Loran-C is a hyperbolic radio navigation system that allows a receiver to determine its position by listening to low frequency radio signals that are transmitted by fixed land-based radio beacons. Loran-C combined two different techniques to provide a signal that was both long-range and highly accurate, features that had been incompatible. Its disadvantage was the expense of the equipment needed to interpret the signals, which meant that Loran-C was used primarily by militaries after it was introduced in 1957.
Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. During the daytime, reception is usually limited to more local stations, though this is dependent on the signal conditions and quality of radio receiver used. Improved signal propagation at night allows the reception of much longer distance signals. This can cause increased interference because on most channels multiple transmitters operate simultaneously worldwide. In addition, amplitude modulation (AM) is often more prone to interference by various electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy and longer antennas. Digital modes are possible but have not reached momentum yet.
Minamitorishima sometimes Minami-Tori-shima or Minami-Torishima, also known as Marcus Island, is an isolated Japanese coral atoll in the northwestern Pacific Ocean, located some 1,848 km southeast of Tokyo and 1,267 km east of the closest Japanese island, South Iwo Jima of the Volcano Islands, and nearly on a straight line between mainland Tokyo and Wake Island, 1,415 km further to the east-southeast. The closest island to Minamitorishima is East Island in the Mariana Islands, which is 1,015 km to the west-southwest.
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 Hellissandur longwave radio mast is a 412 m (1,352 ft) tall guyed radio mast 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.
Sender Zehlendorf or Zehlendorf (radio) transmission facility was a radio transmission facility which was in service since 1936, when a short wave transmitter was built on the occasion of the Berlin 1936 Summer Olympics in Zehlendorf as part of the establishment of permanent radio services. This Zehlendorf site, which until the end of World War II was referred to as the Rehmate Radio Transmission Centre, had 26 different antennas at the time.
The Longwave transmitter Europe 1 was the oldest privately owned radio station in Germany, situated between Felsberg and Berus/Saar, Germany. It transmitted on 183 kHz with a power of 2,000 kilowatts a French speaking programme, Europe 1 toward France. It was the highest power radio broadcasting transmitter in Germany. Longwave transmissions stopped on 31 December 2019.
The LORAN-C transmitter Rantum is a transmission facility for LORAN-C on the German island Sylt near the village Rantum at 54°48′30″N8°17′37″E. It was established in the 1960s, initially using a guyed steel framework mast with a triangular cross section, approximately 190 metres tall. In 1996 this mast was replaced by a 193-metre-high mast of the same type but of a better mechanical design. The new mast is, as its forerunner, insulated from ground and has a triangular cross section. The construction, weighing 65 tonnes, is guyed in four levels at 60.52 metres (198.6 ft), 120.87 metres (396.6 ft), 154.95 metres (508.4 ft) and 190 metres (620 ft). The transmitter was shut down on Dec 31, 2015.
The LORAN-C transmitter Gillette was a LORAN-C transmission facility near Gillette, Wyoming at 44°00′11″N105°37′24″W. Its aerial, a 700-foot (210 m) guyed radio mast, was the tallest structure in Wyoming at one time.
The LORAN-C transmitter Jan Mayen was a LORAN-C transmission facility on the island of Jan Mayen at 70°54′51″N8°43′57″W. The LORAN-C transmitter Jan Mayen used as an antenna had a 190-metre tall (625 ft) guyed mast.
Iwo Jima LORAN-C transmitter was a LORAN-C transmitter at Iwo Jima, Japan of Grid 9970 at 24°48′8″N141°19′32″E. The Iwo Jima LORAN-C transmitter had a transmission power of 4 megawatts, which is more than the most powerful broadcasting stations. The Iwo Jima LORAN-C transmitter had a 411.5 meter (1350 ft) tall guyed mast, which was built in 1963. A guy wire insulator eyebolt failed sending the insulator crashing into the tower, knocking it out of plumb. It collapsed in 1964 on repair of the structural damage caused by the insulator. The collapsing tower killed four construction contract workers, three on the tower and one on the ground. The collapse also destroyed the transmitter building.
The Cape Race LORAN-C transmitter was a LORAN-C transmitter at Cape Race, Newfoundland and Labrador, Canada.
Angissoq LORAN-C transmitter was a LORAN-C transmitter at Nanortalik-Angissoq, Greenland at GRI 7930, 59°59'18"N, 45°10'24" W. It had a transmission power of 1000 kilowatts. Until July 27, 1964, it used a 1350 ft mast radiator, built in 1963. On July 27, 1964, it collapsed from the fatigue failure of an eyebolt head in a compression cone insulator on a structural guy. It was replaced by a 704 ft mast radiator. On December 31, 1994, the transmitter was shut down and the tower dismantled.
LORAN-C transmitter Malone was the master station of the Southeast U.S. LORAN-C Chain and the Whiskey Secondary of the Great Lakes chain. It used a transmission power of 800 kW for both chains.
LORAN-C transmitter Lampedusa was the X-Ray secondary station of the Mediterranean Sea LORAN-C Chain. It used a transmission power of 325 kW. The Lampedusa LORAN-C transmitter was situated on the island of Lampedusa at 35°31′21″N12°31′31″E. The Lampedusa LORAN-C transmitter uses as an antenna a 190.5 metre (625 ft) tall mast radiator, which was commissioned in 1972. An Omega monitoring station was also constructed on the base. The LORAN Station ceased transmission on 312400Z DEC 94 and was decommissioned in January 1995.
LORAN-C transmitter Jupiter was the Yankee secondary station of the Southeast U.S. LORAN-C Chain. It was operated from years 1962 to 2010 by the U.S. Coast Guard, located on Florida land that was originally Camp Murphy and now Jonathan Dickinson State Park, near the town of Jupiter, Florida. The choice of this site followed the earlier LORAN-A station established in 1957 nearby on the Atlantic beach at Hobe Sound.
The LORAN-C transmitter Havre was the master station of the North-Central U.S. LORAN-C Chain, situated at Havre, Montana at 48°44′39″N109°58′54″W. It used a 700-foot (210 m) tall mast radiator as an antenna with a transmission power of 400 kW.
The LORAN-C transmitter Seneca was the master station of the Northeastern United States LORAN-C Chain and the X-Ray secondary station of the Great Lakes Chain. It was located within the Seneca Army Depot in Romulus, New York, south of Geneva. It used a 1000-kilowatt, 742-foot guyed mast that was constructed in 1977 and dedicated on August 2, 1978. The station was operated by United States Coast Guard and was located on a 250-acre (1.0 km2) piece of land within the 10,587-acre (42.84 km2) facility. The transmitter was used to guide ships and aircraft up to 1,000 miles (1,600 km) away. It was the first LORAN station to use solid-state electronics versus vacuum tube components.
Minami Torishima Airbase is a one runway airport serving the island of Minami Torishima, Japan. The aerodrome used to be a military airstrip and according to the Japanese Aeronautical Information Service, is still operated by the Japan Maritime Self-Defense Force.
Japan Self-Defense Forces 