Non-directional beacon - Wikipedia
Why is it called a “Compass Locator?”
Aircraft Instrument Landing Systems (ILS)
Confluence Mobile - AIXM Confluence
Marker beacon | Article about marker beacon by The Free Dictionary
What is an NDB or Non-Directional Beacon?
ATPL Theory - Marker Beacons Marker Beacons are stations on the ground. When you fly overhead they will let you know by means of a visual or a sound (can be both).
Terminal NDB Approach
London Gatwick Airport - Historical approach charts - Military Airfield Directory
London Gatwick Airport - Historical approach charts - Military Airfield Directory
Non-Terminal NDB Approach
Non-directional beacon - Wikiwand
Historical radio beacons, Yugoslavia 1950s - Military Airfield Directory
Radio navigation in Switzerland in the 1950s - Military Airfield Directory
ENR 4.1 Navigation Aids – En Route
Confluence Mobile - AIXM Confluence
Marker beacon - Wikipedia
Non-Directional Radio Beacon (NDB)
Radio beacons - FlightGear wiki
automatic direction finder ADF NDB
Radio beacons in Ireland in the 1950s - Military Airfield Directory
Marker Beacon (Beacon) | IVAO Documentation Library
GoldMethod
Non-directional beacon - Wikipedia
