What is the purpose of the preselector in a communications receiver?

A preselector is an RF filter placed at the very front end of a communications receiver, before the first amplifier or mixer stages. Its primary job is to act as a band-pass filter, allowing desired signals through while attenuating strong out-of-band signals. By restricting the bandwidth of signals entering the receiver's front end, the preselector prevents strong out-of-band signals from overloading the RF amplifier or mixer. This significantly reduces the likelihood of front-end overload, desensitization, and intermodulation. Distractors mentioning broadband attenuation or storing frequencies are incorrect. A preselector does not store frequencies in memory, and broadband attenuation reduces all signals equally, whereas a preselector selectively filters out unwanted frequencies.