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Iwo Jima LORAN-C Transmitter
Iwo Jima LORAN-C transmitter was a LORAN-C transmitter at Iwo Jima, Japan of Grid 9970 at . 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 tower was later replaced by another tower of the same height. On September 29, 1993 the Iwo Jima LORAN-C transmitter was transferred from the U.S. Coast Guard to the Government of Japan. In 1994, the transmitter was shut down, and its tower was demolished. After closing the Iwo Jima transmitter, the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Masts And Towers
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. In the case of a mast radiator or radiating tower, the whole mast or tower is itself the transmitting antenna. Terminology The terms "mast" and "tower" are often used interchangeably. However, in structural engineering terms, a tower is a self-supporting or cantilevered structure, while a mast is held up by stays or guys. Broadcast engineers in the UK use the same terminology. A mast is a ground-based or rooftop structure that supports antennas at a height where they can satisfactorily send or receive radio waves. Typical masts are of steel lattice or tubular steel construction. Masts themselves play no part in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iwo Jima
Iwo Jima (, also ), known in Japan as , is one of the Japanese Volcano Islands and lies south of the Bonin Islands. Together with other islands, they form the Ogasawara Archipelago. The highest point of Iwo Jima is Mount Suribachi at high. Although south of the metropolis of Tokyo on the mainland, this island of 21 km2 (8 square miles) is administered as part of the Ogasawara Subprefecture of Tokyo. Since July 1944, when all the civilians were forcibly evacuated, the island has had a military-only population. The island was the location of the Battle of Iwo Jima between February 1945 and March 1945. This engagement saw some of the fiercest fighting of the Pacific War, with each side suffering over 20,000 casualties in the battle. The island became globally recognized when Joe Rosenthal, of the Associated Press, published his photograph '' Raising the Flag on Iwo Jima'', taken on Mount Suribachi. The US military occupied Iwo Jima until 1968, when it was returned to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north toward the East China Sea, Philippine Sea, and Taiwan in the south. Japan is a part of the Ring of Fire, and spans Japanese archipelago, an archipelago of List of islands of Japan, 6852 islands covering ; the five main islands are Hokkaido, Honshu (the "mainland"), Shikoku, Kyushu, and Okinawa Island, Okinawa. Tokyo is the Capital of Japan, nation's capital and largest city, followed by Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe, and Kyoto. Japan is the List of countries and dependencies by population, eleventh most populous country in the world, as well as one of the List of countries and dependencies by population density, most densely populated and Urbanization by country, urbanized. About three-fourths of Geography of Japan, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LORAN-C
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. By the 1970s, the cost, weight and size of electronics needed to implement Loran-C had been dramatically reduced because of the introduction of solid-state electronics and, from the mid-1970s, early microcontrollers to process the signal. Low-cost and easy-to-use Loran-C units became common from the late 1970s, especially in the early 1980s, and the earlier LORAN system was discontinued in favor of installing more Loran-C stations around the world. Loran-C became one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nii-jima
is a volcanic Japanese island administered by the Tokyo Metropolitan Government. It is one of the Izu Seven Islands group of the seven northern islands of the Izu archipelago, and is located approximately south of Tōkyō and south of Shimoda Shizuoka Prefecture. The island is the larger inhabited component of the village of Niijima Village, Ōshima Subprefecture of Tokyo Metropolis, which also contains the neighboring island of Shikine-jima and the smaller, uninhabited Jinai-tō. Nii-jima is also within the boundaries of the Fuji-Hakone-Izu National Park. On the southern tip of Nii-jima, there was formerly a launch site for experimental and sounding rockets. Geography Nii-jima is unusual amongst the Izu Islands in that it has an elongated shape. Measuring approximately long by wide, it has a land area of 23.87 km2. The island is made of eight rhyolitic lava domes in two groups at the northern and southern ends of the island, separated by a low, flat isthmus. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Masts
The tallest structure in the world is the Burj Khalifa skyscraper at . Listed are guyed masts (such as telecommunication masts), self-supporting towers (such as the CN Tower), skyscrapers (such as the Willis Tower), oil platforms, electricity transmission towers, and bridge support towers. This list is organized by absolute height. See List of tallest buildings and structures, List of tallest freestanding structures and List of tallest buildings and List of tallest towers for additional information about these types of structures. Terminology Terminological and listing criteria follow Council on Tall Buildings and Urban Habitat definitions. Guyed masts are differentiated from towers – the latter not featuring any guy wires or other support structures; and buildings are differentiated from towers – the former having at least 50% of occupiable floor space although both are self-supporting structures. List by height This list includes structures with a minimum height of to k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Catastrophic Collapses Of Broadcast Masts And Towers
This is a list of catastrophic collapses of broadcast masts and towers. Masts and towers can collapse as a result of natural disasters, such as storms and fires; from engineering defects; and from accidents, sabotage and bendover. __TOC__ List of collapses References {{Disasters Antennas (radio) * History of structural engineering * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LORAN-C Transmitters In Japan
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. By the 1970s, the cost, weight and size of electronics needed to implement Loran-C had been dramatically reduced because of the introduction of solid-state electronics and, from the mid-1970s, early microcontrollers to process the signal. Low-cost and easy-to-use Loran-C units became common from the late 1970s, especially in the early 1980s, and the earlier LORAN system was discontinued in favor of installing more Loran-C stations around the world. Loran-C became one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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