*Question G4C10:
What could be a symptom caused by a ground loop in your station’s audio connections?*  

*Correct Answer is  A: You receive reports of “hum” on your station’s transmitted signal*  

### AI Response: (may contain errors)  

A ground loop in your station’s audio connections can lead to unwanted noise, often described as a "hum." This occurs when there are multiple grounding points in your audio system, creating a loop that can pick up electromagnetic interference (EMI) from nearby electrical devices or power lines.

### Explanation of the Correct Answer:
- **Correct Answer: A: You receive reports of “hum” on your station’s transmitted signal.**
  - Ground loops can introduce a 60 Hz hum (or 50 Hz in some regions) into your audio signal. This is due to the alternating current (AC) frequency of the electrical power supply, which can couple into the audio lines through the ground loop. This hum is often noticeable in transmitted audio, leading to reports from listeners.

### Explanation of the Incorrect Answers:
- **B: The SWR reading for one or more antennas is suddenly very high.**
  - A high Standing Wave Ratio (SWR) typically indicates issues with the antenna system, such as a mismatch between the antenna and the transmission line or physical damage to the antenna. This is not related to audio connections or ground loops.

- **C: An item of station equipment starts to draw excessive amounts of current.**
  - Excessive current draw is usually a sign of a malfunctioning device or a short circuit, not a ground loop. Ground loops affect audio quality rather than the power consumption of equipment.

- **D: You receive reports of harmonic interference from your station.**
  - Harmonic interference is related to the transmission frequency and the non-linear operation of transmitters. It is not caused by ground loops, which primarily affect audio signals rather than the fundamental frequency of the transmitted signal.

### Summary:
Ground loops primarily introduce noise (hum) into audio signals, making option A the correct choice. The other options relate to different issues in the station's operation and are not symptoms of ground loops. 

### Useful Rule of Thumb:
To minimize ground loops:
- Use a single point ground for all equipment.
- Isolate audio connections with transformers or use balanced audio lines to reduce noise pickup.