There are preamps and "distribution amplifiers" which are made to boost TV antenna signals, when there is signal loss due to the signal being sent to multiple televisions. They probably should work for you also? They probably make them for satellite also (probably the same/similar). They come in 75 ohm models so they should work fine for regular and digital 75 ohm cable TV (regular old type TV signals are 300 ohm).
I use a distribution amplifier with good results, though not for the same reason you state.
Check out this website and give them a call.
http://www.starkelectronic.com/
http://www.starkelectronic.com/allamps.htm