Clear-Com CellCom Battery Pack Charger - Manual (Page 149)

Clear-Com Communication Systems
CellCom V2.0.3 Instruction Manual
9 - 5
so that there is no area where the signal strength is below 30, and
no area where the error rate is above a few percent.
8. The antenna placement will need to be adjusted to get the best
coverage.
Figure 9-2: Mapping overlapping coverage zones
In some environments the user may observe that despite having a high
signal strength, the beltpack consistently reports a high error rate.
This could be due to two things:
• In-band interference from an RF source broadcasting in the DECT
area of the spectrum. This can be verified using a DECT band
monitor or by using a Spectrum Analyzer.
• Long Delay Spread Multipath, where the signal is bounced off a
number of reflective surfaces, such as metal ceilings, gantries,
walkways or other large structures. This problem is greatest
where the reflective surface is large and exists at a range of
distances from the antenna. To resolve this problem, consider
siting the antenna where it cannot “see” the reflective surface,
installing a reflector close to the antenna between it and the
reflective surface, or purchasing directional antennas. Contact
VGC customer support for more information.
TESTING ANTENNA HANDOFF
After testing the coverage areas for individual antennas, test the
handoff between the antennas. When the user walks through a
coverage area with the beltpack, the beltpack searches to find the
antenna with the best signal strength, and switches transmission to
that antenna. Therefore the beltpack continually hands off
transmission among antennas as the user moves through the
coverage area.
To test antenna handoff, connect any additional antennas in the
installation and walk through the coverage areas to ensure that the
coverage is continuous and complete, without audio breakups. The
user can tell which antenna the beltpack transmits to by looking at the
RPN number in the top rightmost corner of the beltpack’s display when
the beltpack is in “site survey” mode. Reposition antennas if
Zone A
Zone B
Zone C
1 User
5 Users
4 Users