Building a Radio Community Across Students, Industry and Enthusiasts with Capture the Flag

We present a communications-themed Capture the Flag (CTF) tournament, featuring both virtual and in-person formats. In the virtual edition we post online several challenges containing a signal recording and an accompanying story. Registered teams analyze the signal and try to unveil a hidden message, which upon submission earns them points. The in-person variant is a treasure hunt, where hints are provided by signals obtained from any smartphone; e.g. bluetooth or audio. We share pivotal lessons learned in our four years' experience and highlight the role of these recreational activities in fostering community engagement and promoting the dissemination of the discipline.