Well there's a problem you need to deal with. If you have the time and ability, start turning off breakers in your house so that the only thing on is the circuit that is feeding the Omni Pro II. If the noise is still there, then turn off the Omni branch, turn on a different branch and go plug in there and test.
We need to isolate what's causing your noise problems. By doing just the Omni, and then just one other branch, we can test if the noise is coming from outside your home, the Omni circuit, or a different circuit.
Noise on both tests - Coming from Outside
Noise on Omni but not on second test - Noise is on the Omni branch
No noise on Omni - it's something in your house that you will need to search for
If you get no noise with just the Omni on, start turning breakers back on until it reappears. That's the branch that has something misbehaving on it.