Motorola Solutions Inc. 99FT4100 Manual De Usuario

(1)

where

 

 available power at the antenna port (W);

 

 physical antenna length (metres);

 peak antenna directivity (unit-less), assumed equal to the peak gain

;

 electrical down-tilt angle of the antenna main beam (radians), and

is the distance from the antenna center (metres). Spatial power density averaging may be required by
some regulations. As the formula (1) predicts the peak power density, it represents a conservative
estimate of the average power density. Thus there is no need to compute the latter.

Several methods can be employed to determine the EME exposure at ground level.

Such an assessment is not necessary if the mounting height of the antenna is larger than the
compliance distance in front of the antenna, computed using the EN50383:2010 methodology outlined
in 

Exposure in Front of the Antenna on page 102

. If this is not feasible, then the following approach can

be employed.

At ground level exposure occurs in the antenna far-field. The antenna phase center is assumed to be
the mounting height. The resulting predictive equation for the power density is:

where 

 is the elevation gain pattern, which is approximated by the following expression:

MN003557A01-AA

Appendix E: MOTOTRBO Repeater EME Assessment

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