Definition
A measure comparing the strength of a desired radio or navigation signal to the level of background noise present on the same frequency or channel, usually expressed in decibels (dB). A higher SNR means the signal is clearer and more reliably usable; a lower SNR means the signal is being lost in noise.
Plain English
How much louder the signal you want is compared to the random hiss and interference around it. The bigger the gap, the cleaner and more usable the signal.
Context Anchor
Seen in radio, navigation, and avionics discussions when describing how clean a received signal is.
Why Pilots Care
A higher value means clearer voice communications and more reliable digital data links, directly affecting the pilot’s ability to receive ATC instructions and traffic information.
Analogy
Like trying to hear someone speak in a quiet room versus a crowded bar. Same voice, but the background noise determines whether you can actually understand the words.
Grounding Statement
SNR is about how clearly the useful signal stands out from the unwanted background.
Intuition Check
Noise does not only mean sound you can hear. In this term, noise means any unwanted electrical or radio interference that competes with the useful signal.
Example Sentence 1
The controller's transmission was breaking up because the SNR on that frequency was too low at our distance from the antenna.
Example Sentence 2
Low SNR on the ADS-B receiver caused the traffic display to drop targets intermittently.