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14 terms

Extra Exam - E4E

STUDY
PLAY
A
E4E01 Which of the following types of receiver noise can often be reduced by use of a receiver noise blanker? / A. Ignition Noise / B. Broadband "white" noise / C. Heterodyne interference / D. All of these choices are correct
D
E4E02 Which of the following types of receiver noise can often be reduced with a DSP noise filter? / A. Broadband "white" noise / B. Ignition noise / C. Power line noise / D. All of these choices are correct
B
E4E03 Which of the following signals might a receiver noise blanker be able to remove from desired signals? / A. Signals which are constant at all IF levels / B. Signals which appear correlated across a wide bandwidth / C. Signals which appear at one IF but not another / D. Signals which have a sharply peaked frequency distribution
D
E4E04 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 line with the alternator leads
B
E4E05 How can noise from an electric motor be suppressed? / A. By installing a ferrite bead on the AC line used to power the motor / B. By installing a brute-force AC-line filter in series with the motor leads / C. By installing a bypass capacitor in series with the motor leads / D. By using a ground-fault current interrupter in the circuit used to power the motor
B
E4E06 What is a major cause of atmospheric static? / A. Solar radio frequency emissions / B. Thunderstorms / C. Geomagnetic storms / D. Meteor showers
C
E4E07 How can you determine if line-noise interference is being generated within your home? / A. By checking the power-line voltage with a time-domain reflectometer / B. By observing the AC power line waveform with an oscilloscope / C. By turning off the AC power line main circuit breaker and listening on a battery-operated radio / D. By observing the AC power line voltage with a spectrum analyzer
A
E4E08 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 power line frequency / D. Harmonics of the AC power line frequency
C
E4E09 What undesirable effect can occur when using an IF type noise blanker? / A. Received audio in the speech range might have an echo effect / B. The audio frequency bandwidth of the received signal might be compressed / C. Nearby signals may appear to be excessively wide even if they meet emission standards / D. FM signals can no longer be demodulated
D
E4E10 What is a common characteristic of interference caused by a "touch controlled" electrical device? / A. The interfering signal sounds like AC hum on an AM receiver or a carrier modulated by 60 Hz FM on a SSB or CW receiver / B. The interfering signal may drift slowly across the HF spectrum / C. The interfering signal can be several kHz in width and usually repeats at regular intervals across a HF band / D. All of these answers are correct
B
E4E11 What is the most likely cause if you are hearing combinations of local AM broadcast signals inside one or more of the MF or HF ham bands? / A. The broadcast station is transmitting an over-modulated signal / B. Nearby corroded metal joints are mixing and re-radiating the BC signals / C. You are receiving sky-wave signals from a distant station / D. Your station receiver IF amplifier stage is defective
A
E4E12 What is one disadvantage of using some automatic DSP notch-filters when attempting to copy CW signals? / A. The DSP filter can remove the desired signal at the same time as it removes interfering signals / B. Any nearby signal passing through the DSP system will always overwhelm the desired signal / C. Received CW signals will appear to be modulated at the DSP clock frequency / D. Ringing in the DSP filter will completely remove the spaces between the CW characters
D
E4E13 What might be the cause of a loud "roaring" or "buzzing" AC line type of interference that comes and goes at intervals? / A. Arcing contacts in a thermostatically controlled device / B. A defective doorbell or doorbell transformer inside a nearby residence / C. A malfunctioning illuminated advertising display / D. All of these answers are correct
C
E4E14 What is one type of electrical interference that might be caused by the operation of a nearby personal computer? / A. A loud AC hum in the audio output of your station receiver / B. A clicking noise at intervals of a few seconds / C. The appearance of unstable modulated or unmodulated signals at specific frequencies / D. A whining type noise that continually pulses off and on