Low signal through cable tv, is usually poor connections, low quality cable or electrical noise, make sure the cable connections are tight, they screw together, use a high quality cable, and make sure the cable is away from any other electrical cable as best as you can. Also make sure the cable is as straight as it can be, i.e. dont coil it up as this produces its own aerial effect pulling it away from the tv/box
Will, August 2009