LORAN-C transmitter Helong is the Yankee secondary of the China North Sea LORAN-C Chain ( GRI 7430 ). It uses a transmission power of 1200 kW. LORAN-C transmitter Helong is situated near Helong at (42°43′12″N 129°6′27″E / 42.72°N 129.1075°E / 42.72; 129.1075).