The FCC regulates radio spectrum use in the United States. Operating a professional two-way radio on a non-license-free frequency without an FCC license is a federal violation. An FCC license for a commercial radio system specifies the licensee, the authorized frequencies, the geographic coverage area, power limits, and antenna specifications. Licenses must be renewed periodically and tie to specific frequency assignments. Obtaining a license involves frequency coordination — identifying channels that do not conflict with existing licensees in the same area — followed by submitting an application to the FCC. Repeater systems require separate licensing in addition to handheld radio licenses.