Comcast cable comes up out of the ground at the corner of the house. before it goes up to the attic, the cable modum is split off. Previous home owner had every room but kitchen and dining room set up with a cable outlet. Once in the attic the cable goes who-knows-where and may split off as it goes along the attic. I dont believe there is one master splitter with each tv's cable running from it. the cable comes out of the attic at the other end of the house, runs along the roof line to the back addition, along the rain gutter, down the corner, in thru the siding to a cable outlet on the inside of the addition. Approx. 30' of cable then runs to the last tv in the line. reception on all the other tv's is fine, but this tv gets a slighty snowy picture. Bought a Radio Shack in-line amp (with DC blocker) that comes with a in-line (plug-in)booster. When I attached the amp to the first outside splitter (modum/tv) all I get is heavy snow on all the tv's. I get the feeling this is not the device I need. Any thoughts? Thanks?