What shape is the radiation pattern?
Free standing whip antennas exhibit an omnidirectional radiation pattern in the azimuth plane which is typical of vertical monopole antennas. The field is strongest at low elevation angles and diminishes with higher angles to become zero straight up. Any resulting disturbances in the uniformity of the field are usually due to factors outside the antenna system such as the proximity and construction materials of buildings and other structures, ground connections to other site equipment and geographic land features. In general, the exact shape of the radiation pattern profile in the elevation plane is complex and will depend on the particular antenna, the operating frequency and the surface condition over which the antenna is operated. These factors will determine the antenna electrical height in wavelengths and the ground plane reflection coefficient upon which the shape of the radiation pattern depends. Antenna and radio textbooks and handbooks provide general graphs of radiation patte
