Low Frequency (LF)

Low frequency (LF) refers to the radio frequency band from 30 to 300 kHz. In aviation, LF frequencies (particularly the 190–535 kHz range) are used for Non-Directional Beacons (NDBs) and some navigation aids. LF/MF signals can follow the earth’s curvature (ground wave propagation) over long distances, particularly over water.

LF in Aviation

NDBs operating in the LF/MF range have longer range than VHF navaids because ground waves follow the earth’s surface. However, LF signals are susceptible to significant errors from atmospheric effects, coastal refraction, and night effect. This limits their precision compared to VHF-based navigation systems.

Related Terms

See also: NDB, ADF, Medium Frequency.