Radioreference.com is one of the world’s largest radio communications reference website, featuring a complete frequency database, trunked radio system information, FCC License assignments and call sign maps, 10-Code Lists, agency maps, files, downloads, links, and detailed agency information for most public safety, military, and local government communications.
Registration and access to all the data is free, however some special reporting features and downloads are only available for premium subscribers of the site. 
