Definition
The control on a DME (Distance Measuring Equipment) unit used by the pilot to tune the equipment to a specific paired VHF frequency or channel, so the airborne DME interrogates the correct ground station and displays distance information from that station.
Plain English
The knob or control the pilot uses to pick which ground station the distance-measuring equipment talks to.
Context Anchor
Seen in DME equipment descriptions and on cockpit navigation controls, especially when selecting a station that provides distance information.
Derivation
Channel comes from the Latin canalis, meaning a pipe or groove — a single dedicated path. In radio, a channel is one specific path (frequency) the equipment uses to communicate, so the channel selector is simply the control that chooses which path the radio is set to.
Why Pilots Care
If the channel selector is set to the wrong frequency, the DME will either fail to lock on or display distance from a different station — leading to incorrect distance information during navigation or an approach.
Analogy
It is like choosing the right station on a radio, except the DME is not choosing music or voice audio; it is choosing the signal path used to measure distance.
Intuition Check
Do not think of “channel” as a TV channel or a casual label. Here it means a specific assigned radio setting that tells the DME which ground station to work with.
Example Sentence 1
After identifying the VOR, the pilot used the channel selector to tune the DME to the same station and confirmed the distance readout.
Example Sentence 2
Before the approach the instructor had the student verify the channel selector was set to the correct paired frequency for accurate slant-range readings.