How Does the Antenna on a Radio Work?
The wire antenna in a radio picks up radio waves sent out through the air by broadcasting stations. These waves create weak electrical signals in the antenna. An amplifier in the radio strengthens the signals, sending them to the loudspeaker, and we hear the program being broadcast. A radio antenna picks up radio waves from many different stations at the same time. Each station broadcasts on a different wavelength (the distance between the waves). By turning the tuner knob, we can select the station we want to listen to.
An antenna, or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna’s terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals that is applied to a receiver to be amplified.
Antennas are essential components of all equipment that uses radio. They are used in systems such as radio broadcasting, broadcast television, two-way radio, communications receivers, radar, cell phones, and satellite communications, as well as other devices such as garage door openers, wireless microphones, Bluetooth-enabled devices, wireless computer networks, baby monitors, and RFID tags on merchandise.