Track down alternator whine, LED interference, charger noise and RF feedback.
Describe the noise
A high-pitched tone that changes with engine speed suggests a different source than bursts of electrical noise from an LED driver. Compare engine off/on, accessories off/on, and separate power sources if safe.
Isolation test sequence
Record the conditions, turn off one nearby electrical device at a time, and compare the result. If safe, isolate whether interference enters through the antenna path or the radio power line. Never defeat a safety ground or open live electrical equipment.
- Check chargers, inverters and LED lighting
- Keep coax and power lines separated where practical
- Use ferrites or filtering appropriate to the source, not as a substitute for repairs
RF feedback in transmitted audio
A strong RF field can enter microphones, accessories or nearby electronics. Check coax and antenna grounding, cable routing and properly assembled connectors. If necessary, consult a technician.