Product manual

Configuration directions, Base station planning - additional information
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
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corner reach the cordless phone at approximately the same time. If you now place the base station
in the centre of the hall (point C) you can work out for yourself that this is much worse than position
A because you will have a greater time delay spread between the various signals.
Assume that the hall has a non-reflective wall at position D; you can then consider installing the base
station opposite this, i.e. at position E.
All these considerations, of course, depend on the dimensions of the hall and the type of antenna
which you are using.
Directional antennas
It is quite possible to use directional antennas in small corridors and halls. Give careful consideration
to the type of antenna that you intend using for your application: why that antenna in particular? The
fact is that there are many different types of antenna, all with a different radiation pattern. It is difficult
to summarise the type of antenna and the application; it is often a question of experience and
empiricism. It may be, for example, that you achieve the best result by mounting the base stations on
the ceiling, allowing the antennas to radiate vertically downwards. It is possible that you need a beam
that is very directional horizontally but has a wider radiation pattern vertically (for example, an extremely
high hall), or precisely the opposite. It is advisable to consider this before carrying out the
measurement, but the fact remains that you must always carry out a measurement to ensure the best
possible operation.
Tips
Although most of the tips have already been given, a sum up of a few important ones is given below:
• Always involve the client in the site survey. Ensure that the client shares the responsibility for the
decision on the siting of base stations. Also always involve the client in problems which you
encounter (a difficult area to cover), and ensure that the client is not faced with surprises
afterwards.
• In a site survey with a DT360 cordless phone, you can use the following values for your signal
strength (SS): 20 for an office environment and 15-18 for outdoors and halls. Don’t forget that the
signal strength figure is a relative value which means that it can vary somewhat from cordless
phone to cordless phone. The advice then is: always listen to the quality at the limit of your
measured cell! The quality indicator must be at 20 (QU), but this too can occasionally be somewhat
lower (hence listening).
• Always mount a base station at least 30 cm away from a metal wall, to avoid a substantial
impedance change for the antennas.
• Pay particular attention to the ‘non-standard’ areas such as toilet rooms, stairwells, lifts,
maintenance shafts etc.
• Provide a few spare metres of cable when installing a base station to assist when possibly moving
the base station.
• If the client subsequently complains of ‘crackling’ during calls in a particular area or if the client
is being troubled by calls being dropped, this is very probably attributable to coverage problems.
• Always try to site the base station (if possible) such that it can see as much as possible of the
area to be covered (i.e. not behind a large pillar).