Definition
In radio reception, the strength of the desired signal at the antenna or receiver input that is just sufficient to produce a usable, intelligible output under specified conditions. It serves as a reference value used to express the sensitivity and performance of a receiver.
Plain English
The lowest signal strength a radio receiver needs in order to give the pilot a clear, useful output. It's the benchmark used to describe how sensitive a receiver is.
Context Anchor
Seen in aircraft noise certification, environmental compliance, and noise limit discussions rather than in normal cockpit procedures.
Derivation
From 'characteristic' (a defining feature) and 'level' (a measured amount). Together it means a defined signal level that characterizes how the receiver performs.
Why Pilots Care
Receiver sensitivity affects how far from a navaid or transmitter you can be and still get a reliable signal. A receiver with a lower characteristic level can pick up weaker signals.
Grounding Statement
Several test flights are measured, the results are adjusted to the same test basis, and the final representative noise number is the characteristic level.
Intuition Check
Characteristic Level does not mean the aircraft's usual cruising altitude or a general quality of the airplane. Here it means a calculated noise value used to represent the aircraft type for certification.
Example Sentence 1
The avionics technician compared the characteristic level of the new VHF receiver against the manufacturer's specification.
Example Sentence 2
At the characteristic level the wind was stronger than expected, requiring a heading change.