Radio waves are widely used in broadcasting to transmit audio and video signals over long distances. Here’s how they are used:
1. Modulation of Information
- Audio (for radio) or video and audio (for television) signals are first converted into electrical signals.
- These signals modulate a carrier radio wave — either by amplitude (AM), frequency (FM), or digital modulation (like DAB or DVB for digital broadcasts).
2. Transmission via Antennas
- The modulated signal is then transmitted through an antenna as electromagnetic radio waves.
- These waves travel through the air and can reach receivers miles away, depending on frequency, power, and terrain.
3. Reception by Devices
- A radio or TV receiver has an antenna that captures the incoming radio waves.
- The device then demodulates the signal to retrieve the original sound or video content.
4. Frequency Bands
- AM broadcasting typically uses the medium frequency (MF) band.
- FM radio operates in the very high frequency (VHF) range.
- Television broadcasts use both VHF and ultra high frequency (UHF) bands.