Wireless Network Administration: Spectrums and the FCC - dummies

Wireless Network Administration: Spectrums and the FCC

The term spectrum refers to a continuous range of frequencies on which radio can operate. In the United States, the Federal Communications Commission (FCC) regulates not only how much of Janet Jackson can be shown at the Super Bowl, but also how various portions of the radio spectrum can be used. Essentially, the FCC has divided the radio spectrum into dozens of small ranges called bands and restricted certain uses to certain bands. For example, AM radio operates in the band from 535 KHz to 1,700 KHz.

The following table lists some of the most popular bands. Note that some of these bands are wide — for example, UHF television begins at 470 MHz and ends at 806 MHz, but other bands are restricted to a specific frequency. The difference between the lowest and highest frequency within a band is called the bandwidth.

Popular Bands of the Radio Spectrum
Band Use
535 KHz–1,700 KHz AM radio
5.9 MHz–26.1 MHz Short wave radio
26.96 MHz–27.41 MHz Citizens Band (CB) radio
54 MHz–88 MHz Television (VHF channels 2 through 6)
88 MHz–108 MHz FM radio
174 MHz–220 MHz Television (VHF channels 7 through 13)
470 MHz–806 MHz Television (UHF channels)
806 MHz–890 MHz Cellular networks
900 MHz Cordless phones
1850 MHz–1990 MHz PCS cellular
2.4 GHz–2.4835 GHz Cordless phones and wireless networks (802.11b and
4 GHz–5 GHz Large dish satellite TV
5 GHz Wireless networks (802.11a)
11.7 GHz–12.7 GHz Small dish satellite TV

Two of the bands in the spectrum are allocated for use by wireless networks: 2.4 GHz and 5 GHz. Note that these bands aren’t devoted exclusively to wireless networks. In particular, the 2.4-GHz band shares its space with cordless phones. As a result, cordless phones can sometimes interfere with wireless networks.