Extremely low frequency designates radio waves in the 3 to 30 Hz range. These massive wavelengths can penetrate seawater and solid rock, making them highly specialized for communicating with deeply submerged submarines or underground mines. Because the bandwidth is so narrow, data transmission is incredibly slow, often limited to just a few characters per minute.
The Navy uses ELF transmissions to send simple code groups to submarines without requiring them to surface.
Also heard as
- Extremely low frequency
Related terms
VLF
Very low frequency designates radio waves operating in the 3 to 30 kilohertz range.
ULF
The band of radio frequencies extending from 300 to 3000 hertz.
Frequency band
A defined contiguous range of radio frequencies allocated for a specific purpose.
Spectrum
The entire range of electromagnetic frequencies available for transmitting wireless communication signals.