A system uses a large loop antenna, connected with a transceiver operating below 1 MHz. The loop antenna is deployed from a spool to surround a crime scene, and may carry indicia communicating that it is a crime scene boundary. The system interrogates devices, including evidence bags and badged personnel, as they enter and leave the scene. The system can optionally log the time of salient events. A second loop antenna can log evidence bags as they enter a vehicle. The devices can be silenced by the transceiver and thus collisions can be reduced and avoided among responses from devices. The system performs “area reads” that would not be possible if higher RF frequencies were employed.