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Next Generation
Signal Enhancement
is adequate, in such condition, reduce the forward path signal using the
forward attenuation in the repeater and minimize the forward signal level in
step of 1dB until the problem subsides.
But ensure that the In-Building signal level remains adequate for the
coverage area.
9.3 Antenna
Isolation
Antenna isolation is defined by the path loss or attenuation, between the
donor and server antennas. It is important to ensure that the antennas are
sufficiently separated, such that the signals transmitted by donor antenna
are not intercepted by server antenna and vice versa. For optimal
performance, the separation of the two antennas must provide a path loss
of at least 15 dB greater than the gain of the R-20-930 unit.
In most cases, isolation will be achieved by properly locating the donor
and server antennas, respectively. The optimal location for the donor
antenna is high above the roofline, and exterior to the building. The indoor
coverage antenna (server) should be installed inside, near or below the
ceiling. Following guidelines should ensure adequate isolation between
antennas.
I) Installation of the donor and server antennas near windows is to be
avoided from where signals can easily pass through the glass resulting
in poor isolation.
II) Mount the donor antenna as high as physically possible to the exterior
of the building, maximizing the vertical separation between the donor
and server antennas. The donor antenna should point towards the
base station site.
III) Install the antennas taking advantage of any existing building structure
such as brick walls, metal roofs, or multiple wall structures to provide
additional attenuation in the possible link path between them.
IV) Whenever using directional antennas inside the building to provide
coverage in the corridors and hallways, point the indoor antenna away
from the donor antenna location.
V) In extreme cases, the building configuration may not allow for such
separation and isolation. If additional isolation is required, coaxial
attenuator may be inserted between the donor antenna and the
repeater or reduce the forward path signal using the attenuator.
