Masthead amplifiers are designed to amplify the aerial signal before any loss occurs due to cable runs. Ideally they are installed on the same mast as the aerial, approximately 1 meter from the actual aerial. They can however be used further down the cable, in lofts etc. as long as the signal is good enough to handle a bit of cable attenuation. The masthead amplifier is powered remotely via the aerial cable by means of an inline plug in power supply unit, PSU.
Masthead amplifiers come in a number of formats including 1 way, up to 8 way, low gain/amplification, high gain, variable gain, TV & Radio Combiners and amplifiers.
The PSU can usually be connected to any one of the outputs of the masthead amplifiers and is usually fitted inline next to one of the TVs. They run on very little power, approx. 8volts and have short circuit protection in them to avoid any problems.