Other Electrical Noises; Wheel Static; Ground Bonding - Motorola GM1200E Installation Manual

5.7

Other Electrical Noises

Other elements of the electrical system which can generate noise are listed below. These can be
suppressed by connecting a 0.5 µF bypass capacitor between the noises source and ground.
1. Ammeter-to-battery lead
2. Gauges (oil, fuel, temperature)
3. Ignition Switch
4. Lamp bulbs (headlamps, tail lamps, dome lamps, etc.)
5. Accessory wiring (electrical fuel pump, electric windshield wipers, heater fan motor, window
openers, etc.)
5.8

Wheel Static

Road friction can cause static build-up on the front wheels. Suppress noise from this source using
wheel static collector rings (Motorola Part No. 1K534254 regular type - 1K653173 small type).
5.9

Ground Bonding

Static charges can build up on various parts of a vehicle if not properly bonded and cause noise
through arcing. This type of noise is suppressed by bonding the part using one-inch wide ground
straps (keep them as short as possible). Some common points where bonding may be helpful are
listed below, see Figure 2-9.
A. From engine block to the firewall.
B. From engine block to vehicle frame at points where the engine is shock-mounted.
C. From the battery ground terminal to the vehicle body.
D. From top of front wheel "A" frames to chassis, particularly in cases where rubber-mounted
members are used.
Reducing Noise Interference in Mobile Two-Way Radio Installations
Firewall
Battery
C
D
Figure 2-9 Ground Bonding.
A
Fender
Chassis Well
Front Wheel
"A" Frame
D
B
Noise Reduction Techniques
2-11