10-2-2. Noise reduction
In motor vehicles, noise is generated by the ignition system. Other sources of noise include the wiper and
heater motors.
Although the transceiver is equipped with a noise blanker to minimize ignition noise, it is imperative that some preventiye measures be taken to reduce the noise to the lowest possible level.
( 1) Antenna location selection
Since ignition noise is generated by the vehicles en gine, the antenna must be installed as far from the en gine as possible.
(2)Bonding
The component parts of motor vehicles, such as the engine, transmission, muffler system, accelerator, etc., are coupled to one another at DC and low frequencies, but are isolated at high frequencies. By connecting these parts using heavy, braided ground straps, igni- tion noise can be reduced. This connection is called
"bonding".
(3) Use ignition suppressor cable or suppressor spark
plugs
Noise can be reduced by using spark plugs with inter- nal resistors, or resistive suppressor ignition cable.
The power system of a motor vehicle is comprised of a battery and an alternator (which generates power while the engine is running) to supply current to loads or to charge the battery.
Since the transceiver draws high current during trans- mit, care should be exercised so the power system is not overloaded. When using the transciever, the fol- lowing points should be observed from the viewpont of battery maintenance:
1.Turn the transceiver OFF when the lights, heater, wipers and other
2.Avoid transceiver operation when the engine is not running.
3.If necessary. use an ammeter and/or a voltmeter
to check battery condition.
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