Shortwave radio refers to radio broadcasts on a portion of the radio spectrum in the frequency range of 3,000–30,000 kHz (3–30 MHz). Because smaller wavelengths correspond to higher frequencies (given the inverse relationship between frequency and wavelength), shortwave radio received its name because its wavelengths are shorter than the longer wavelengths used in early radio communications. A longer wavelength example is the medium wave AM broadcast band: 1 MHz = 300 meters. An example of shortwave would be 10 MHz which is 30 meters.