China has completed construction of a secretive project to build a giant antennae five times the size of New York City. 

The experimental radio antennae is rumoured to have taken 13 years to finish and will communicate long range with military submarines.  

Extremely low frequency radio waves (ELF waves) will be emitted by the machine which will send messages to subs hundreds of metres underwater.  

The Wireless Electro-magnetic Method (WEM) project is officially pegged for use on earthquake and mineral detection and  but has clear potential applications for the military. 

China has completed construction of a secretive project to build a giant antennae five times the size of New York City. The experimental radio antennae is rumoured to have taken 13 years to finish and will communicate long range with military submarines (file photo)

China has been hotly pursuing ELF technology for some time and the facility, which sits on a 1,400 square mile (3,700 sq km) patch of land, is the culmination of the technology.  

Project WEM is made of a pair of high voltage power supply line which criss-cross a 100 km by 60 km steel lattice across the region. 

Each power line is finished with an underground hole to two power stations and generators that electrify the ground.

This process produces electromagnetic radiation capable of passing thousands of miles through the air or through the Earth's crust. 

WHAT ARE ELF WAVES?  

Extremely low frequency (ELF) waves are produced in the range of 0.1 and 30 hertz.

They are unlikely to cause harm as they are of little energy and have huge wavelengths. 

The huge wavelengths allow it to transmit information a great distance.     

It is estimated the machine has a 3,500 km range and signals closer to the source would be stronger than those received further away.   

A department of the World Health Organisation has previously revealed that ELF waves are 'possibly carcinogenic to humans'.

The WHO claims an ELF field affects human nerves and stimulates synaptic transmissions.

It is also believed to alter retina cells by generating a flash of light.

Huang Zhiwei, professor with the department of electrical engineering at Nanhua University in Hengyang, Hunan, said the ELF radio was unlikely to cause serious damage to the human body due to its enormous wavelength, which could stretch over thousands of kilometres.

The researcher did also confess it could interfere with the sensory organs. 

Researchers say the ELF signals will be produced at a frequency of between 0.1 and 30 hertz and may be detectable to vessels submerged hundreds of metres below the waves. 

The Chinese authorities have not released the exact location of the facility to the public, but it is believed to be in the Huazhong region, an area in central China that includes Hubei, Henan and Hunan provinces.

China has been hotly pursuing ELF technology for some time and the facility, which sits on a 1,400 square mile (3,700 sq km) patch of land, is the culmination of the technology. 

The Chinese authorities have not released the exact location of the facility to the public, but it is believed to be in the Huazhong region, an area in central China that includes Hubei, Henan and Hunan provinces. 

One researcher who is involved with the project from the Institute of Geology, China Earthquake Administration, told South China Morning Post: 'This facility will have important military uses if a war breaks out.

'Though I am involved in the project, I have no idea where it is. It should be up and running by now.' 

The project is believed to build on the earlier success of another similar project which was finished in 2009. 

Its first military-grade Super Low Frequency transmission station was finished in 2009 and was successfully able to communicate with a submerged sub a year later. 

According to researchers and sources close to the subject, the military applications of the technology are not the machinery's only use. 

It is able to use its long wavelength waves to identify and study mineral and oil deposits.

ELF waves can be manipulated to detect specific rock deformations, which could help identify earthquake precursors.