Physics 1G- Wireless Signals

Physics 1G- Wireless Signals

1. Radiation for communication

   • Can be reflected by the atmosphere allowing broadcasts to be watched in different countries
   • Radio stations and nearby broadcasters must transmit using different frequencies to avoid interference
   • Wireless technology is used (wireless internet)
     • Advantages
       • No landline required
       • Portable and convient, allowing access everywhere
     • Disadvantages
       • Aerial needed for signal

2. Transmitting signals

   • Satellites
     • Can be used for global communication
     • Signal sent from ground station transmitter dish to a satellite receiver dish
       • A return signal is then sent by the satellite transmitter to a ground receiver dish, which may be in a different country/ continent
   • Ionosphere
     • Electrically charged layer in Earth's upper atmosphere
     • Longer wavelengths are reflected by it
       • This enables radio and television shows to be transmitted to different places
   • Refraction results in signal loss
     • The refraction means a change of direction of the signal

3. DAB radio

   • Digital Audio Broadcasting Radio
     • Receive Digital signals
   • Most able to reach old FM stations which use analogue
   • Advantages
     • More stations available
     • Less interference from other stations
   • Disadvantages
     • Audio quality not as good as FM broadcasts
     • Some areas cannot receive DAB signals
       • For example short wavelength signals can't diffract around hills