[App_rpt-users] Another newbie question from Australia

Hi Everybody, I've finally got around to setting my transmit and receive audio levels today. It was straightforward and now things sound a whole lot better on transmit... except for this one strange thing... every now and then, and it appears to be random, transmitted audio seems to break into (for lack of a better description) a robotic cycon-style voice. It affects both incoming voice and also telemetry tones. My node is using a DMK URI and it's plugged into it's own USB socket. Any idea what is going on and where I should look to fix it? Michael. VK5ZEA