Radio Waves are of Two Types
Radio Waves are of Two Types | Reason for Sounds Coming from Radio When It Is Not Tuned
Radio waves are the electromagnetic waves. They are shown on radio as Medium wave (M.W) and Short Wave (S.W). Some radio stations will run programs in these two bands. Short Wave radiations travel longer distances by oscillating up and down like a rubber ball between the Earth and central Ionosphere in the climate. These radiations are extremely powerful. So they can travel longer distances. But in the case of Medium Wave radiations, they travel close to the Earth’s surface. They lose their energy after traveling certain distance as they are not powerful. Thus, they cannot travel long distances. For that reason, live programs are broadcasted using transmission process involving Short Wave radiations only.
Sometimes, if the radio is already tuned to a frequency of nearest radio station, then programs will be heard as soon as the radio is turned on. But if the radio is not tuned to any radio station, then hiss like noise comes after switching on the radio. Reason behind it is the absorption of powerful radio waves expanded all over the surroundings by the antenna of the radio. Antenna of the radio then absorbs the radiations not from any radio station but absorbs the radio waves emitted by Stars, planets, black holes and other astronomical bodies. By absorbing those radio waves, hiss or kichh like sounds comes from the radio. Noise comes until the radio is tuned finely to a nearest radio station.