The SLx DVB-T Signal Finder is a great tool for getting the maximum Freeview signal strength.
The Freeview signal finder is very simple to use too, just connect the Freeview Signal Finder to the aerial output and align the aerial until you have the strongest signal indicated. The indicators are LEDs on the front of the unit.
Powered by one 9V PP9 battery. Comes with a f-plug to coaxial plug adapter and a jumper cable.