First you need to see what kind of splitter you bought. Some have very large built in losses. Second make sure your connectors are good. It sounds almost like one of the grounds isnt made correctly. As for a powered amp I am using one with 8 outputs. I have a splitter ahead of it so that my cable modem signal doesnt go thru it. From the 8 way splitter it is about 100 feet to my Tivo. I also have a Comcast DVR sitting next to the Tivo. It also has it's own feed from the 8 way splitter. I dont have any problems with pixielization. When I originally did the jpb I ran three Rg 6 quads and three cat5 cables to the Tivo location.