Getting a ‘good ground’

This chapter highlights the importance of antenna grounds. The effectiveness and safety of a radio antenna often hangs on whether it has a good radio frequency (RF) ground. Poor grounds cause most forms of antenna to operate at less than best efficiency. The ideal ground depth is rarely right on the surface, and depending on the local water table level, might be a couple of meters or so below the surface. Grounds for radio installations are intended for two purposes: making the radio antenna work better and lightning protection. The goal in making a radio ground is to provide a low resistance path to the earth for radio signals. An additional goal is to make a path to the earth for lightning that strikes the antenna, or even nearby. The conductivity of the soil determines how well, or how poorly, it conducts electrical current. The key to a low-resistance ground is the surface area in contact with the soil. One means for gaining surface area, thereby reducing ground resistance, is to use multiple ground rods. The effectiveness of the ground system is enhanced substantially by the use of radials either above ground, on the surface, or buried under the surface.