Communications: radio wave antennas – Antennas – With support for antenna – reflector or director
Patent
1995-07-12
1998-05-26
Hajec, Donald T.
Communications: radio wave antennas
Antennas
With support for antenna, reflector or director
343840, 343880, 343915, H01Q 302
Patent
active
057573352
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention concerns rigid structures. It also concerns dish antennas of the type used for radio telescopes, solar collectors, satellite communication, and the like. In particular, this invention concerns structures for supporting the dishes of such, preferably using a novel hydraulic arrangement for the controlled rotation of the dish supporting structure about a vertical axis.
BACKGROUND OF THE INVENTION
Dish-like antennas which are used as, for example, receivers of signals from satellites, solar collectors and radio telescopes, utilise a reflecting dish to focus electro-magnetic radiation upon a receiver. The dish comprises a reflective or conductive surface which is mounted on a rigid frame. The dish, with its supporting frame, is manipulated by one of a number of conventional techniques, discussed below, to point continuously to the object from which the antenna receives electro-magnetic radiation.
In a typical dish antenna, the frame which supports the reflector dish is usually a complex structure. It may be an inverted geodesic dome, or a series of concentric hoops supported by a plurality of identical sub-frames extending radially from below the centre of the dish. Such basic dish support frames are relatively weak structures and quite complex bracing arrangements are required to strengthen them. Even with such bracing, if the dish has a continuous surface (which is usually the case when the dish is used to receive and focus solar radiation), it can distort to a significant extent when the antenna is subjected to moderate wind loads.
A further disadvantage of the existing dish supporting frames is that, unless detailed and time-consuming design procedures are used to produce the support frame design, they are not constructed so that the points (called "mounting points") on the support frame to which the dish surface is attached lie accurately on the envelope of the surface of the dish. Thus, when assembling the antenna structure, and in particular when mounting a large reflecting surface on the dish supporting frame, it is usually necessary to adjust the mounting of each portion of the reflecting surface to form the required surface shape of the dish. The cost of producing the existing dish antennas is thus quite high, partly due to the complex configuration of the supporting frame and partly due to the amount of skilled labour required in the assembly of the antenna structure.
As mentioned above, the distortion of the dish surface under even moderate wind loads is particularly significant in the case of antennas used as solar collectors, which have continuous reflector surfaces and which need to be cost effective. Such antennas must be capable of receiving radiation from the sun even when the sun is at the horizon.
Since a change in the elevation of the line of sight of a dish is effected by movement of the dish and its associated support frame about a horizontal axis which is positioned below the centre of the dish when the dish is pointing directly upwards, the axis of rotation of the dish structure must be at a distance above the ground that is at least half the vertical extent of the dish, measured when the dish has its line of sight directed to the horizon. This horizontal axis of rotation is invariably at the top of a tower. Thus, when the dish is moved so that its line of sight is vertically above this axis, all of the dish surface is positioned well above the ground, where it is fully exposed to the wind. In other than light breezes, the wind loads will distort a reflector dish surface unless the support frame is a complex structure which includes a number of bracing members and the dish is constructed from a strong, and therefore heavy, material (in which case there must be an increase in the handling capabilities of ancillary equipment). If the dish is not made from a heavy, rigid material, it may be necessary to curtail the operation of the antenna in strong winds to avoid the possibility that the dish will be damaged. In either case, an economic penalty is incur
REFERENCES:
patent: 3220152 (1965-11-01), Sturm
patent: 3725946 (1973-04-01), Quequen
patent: 3913105 (1975-10-01), Williamson et al.
patent: 3986434 (1976-10-01), Kohler
patent: 4256088 (1981-03-01), Vindum
patent: 4337560 (1982-07-01), Slysh
patent: 4558551 (1985-12-01), Sevelinge et al.
patent: 4650361 (1987-03-01), Seuster
patent: 5228258 (1993-07-01), Onoda et al.
Derwent Soviet Inventions Illustrated, Section 3, Mechanical and General, issued Apr. 1969 Engines, Pumps, Boilers, Refrigerators, p. 13, SU 223553 (NAZININ) 13 Nov. 1968.
Kaneff Stephen
Whelan Robert Edgar
Anutech PTY. Limited
Hajec Donald T.
Phan Tho
LandOfFree
Dish antenna structures and hydraulic control of the orientation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dish antenna structures and hydraulic control of the orientation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dish antenna structures and hydraulic control of the orientation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1967076