Aerial Siting - CSL DualCom GSM Mk1 Installation Manual

Aerial Siting

ALWAYS do a site survey to find an area of strong signal before installation.
Installing DualCom with a weak signal is bad installation practice. The DualCom
is likely to suffer signal failure, causing wasted site vists, wasted time & money.
The aerial should be mounted vertically at the point of strongest signal. This
is usually the highest point in the building (often the loft area).
Large metal structures can affect radio signals. Avoid installing the aerial
directly under metal roofs or within metal skinned buildings because this will
reduce the signal strength and may inhibit operation completely. If this
is unavoidable, the strongest signal will be found away from the metal roof or
close to large external windows or skylights.
Avoid installing the aerial close (2 metres) to cable runs, ducting, structural
metalwork, metal pipes, water tanks and electronic equipment, e.g. photocopi-
ers, fax machines etc. These can have similar effects as metal roofs.
The Signal Strength LEDs on the front of the DualCom (see Fig 1 & 2 and
Appendix 1) will give an indication of signal strength that DualCom is receiving
from the GSM Network. Note: These will not work with an unprogrammed NVM.
Green On:
Red & Green On:
Red On:
Reliable operation is unlikely with a low signal strength. If the display shows
that the signal strength is low, you should improve the signal strength. This
may be achieved by repositioning the aerial. The GPRS aerial lead should not
be cut or extended, therefore repositioning the aerial may require that the
DualCom is also repositioned.
A site survey should provide information on the availability, signal strength and
interference status of all radio Base Stations in the surrounding area.
The CS2366 Radio Test Set is ideal for surveying a site. This handheld unit can
check the availability, signal strength and interference status of all surrounding
Base Stations. In addition, it will identify the best location for a DualCom GPRS
aerial within the building, it will help to avoid sources of interference and can
confirm the availability of a GPRS service at the proposed site.
Where a CS2366 Radio Test Set is unavailable, a DualCom GPRS, aerial and
fully charged battery may be used to locate the point of strongest signal. En-
sure that the DualCom is fully operational then walk around the site carrying the
equipment observing the signal strength display.
High Signal Strength
Medium Signal Strength
Low Signal Strength
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