Radio frequency systems and equipment not included in Regulation (EU) 2021/821, components and accessories, specially designed or modified to develop any of the following functions: a. Take control and command of unmanned aerial vehicles (UAVs); b. Deliberately and selectively interfere with, deny, inhibit, degrade or deceive radio frequency signals for the control and command of UAVs; c. Use the specific features of the radio frequency protocol used by UAVs to interfere with their operation. Technical Note : Such systems and equipment may include radio frequency jammers, protocol analysers, signal spoofers, takeover systems, directional antennas, software-defined radio (SDR) platforms, electronic warfare modules, and associated control software or firmware specifically adapted for counter-UAV applications.