the Global Positioning System.
The Warsaw Radio Mast was a radio mast located near Gąbin, Poland, and was the world's tallest structure at 2,120 ft from 1974 until its collapse on 8 August 1991. The mast was designed for extreme height in order to broadcast Communist propaganda around the world, including to the remotest areas such as Antarctica. As of 2023, it was the third-tallest manmade structure ever built, after the Burj Khalifa tower in the United Arab Emirates in 2009, and Merdeka 118 tower in Malaysia in 2022.
A guyed mast is a tall thin vertical structure that depends on guy lines for stability. The mast itself has the compressive strength to support its own weight, but does not have the shear strength to stand unsupported or bear loads. It requires guy lines to stay upright and to resist lateral (shear) forces such as wind loads. Examples include masts on sailing vessels, towers for telecommunications, meteorology, and masts on cranes, power shovels, draglines, and derricks, starting with the simple gin pole.
The Hellissandur longwave radio mast is a 412 m (1,352 ft) tall guyed radio mast formerly used for longwave radio transmissions of RÚV. It is situated at Gufuskálar, near Hellissandur on the Snæfellsnes peninsula of West Iceland. It is currently the tallest longwave radio mast in the world and the tallest above ground structure in Western Europe.
The Mühlacker Broadcasting Transmission Facility is a radio transmission facility near Mühlacker, Germany, first put into service on November 21, 1930. It uses two guyed steel tube masts as aerials and one guyed steel framework mast, which are insulated against ground. It has two transmission aerials for shortwave and one free standing steel framework tower for directional radio services. The shortwave transmitter was shut off on October 19, 2004. The medium wave transmitter was switched off in January 2012.
The Sendeanlage Bisamberg was an Austrian medium wave transmission facility built in 1933 and demolished on February 24, 2010.
Rugby Radio Station was a large British government radio transmission facility just east of the Hillmorton area of the town of Rugby, Warwickshire in England. The site straddled the A5 trunk road, with most of it in Warwickshire, and part on the other side of the A5 in Northamptonshire. First opened in 1926, at its height in the 1950s it was the largest radio transmitting station in the world, with a total of 57 radio transmitters, covering an area of 1,600 acres (650 ha). Traffic slowly dwindled from the 1980s onwards, and the site was closed between 2003 and 2007.
The Monte Ceneri transmitter was first established as the nationwide medium-wave radio transmission station for Italian-speaking Switzerland in 1933. Located on Monte Ceneri in Ticino, it broadcast on a frequency of 558 kHz.
The Lakihegy Tower is a 314-metre-high (1,031 ft) radio mast at Szigetszentmiklós-Lakihegy in Hungary. The Blaw-Knox type tower was built in 1933 and was one of Europe's tallest structures at the time of construction. It was designed to provide broadcast coverage for Hungary with a 120 kW transmitter. It was built for the purpose of transmitting the radio station "Budapest I.", which it served until 1977.
Radio masts and towers are typically tall structures designed to support antennas for telecommunications and broadcasting, including television. There are two main types: guyed and self-supporting structures. They are among the tallest human-made structures. Masts are often named after the broadcasting organizations that originally built them or currently use them.
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 Cape Race LORAN-C transmitter was a LORAN-C transmitter at Cape Race, Newfoundland and Labrador, Canada.
VLF transmitter Lualualei is a facility of the United States Navy near Lualualei, Hawaii transmitting orders to submerged submarines in the very low frequency (VLF) range.
Krasny Bor transmitter is a large facility for longwave, mediumwave and shortwave broadcasting at Krasny Bor near Saint Petersburg, Russia. Krasny Bor transmitter was established in 1961 and belongs to the most powerful broadcasting stations in the world. It uses four mast radiators and several shortwave antennas. The tallest of these mast radiators is a 271.5 metres high guyed mast, which is equipped with a cage antenna and used for longwave broadcasting. It was built in 2002 as replacement for a 257.5 metres tall guyed mast, destroyed at a helicopter collision, which killed 6 people, on November 5, 2001. Further, there is a 257 metres tall mast radiator, which is insulated against ground and equipped with a cage antenna for medium wave broadcasting, a 106 metres tall steel tube mast radiator carrying several cage antennas in multiple levels and a 93 metres tall guyed mast radiator.
The NHK Kawaguchi Transmitter was a medium-wave broadcasting station at Kawaguchi, Saitama, Japan, which was built in 1937. It used for transmissions on 590 kHz with a power of 150 kW, a T-antenna, which was spun between two 312.78-metre-tall guyed masts, which were 463 m apart and which were both insulated against ground.
The Emley Moor transmitting station is a telecommunications and broadcasting facility on Emley Moor, 1 mile (1.6 km) west of the village centre of Emley, in Huddersfield, West Yorkshire, England.
