Listen-only by design. The DF-04 never transmits. It reads the drone link that is already in the air, converts it into a bearing, and hands the operator a target list — which keeps the site radio-quiet and the operator undetectable while monitoring is underway.

DF-04 is built for electromagnetic environments that ordinary threshold detectors cannot handle: broadcast towers, rail corridors, port radar and dense Wi-Fi all raise the noise floor, and the SDR architecture keeps separating drone emissions from that clutter. DID and RID payloads decoded from the link are reported alongside the bearing, giving the operator an airframe identity next to the direction instead of a direction alone.

• Airport and stadium perimeters — bearing lines from a single unit already narrow the search sector, so patrol teams are dispatched by direction instead of by grid sweep.
• Power hubs, refineries and substations — passive sensing suits sites where an active emitter would be prohibited, and RID decoding separates registered inspection flights from unknown traffic.
• Event and convoy protection — multi-target tracking keeps several consumer drones in view during crowded low-altitude activity.
• Spectrum survey duty — the same receiver doubles as a monitoring node when no drone threat is present.

The DF-04 is produced by Chongqing Miao Yi Tang Technology Co., Ltd., a company established with a USD 12 million founding investment and built on cooperation with the IoT Research and Development Center of the Chinese Academy of Sciences and Sichuan University Zhisheng Software Co., Ltd. (002253). Its engineering work concentrates on AIoT cloud-plus-edge architectures that fuse electromagnetic, optoelectronic, visual and positional sensing into one intrusion picture for ground and low-altitude security.

Each unit ships with factory acceptance records and a band plan matching the buyer's electromagnetic survey. Our engineers stay reachable around the clock for troubleshooting, cover installation and commissioning either remotely or on site, and supply spare antenna and processing modules from stock. Custom band segmentation, RID output formats and integration into an existing command platform are quoted per project.

Technical parameters in this page are production values for the standard configuration; customized band segments and integration interfaces are confirmed at order review.