Radio system, vehicle including same and method of setting radio frequency

A method of operation a radio system, the method comprising:

• storing, by a control device of the radio system, a first radio frequency of an audio device as a preset frequency;
• determining, by the control device, whether a second broadcast signal received through a second radio frequency is equal to a first broadcast signal received through the first radio frequency stored in a preset list in response that the second radio frequency of the audio device is added as the preset frequency;
• generating, by the control device, the preset list including the first radio frequency and the second radio frequency in response that the first broadcast signal is different from the second broadcast signal;
• generating, by the control device, the preset list including the first radio frequency or the second radio frequency in response that the first broadcast signal and the second broadcast signal are broadcast signals of a same radio broadcast;
• selecting, by the control device, the second radio frequency corresponding to the second broadcast signal having a reception sensitivity higher than or equal to a reference sensitivity while changing the first radio frequency at a predetermined interval;
• and
• adding, by the control device, the selected second radio frequency as the preset frequency.