Huawei DBS3900 Installation Manual page 117

1 Safety
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Location of BTS
The BTS is shielded from RF radiation hazards. The device has been tested to comply with
the radioactive spurious emission requirements of international standards or local regulations.
Therefore, the BTS under normal operating conditions does not cause danger to the public and
O&M engineers. However, the limits for RF radiation might be exceeded due to faulty
antenna cables or for other causes.
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Prediction of the Exposure to Electromagnetic Fields
This section provides a theoretical approach to calculate possible exposure to electromagnetic
radiation around a BTS antenna. Precise statements are possible either with measurements or
complex calculations considering the complexity of the environment, such as soil conditions,
nearby buildings and other obstacles. The complexity may cause reflection, deflection, and
scattering of electromagnetic fields.
The maximum output power (given in EIRP) of a BTS is usually limited by license conditions
of the network operator.
A rough estimation of the expected exposure in power flux density on a given point can be
made with the following equation:
S = (P(W) x G
Where,
P = Maximum output power at antenna port of the BTS in W
G
numeric
r = Distance between the antenna and the point of exposure in meters
For the calculation of the G
G
numeric
GdB = G
B = attenuation in dB
1-12
Exercise extra caution when designing co-location sites, that is, antennas owned by
different companies are located in the same site or are co-sited. This applies particularly
to sites that include high-power broadcast (FM/TV) antennas. Local zone often favors
co-location, but co-location may cause safety problems.
Take special precautions for antenna sites near hospital and schools.
BTS sites shall not be accessible to the public. Only authorized and trained personnel can
access BTS sites or equipment rooms.
A sign of excessive RF radiation must be present on the doors of the sites or equipment
rooms to warn the personnel inside the site or equipment room of excessive RF radiation.
BTS sites must be regularly monitored and inspected after installation.
)/(4 x r²(m) x π)
numeric
= Numeric gain (see below)
numeric
GdB/10
= 10
(dB) – B (dB) – B
antenna cable
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(dB) – B
vertical-attenutation
(dB)
horizontal-attenuation
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