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DENNY 81 ASSOCIATES, P.G. ' <br /> CONSULTING ENGINEERS 47 <br /> WASHINGTON, OC <br /> Engineering Statement - Page 4 <br /> KNKA293, Carrboro, North Carolina <br /> frequency range is the same as the 1982 protection guide level and, therefore, may be <br /> calculated using the formula given above. The averaging time for controlled <br /> environment exposures is also 0.1 hour as with the 1982 standard. Thus, in this case, <br /> the MPE for controlled environments would be the same as the protection guide level, <br /> 2.9 mW/cmz. The base of the KNKA293 tower, which is enclosed by a fence, is an <br /> example of a controlled environment. Locations inside the KNKA293 equipment <br /> shelter also are examples of a controlled environment. <br /> Uncontrolled environments are locations where there is exposure of <br /> individuals who have no knowledge or control of their exposure. A residential area <br /> would be an example of an uncontrolled environment. The MPE for uncontrolled <br /> environments for emissions in the 300 to 3000 MHz frequency range may be calculated <br /> using the formula <br /> S= f <br /> 1500 <br /> where, as before, f is the frequency in megahertz, and S is power density in mW/cm2. <br /> While there are some exceptions, in general, the MPEs for uncontrolled environments <br /> are one-fifth the MPEs for controlled environments, and the averaging times for <br /> uncontrolled environments are five time's longer than for controlled environments. As <br /> was the cage with the protection guide level and the MPE for controlled environments, <br /> the most reanctive MPE for uncontrolled environments occurs at 869 MHz. Applying <br /> this frequency to the formula yields an MPE for uncontrolled environments of <br /> 0.58 MW/cm=. <br />