Westell CSI-DSP85-252-C, Installation Manual

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System Set-Up Considerations
All cables should be checked for shorts and opens. Also verify that there are no cables with loose or poor connec-
tions. RF leakage could cause oscillation to occur under some conditions.
The rooftop antenna (Donor Antenna), if directional, should be checked for proper alignment along the calculated
compass heading. Typically, the directional antenna would be aimed at the same site that your handset uses, but it
may not always be so.
It is critical the installer contact the service provider for information on,
and approval of the cell site he or she has selected before the system is turned on.
If cables and alignment are acceptable and a problem persists, it may be necessary to use a spectrum analyzer to
examine the signal environment in which the repeater is operating. The existence of strong adjacent channel sig-
nals within the frequency band(s) can cause the AGC to reduce the amplifi er’s gain or cause alarms. In some cases
additional fi ltering or attenuation might be required to reject these unwanted signals. In some instances, the donor
antenna can be reoriented horizontally, to place the interference source in an antenna pattern “null”. There also
may be some cases where the interference from outside signals is so great that they cannot be fi ltered or otherwise
reduced or eliminated without expensive and possibly prohibitive measures. In these cases it may not be practical to
use the repeater for providing coverage to these sites.
Selection of external attenuators to be used in line with the Repeater
Antenna Port(s):
- 10 -
DONOR PORT
If a repeater is installed in an area with very strong desired and/or undesired signals, it is important to ensure
that the overall signal levels are optimized to be within the best operating range of the repeater. Additionally, de-
sensing of a nearby base station site must be avoided. These goals can be accomplished by properly attenuating
the antenna port(s) in the path of the donor antenna(s). In effect, one can imagine that the particular repeater
deployment is electrically moved farther from the base station using attenuators that are equivalent to increasing
the path loss
from the donor antenna to the base station.
The following potential outcomes result from the use of attenuators on the donor port(s) of the repeater : Uplink
output power, as reported by the unit, is reduced by the value of the attenuation, protecting nearby base stations.
Downlink signal to noise ratio is high at the point of the attenuator, resulting in slight but negligible reduction in
downlink performance. Other performance is essentially unchanged.
1:1 PORT CONFIGURATION
Input: One dual band duplex port, from the dual
band donor.
Output: One dual band duplex port, to the DAS.
DONER-INDOOR SERVER-OUTDOOR ETHERNET USB STATUS 2 STATUS 1