I know people are going out looking for the drones at these bases in the UK. Quick reminder, without lights on they are very hard to spot, especially from a distance. Counter-UAS (C-UAS) systems primarily rely on passive detection of the radio frequency energy the drones emit (if they emit), but the more advanced suites include radars (often in Ku-band) to spot them even if they are operating without emitting. These active and passive sensors work together to better detect and classify the object. They also allow for critical intelligence to be collected on them. EO/IR systems are also almost always part of the C-UAS suite so that visual ID can be made. They can also help search and detect drones as well. The radar systems have short range and the passive detection systems can also be limited in range, especially if the drone flies low and amongst ground clutter. This makes it hard to track where they are launched and recovered from without physically tracking them in a vehicle. A bad actor well versed in these basic capabilities would design their drone operations plan to exploit common C-UAS suite limitations.