The Selection of ILS Localizer Antenna Patterns for Use in the Frequency Assignment Process.

摘要

The frequency assignment process is meant to insure interference-free service within the service volume. This is done by choosing frequencies in a manner which provides certain minimum cochannel and adjacent channel desired to undesired signal ratios at critical points of the service volume. One of the factors which affects a station's signal strength in space is its horizontal antenna pattern. ILS localizer antennas have undergone significant changes in recent years. In order to reduce siting effects, antenna patterns have evolved from the nearly omnidirectional 8-loop to the highly directional traveling wave and log periodic dipole antennas. The horizontal localizer antenna pattern now has a substantial effect on the separation required between localizer stations. This report compares measured and theoretical data with FAA antenna pattern specifications. For each antenna type, a single horizontal antenna pattern is recommended for use in the frequency assignment process. (Author)