Non-Directional Beacon (NDB) Definition
A Non-Directional Beacon (NDB) is a radio frequency transmitter that emits a Morse code identification signal for the purpose of navigation. Aircraft equipped with Automatic Direction Finding (ADF) technology use NDBs to determine their position and navigate between them. NDBs are a type of radio navigation aid that are primarily used for aircraft navigation, but can also be used for maritime and land-based applications.
NDBs work by transmitting a continuous radio wave signal on a specific frequency that can be received by ADF-equipped aircraft. The signal emitted by an NDB is omnidirectional, meaning that it is transmitted equally in all directions. As a result, it provides no directional information, hence its name. Instead, pilots use the ADF equipment to determine their position relative to the NDB by detecting the strength and phase of the signal.
NDBs are commonly used for non-precision approaches and instrument approaches to airports, as well as for en route navigation. Despite being one of the oldest forms of radio navigation aids, they continue to be used today due to their low cost and simplicity. However, the increasing popularity of modern GPS systems is making them less relevant in the aviation industry.
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