subject: The establishment of stable and reliable to meet the needs of the satellite ground receiving antenna - satellite ground receiving antennas, wireless [print this page] The establishment of stable and reliable to meet the needs of the satellite ground receiving antenna - satellite ground receiving antennas, wireless
Is well known that the development of the modern radio and television satellite communications increasingly dependent. How to set up a satellite ground receiving antenna, in particular choice of servo-tracking mode, both stable and reliable to meet the demand, but also simple structure, easy maintenance, a task faced by the various television stations. Now, with the new 7.5 m CCTV satellite ground receiving antenna, for example, its system structure, working principle, servo tracking equipment, performance, installation and use and maintenance, for an introduction to colleagues.
Space satellite communications is a microwave relay, electromagnetic wave propagation in the line of sight, man-made earth satellite as a transit point, after receiving the signal and then transmitted down the signal processing, synchronous satellites orbiting the earth and the earth rotation angular velocity of rotation angular velocity the same point of view from the ground to satellites floating in space as fixed as it is also called geostationary satellites. Use of a synchronous satellite communication channel stability, communication range, a simple tracking devices, communication capacity is very large,.
Satellite ground receiving antenna (hereinafter referred to as "antenna") is a wireless communication system in all important part, especially for the synchronous satellite communications, because of long distance communications, channel loss of a large, require high gain and low noise antenna With the continuous economic and cultural development, communication capacity requirements growing to meet this demand, more and more closely synchronous orbit satellites, and almost all of the implementation of spectrum reuse, and opening up new frequency bands such as Ku and Ka The original band has to be broadened, in order to improve the communication quality, to achieve the mutual interference between the satellite and the satellite and the same stars-ordination between the orthogonal polarization, the antenna must be within the operating frequency and high-low sidelobe Cross Polarization Discrimination.
CCTV chosen 7.5 m C / KU antenna is designed to meet the requirements of satellite communications, and has high gain, low noise temperature, low sidelobe, high rate of cross-polarization discrimination characteristics of the antenna and tracking equipment found antenna performance to meet ISO, CCIR-REC580, ITU standards. The design of the antenna main and side rectification to achieve high efficiency and low sidelobe. Advanced structural design and processing technology to make the antenna structure of a solid, panel accuracy, precision assembly, orientation, pitch drive system work smoothly and easily point to meet the requirements of precision and careful handling of three against the antenna can work in all kinds of bad environment, through strict quality guarantee system and reasonable reliability design, antenna and tracking system to ensure quality and reliability.
1, the system constitutes Antenna reflector and back from the main frame, the Deputy reflector and supporting structure, four-port feed system, polarization adjusting device, bearing a seat pitch antenna, the azimuth and elevation drives, etc; Servo System is made by the tracking downconverter of servo, tracking receiver, antenna controller, etc.; other ancillary equipment: feed de-icing units, waveguide inflator, lightning rod and the antenna operation and maintenance special tools. 7.5m fixed-station antenna structure diagram shown in Figure 1.
Figure 1 Main reflector and the reflector frame composed of 16 fan-shaped reflector. Fan-shaped reflector formed by the thickness of 2mm aluminum sheet stretch forming and bending of the Z-formed aluminum ribs riveted. Reflector from the center of body frame, 16 radiation beams, ring three times to tie the composition. Fan-shaped reflector and the reflector frame accurate positioning between the positioning cone.
By the Deputy Vice-surface reflector, Vice side struts and support institutions to adjust the composition. The Vice-reflector antenna for the elliptic curve bus, which consists of four struts supporting the main reflector in the framework of the radiation beam, the Deputy side struts are used at both ends pin positioning to ensure accuracy, Vice surface re-installed, Vice-side support adjustment body surface can be fine tuned, Vice, Vice surface in order to achieve the best position.
Feed from the corrugated horn, Garden Bird, diplexers, filters and other components blocking send, send and receive port interfaces in the form of WR-75.
Polarization adjustment device by a fixed cylinder, actuator, and locking device component. The adjustment device rotating smooth, easy adjustment, and can carry four-port spectrum multiplexing network, the main guide for LNA and other large equipment weight and size of the load.
Bearings and one pitch antenna tripod mountings for the three-dimensional structure of space, three anchor bolts and three by the seamless steel tube column composition; position driver seat rack placed in the Ministry, so the orientation of the antenna to withstand the torque screw through the orientation Main bearings bearing mountings commitment to pass, the azimuth - elevation mix does not bear torque, pitch drive support in the seat bottom frame, so antenna bear pitching moment and vertical force directly on the ground. The main seat frame does not bear this part of the force, with a corresponding increase of the main seat frame strength and stiffness.
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