Amateur radio, also known as ham radio, is a hobby and service that brings people, electronics, and communication together. People use amateur radio to exchange messages, conduct experiments, and enjoy worldwide communication. Unlike commercial radio, amateur radio is operated by licensed amateurs for non-commercial purposes.

Amateur radio enthusiasts come from various backgrounds and use radio equipment to communicate with others over radio frequencies allocated to the amateur radio service. Operators must pass examinations that test their knowledge of electronics, radio theory, and radio regulations to obtain a license from their national communications authority. These licenses allow access to a wide range of frequencies and the ability to use different types of communication modes.

Amateur radio encompasses a variety of communication modes, including:
• Voice communication using frequency modulation (FM) or single sideband (SSB) modulation.
• Morse code (CW), which is still popular for its simplicity and efficiency.
• Digital modes, such as RTTY (Radio Teletype), PSK31 (Phase Shift Keying for efficient data communication), and FT8 (a recent digital mode designed for weak signal communication).
• Satellite communication, where hams communicate through amateur radio satellites.
• Television, using amateur television (ATV) broadcasts.

Radio amateurs engage in many different activities:
• Emergency and disaster communication: Amateur radio operators often volunteer for emergency communication services when conventional communication systems fail.
• Contests (Radiosport): Competitions to contact as many stations or specific geographic areas as possible within a given time frame.
• DXing: The pursuit of confirming contact with distant stations.
• Moonbounce (EME): Communicating by bouncing radio waves off the moon's surface.
• Radio direction finding (Fox hunting): A competitive form of orienteering and a way to locate sources of interference or unauthorized transmissions.

Amateur radio fosters a global community of friends who share a passion for communication and technology. It also serves as an educational platform, teaching electronics, physics, and operational skills. The hobby is regulated internationally by the International Telecommunication Union (ITU) and nationally by each country's communications authority. The hobby and service of amateur radio aim to advance skills in the technical and communication realms and enhance international goodwill.