Bandpass filters or frequency channel filters solve the "near far" problem (see diagram at any listing below). Without filtering, boosters will react to the strongest detected tower signal. Boosters will consequently reduce their gain, in accordance with FCC rules. With filtering irrelevant carrier tower signals, consumer or commercial booster kits will optimize signal from relevant cell tower to maximum allowed increase in gain. Channelized filters allow enterprises to highly target booster amplification for carriers and bands that need the signal improvement.