masthead amplifiers generally need a power injector which might have coax in coax out and a port for power. The amp is on the mast.

Other amplifiers may just need a power source and are not remotely mounted.

I'm currently using a channel master CM-7777 at the mast with an 18db amp in the attic with an attenuator, so 0-18db. i think the CM-7777 is defective. For distribution to about 12 locations I was using a 30-45db amplifier until it went south. Currently distributing the signal to two locations.