What could be a symptom caused by a ground loop in your station’s audio connections?
You receive reports of “hum” on your station’s transmitted signal✓Correct answer
The SWR reading for one or more antennas is suddenly very high
An item of station equipment starts to draw excessive amounts of current
You receive reports of harmonic interference from your station
Explanation
A ground loop lets power line frequency current circulate through the shield of an audio cable, and the resulting voltage adds to the microphone signal. It is transmitted along with the speech, so the symptom is reports of hum on the outgoing signal.