Communicating With Electromagnetic Waves

How do antennas transmit and receive signals?

Antennas for radio and television signals are used to either transmit or receive electromagnetic radio waves. Oscillating voltages produced by the transmitter cause the electrons in a metal wire or rod, the transmitting antenna, to oscillate, creating an oscillating electric field that in turn creates an oscillating magnetic field that creates another oscillating electric field. The combined electric and magnetic wave moves away from the antenna at the speed of light. A receiving antenna is a metal rod, wire, or a loop. When an electromagnetic wave strikes the antenna it causes the electrons in the metal to oscillate at the same frequency as that of the wave. The oscillating electrons produce a voltage in the receiver that eventually results in the sounds and/or pictures produced by a radio or television.


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