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ALTAIR (Radar)
ALTAIR (Advanced Research Projects Agency, ARPA Long-Range Tracking And Instrumentation Radar) is a radar tracking station on Roi-Namur island in the north part of the Kwajalein atoll in the Marshall Islands. It is a high-sensitivity, wide-bandwidth, coherent, instrumentation and tracking radar that is capable of collecting precise measurements on small targets at long-ranges. ALTAIR supports several operating modes, including tracking and signature collection at Very high frequency, VHF and Ultra high frequency, UHF. It is part of a network of contributing radar sensors that perform deep-space tracking.Card Index of Radar Sets in Radartutorial The antenna uses a steerable 150-ft dish (46-m-diameter) and employs a focal point VHF feed and multimode Cassegrain UHF feed in conjunction with a frequency selective su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassegrain Antenna
In telecommunications and radar, a Cassegrain antenna is a parabolic antenna in which the Antenna feed, feed antenna is mounted at or behind the surface of the concave main parabolic reflector dish and is aimed at a smaller Convex mirror, convex secondary reflector suspended in front of the primary reflector. The beam of radio waves from the feed illuminates the secondary reflector, which reflects it back to the main reflector dish, which reflects it forward again to form the desired wikt:beam, beam. The Cassegrain design is widely used in parabolic antennas, particularly in large antennas such as those in satellite ground stations, radio telescopes, and communication satellites. Geometry The primary reflector is a paraboloid, while the shape of the convex secondary reflector is a hyperboloid. The geometrical condition for radiating a collimated, plane wave beam is that the Feed horn, feed antenna is located at the far focus (geometry), focus of the hyperboloid, while the foc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |