Marcus Island LORAN-C transmitter

Antenna of Minami Torishima LORAN-C transmitter.

Minami Torishima LORAN-C transmitter is a LORAN-C transmitter on Marcus Island ( Minami Torishima), Japan at 24°17'8" N, 153°58'54" E(24°17′8″N, 153°58′54″E). It was until 1993 part of Grid 9970 and used a transmission power of 4000 kilowatts, which was more than the most powerful broadcasting stations ever used.

Until 1985 Markus Island LORAN-C transmitter had a 411.48 metre (1350 ft) tall guyed mast radiator as antenna, which was built in 1964.

In 1985/86 the 411.48 metre tower was replaced by a 213.4 metre tall tower.

In October 1993 the authority over the transmitter was given from the US Coast Guard to Japan Coast Guard. In 2000 the tower of the station was again dismantled and replaced by a new one with a height of 213 metres.

Today Marcus Island LORAN-C transmitter is the X-Ray secondary station of the North West Pacific LORAN-C Chain GRI 8930. Its transmission power was reduced to 1100 kW.