Using an AirTag on my dog's collar and WifiMan on my phone to track BLE signals, I could pick it up (just... not enough to interact with it, but enough to detec

Using an AirTag on my dog's collar and WifiMan on my phone to track BLE signals, I could pick it up (just... not enough to interact with it, but enough to detect it above -100dbM) about 8 - 10m with a clear line of sight, and about 2m when she was in dense scrub. So yeah, I imagine concrete is going to be even worse than a shrubbery, that said, might get some interesting propagation paths if there's metal surfaces in the rubble to reflect waves.