China has completed construction of the Very Low Frequencies (ELF) antenna facility. Approximately the size of the province of Nur-Holland with an antenna on site, the Chinese Navy can send submarines to a depth of up to a hundred meters.

Member of a Chinese naval vessel. (Photo: US Navy)

Officially, the Chinese government’s Wireless Electromagnetic Method (WEM) project is for earthquake detection and mineral discovery. However, according to Hong Kong’s South China Morning Post, it is a submarine broadcaster; A system for communication with submarines. In this case especially for sending messages to nuclear submarines with nuclear missiles (SSBNs).

Communication with submarines under water is very difficult. Connection to an underwater radio or internet is not possible, the submarine has to go to periscope depth to mount the mast over the water. To penetrate saltwater, it can be used at very low frequencies (VLFs). Readers of the book Orca will be familiar with this as ‘rugby’, one of the facilities for sending messages in submarines near the United Kingdom and plays an important role in the book. Rugby had 250-meter-high antennas, which could send messages up to a depth of about 30 meters.

To webshop for the submarine thriller ‘Orca’.

Elf
The Rugby radio station was demolished in 2007, but several other VLF stations are still active. However, the depth at which a VLF message can be received is limited. Certainly prefer to stay deeper during their patrols to avoid detecting submarines with nuclear missiles. This is why an initiative was launched in the US in the early 1960s that was able to reach submarines under Arctic ice at depths of 100 meters or with lower frequencies. The station finally became operational in 1988.

Along with the US, Russia and India have also manufactured LLF transmitters. However, an ELF facility requires considerable effort. This is also evident from the Chinese WEM project. The deep, precise location in the interiors of China is unknown, with such a facility built on an area of ​​3,500 sq km (slightly larger than Noord-Holland without Texel). It has been working for 13 years. Among other things, there is a huge antenna on that site. ELF antennas are huge because the wavelength of the signal is also large and preferably the length of the antenna corresponds to the wavelength. In the plans of the US Navy, an underground antenna of about 10,000 km was planned, but that was a very good thing. The exact length of the Chinese transmitter is not known, but it is considerable: underground cables are 60 to 80 to 100 km apart.

Short messages can be sent to submarines with huge transmitters. Due to extremely low frequencies (between 0.1 and 300 Hz according to China), communication is very slow and some characters can take minutes to transmit. Ordering a submarine to launch ballistic missiles is very slow. It is indeed a huge beeper. By sending a certain code, a submarine knows that there is a message and VLF, for example, can go to a different depth for satellite or radio reception.

Incidentally, a submarine cannot receive and transmit VLF or ELF messages only, due to the required power and antenna dimensions.

To care
The American ELF Broadcast Station was unexpectedly shut down in 2004. According to the US Navy, the system was obsolete and replaced with improved VLF technology. Until its closure, the facility had been opposed for years, primarily viewed by opponents as an instrument for aggressive deployment of the SSBN, in other words the use of nuclear weapons in retaliation rather than the first nuclear attack. For. In China, opponents are mainly concerned about the impact on public health. Studies by the World Health Organization (WHO) suggest that ELF signals can cause cancer.

Messages sent by China will be addressed to the current five Chinese SSBNs: EN Type 094 and four Type 092. The latter version is the latest and has been in service since 2007, with new types of 092 (Zincalus) submarines currently being built.

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