Installation Notes; Radio Interference; Radio Range - EMS 7703 Installation Instructions Manual

EMS SYSTEM 7000

3. Installation Notes

3.1 Radio Interference.

3.1.1 Door access systems, photocopiers, fax machines, modems, processor controlled security
controllers and digital telephone exchanges are a few of the items that on occasion may
emit spurious signals. If the spurious emissions correspond to the co-channel or adjacent
channel frequencies, they may interfere with the performance despite the careful 7703
receiver design.
3.1.2 Two meters distance from the aerial is usually sufficient to eliminate their effects but door
access systems have been known to require a greater distance.
possibility of there being apparatus on the opposite side of the wall to which the receiver is
to be installed, which is not the property of the installation site.
3.1.3 With TEST mode selected the RADIO INTERFERENCE LED is connected to an integral
carrier detector. This detector will turn ON if any radio signal exceeding -110 DBM is found
within the channel used by the 7703.

3.2 Radio Range.

3.2.1 The expected range of a transmitter may not be achieved for a variety of reasons. The
local environment is normally responsible and a few of these reasons are as follows:-
(a) Radio interference.
(b) Metal tiled floors, walls or ceilings.
(c) Metal framed suspended ceilings.
(d) Metal foil wall covering under the decorations used for thermal insulation
(e) Metal objects or equipment on the opposite side of the wall to which the receiver
is installed.
Problems caused by the above may be reduced by:-
(1) Re-siting the receiver.
(2) Fitting a remote aerial.
7703 INSTALLATION, ISSUE V2.2 – 13/04/10
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Do not over look the