Nortel 7430 Deployment Manual page 18

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Below given values are only to be used as a guideline in a situation where no reflections from
surroundings are present and where there is no interference from other equipment.
3.4.4 Impact of Environmental Items on Radio Coverage
Different weather conditions can have an influence regarding radio coverage. For example, a wet
roof or wall can act as a shield. Different seasons of the year can also have an influence
regarding radio coverage. For example, the growth of leaves on trees in the spring that were not
present when the system was installed in the winter might affect the radio coverage of Base
Stations and Repeaters.
3.4.5 Metal Construction
In situations where there are additional metallic materials within the construction of the building,
signal reflection may occur. In the case where reflections occur, signal may be affected even
when the handset is very close to the base station. These areas should be documented by the
technician and the customer. Reflections can often be identified as unstable Q-value in positions
where the RSSI value is high. In a situation where the Q-value is stable as long as the handsets
is placed in a fixed position (not moving) but fluctuating significant when moved the reason for
this behavior is probably caused by reflections from surroundings.
When it is known there is a lot of metal in the site, a thorough survey is necessary. A more
accurate survey may be better obtained in these circumstances using a Digital Mobility Controller
and a minimum of four base stations to get proper knowledge of the radio signal propagation.
NN40110-304 1.1
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