What is a scanner?

• A. A device that amplifies signals
• B. A device that emits tones
• C. A device that stores frequency lists
• D. A receiver that searches across frequencies and stops when a broadcast is heard, then continues

Answer: (D)

A scanner is a radio receiver that automatically sweeps through a range of frequencies, listens for activity, and stops on an active transmission so you can hear it, then resumes scanning to the next channel. This behavior—searching across frequencies and pausing on a broadcast—is what defines a scanner. It lets you monitor multiple channels without manually tuning each one, which is different from a device that only amplifies signals or a transmitter that emits tones. Some scanners can store frequency lists, but the essential idea is the automatic scanning and stopping on active transmissions, with the ability to continue afterward.