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In addition to the high-gain antenna, there are two backup low-gain antennas and a medium-gain dish. The high-gain dish has a Cassegrain reflector layout, composite construction, of 2.1-meter (7 ft) diameter providing over 42 dBi of gain and a half-power beam width of about a degree. The prime-focus medium-gain antenna, with a 0.3-meter (1 ft ...
The theoretical gain (directive gain) of a dish increases as the frequency increases. The actual gain depends on many factors including surface finish, accuracy of shape, feedhorn matching. A typical value for a consumer type 60 cm satellite dish at 11.75 GHz is 37.50 dB.
A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. 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.
RT-7.5 ( Bauman's radio telescope) Moscow Oblast, Russia. Two 7.75-meter diameter antennas (only one is working at the moment) [35] Yebes RT 40 m. Spanish National Observatory, Yebes, Guadalajara, Spain [36] 40 m parabolic steerable telescope for mm and cm wavelengths. Toruń RT4 32 m.
In electromagnetics, an antenna's gain is a key performance parameter which combines the antenna 's directivity and radiation efficiency. The term power gain has been deprecated by IEEE. [1] In a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction. In a receiving ...
In November 1990, Primestar launched as the first North American direct-broadcast satellite service. Hughes's DirecTV, the first national high-powered upper K u -band satellite TV system, went online in 1994. The DirecTV system became the new delivery vehicle for USSB. In 1996, EchoStar 's Dish Network went online in the United States and has ...
Inmarsat satellite telephone in use after a natural disaster in Nias, Indonesia. The unit depicted was manufactured by Thrane & Thrane A/S of Denmark. (April 2005) Inmarsat is a British satellite telecommunications company, offering global mobile services. It provides telephone and data services to users worldwide, via portable or mobile ...
A parameter often encountered in specification sheets for antennas that operate in certain environments is the ratio of gain of the antenna divided by the antenna temperature (or system temperature if a receiver is specified). This parameter is written as G/T, and has units of dB·K −1. G/T Calculation. G/T is the figure of merit for a ...