Motorola MOTOwi4 Canopy 30, Руководство пользователя

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Issue 3.1, July 2006 Page 154 of 162
15.3 EXPOSURE
15.3.1 Preventing Overexposure to RF Energy
Caution!
To protect from overexposure to RF energy, install Canopy radios so as to provide
and maintain the minimum separation distances from all persons.
When the system is operational, avoid standing directly in front of the antenna. Strong RF fields
are present when the transmitter is on. The Outdoor Unit (ODU) must not be deployed in a
location where it is possible for people to stand or walk inadvertently in front of the antenna.
15.3.2
Calculations for Separation Distances and Power Compliance Margins
Limits and guidelines for RF exposure come from:
◦
US FCC limits for the general population. See the FCC web site at http://www.fcc.gov ,
and the policies, guidelines, and requirements in Part 1 of Title 47 of the Code of
Federal Regulations, as well as the guidelines and suggestions for evaluating
compliance in FCC OET Bulletin 65.
◦
Health Canada limits for the general population. See the Health Canada web site at
http://www.hc-sc.gc.ca/rpb and Safety Code 6.
◦
ICNIRP (International Commission on Non-Ionizing Radiation Protection) guidelines for
the general public. See the ICNIRP web site at http://www.icnirp.de/ and Guidelines for
Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields.
The applicable power density exposure limits from the documents referenced above are
1. 10 W/m
2
for RF energy in the 2.4-, 5.2-, 5.4-, and 5.7-GHz frequency bands.
Peak power density in the far field of a radio frequency point source is calculated as follows:
where
S = power density in W/m
2
P = RMS transmit power capability of the radio, in W
G = total Tx gain as a factor, converted from dB
d = distance from point source, in m
Rearranging terms to solve for distance yields
P G
.
4
p
d
S
=
Table 16: Exposure Separation Distances
S =
P
•
G
4
π
d
2