HF Radio, or High Frequency Radio, refers to a range of radio frequencies from 3 to 30 megahertz. It is commonly used for long-distance communication because it can reflect off the ionosphere, allowing signals to travel beyond the horizon. This makes it ideal for maritime, aviation, and amateur radio operators. HF Radio is often utilized in situations where other forms of communication may be unreliable, such as during emergencies or in remote areas. It requires specific equipment, including antennas and transceivers, to effectively transmit and receive signals over vast distances.