User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
Appendix D Electromagnetic Radiation
D-3
Power density S [mW/cm
2
] for uncontrolled area at 880 MHz
2
/
58
.
0
1500
880
1500
]
[
cm
mW
MHz
f
S
=
=
=
D.3 Estimation of Exposure to Electromagnetic Fields
Below method describes a theoretical approach to calculate possible exposure to
electromagnetic radiation around a base station transceiver antenna. Precise
statements are basically only possible either with measurements or complex
calculations considering the complexity of the environment (e.g. soil conditions, near
buildings and other obstacles) which causes reflections, scattering of
electromagnetic fields.
The maximum output power (given in EIRP) of a base station is usually limited by
license conditions of the network operator.
A rough estimation of the expected exposure in power flux dens ity on a given point
can be made with the following equation. The calcualtions are based on FCC OET
65 Appendix B.
π
∗
∗
∗
=
)
(
4
)
(
2
m
r
G
W
P
S
numeric
Whereas:
P = Maximum output power in W of the site
G
numeric
= Numeric gain of the antenna relative to isotropic antenna
R = distance between the antenna and the point of exposure in meters
D.4 Calculation of Safe Distance
Calculations can be made on a site by site basis to ensure the power density is below
the limits given above, or guidelines can be done beforehand t o ensure the minimum
distances from the antenna is maintained through the site planning.
S
Pt
G
r
d
π
4
*
*
64
.
1
=
Whereas:
r = distance from the antenna [m]