Wide Band vs. Narrow Band
The radio spectrum is a finite resource. There is only so much room so frequencies must be regulated to be efficient to prevent interference. Essentially a wide band transmission takes up more room on the frequency. Components of the transmitter and receiver can make transmissions take up less room or narrowband. An advantage of narrow banding is more radios can co-exist on the same frequencies without interference while a disadvantage is that data-speed is decreased. The Federal Communications Commission (FCC) has required implementation of narrow banding. Agencies were required to drop from using 25 KHz to 12.5 KHz during Phase I. By 2016, Phase II will be implemented requiring the bands be narrowed to 6.25 KHz. Many think this phase will be re-assessed and possibly eliminated.
The FCC regulates interstate and international communications by radio, television, wire, satellite and cable in all 50 states, the District of Columbia and U.S. territories. It was established by the Communications Act of 1934 and operates as an independent U.S. government agency overseen by Congress. Regulatory responsibility for the radio spectrum is divided between the FCC and the National Telecommunications and Information Administration (NTIA). Non-federal use is regulated by the FCC while the NTIA regulates federal use. Allocation of space on the radio spectrum for non-federal public safety is the responsibility of the Office of Engineering and Technology (OET) a division of the FCC. The Public Safety and Homeland Security Bureau (PSHSB) is the division that develops, recommends and administers the FCC’s policies that pertain to public safety communication’s issues. The FCC has numerous rules that must be followed and this agency has the power to impose fines and shut down use. Public safety communication centers must have an FCC-issued license to broadcast. An agency cannot just apply to the FCC for this license but instead must use an approved licensing service, such as APCO. Part of this process is to have an appropriate frequency chosen which requires a frequency coordinator. APCO offers this management service as well. Violation of FCC law, even if it’s un-willful such as letting a license lapse, will result in penalties.
I hope this has helped clear up some basic questions about frequencies and how the radio system that we use day-in-and-day-out works. In my next column, we’ll go over legacy vs. P25, NG9-11, FirstNet and other acronym heavy terms such as LMR and LTE. Until then, be safe.