Radio communications use radio waves at different frequencies (the number of times that a wave repeats in a second), grouped within bands, which are part of the radio spectrum. The radio spectrum is the complete range of frequencies that can be used for radio communications, with various frequency ranges composing bands. The bands of interest to public safety agencies include high frequency (HF), very high frequency (VHF), and ultra high frequency (UHF). Spectrum allocations for State and local public safety agencies are fragmented into many slices of the radio spectrum. Regulation of specific frequencies for Federal Agency use occurs within the National Telecommunications and Information Administration, and the Federal Communications Commission (FCC) regulates the spectrum for non-Federal users. The total amount of State and local public safety spectrum allocated within bands is approximately 97 MHz and is subject to change pending resolution of re-banding issues in the 800 MHz bands. The FCC is reviewing a mandate that directs all public safety agencies to move to systems based on 12.5 kHz narrowband channels by some future data. To avoid interference between systems that use the same or adjacent frequencies, the FCC licenses a channel to only one user in a given area. 2 notes