14
REDUCING NOISE
The Automatic Noise Limiting (ANL)
circuit helps keep background noise
to a minimum. However, strong
sources of electrical noise (such as
your vehicle’s ignition, another radio,
or spark plugs) might be more than
the circuit can compensate for.
If you operate the TRC-499 with a ve-
hicle’s engine off, you should not
have any problems with noise. If you
use the CB with the engine on, you
can determine the source of the
noise by turning off the engine and
operating the CB with the ignition set
to ACC. If most or all of the noise
goes away, the problem is in your ve-
hicle’s ignition or electrical system.
Here are a few hints to help you re-
duce or eliminate such noise:
• Replace old ignition wires with
new, high-voltage, noise-sup-
pression wires.
• Install noise suppressors on
your spark plugs, or install new
spark plugs that have built-in
suppressors.
• Be sure that the ground connec-
tion (black wire) is secure.
If problems persist, check your alter-
nator/generator, regulator, and gaug-
es. Noise from these sources can be
reduced or eliminated using bypass
capacitors at various output voltage
points.
Your local Radio Shack store has a
wide selection of noise-suppression
accessories.
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