User's Manual

INSTALLATION

MOBILE STATIONS

ENVOY™ TRANSCEIVER REFERENCE MANUAL 359

Electrical protection

The transceiver is provided with adequate internal protection. The transceiver supply

is also fitted with adequate protection.

If a battery is used, Codan recommends that a suitable cartridge fuse (32 A, Codan

part number 15-00711) is fitted in the positive wire, close to the battery. This protects

the power cable from risk of fire if damaged insulation should touch surrounding

metalwork.

As the fuse is not included to protect the transceiver circuits, it should be of large

physical and electrical size to eliminate the possibility of voltage drops across the

fuse.

WARNING: Do not use normal glass in-line automotive fuses.

Earthing the transceiver in a mobile station

A good RF earth is essential for efficient operation of the mobile station. The

transceiver chassis should be connected to earth via the earth screw on the rear panel

of the transceiver. Use a copper braid of at least 12 mm (½ in) width to connect the

transceiver to the earthing point.

NOTE: Keep the earth braid as short as possible.

All individual units in a mobile station should be earthed to prevent RF interference

corrupting the data and audio circuits. Equipment that requires earthing has an earth

screw fitted. To achieve good earthing, connect separate earth braids to the earth

screws on each piece of equipment and connect them back to the same earthing point.

NOTE: Ideally, all earth braids should connect directly back to a single point

to prevent earth loops.

An adequate earthing system is necessary for:

• static drain

• noise reduction