Marcus Island LORAN-C transmitter, or Minami Torishima LORAN-C transmitter, is a former LORAN-C transmitter on Minami-Tori-shima (Marcus Island) in Ogasawara, Tokyo, Japan at (24°17′8″N 153°58′54″E / 24.28556°N 153.98167°E). Until 1993 it was part of Grid 9970 and used a transmission power of 4000 kilowatts, which was more than the most powerful broadcasting stations ever used.
| Marcus Island LORAN-C Mast (1st) Island) overview with transmitter | |
|---|---|
 | |
| General information | |
| Status | Dismantled |
| Type | Mast radiator insulated against ground |
| Location | Minami-Tori-shima (Marcus Island), Japan |
| Completed | 1963 |
| Destroyed | 1985 |
| Height | 76 m (249 ft) |
| Marcus Island LORAN-C Mast (2nd) | |
|---|---|
| |
| General information | |
| Status | Dismantled |
| Type | Mast radiator insulated against ground |
| Location | Minami-Tori-shima (Marcus Island), Japan |
| Completed | 1986 |
| Destroyed | 2000 |
| Height | 21.4 m (70 ft) |
| Marcus Island LORAN-C Mast (3rd) | |
|---|---|
| |
| General information | |
| Status | Dismantled |
| Type | Mast radiator insulated against ground |
| Location | Minami-Tori-shima (Marcus Island), Japan |
| Completed | 2000 |
| Destroyed | 2010 |
| Height | 76 m (249.34 ft) |
| Design and construction | |
| Main contractor |  Japan Self-Defense Forces |
Until 1985 Marcus Island LORAN-C transmitter had a 411.5-meter (1,350 ft) tall guyed mast radiator as an antenna, which was built in 1964. In 1985/86 this tower was replaced by a 213.4 m-tall (700 ft) tall tower.[1][2]
In October 1993 the authority over the transmitter was transferred from the United States Coast Guard to the Japan Coast Guard. In 2000 the tower of the station was again dismantled and replaced by a new one with a height of 213 meters.
Marcus Island LORAN-C transmitter was the X-Ray secondary station of the North West Pacific LORAN-C Chain GRI 8930. Its transmission power was reduced to 1100 kilowatts.
On December 1, 2009, the station was abolished due to a decline in users.[3] The mast has been demolished.
See also edit
References edit
- ^ "Loran Station Marcus". loran-history.info. 1993. Retrieved 2023-12-21.
- ^ "14年前の工事の状況" (in Japanese). loran-history.info. Retrieved 2016-10-08.
- ^ "北西太平洋ロランCチェーンの縮小（南鳥島局の廃止）について" (PDF) (in Japanese). Japanese Coast Guard. 2009-06-01. Retrieved 2016-10-08.
External links edit
- Excel-File with information about LORAN-C transmitters
- Image Gallery at the Wayback Machine (archived December 13, 2010)
- Building 56828
- Building 57079
- Building 57185
- Minami Torishima LORAN-C transmission mast (1964) at Structurae
- Minami Torishima LORAN-C transmission mast (1986) at Structurae
- Minami Torishima LORAN-C transmission mast (1993) at Structurae