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).
Marker Beacons | ifr-review.com
Marker callouts - Features - Infinite Flight Community
Marker Beacon (Wikipedia Reference) | PDF | Geography | Wireless
Aircraft Technic on X: "Here is a Marker Beacon antenna. Marker beacons are part of the ILS(Instrument Landing System) landing system. https://t.co/pnY9qq1GTI" / X
Instrument Landing System - Electrical e-Library.com
Marker Beacon System * Function The marker beacon system is a radio navigation aid which determines the distance between the aircraft and the runway threshold. The system provides visual and aural indications