How to Make a Dipole Antenna

Radio transmission and reception of any variety requires an antenna to convert electrical currents from the transmitter into electromagnetic waves and vice versa. The type and dimensions of the required antenna are functions of the frequency of radio waves being transmitted or received. A dipole is one of the most basic types of radio antenna and is relatively easy to construct with basic materials and a modicum of knowledge of mechanical and electrical construction techniques, such as soldering. A dipole antenna can be used for nearly any radio purpose, including ham radio, television reception, Citizen's Band, marine radio, etc. The only difference between a dipole for one radio service and a dipole for another will be the dipole antenna's length.

As the name indicates, a dipole has two elements, which are usually constructed from copper wire. The wire may be insulated or uninsulated, but an important consideration is the mechanical strength of whatever gauge wire you choose to use. The two elements are separated by a piece of non-conductive material, known as an insulator. A feed line, which connects the antenna to the transmitter or receiver, is attached to the dipole's two elements at the insulator as well.

The first step in designing your antenna is to figure out the length of the dipole's two elements. As stated above, this is a function of the frequency of the radio service you are interested in using. Click here to see a chart listing the frequency ranges for common radio services. The total length of your dipole, to maximize its efficiency, must be calculated by the following formula: 468/frequency (in megahertz) = total dipole length in feet. You can use the aforementioned frequency chart along with the equation above to calculate how long your dipole should be from end to end (including both wire elements and the center insulator).