ndB
NDB, or non-directional beacon, is a ground-based radio transmitter used in aviation navigation. It operates in the low-frequency or medium-frequency bands, typically around 190 to 535 kHz, and broadcasts a continuous carrier with an identifying Morse code signal. Aircraft equipped with an Automatic Direction Finder (ADF) receiver can determine the bearing to or from the beacon by interpreting the direction of the received signal.
Because the beacon itself radiates a non-directional signal, the information provided to the pilot is a relative
NDBs have been a mainstay of en-route navigation and instrument approach procedures since the mid-20th century.
In many regions, the aviation network is shifting toward VOR, DME, and GNSS-based navigation, leading to decommissioning