Master Frequency File Author:James E. Tunnell, Robert Kelly For anyone using a radio scanner or communications receiver, this one-of-a-kind reference will unlock a world of listening possibilities. Robert Kelly and James E. Tunnell have compiled the largest, most accurate source of services, frequencies, callsigns, and user IDs on the 25 Mhz to 2110 Mhz radio spectrum. This unsurpassed work makes it easy... more » for radio professionals and hobbyists alike to tune in and listen to the confidential communications of the FBI, Secret Service, National Parks, Forest Service, Drug Enforcement Administration, and other agencies.« less