Abstract: An inverted offset system is used for sending and/or receiving electromagnetic energy. The system, which is preferably a Cassegrainian microwave antenna system, includes a water-tight cover to protect the feed compartment, subreflector, and main reflector of the antenna. The cover protects against the effects of precipitation and is especially useful when the system is used for measuring atmospheric conditions such as rain or snow. A waterguard ridge and drain passageway are used to protect the feed compartment from precipitation when the antenna is disposed in a position to send or receive beams which are substantially vertical.

Abstract: A diagonal phased antenna array for use as a wind profiler by means of Doer shift measurements comprises a plurality of Yagi-Uda antennas which are oriented in a predetermined direction such that Yagi-Uda antennas have a polarization 45.degree. offset from the principal planes of operation of the antenna array resulting in similar radiation patterns subject to a geometric taper in the array aperture with respect to the principal planes.

Abstract: A triple-beam offset paraboloidal antenna minimizes the offset of each of ree antenna feeds from the focal point of the paraboloid to thereby minimize beam aberrations, while at the same time maximizing the beam steering capability of the antenna. Three beams are produced, two being in mutually orthogonal planes. The axis of the third beam corresponds to the intersection of the orthogonal planes. The antenna in accordance with the present invention finds particular utility in the measurement of three dimensional wind profiles employing doppler radar techniques.