Deep Dive: G4C10
The correct answer is A: You receive reports of 'hum' on your station's transmitted signal. A symptom caused by a ground loop in your station's audio connections is that you receive reports of 'hum' on your station's transmitted signal. Ground loops can cause 60 Hz (or 50 Hz) hum that gets into your audio and is transmitted. For amateur radio operators, this is a common ground loop symptom. Understanding this helps identify ground loop problems.
Why Other Answers Are Wrong
Option B: Incorrect. Ground loops don't cause high SWR - SWR is about antenna matching, not ground loops. High SWR is a different problem. Option C: Incorrect. Ground loops don't cause excessive current draw - that's a different problem. Excessive current isn't a ground loop symptom. Option D: Incorrect. Ground loops don't cause harmonic interference - harmonics come from non-linear operation, not ground loops. Harmonics are different.
Exam Tip
Ground loop symptom = hum on transmitted signal. Think 'G'round 'L'oop = 'G'enerates 'L'ow-frequency hum (60 Hz). Ground loops cause 60 Hz hum that gets into audio and is transmitted. Not high SWR, not excessive current, not harmonics - just hum.
Memory Aid
Ground loop symptom = hum on transmitted signal. Think 'G'round 'L'oop = 'G'enerates 'L'ow-frequency hum. Ground loops cause 60 Hz hum that gets into audio and is transmitted. Characteristic ground loop symptom.
Real-World Example
You have a ground loop in your station's audio connections. Other operators report hearing 60 Hz hum on your transmitted signal. The ground loop causes the hum to get into your audio chain and be transmitted. Fixing the ground loop eliminates the hum.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G4C
Reference: 2023-2027 Question Pool · G4 - Amateur Radio Practices
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G4C topic.