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Installation Manual - Hardware Installation
BBU3806 WCDMA Base Band Unit
4.2 Definitions of Environment
There are two kinds of environment under electromagnet radiation.
Controlled environment
In such an area, people are aware of the potential danger of the radio frequency
radiation.
Uncontrolled environment
In such an area, people are not aware of the potential danger of the radio frequency
radiation. They are not able to evade the radiation. The area may include living or
working places.
4.3 Minimal Distance Formula
This section shows how to calculate the minimal safety distance.
Use the following formula to calculate the minimal safety distance from various
antennas.
N10
r
=
4 W
min
The elements in the formula include:
R
min
N is the number of frequency carriers.
P
out
L is the loss from transmitting party to the receiving party. Its unit is dB.
G is the antenna gain. Its unit is dB.
W is the greatest field power density permitted. Its unit is W/m
In the uncontrolled environment, the greatest field power density permitted is f/150, in
which f is the frequency, whose unit is MHz. Its tested value is the mean value
measured when the testing time is over 30 minutes.
In the controlled environment, the greatest filed power density permitted is f/30, and
its tested value is the mean value measured when the testing time is over 6 minutes.
Table 2 shows the minimal safety distance on the axial line of the antenna field
calculated by the above formula.
Table 2 Typical minimal safety distance
Frequency output power
（
）
G-L
P
10
OUT
is the minimal safety distance. Its unit is meter.
is the output power of the frequency carrier. Its unit is W.
Frequency
Huawei Technologies Proprietary
f (MHz)
P
(W)
out
9
Safety Precautions
2
.
1800
40
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