A transmission using shortwave radio frequency is one that transmits radio signals within a narrow range. This includes the entire frequency band. Shortwave radio's advantage is its ability to travel long distances and allow for easy listening to international broadcasts. On the other side, longwave radio is transmissions that use longwave radio frequencies. These radio frequencies are usually lower than the AM frequency, so they cannot be accessed by normal AM/FM radios. The longwave radio bands travel along the Earth's contours and are therefore not affected by large mountains or other geographical disturbances. Longwave radio can also be used to listen to foreign broadcasts that are not easily heard.