Definition
The band of radio frequencies from 30 kHz to 300 kHz. In aviation, this band is used by non-directional beacons (NDBs) and is received by automatic direction finder (ADF) equipment in the aircraft.
Plain English
A specific slice of the radio spectrum, sitting between 30,000 and 300,000 cycles per second, that aviation uses for certain ground-based navigation beacons.
Context Anchor
Seen in automatic direction finder and non-directional beacon discussions, where the handbook describes the type of radio signal the receiver can use.
Derivation
Frequency comes from a Latin word meaning repeated occurrence. In radio, frequency means how often a wave repeats each second; low frequency repeats fewer times per second than higher-frequency radio signals.
Why Pilots Care
Signals in this band follow the Earth's curvature, giving ADF greater range than higher-frequency systems.
Intuition Check
Do not read low frequency as weak signal. Here, low means a lower number of wave repeats per second within the radio spectrum.
Example Sentence 1
The NDB transmits in the low frequency band, so the pilot tunes the ADF receiver to 350 kHz to identify the station.
Example Sentence 2
Low frequency signals remained usable even when the aircraft flew beyond line-of-sight range.