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Offset dish antennas are more difficult to design than front-fed antennas because the dish is an asymmetric segment of a paraboloid with different curvatures in the two axes. Before the 1970s offset designs were mostly limited to radar antennas, which required asymmetric reflectors anyway to create shaped beams.
For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial-fed dish antennas, the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna radiation pattern (the main lobe) is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed.
The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity . It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only.
The angle is the angle between the direction of the current and the direction to the point where the field is measured. The electrical field and the radiated power are maximal in the plane perpendicular to the current element. They are zero in the direction of the current.
A beam waveguide antenna is a type of complicated Cassegrain antenna with a long radio wave path to allow the feed electronics to be located at ground level. It is used in very large steerable radio telescopes and satellite ground antennas, where the feed electronics are too complicated and bulky, or requires too much maintenance and alterations, to locate on the dish; for example those using ...
The precursor: Cheese and charcuterie boards. Serving food on boards is nothing new. Cheese and charcuterie boards have been popular for years and are hardly controversial.
A polar mount is a movable mount for satellite dishes that allows the dish to be pointed at many geostationary satellites by slewing around one axis. [1] It works by having its slewing axis parallel, or almost parallel, to the Earth's polar axis so that the attached dish can follow, approximately, the geostationary orbit, which lies in the plane of the Earth's equator.
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