I have a tone (approximately 1000 Hz) in the receive audio of my Omni V. It's very low level, but it's still annoying. I can remove it by setting the notch filter at the 12 O'clock position, but I'd prefer to remove this without depending on the notch. Is this a common problem on the Omni V. If not, then does anyone have a clue as to the likely source. <Alan>