Common Mode Noise Filter – Coax 50:400 ohm (8:1) Transformers Store/Antenna Products/CUBE Impedance Transformers (<1:1, 1:1, >1:1)/50:400 ohm (8:1) Transformers 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