Common Mode Noise Filter – Coax 50:112 ohm (2.25:1) Transformer Store/Antenna Products/CUBE Impedance Transformers (<1:1, 1:1, >1:1)/50:112 ohm (2.25:1) Transformer 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