How to Set Up Amateur Dipole Antennas

Determine the length of the antenna with this formula. One wavelength is equal to the speed of light divided by the frequency. For instance, the wavelength of a 28.4MHz signal is 10.56 meters. Divide the speed of light in meters per second by the frequency in Hertz to obtain the wavelength. A dipole antenna is half the wavelength, so the theoretical antenna should be 5.28 meters long. In practice, the antenna will be shorter due to the velocity loss when a radio signal travels through a solid material. The velocity factor is usually a 5 percent loss, so the antenna will probably be about 5.02 meters long.

Cut the wire to the approximate wavelength, but be sure it's longer than the calculations. Cut it in half at the mid-point and join the two pieces with an antenna insulator. Put an antenna insulator on each end, and attach a rope or stout cord to the opposite ends of the insulators. The rope serves two purposes: it supports the wire antenna and it keeps the antenna away from any supporting structures.

Solder the feed line to the antenna midpoint, splitting the feed line on opposite ends of the center insulator. Wrap the feed line conductors around the antenna wire several times and solder it in place with a high-wattage soldering gun. Clean the joints with alcohol and cover them with silicone rubber sealant.

Attach the feed line to the output terminal on the antenna tuner. Tuners designed for HF have terminals for both PL-258 connectors and ladder line. VHF tuners have BNC connectors. Attach the antenna analyzer to the input of the antenna tuner. Antenna analyzers allow the operator to tune the antenna without transmitting. Select the desired center frequency of the antenna, then adjust the antenna tuner to obtain the best signal on the analyzer. If necessary, the antenna can be trimmed shorter if the center frequency is too low.