NDB

NDB, Non-Directional (radio) Beacon is a radio transmitter at a known location, used as an aviation or marine navigational aid. As the name implies, the signal transmitted does not include inherent directional information, in contrast to other navigational aids such as low frequency radio range, VHF omnidirectional range (VOR) and TACAN. NDB signals follow the curvature of the earth, so they can be received at much greater distances at lower altitudes, a major advantage over VOR. However, NDB signals are also affected more by atmospheric conditions, mountainous terrain, coastal refraction and electrical storms, particularly at long range. NDBs be operated on a frequency between 190 kHz and 1750 kHz. NDBs in North America operate between 190 kHz and 535 kHz.

Here is how an Aviator determine the distance in relation to an NDB station in nautical miles:

• Turns the aircraft so that the station is directly off one of the wingtips. 
• Flies that heading, timing how long it takes to cross a specific number of NDB bearings.
• Uses the formula: Time to station = 60 x number of minutes flown / degrees of bearing change.
• Uses the flight computer to calculate the distance the aircraft is from the station; time * speed = distance.

Updated On: 12.02.19