Question
Which of the following could be a cause of interference covering a wide range of frequencies?
Answer Options
- 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
Correct Answer: C
Explanation
Radio Frequency Interference (RFI) that covers a wide spectrum of frequencies is typically generated by a non-linear process that creates many harmonics. One of the most common sources of this type of interference is arcing at a poor electrical connection (sometimes called ‘dirty electricity’ or ‘power line noise’).
When a spark or arc occurs across a loose or corroded connection (e.g., rusty power pole hardware, poor splice), the rapid on/off nature of the discharge generates broadband noise across a very wide range of frequencies, often heard as a buzzing or scratching sound across the entire HF spectrum.
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