FCC/LSGAC
Local Official's Guide to RF
Before we start, however, let's take a short tour of the radiofrequency spectrum. RF signals may be transmitted over a wide range of frequencies. The frequency of an RF signal is expressed in terms of cycles per second or "Hertz," abbreviated "Hz." One kilohertz (kHz) equals one thousand Hz, one megahertz (MHz) equals one million Hz, and one gigahertz (GHz) equals one billion Hz. fu the figure below, you'll see that AM radio signals are at the lower end of the RF spectrum, while other radio services, such as analog and digital TV (D TV) , cellular and PCS telephony, and point-to-point microwave services are much higher in frequency.

The FCC ' s limits for maximum permissible exposure (MPE) to RF emissions depend on the frequency or frequencies that a person is exposed to. Different frequencies may have different MPE levels. Later in this document we'll show you how this relationship of frequency to MPE limit works.
I.
The FCC ' s RF Exposure Guidelines and Rules.
Part 1 of the FCC'sRules and Regulations contains provisions implementing the National Environmental Policy Act of 1969 (NEPA). NEPA requires all federal agencies to evaluate the potential environmental significance of an agency action. Exposure to RF energy has been identified by the FCC as a potential environmental factor that must be considered before a facility, operation or transmitter can be authorized or licensed. The FCC ' s requirements dealing with RF exposure can be found in Part 1 of its rules at 47 C.F.R. § 1.1307(b). The exposure limits themselves are specified in 47 C.F.R. § 1.1310 in terms of frequency, field strength, power density and averaging time. Facilities and transmitters licensed and authorized by the FCC ~ either comply with these guidelines or else an applicant must fIle an Environmental Assessment (EA) with the FCC as specified in 47 C.F.R. § 1.1301 etseq. An EA is an official document required by the FCC ' s rules whenever an action may have a significant environmental impact
(see discussion below). In practice, however, a potential environmental RF exposure problem is typically resolved before an EA would become necessary. Therefore, compliance with the
FCC ' s RF guidelines constitutes a de facto threshold for obtaining FCC approval to construct or operate a station or transmitter. The FCC guidelines are based on exposure criteria
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