E4E01

Which of the following types of receiver noise can often be reduced by use of a receiver noise blanker?

  1. Ignition Noise

E4E02

Which of the following types of receiver noise can often be reduced with a DSP noise filter?

  1. A. Broadband “white” noise
  2. B. Ignition noise
  3. C. Power line noise
  4. D. All of these choices are correct

E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

  1. Signals which appear correlated across a wide bandwidth

E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

  1. By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

E4E05

How can noise from an electric motor be suppressed?

  1. By installing a brute-force AC-line filter in series with the motor leads

E4E06

What is a major cause of atmospheric static?

  1. Thunderstorms

E4E07

How can you determine if line-noise interference is being generated within your home?

  1. By turning off the AC power line main circuit breaker and listening on a battery-operated radio

E4E08

What type of signal is picked up by electrical wiring near a radio transmitter?

  1. A common-mode signal at the frequency of the radio transmitter

E4E09

What undesirable effect can occur when using an IF type noise blanker?

  1. Nearby signals may appear to be excessively wide even if they meet emission standards

E4E10

What is a common characteristic of interference caused by a "touch controlled" electrical device?

  1. 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
  2. B. The interfering signal may drift slowly across the HF spectrum
  3. C. The interfering signal can be several kHz in width and usually repeats at regular intervals across a HF band
  4. D. All of these answers are correct

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?

  1. Nearby corroded metal joints are mixing and re-radiating the BC signals

E4E12

What is one disadvantage of using some automatic DSP notch-filters when attempting to copy CW signals?

  1. The DSP filter can remove the desired signal at the same time as it removes interfering signals

E4E13

What might be the cause of a loud "roaring" or "buzzing" AC line type of interference that comes and goes at intervals?

  1. A. Arcing contacts in a thermostatically controlled device
  2. B. A defective doorbell or doorbell transformer inside a nearby residence
  3. C. A malfunctioning illuminated advertising display
  4. D. All of these answers are correct

E4E14

What is one type of electrical interference that might be caused by the operation of a nearby personal computer?

  1. The appearance of unstable modulated or unmodulated signals at specific frequencies

 

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