A quad LNB gives you 4 independent LNB feeds which can receive switching signals from 4 digital tuners and allows the full range of tuning options to be used. These being Horizontal, Vertical, High Band and Low Band. The LNB outputs are switched by the satellite receiver, with a 22Hz tone and a switching voltage which makes it like a universal LNB with four outputs. A quad LNB is ideal where a maximum of four satellite feeds is required and there is not much possibility of expansion.