I recently received a Sentry ZX100 Wireless Headset from a friend and got everything to work just fine. Except, when there is no audio input there is a static noise coming from the headset. It isn't loud, but it's audible enough to be annoying. And, when I turn my head to look at my secondary monitor, it gets louder and sometimes there is is a loud beeping. What can I do to fix this. I have the transmitter hidden behind the monitor.