What Does Very Low Frequency (VLF) Mean?
Very low frequency (VLF) is a radio frequency band in the range of 3 to 30 kHz with wavelengths from 10 to 100 km. It is also the name of the band designated by the International Telecommunication Union (ITU). VLF has a limited bandwidth so it is mostly impractical for audio transmission and is mostly only used for coded signals with a low data rate such as underwater communication.
Techopedia Explains Very Low Frequency (VLF)
Very low frequency signals have large wavelengths that allow them to diffract around large obstacles, propagate as ground waves along the earth’s curvature and penetrate salt water, which is why they have been used by the military for communicating with submarines. In fact, the most powerful radio station in the world was designed to transmit VLF signals at 24 kHz at a power of 1.8 MW. This station is the US Navy’s Naval Radio Station Cutler located in Cutler, Maine, which features an antenna array 1.2 miles in diameter with a central mast used as the radiating element and a star-shaped horizontal wire array acting as a capacitive top load. It is used to communicate with US submarines.
