Abstract:
A compact, portable satellite dish antenna system comprises a dish-shaped member having an inner surface that includes a central circular flat area and a plurality of annular parabolically-shaped segments concentric with the central circular flat area for providing a plurality of focal points over the inner surface of the dish-shaped member to thereby improve the signal gathering characteristics of the dish antenna system.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of Ser. No. 07/879,051, filed Apr. 30, 1992, and now abandoned, which is a continuation of Ser. No. 07/700,097 filed May 7, 1991, and now abandoned, which is a continuation of Ser. No. 07/499,061 filed Mar. 26, 1990, and now abandoned. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     This invention relates generally to satellite dish antennas and more particularly to an improved portable satellite dish antenna for receiving Ku-band, or direct broadcast, satellite signals carrying audio, video, or computer data information. Prior art satellite dish antennas for receiving C-band satellite television signals are typically at least eight feet in diameter and are therefore large, bulky, expensive, and generally unattractive structures that are permanently mounted using base posts set in the ground. Even prior art Ku-band satellite dish antennas involve bulky support arrangements that significantly reduce their portability. In addition, the signal reception characteristics of these known Ku-band satellite dish antennas suffer due to their susceptibility to noise resulting from a uniform parabolic dish shape. 
     It is therefore a principal object of the present invention to provide a compact, portable satellite dish antenna that can be easily assembled and disassembled for location either outdoors or indoors adjacent the user&#39;s television receiver or computer and that exhibits improved reception of Ku-band signals. This and other objects are accomplished in accordance with the illustrated preferred embodiments of the present invention by providing a satellite dish antenna having an inner or working surface formed to have a central flat area and a series of annular, separate parabolically-shaped segments that are concentric with the central flat area. A fork-like feed mount and a three-point dish support structure that includes an elevation adjustment facilitate easy assembly and disassembly of the present satellite dish antenna to enhance its portability. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side pictorial diagram of a Ku-band satellite dish antenna system constructed in accordance with a preferred embodiment of the present invention. 
     FIG. 2 is a side pictorial diagram of the Ku-band satellite dish antenna system of FIG. 1 in which an alternative support mechanism i s employed. 
     FIG. 3 is a broken away pictorial of the satellite dish antenna system of FIG. 1 illustrating how the forked feed mount is attached to the dish itself. 
     FIG. 4 is a cross-sectional view of the dish portion of the Ku-band satellite dish antenna system of FIG. 1 illustrating the shape of the inner surface of the dish. 
     FIG. 5 is a partial assembly diagram of the satellite dish antenna system of FIG. 1 illustrating the way in which the dish and an elevation adjustment member are connected to a base support member. 
     FIG. 6 is a broken away pictorial diagram of a portion of the Ku-band satellite dish antenna system of FIG. 2 illustrating the way in which a circular support member can be folded behind the dish to enhance its portability. 
     FIG. 7 is a partial cross-sectional view of the dish of FIGS. 2 and 6 illustrating the way in which the circular Support member engages a rear arcuate lip formed along the periphery of the dish. 
     FIG. 8 is a pictorial diagram of the rear or convex surface of the Ku-band satellite dish antenna of FIG. 6 illustrating the way in which the circular support member is completely folded behind the dish in the stowed position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIGS. 1 and 2, there are shown pictorial diagrams of a satellite dish antenna system constructed in accordance with alternative embodiments of the present invention. Each embodiment includes a dish 10 and a feed mount 12 for supporting a conventional feed horn and amplifier assembly 14. In the embodiment of FIG. 1, dish 10 is supported by a U-shaped base 16 that comprises a pair of rearwardly extending parallel leg members 18, 20 and a cross member 22 connecting parallel leg members 18, 20 at their rearward ends. U-shaped base 16 may be conveniently fabricated using readily available PVC tubing and connecting elements, for example. The use of such material results in a non-penetrating, non-abrasive mounting arrangement for dish 10. As illustrated in greater detail in FIG. 5, the forward ends of parallel leg members 18, 20 are fitted with upwardly projecting right angle elbow members 24, 26 for receiving downwardly projecting legs 28, 30 that are fixedly mounted along the bottom peripheral edge of dish 10. Cross member 22 at the rear of base 16 includes an upwardly projecting T-member for receiving an elevation adjustment assembly 32 that is hingedly attached at the top peripheral edge of dish 10. Elevation adjustment assembly 32 may comprise a telescoping rod whose overall length is fixed by means of a thumbscrew 34. A scale 36 may be provided on one of the telescoping rods comprising elevation adjustment assembly 32 so that the user can adjust the elevation of dish 10 to known angles of elevation corresponding to certain satellite positions. Feed mount 12 is fabricated in the shape of a fork that includes a pair of downwardly projecting legs 38, 40 that converge at their top ends to receive a feed bracket 42 which, in turn, receives a feed horn and amplifier assembly 14. The bottom ends of forks 38, 40 are removably attached to the peripheral edge of dish 10 by means of a pair of receptacles 44, 46 into which forks 38, 40 are inserted. 
     In the embodiment of FIG. 2, a circular base ring 50 is hingedly attached behind dish 10 along the peripheral edge thereof, as shown in more detail in FIGS. 6-8. Hinged attachement of base ring 50 may be made, for example, by a sleeve 52 fixedly connected behind a peripheral lip area formed along the edge of dish 10. Base ring 50 is then permitted to rotate within sleeve 52 from a stowed position in which base ring 50 resides within the peripheral lip area to an operating position in which dish 10 is rotated upward from base ring 50 to a desired elevation that is then fixed by means of thumbscrew 34 of elevation adjustment assembly 32. Elevation adjustment assembly 32 is removably received by a rotatable T-sleeve 54 over base ring 50 that can be rotated from an upwardly projecting position for receiving elevation adjustment assembly 32 to an outwardly projecting position to permit base ring 50 to be rotated into its stowed position behind dish 10, as illustrated in FIG. 8. 
     Referring now to FIG. 4, there is Shown a cross section of dish 10 of the Ku-band satellite dish antenna system of FIGS. 1 and 2 shaped in accordance with the present invention. Unlike the prior art dish antennas which have a uniform parabolic working surface, dish 10 is shaped to include a central area 60 whose working surface is formed to be flat. Extending outwardly from central area 60 are three annular segments 62, 64, 66 that are concentric with central area 60 and whose working surfaces are separately parabolically shaped. The annular segments 62, 64, 66 provide circular lines of discontinuity 68, 70, 72 over the working surface of dish 10. In accordance with one set of workable design parameters for dish 10, its overall diameter is 32 inches and its depth is 5.75 inches. The flat central area 60 is approximately 6 inches in diameter and each of the three annular segments 62, 64, 66 is approximately 4.33 inches in width. While FIG. 4 illustrates three annular segments 62, 64, 66, a larger number of such segments could be provided. Alternatively, two such segments could be provided. The use of such annular segments, each of which is separately parabolically shaped, results in a plurality of separate focal points over the working surface of dish 10. This important feature reduces the need for absolutely precise positioning of dish 10 and generally increases its signal gathering capabilities over prior art uniform dish designs.