RF margin is the extra signal strength a radio link has above the minimum level needed to work reliably. It is usually expressed as headroom in a link budget: the more margin a system has, the better it can tolerate distance, obstacles, antenna mismatch, noise, or fading before packets start to drop.
In cyber security, RF margin matters because many critical systems depend on wireless links, including drones, industrial controllers, alarms, and IoT devices. A link with poor margin is easier to disrupt with interference or intentional jamming, and it may fail under normal environmental stress. Defenders improve RF margin by using better antennas, cleaner placement, appropriate transmit power, lower-noise receivers, and conservative modulation or packet settings. Attackers often target the weakest point in the RF chain, so understanding margin helps operators judge whether a link is robust or only barely connected.