Westell Inc. CSI-DSP25XCP ユーザーズマニュアル
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.
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.
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
signals within the frequency band(s) can cause the AGC to reduce the amplifier’s gain or cause alarms. In some
cases additional filtering 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 filtered 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.
examine the signal environment in which the repeater is operating. The existence of strong adjacent channel
signals within the frequency band(s) can cause the AGC to reduce the amplifier’s gain or cause alarms. In some
cases additional filtering 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 filtered 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):
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
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.
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.
Input: Two single band duplex ports, one from the cell donor
and one from the PCS donor.
and one from the PCS donor.
Output: One dual band duplex port to the DAS.
2:1 PORT CONFIGURATION
1:2 PORT CONFIGURATION
Input: One dual band duplex port from the dual band donor.
Output: Two single band duplex ports one to the Cellular DAS and
one to the PCS DAS.
2:2 PORT CONFIGURATION
Input: Two single band duplex ports, one from the cell donor and
one from the PCS donor.
one from the PCS donor.
Output: Two single band duplex ports one to the Cellular DAS and
one to the PCS DAS.
Input: One dual band duplex port, from the dual band donor.
Output: One dual band duplex port to the DAS.
1:1 PORT CONFIGURATION