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Airbridge cBTS3612 CDMA Base Station
G
= Antenna gain relative to half wave dipole
d
Pt
= Power at the antenna terminals [W]
S = power density [W/m
Note: 1mW/cm
D.5 Location of Base Station Antennas
Base stations antennas, the source of the radiation, are usually mounted on
freestanding towers, with a height up to 30 m or on a tower on the top of buildings or
in less cases to the side of the building. Generally the height of the antenna position
does not fall below 10 m. The power usually is focused into a horizontal main beam
and slightly downward tilted. The remaining pow er goes into the weaker beams on
both side of the main beam. The main beam however does not reach ground level
until the distance from the antenna position is around 50 – 200 m.
The highest level of emission would be expected in close vicinity of the antenna and
in line of sight to the antenna.
D.5.1 Exclusion Zones
1)
Antenna location should be designed so that the public cannot access areas
where the RF radiation exceeds the levels as described above. .
2)
If there are areas accessible to workers that exceed the RF radiation exceeds
the levels as described above make sure that workers know where these areas
are, and that they can (and do) power-down (or shut down) the transmitters
when entering these areas. Such areas may not exist; but if they do, they will be
confined to areas within 10 m of the antennas.
3)
Each Exclusion zone should be defined by a physical barrier and by a easy
recognizable sign warning the public or workers that inside the exclusion zone
the RF radiation might exceed national limits.
D.5.2 Guidelines on Arranging Antenna Locations
1)
For roof-mounted antennas, elevate the transmitting antennas above the height
of people who may have to be on the roof.
2)
For roof-mounted antennas, keep the transmitting antennas away from the
areas where people are most likely to be (e.g., roof access points, telephone
service points, HVAC equipment).
3)
For roof-mounted directional antennas, place the antennas near the periphery
and point them away from the building.
2
] see also MPE Limits
2
2
= 10W/m
D-4
System Description
Appendix D Electromagnetic Radiation
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