The Synergetics Model 18B is a high-gain, lightweight antenna designed to provide optimum performance for all fixed-location, timed Satellite Data Collection Platforms (DCP's). It is also well-suited for other 400 MHz applications. The basic 18B design consists of two quadrature-phased, five-element Yagi antennae, orthogonally mounted on a common aluminum boom. The driven elements are fed via a unique micro-strip matching circuit. The combination of a precision aluminum structure driven by a photo-reproduced matching circuit results in exceptionally uniform electrical and mechanical performance. The antenna is supplied with screw-in elements for ease of shipping, storage, and field installation.