An antenna captures electromagnetic waves and transforms them into electric current. If you want to listen to radio communications of fire and police departments or even air traffic control radio systems, a homemade antenna combined with a radio receiver capable of tuning in those frequencies can help you to do that. You can construct a UHF/VHF antenna from materials available at a hardware shop at a very low cost.
Use galvanised steel or aluminium for constructing the antenna's aerial tubing. These metals have good conductivity of electromagnetic waves. The other components required are coaxial wire, screws, insulation tape, a soldering gun and a wire cutter.
The antenna's aerial tubing should be constructed to form a half-wave dipole. Calculate the length of aerial tubing of the antenna by using the formula, I=486/f, where "f" is frequency in megahertz and "I" is dipole length. Connect both ends of a half-wave dipole shaped aerial tubing with one end of coaxial cable and the other end to the scanner radio.
The quality of the scanner antenna is subject to interferences from local broadcasting channels and such other communication channels as mobile phones