Definition
A radio navigation technique in which a ground station or aircraft receiver determines the bearing (direction) to or from a transmitting radio source by measuring the angle from which the signal arrives. Direction finding equipment can be used to provide a pilot with bearing information to a station, or to allow a ground facility to locate an aircraft by the direction of its transmissions.
Plain English
A way of using radio signals to figure out which direction another radio source is in. The receiver doesn't measure distance — only the direction the signal is coming from.
Context Anchor
Seen in aviation abbreviations, radio-navigation discussions, emergency signal location, and notices about direction-finding equipment or services.
Why Pilots Care
Enables rapid location of distress signals or navigation references during lost-communication or search-and-rescue situations.
Intuition Check
Do not read direction finding as simply choosing where to go. In this aviation use, it means finding the direction a radio signal is coming from.
Example Sentence 1
The controller used direction finding equipment to provide the disoriented pilot with a heading toward the nearest airport.
Example Sentence 2
Ground stations used DIRF to provide vectors that guided the lost aircraft back to the airport.