MA REV A
11
TROUBLESHOOTING
All external cables should be carefully checked for “shorts” and “opens”.
The rooftop antenna, if directional, should be checked for proper alignment along the
calculated compass heading. Typically, the directional antenna should be aimed at
the same sight that your handset uses in the area where the outside antenna is to be
placed.
If cables and alignment are O.K. it may be necessary to use a spectrum analyzer to
examine the signal environment in which the IBA is operating. The existence of
strong analog signals within the frequency bands can cause problems particularly on
the downlink. In some cases additional filtering might be required to reject these
unwanted signals. Automatic Gain Control (AGC) may be switched on by moving the
leftmost dip switch to the on (down) position. In some instances the directional
outside antenna can be reoriented, horizontally to place the interfering source in an
antenna pattern “null”. There also may be some cases where the interference from
outside signals is so great that they can not be filtered or otherwise reduced or
eliminated without expensive and possibly prohibitive measures. In these cases it
may not be practical to use the IBA for providing coverage at these sites.
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