Common Mode Noise Filter – Coax +3 UHF Female to BNC Male - PL-259 to BNC Adapter - Elecraft UHFFBNCM $3.95 In stock Quantity: 1 Add to Bag Product Details MPN: UHFMBNCF Save this product for later Favorite 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