# Radio Wave Transmission ## What are Radio Waves Radio waves are a form of electromagnetic radiation with frequencies ranging from about 3 kilohertz to 300 gigahertz. In the context of computer networking and telecommunications, radio waves are used as the transmission medium for wireless communication. Radio waves can travel through the air and even through some solid materials, making them suitable for communication where running cables is impractical or impossible. Radio waves are used in WiFi networks, cellular telephone networks, Bluetooth, radio broadcasting, and many other wireless communication systems. ## Properties of Radio Waves Radio waves travel at the speed of light in a vacuum and close to the speed of light in air. The frequency of a radio wave determines its wavelength and its behavior. Lower frequency radio waves have longer wavelengths and can travel further and penetrate obstacles more effectively, but they carry less information per unit time. Higher frequency radio waves have shorter wavelengths, can carry more information, but have shorter range and are blocked more easily by obstacles. Radio waves can be reflected by metal surfaces, refracted by the atmosphere, and diffracted around obstacles. ## Radio Wave Frequency Bands The radio spectrum is divided into frequency bands that are allocated for specific uses. Very Low Frequency waves between 3 and 30 kilohertz can travel very long distances and are used for submarine communication. Medium Frequency waves between 300 kilohertz and 3 megahertz are used for AM radio broadcasting. High Frequency waves between 3 and 30 megahertz are used for shortwave radio that can bounce off the ionosphere and travel around the world. Very High Frequency between 30 and 300 megahertz is used for FM radio and television broadcasting. Ultra High Frequency between 300 megahertz and 3 gigahertz is used for television, cellular networks, and WiFi. Extremely High Frequency above 30 gigahertz is used for high-capacity point-to-point links and emerging 5G applications. ## Radio Waves in Computer Networking WiFi networks operate on radio waves in the 2.4 gigahertz and 5 gigahertz frequency bands. Cellular data networks use various frequency bands depending on the generation and operator. Bluetooth uses the 2.4 gigahertz band for short-range personal area network connections. RFID systems use radio waves for identification and tracking. The unlicensed frequency bands that WiFi and Bluetooth use can become congested in areas with many wireless devices, leading to interference and reduced performance. ## Advantages and Disadvantages Radio waves can pass through walls and other obstacles, allowing devices to communicate without line of sight. They can cover large areas from a single transmitter. They do not require physical cables. The main disadvantages are that radio waves are susceptible to interference from other wireless devices, atmospheric conditions, and physical obstacles. The available radio spectrum is a limited resource that must be managed to prevent interference between users. Radio waves are also relatively easy to intercept, requiring encryption to secure wireless communications.