JJY is the callsign of two Japanese long-wave transmitter for the dissemination of time mark of UTC time.
Send time signals on two long wave frequencies: 40 kHz from 790 m high mountain Ōtakadoya (大鹰 鸟 谷 山, -yama, 37 ° 22 ' 21 " N, 140 ° 50' 56 " O37.3725140.84888888889790 ) on the border between Tamura and Kawauchi in Fukushima Prefecture and 60 kHz from 900 m high mountain Hagane (羽 金山, -yama, 33 ° 27 ' 56 "N, 130 ° 10' 32 " O33.465555555556130.17555555556900 ) on the island of Kyushu on the border of Saga, Saga Prefecture and Itoshima, Fukuoka. After the transmission frequency used in each case, a distinction between JJY40 and JJY60.
On March 12, 2011 19:46 JST (UTC 9) of the 40 -kHz transmitter JJY40 was due to the Fukushima nuclear disaster out of service (the station is about 16 km away from power plant ) is switched off, but already back at 21 April. , 2011 included the transmit mode.