What is an NDB?
NDB stands for ‘Non-Directional Beacon’; essentially they are (usually) low-power transmitters operating between 190kHz and 530kHz, bleating out nothing more than a repeated callsign in slow morse code. Once used by both aviators and sailors as a location-fixing aid; the ones we will describe and discuss here are those intended for aircraft navigation, the maritime systems having been turned off some time ago. Their slice of the NDB spectrum, around 300kHz, now contains DGPS (Differential Global Positioning System) stations often using the same sites as the old maritime beacons. For the most part it’s aero NDBs that you’ll hear, tuning around the LF band. NDBs were one of the first radio aids to navigation as the technology involved in setting them up and more importantly using them was simple. It is still possible to use them as a sole navigation means today, indeed learning how to is still mandatory (and wise) for piloting, but few do since more technologically sophisticated systems
