Line amps
I've use a line amplifier before when we were first wiring our school for TV, figuring that it would help with signal level with all those long coax lines. As it turned out, the amplifier put out a signal so strong that it overloaded all the TVs to the point that their AVC circuits were worthless. Things were fine without the amp. So, before you invest in the amp, try out the system. Calculate out how many decibels your splitters are killing you. You probably have to insert a lot of them to kill the cable signal down enough that it affects reception.
Dean