Thanks for everyone's help. I opened up the TWC cable box and found multiple splitters. I replaced these with a single 8-way splitter. I mounted the pictured antenna in the attic and ran cable to the splitter. In the room closest to the splitter I am able to pick up all major networks (some slightly broken up), but am missing some in the other rooms of the house. All are able to pick up at least a few channels now. I am considering purchasing one of the following two products:
PCT Booster
or
Motorola Booster
If you have other suggestions, those would be great as well. Thanks again for the help.