| 摘要 |
889,490. Aerials; radio direction-finding. WESTERN ELECTRIC CO. Inc. May 25, 1960 [May 28, 1959], No. 18454/60. Class 40(7). A directional aerial system capable of providing signals for automatic tracking comprises a waveguide horn radiator feeding a paraboloidal reflector, with an elongated body of dielectric material mounted between the two for rotation about the horn axis. As described a circular waveguide (not shown) feeds a square-section waveguide horn 10, a rotatable joint being provided. The horn 10 is directed towards a paraboloidal reflector 42 and has an aperture in its upper surface through which energy can pass. The radiofrequency stages of a transducer, which may be a receiver for radio astronomy investigation, are mounted in an enclosure 24. A disc 22 mounts the smaller end of the horn for rotation in the front wall of this enclosure and the larger end of the horn carries disc 14 supported by rollers 16 and 18 so that the horn and reflector assembly can be rotated about the horn axis by motor 36, reduction gearing 20 and belt 38 asnecessary for alignment and tracking. The aerial system is carried on a turntable 12 rotatable by motor 28 for movement in azimuth for the same purpose. To provide a conical scan for automatic tracking an elongated bi-conical body 44 of dielectric material is mounted within the horn 10 so that its axis makes an angle with the horn axis. This body is supported at its centre by an oblique conical structure 46 of material of low dielectric constant mounted for rotation in rollers 48. A motor 50 is provided to drive the support 46 and thus rotate the body 44 round the horn axis. The dielectric material used to form body 44 may be a ferrite and whilst it is not essential to use a bi-conical shape tapering is 'desirable to reduce reflections. |
