The Japanese public-service broadcaster NHK switched off its Sakuma Radio Relay Station at the end of September.
The AM station, which went on the air in 1964, was one of three stations in Japan to use electrical power lines instead of a traditional antenna system.
Jointly operated by NHK and J-POWER Electric Power Development Co. Ltd., the station was designed to ensure people in the region could still tune to NHK’s AM broadcasts despite electrical interference generated by the 350 MW hydroelectric power plant.
Following the 2011 Tōhoku earthquake, Japan began an effort to interconnect its power grid so that electricity could be transferred efficiently between eastern and western Japan. As part of this effort, J-POWER is replacing the power lines used by the NHK station.
According to documents presented to the NHK Board of Directors in April, the new power lines are not expected to cause the same sort of interference, and NHK has determined that its other stations in the region can sufficiently serve the area’s nearly 5,000 households.
The relay station used a 100 W transmitter operating on 1341 kHz to carry the NHK Radio 1 program. To support the switchoff, NHK launched in June the informational website radio1341.jp to help direct listeners to traditional over-the-air AM broadcasts for NHK Radio 1.
NHK continues to operate two other power line broadcasting stations: NHK Tsunan Radio Relay in Niigata Prefecture and NHK Shiratori Radio Relay in Gifu. The station in Gifu was temporarily switched off for two months in late 2020 for a similar power line replacement project.
