RF signals don’t appear in logs. They pass through walls, bypass controls, and leave no trace. This article shows how RF activity can be detected and analysed outside of traditional security controls using a GNU Radio setup with a HackRF One. Most organisations monitor their networks extensively. Firewalls, SIEM platforms, EDR tools and intrusion detection systems continuously observe the digital perimeter. However, one attack surface is rarely monitored: the radio frequency spectrum inside the physical environment. A compromised device transmitting over RF, a covert hardware implant beaconing on a schedule, or a receiver positioned just outside a facility will not appear in traditional monitoring systems. If RF is not being monitored, there is a blind spot.…