I'm a pilot and we have a comm setup that I need some help with because of noise. We have a USB cable that supplies power to one of our GoPro cameras mounted in the cockpit. When this cable is plugged into the Apple USB adapter (or any 110 USB adapter for USB A (male) to USB mini, we get a lot of "hum/noise" in the audio. When we disconnect the USB from power, it's a clean recording.
A link to the noise and video is here, if anyone would be willing to offer their opinion. We have tried USB shielded cables and ferrite filters that go around the cable. No luck. While we don't have to have the cable plugged in for power and the camera is designed to run on battery, we would like to see if we can filter out this noise. We are not sure if it's something in the camera or if it's the line picking up noise.