An antenna (or aerial) is an electrical device which couples radio waves in free space to an electrical current used by a radio receiver or transmitter. In reception, the antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage that the radio receiver can amplify.
Alternatively, a radio transmitter will produce a large radio frequency current that may be applied to the terminals of the same antenna in order to convert it into an electromagnetic wave (radio wave) radiated into free space. Antennas are thus essential to the operation of all radio equipment, both transmitters and receivers. They are used in systems such as radio and television broadcasting, two-way radio, wireless LAN, mobile telephony, radar, and satellite communications.
Typically an antenna consists of an arrangement of metallic conductors (or "elements") with an electrical connection (often through a transmission line) to the receiver or transmitter. A current forced through such a conductor by a radio transmitter will create an alternating magnetic field according to Ampère's law.
Or the alternating magnetic field due to a distant radio transmitter will induce a voltage at the antenna terminals, according to Faraday's law, which is connected to the input of a receiver.
TV and FM Antenna Tips, Reception Help, Interference and Amplifier Guide, Beams/Yagis, Dipoles, J-Poles, Loops, Mobiles, Quads, Slopers, Trapped Antennas, Verticals, Other HF Antennas, VHF Antennas Loaded with antenna projects to choose from.
Lots of Antenna projects for every hobbyist, technician, student, and design professional. An nice reference tool which includes lots of Antenna projects. look at these project ideas, some of them may need some modification if they are to work as advertised. Ideas along with pretty good descriptions for each project.