Typical System Configuration
The MOTOTRBO SLR 5000 Series Repeater operates in different frequency ranges with different
channels transmitting 100 W radio frequency (RF) power. The typical system configuration comprises
an omnidirectional array antenna featuring 6–10 dBd gain, installed at or above 20 m from ground
level, and fed by the SLR 5000 Series Repeater through a combiner characterized by a typical 3 dB
transmission loss, and a 30 m 7/8” coaxial cable characterized by a typical 2.7 dB/100m loss, resulting
in a total 3.9 dB transmission loss. Based on these characteristics, the RF power at the antenna input
is about 200 W.
Since shorter antennas provide a conservative EME exposure assessment from equation (1), when
, the parameters of a typical 6.6 dBd antennas are employed (it will have to be verified that
the resulting compliance distances are indeed smaller than
). Such an antenna (e.g., Andrew
DB408) would exhibit a typical elevation beamwidth of about 14 degrees.
Exposure Limits
Based on the SLR 5000 Series operating frequency range, the most conservative power density limits
are those defined in the ICNIRP guidelines [1]. They are 10.1 W/m2 for occupational exposure, and
2.02 W/m2 for general public exposure. They will be used for the EME exposure assessment.
EME Exposure Evaluation
Exposure in Front of the Antenna
The assessment is based on the following characteristics of the Andrew DB408 antenna:
6.6
+
2.15
G
A
= 10
10
= 7.5 P = 200 W
The parameter is thus . Upon inserting the power density limits established in
Exposure Limits on page 158 into formula (1), the following distances for occupational and general
public exposure compliance are respectively determined:
and
As both these distances are less than , the aforementioned choice (Typical System
Configuration on page 158) of considering the shorter, lower gain antenna to perform the assessment
is deemed valid. Longer, higher gain antennas would yield shorter compliance distances, for the same
input antenna power and operating frequency range.
Appendix F : MOTOTRBO Repeater – EME ASSESSMENT
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