Ham radio, or amateur radio, is a licensed form of radio communication used for experimentation, learning, and non-commercial contact between operators. It often involves VHF, HF, repeaters, and home-built or modified equipment, which makes it a popular field for testing antennas, radios, and digital modes.
In cyber security, ham radio matters because it sits at the boundary between software, hardware, and the physical world. Modern setups may use computers, sound cards, or web-based control interfaces to key a transmitter, change frequency, or manage logging. That creates a larger trust boundary: if the software layer is misconfigured or compromised, an attacker may influence real-world transmissions. Defenders also use ham radio as a resilient backup channel for emergency communication, where simple, offline, and local controls reduce dependence on internet services.