Thanks for the quick response.
The line going to the modem goes to the electrical box on the side of my house and feeds into this metal clip which immediately feeds into another line which goes up the side of the house. So it's not split, but I would assume that a line directly from the tap straight to the modem would be better.
So as for the premium channels, there's no box that can access the additional channels without a subscription?
I would check my modem's status but I'm not at home right now. About the signal to noise ratios, what are the determining factors for this? Additionally is there any differences between brands of coaxial cable?