Radio systems are communication systems that use radio waves to transmit and receive information. They consist of a transmitter, which sends out radio signals, and a receiver, which captures those signals. These systems are widely used in various applications, including broadcasting, two-way radios, and cellular networks. Radio waves are a type of electromagnetic radiation, and they can travel long distances, making them ideal for wireless communication. Different frequencies are used for different purposes, such as AM and FM radio for audio broadcasting, and microwave frequencies for data transmission in mobile phones and satellite communications.