Common Mode Noise Filter – Coax Antenna Rotor RFI Solutions Store / Antenna Rotor RFI Solutions Antenna Rotor RFI Kit - fits all Wired Rotors up to 1/2" cable size Antenna Rotor RFI Kit - fits all Wired Rotors up to 1/2" cable size SKU RFI-Rotor $39.95 Buy Now Typical user comment: The filter was quite effective. Was surprised that it actually reduced the noise level more than the signal so S+N/N improved by 1.9 S units. Bill