BH3HYO The issue has since been resolved. Initially, the property management refused to cooperate, and we were forced to call the police. However, a surprising turn of events occurred: just as we were about to give up, the manager arrived in his car and asked us if it was a vehicle belonging to the city's radio control department. We confirmed that it was, and he then learned from us that someone had installed a hidden transmitter on the roof of our building. After the police arrived, we went up together to investigate. I provided them with the phone number and information for monitoring the device. Ultimately, the police decided to wait and see, but they were unable to find it. The next day, the police came back and removed the device, and the matter was resolved.