yesterday, I got about 10 minutes after booting my Mac Mini, and this happens on several occasions, without a reason, a radio transmitter through my integrated Mac Mini speaker. I don't know its origin ( no iTunes on, no Safari and even all network connections, including Wifi on Off). I closed all programs, the sound of the transmitter still there. What the hell was happening? This morning, it is until now, away.I( wonder where it came from. The transmitter is a well known radio station in my country.