Q: I find antenna specifications confusing. What are the azimuth and elevation planes, and how do I work out what the actual coverage will be?
A: The easiest way to understand the azimuth and elevation planes is to picture a dipole antenna hanging directly down from the ceiling.
The azimuth plane describes how the signals radiate out from the antenna in the horizontal plane. In the case of a dipole antenna, the signals radiate out in a circular pattern. As the signals radiate out from the antenna, they lose strength; this is signal attenuation. Each circle on the polar plot indicates the level by which the signal has diminished.
When a signal radiates from the antenna, it radiates in three dimensions. The elevation plane shows the radiation pattern as if you were looking at the dipole antenna from the side. This plane is sometimes also referred to as the vertical plane.
The azimuth plane is the pattern that you should look at to determine coverage. Look at the elevation plane to understand how much the signal might spill over to the floors above and below the antenna.