A satellite finder is a specialized signal-strength meter used to point satellite dishes and LNBs.
There are two general classes of satellite finders: analog and digital satellite finders.
Analog Satellite Finder
Most analog satellite finders are inexpensive devices which simply display the strength of the received signal.
To use an analog satellite finder, you point the satellite dish and LNB to where you believe the satellite to be. You then take a reading on the satellite finder and adjust the satellite dish and LNB until you get the strongest reading possible.
Digital Satellite Finder
A digital satellite finder is a significantly more expensive signal strength meter. Digital satellite finders are pre-programmed with the locations of commonly used satellites. With an analog signal finder, you can only know that you have found a satellite. With a digital satellite finder, you can know which satellite you have found.