The Wireless Electromagnetic Method (WEM) project took 13 years and will emit extremely low-frequency radio waves (ELF waves). Those waves have been linked to cancer by the World Health Organisation.
Its transmissions could be picked up by a submarine lurking hundreds of meters under the sea, thus reducing the vessel's risk of having to resurface to receive transmissions.
China built its first military-grade Super Low-Frequency transmission station in 2009. The United States and Russia already have submarine communication systems.
Project WEM's main surface structure is a pair of high voltage power supply lines stretching from north to south, east to west on steel lattice towers, which form a cross that is 60km (37 miles) wide and 80km to 100km (50 to 62 miles) long.