E4D Noise suppression: ignition noise;
alternator noise (whine);
electronic motor noise; static; line noise
E4D01
(A)
What is
one of the most significant problems associated with mobile transceivers?
A. Ignition noise
B. Doppler shift
C. Radar interference
D. Mechanical vibrations
E4D02
(A)
What is
the proper procedure for suppressing electrical noise in a mobile transceiver?
A. Apply shielding and
filtering where necessary
B. Insulate all plane sheet metal surfaces from
each other
C. Apply antistatic spray liberally to all
non-metallic surfaces
D. Install filter capacitors in series with all
DC wiring
E4D03
(C)
Where
can ferrite beads be installed to suppress ignition noise in a mobile
transceiver?
A. In the resistive high-voltage cable
B. Between the starter solenoid and the starter
motor
C. In the primary and
secondary ignition leads
D. In the antenna lead to the transceiver
E4D04
(C)
How can
ensuring good electrical contact between connecting metal surfaces in a vehicle
reduce ignition noise?
A. It reduces the frequency of the ignition
spark
B. It helps radiate the ignition noise away
from the vehicle
C. It encourages lower
frequency electrical resonances in the vehicle
D. It reduces static buildup on the vehicle
body
E4D05
(B)
How can
alternator whine be minimized?
A. By connecting the radio's power leads to the
battery by the longest possible path
B. By connecting the radio's
power leads to the battery by the shortest possible path
C. By installing a high-pass filter in series
with the radio's DC power lead to the vehicle's electrical system
D. By installing filter capacitors in series
with the DC power lead
E4D06
(D)
How can
conducted and radiated noise caused by an automobile alternator be suppressed?
A. By installing filter capacitors in series
with the DC power lead and by installing a blocking capacitor in the field lead
B. By connecting the radio to the battery by
the longest possible path and installing a blocking capacitor in both leads
C. By installing a high-pass filter in series
with the radio's power lead and a low-pass filter in parallel with the field
lead
D. By connecting the radio's
power leads directly to the battery and by installing coaxial capacitors in the
alternator leads
E4D07
(B)
How can
you reduce noise from an electric motor?
A. Install a ferrite bead on the AC line used
to power the motor
B. Install a brute-force,
AC-line filter in series with the motor leads
C. Install a bypass capacitor in series with
the motor leads
D. Use a ground-fault current interrupter in
the circuit used to power the motor
E4D08
(B)
What is
a major cause of atmospheric static?
A. Sunspots
B. Thunderstorms
C. Airplanes
D. Meteor showers
E4D09
(C)
How can
you determine if a line-noise interference problem is being generated within
your home?
A. Check the power-line voltage with a
time-domain reflectometer
B. Observe the AC waveform on an oscilloscope
C. Turn off the main circuit
breaker and listen on a battery-operated radio
D. Observe the power-line voltage on a spectrum
analyzer
E4D10
(A)
What
type of signal is picked up by electrical wiring near a radio transmitter?
A. A common-mode signal at
the frequency of the radio transmitter
B. An electrical-sparking signal
C. A differential-mode signal at the AC-line
frequency
D. Harmonics of the AC-line frequency
E4D11
(B)
What
type of equipment cannot be used to locate power line noise?
A. An AM receiver with a directional antenna
B. An FM receiver with a
directional antenna
C. A hand-held RF sniffer
D. An ultrasonic transducer, amplifier and
parabolic reflector