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