Patent GB-1347026-A (GB)
Title: Radio antenna structure
IPC: H01Q15/16
Filed: 1971-04-28
Abstract: 1347026 Aerials SOC D'ETUDES INDUSTRIELLES ET DE CONSTRUCTIONS CAMUSAT GUEGUEN FRANCE 28 April 1971 [29 April 1970] 11958/71 Heading H4A An aerial structure comprises a concave reflecting surface of revolution made of metal trellis supported on metal frame panels assembled in the form of curvilinear triangles placed edge to edge. Six of the panels are mounted about the axis of the surface, and their projections upon any plane at right angles thereto form a regular hexagon. Three stress bars extend parallel to said axis and connect three non-consecutive apexes of the hexagon to an equilateral triangle which lies in a plane of reference behind the surface, and is perpendicular to its axis. The apexes of the equilateral triangle are also connected to the other apexes of the curvilinear triangles, so that a non- deformable assembly of pyramids is constituted. A described, a paraboloidal reflector S, Fig. 4, with a circular rim is constituted by 24 curvilinear triangular panels which are derived from the intersection of the paraboloidal surface by three sets of three parallel planes, at 60 degrees to each other. Each panel is assembled in a jig and is electrically welded. It comprises sides of U-section material, intermediate stiffeners of smaller U-section material, secondary stiffeners of round section material, rearwardly facing corner gussets each provided with a bolt hole, and a reflecting surface of galvanized steel wires (Fig. 3, not shown). The panels are secured together by means of bolts which pass through transverse holes in their sides. From the three apexes 102, 104, 106, Fig. 4, support bars extend rearwardly. In the half section shown in Fig. 9, only the bar 20, from the apex 104, and the bar 21, from the apex 106 are visible. The bars end in a plane to which they are perpendicular, at points B1, A, B2. Gussets 13, 14 at the points A, B2 are visible in Fig. 9, and the bars 20, 21 terminate therein. The three gussets are tied together by three bars, such as the bar 40 between the gussets 13, 14 which form a triangle lying in said plane (Fig. 6, not shown). From the gusset 13 (point A) bars forming a pyramid are connected to the apexes 100, 103, 113, 114, 115, 105. The bars 24, 25, 26 relating respectively to the points 114, 115, 100 have been shown in Fig. 9. Similarly, pyramids are formed by bars from the point B1 to the apexes 109, 110, 111, 103, 100, 107 and from the point B2 to the apexes 119, 107, 100, 105, 117, 118 (bars 28, 32 from the gusset 14 to the apexes 100, 119 are shown in Fig. 9). Supplementary pyramids are formed by bars extending from points K, L, M, which lie in the reference plane rearward of respective apexes 103, 105, 107 (Fig. 6, not shown). A radiating horn 36 is supported by a tripod structure whose legs bear at the points 103, 105, 107. The legs 37, 39 from the points 107, 105 are visible in Fig. 9. A feed cable 38 is run along the leg 37. The reflector is secured to a pylon by means of screwthreaded rods which extend to the points A, B1, B2. Adjustment in elevation is obtained by means of the rod to the point A, and adjustment in azimuth is obtained by means of the rods to the points B1, B2 (Fig. 10, not shown).