Scanner Listening

Scanner Listening is the hobby of monitoring police, fire, emergency medical and other two-way radio traffic using a radio scanner, a receiver that automatically tunes across a band of discrete frequencies until it finds an active signal and then stops to let the listener hear it. Scanners built for this hobby generally cover the VHF and UHF land mobile bands used by local public safety and utility services, supporting AM, FM and single-sideband reception, and modern handheld and desktop models can store thousands of channels, scan hundreds of them per second, follow trunked radio systems that hop between frequencies automatically, and decode digital formats such as APCO Project 25, Digital Mobile Radio, NXDN and EDACS. Beyond hobbyists who simply enjoy following local radio traffic, scanners also see real use in journalism and criminal investigation, but scanner listening pursued purely for its own sake is, in its own right, a significant hobby worldwide.