Automatic direction finding (ADF) is an electronic tool that helps pilots navigate by determining the relative direction of an aircraft from a radio beacon. This beacon can be a Non-Directional Beacon or a commercial radio station, transmitting in the Medium Frequency (MF) or Low Frequency (LF) bands. ADF uses a loop aerial, which can be rotated either physically or electronically. It identifies the direction where reception from the beacon is at its weakest, which indicates the aircraft’s position relative to the beacon. Pilots can use this information to fly directly to the beacon. Additionally, the aircraft’s equipment combines this relative bearing with heading data from the compass. This allows pilots to create bearing position lines that can be plotted on a chart for more precise navigation.
