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Next Generation
Signal Enhancement
4.
U
ser’s
A
ddress
&
other particulars: ---------------------------------
D
ate:
Prepared
by: -------------
8.2. E
ngineering
C
onsideration
a. S
ite
S
election
S
ite selection is one of the most critical decisions affecting the overall
performance of the system.
A
repeater must be located where it can
receive the maximum signal from the donor site in order to maximize the
repeater’s output and performance, signal strength greater than or equal to
-75
d
B
m is desired.
E
xamples of donor antenna locations include
(
but are not limited to
)
: the
roof of a building adjacent to the affected area, with the antennas mounted
on the highest possible point on the structure; the top of the hill that is
obstructing the donor site’s coverage, with the antennas mounted on poles
at ground level; an existing utility pole with equipment or as the situation
permits.
D
istance from both the donor site as well as from the new area to be
covered must be taken into consideration.
T
he repeater unit should be
located close to the donor site to receive maximum signal strength and at
the same time is located from where the area proposed for coverage can
be reached. In addition, the donor antenna associated should have line of
sight with
BTS
site to reduce the effects of fading.
A
nother important issue when choosing a repeater location is the
availability of
AC
mains for operating the system.
S
ites where repeater unit
is installed should be easily accessible for the maintenance team.
b. A
ntenna
S
election and
P
lacement
P
roper selection of the repeater’s donor and server antennas is crucial in
designing the repeater system.
A
ppropriate antenna characteristics help to
provide proper isolation between the server
(
coverage
)
and donor
antennas, which helps to prevent feedback.
S
pecific ways to achieve proper isolation include: using high gain,
directional antennas with good
F
ront to Back ratios
(25
d
B
or better
)
;
physical separation of the repeater’s donor and server antennas; and
external shielding between antennas.
A
high gain antenna will help
minimize overall path loss to achieve the desired output power.
D
onor
antenna gains are typically
10
to
12
d
B
i, while server antennas can be
installed as per requirement.
•
T
he antennas should have proper frequency band of operation.
