75 lines
3.7 KiB
Markdown
75 lines
3.7 KiB
Markdown
G4C – Interference to consumer electronics; grounding and bonding
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- [[G4C01]] (B)
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Which of the following might be useful in reducing RF interference to audio frequency circuits? #card
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- A. Bypass inductor
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- B. Bypass capacitor
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- C. Forward-biased diode
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- D. Reverse-biased diode
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- [[G4C02]] (C)
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Which of the following could be a cause of interference covering a wide range of frequencies? #card
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- A. Not using a balun or line isolator to feed balanced antennas
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- B. Lack of rectification of the transmitter’s signal in power conductors
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- C. Arcing at a poor electrical connection
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- D. Using a balun to feed an unbalanced antenna
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- [[G4C03]] (C)
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What sound is heard from an audio device experiencing RF interference from a single sideband phone transmitter? #card
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- A. A steady hum whenever the transmitter is on the air
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- B. On-and-off humming or clicking
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- C. Distorted speech
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- D. Clearly audible speech
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- [[G4C04]] (A)
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What sound is heard from an audio device experiencing RF interference from a CW transmitter? #card
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- A. On-and-off humming or clicking
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- B. A CW signal at a nearly pure audio frequency
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- C. A chirpy CW signal
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- D. Severely distorted audio
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- [[G4C05]] (D)
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What is a possible cause of high voltages that produce RF burns? #card
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- A. Flat braid rather than round wire has been used for the ground wire
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- B. Insulated wire has been used for the ground wire
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- C. The ground rod is resonant
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- D. The ground wire has high impedance on that frequency
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- [[G4C06]] (C)
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What is a possible effect of a resonant ground connection? #card
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- A. Overheating of ground straps
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- B. Corrosion of the ground rod
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- C. High RF voltages on the enclosures of station equipment
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- D. A ground loop
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- [[G4C07]] (A)
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Why should soldered joints not be used in lightning protection ground connections? #card
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- A. A soldered joint will likely be destroyed by the heat of a lightning strike
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- B. Solder flux will prevent a low conductivity connection
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- C. Solder has too high a dielectric constant to provide adequate lightning protection
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- D. All these choices are correct
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- [[G4C08]] (A)
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Which of the following would reduce RF interference caused by common-mode current on an audio cable? #card
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- A. Place a ferrite choke on the cable
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- B. Connect the center conductor to the shield of all cables to short circuit the RFI signal
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- C. Ground the center conductor of the audio cable causing the interference
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- D. Add an additional insulating jacket to the cable
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- [[G4C09]] (D)
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How can the effects of ground loops be minimized? #card
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- A. Connect all ground conductors in series
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- B. Connect the AC neutral conductor to the ground wire
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- C. Avoid using lock washers and star washers when making ground connections
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- D. Bond equipment enclosures together
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- [[G4C10]] (A)
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What could be a symptom caused by a ground loop in your station’s audio connections? #card
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- A. You receive reports of “hum” on your station’s transmitted signal
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- B. The SWR reading for one or more antennas is suddenly very high
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- C. An item of station equipment starts to draw excessive amounts of current
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- D. You receive reports of harmonic interference from your station
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- [[G4C11]] (C)
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What technique helps to minimize RF “hot spots” in an amateur station? #card
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- A. Building all equipment in a metal enclosure
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- B. Using surge suppressor power outlets
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- C. Bonding all equipment enclosures together
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- D. Placing low-pass filters on all feed lines
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- [[G4C12]] (D)
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Why must all metal enclosures of station equipment be grounded? #card
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- A. It prevents a blown fuse in the event of an internal short circuit
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- B. It prevents signal overload
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- C. It ensures that the neutral wire is grounded
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- D. It ensures that hazardous voltages cannot appear on the chassis
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