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Description varix 200/varix 14 (DECT)
2 Planning a cordless communications network
For this reason, a building should be inspected prior to installation in order to gather informa-
tion on areas which could cause signal coverage problems (refer to Table 2.1). The vertical
range in most cases covers corridors above and below the respective FP. However, the verti-
cal range is between 0 (concrete ceiling) and 8 metres. If lifts are to be included in the DECT
system coverage, then the FPs are best installed inside the lift car. Similarly, air-conditioning
ducts and anti-static conductive carpeting both affect the DECT hop range.
Typical attenuation values for building materials at 1.9 GHz (values are rounded)
Table 2.1
Using the information on building materials and the attenuation values for open spaces (see
Table 2 in the glossary), it is possible, by simple mathematics, to estimate the size of the
radio cell in advance. However, careful measuring and planning remain essential.
2.4.3
System proposal
Once the number of FPs has been determined, it is possible to draw up a proposal for the
system.
2.4.4
Job list
A list can now be compiled containing the parts required and the cable-laying and installa-
tion jobs to be done. This is required in order to be able to draw up a tender.
Obstacle
Typical attenuation at 1.9 GHz
Interior walls
2-5 dB
Wooden/dry-wall partition walls
5 dB
Steel shelves/cabinets
15 dB
Various types of brick
6-12 dB
Concrete walls
10-20 dB
Conrete ceilings
20 dB
Lift
20-30 dB
