Cant get new cable modem to work w/splitter.Tried 3

Not unless you want to spend big money or they will give you one to use. A normal signal booster that you get for cable only boosts incoming signals. It does not support outgoing ones. They do make boosters that can handle both directions, but they are very expensive and not as easy to find.

I myself have one... but I deal with SHAW and they had no choice but to give me one. The place I was living had a faulty ground line that they could not get to for a number of months. The booster helped big time. When I moved I kept the thing... every time a tech looks at it I tell them if they touch it I break their fingers.... hehehehe. Since I am only able to use SHAW anyways... they really don't care if I still have it or not... they get paid.

It may also be a matter of how many splits have been made in the line. Each time the cable is split it drops anywhere from 3-8 db (usually marked on the good quality splitters). Split two or three times and you kill the signal. The only options for them if that's the case is to boost the signal coming into the house or installing a more dedicated line for the modem from the main house connection.

If they really are a decent company to go through, they should be fairly willing to have a tech come and check the signal strength at the modem itself. All they do is attach a little machine and read the rating. Once they have that number they can see what the options are.

So best bet is to call them and see about getting the tech in. That will also let them know if there are other issues that they need to be concerned about... like a faulty ground wire (like I had).