The receiver front end is the first stage of a radio receiver, before decoding, demodulation, or digital processing. It accepts incoming RF energy and shapes it for later stages, usually with components such as filters, amplifiers, and protection circuits. Because it sees the raw signal first, it also sets the practical limits for sensitivity, selectivity, and dynamic range.
In cyber security, the front end matters because many attacks target the physical layer rather than the protocol layer. A strong nearby transmitter, intentional jammer, or other out-of-band energy can overload this stage, causing desensitization, clipping, or loss of valid packets even when the attacker is not on the target frequency. Defenses often start here too: bandpass filters, shielding, careful antenna placement, and gain control help keep unwanted RF energy out of the receiver and preserve reliable monitoring or communications.