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Science

The electromagnetic spectrum

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Radio waves

You should know some of the properties and uses of radio waves.

Television and radio

Radio waves have lower frequencies and longer wavelengths than microwaves. They are used to transmit television and radio programmes. Television uses higher frequencies than radio.

A radio programme receiver does not need to be directly in view of the transmitter to receive programme signals. For low frequency radio waves diffraction can allow them to be received behind hills, although repeater stations are often used to improve the quality of the signals.

The lowest frequency radio waves are also reflected from an electrically charged layer of the upper atmosphere, called the Ionosphere. This means that they can reach receivers that are not in the line of sight because of the curvature of the Earth's surface.

microwaves pass through the atmosphere, radio waves relected through a charged layer of the upper atmosphere, signal received even though transmitter and receiver are not in the line of sight

Microwaves and radio waves in the atmosphere

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