Vehicular Noise Reduction - Motorola MICOM-2E ALE Owner's Manual

MICOM-2E-ALE Owner's Manual

Vehicular Noise Reduction

Most vehicles are subject to several noise sources which greatly disturb
a received signal. The most noisy sources are the high voltage ignition
sparks that are produced at the vehicle's plugs. The second is the
alternator activity.
In keeping with the following insulation practices and if necessary by
adding some damping components, it may be possible to reduce these
noises to a tolerable level.
1. Keep your antenna tuner and antenna as far as possible from the
engine compartment.
2. Connect the primary power lead of the radio directly to the battery
instead of the starter relay. The battery acts as a large capacitor
(about one farad for 50 Amp capacity batteries) by passing the
noise to ground.
3. If necessary, connect 0.01 - 0.1 micro farad capacitors across the
primary leads of the coil and across the alternator output.
4. Keep your DC and RF cables as short as possible.
5. If your vehicle does not have a resistive ignition wire, it is
recommended to replace it with a such a wire.
6. The MOTOROLA RF noise reduction kit for alternator equipped
vehicles (TLN8845) includes some useful accessories for noise
reduction. Among them being the resistive ignition coil suppresser
cable. In severe noise conditions, you may find this kit helpful.
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