[rabbit73]

First try a preamp at the antenna like an Antennas Direct Juice or a Channel Master 7778 with the power inserter in the basement. See how it does with one TV. Then add a passive 4-way splitter for more than one TV. It is also possible to use two 2-way splitters in cascade, which will allow more signal for one long run when you have 3 TVs.

If the signals are too weak after splitting, replace the splitter with a CM3414.

If you still can't get what you want with the antenna in the attic, try outside with no trees or buildings in the signal path.