Check for sources of FM interference. The FM antenna attached to the system may be picking up outside interference. To determine if this is the case, follow these guidelines:
What can I do to fix poor FM reception?
Check to see if the antenna is within 90 cm of any other electronic or electrical devices such as: televisions, cable boxes, wireless internet routers, dimmer switches, fluorescent/energy-saving lights, blinking seasonal lights, microwaves or similar appliances
Unplug any devices that are near the antenna to eliminate them as possible sources of interference
In some cases, interference can be introduced through the power source connection. Moving the power cable to a different outlet that is not tied to the same circuit as any of the previously mentioned lighting or electronics may help
Relocate the antenna. If this solves the problem, keep it as far away from the other devices and their power cables as possible (at least 90 cm feet)
Try another power outlet. The power outlet may be providing interference, hum, or intermittent or inconsistent voltage
Try moving the FM antenna slightly. If reception improves, continue to move the antenna in that direction. When reception starts to degrade, move the antenna slightly in the opposite direction. Also, keep the antenna stretched out as much as possible. Signals from an FM station are "line-of-sight;" FM reception may be weaker if in a valley or near ground level in cities with tall buildings