| 摘要 |
An enclosed terrestrial antenna system of monocoque construction for receiving television signals from satellites in geostationary orbit. The basic antenna comprises two dish-shaped members having substantially identical configurations, each of which is a surface of revolution. Each member (called a "dish" in the industry) has a central concave parabolic area surrounded by an upstanding frusto-conic rim. One, the antenna dish, has an electromagnetic radiation reflecting surface on the concave side. The other, the cover dish, is substantially transparent to electromagnetic radiation. The cover dish has an opening at the center, along the axis of revolution. The two dishes are secured together, concave face to concave face. A feed mount is secured to the cover dish over the opening and carries the feed assembly in a manner allowing the feed assembly to be moved toward and away from the reflective surface to focus the feed. Suitable ground supports are provided to hold the antenna assembly with the axis of revolution aligned at a selected azimuth and elevation. A cover is provided over the feed assembly, secured to the feed mount or vover dish. Thus, the antenna assembly is fully enclosed and protected from the weather or other outside influences.
|
