Thursday, January 31, 2013

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Parabolic


Satellite dish is a type of dish / parabolic circular / dish designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite TV.

Parabolic-shaped dish that reflects the signal to the dish's focal point. Mounted on brackets at the dish focal point is a device called a feedhorn. This feedhorn is essentially the front-end of a waveguide that gathers the signals at or near the focal point and 'no' was then taken to a block downconverter or LNB low noise. LNB converts the signals from electromagnetic or radio waves to electrical signals and transfers the signals downlinked C-band and / or Ku-band to L-band range. Antennas Direct Broadcast use an LNBF, which integrates the feedhorn with the LNB. (A new form of omnidirectional satellite antenna that does not use one. Directed dish and can be used on mobile platforms such as vehicles advertised by the University of Waterloo 2004

Advantages theoretical gain (directive) this parable increases with increasing frequency. Actual profit depends on many factors, including surface finish, accuracy of shape, feedhorn matching. Typical value for the consumer type satellite dish 60 cm to 11.75 GHz is 37.50 dB.

A common misconception is that the LNBF (low noise block / feedhorn), the device facing the plate to receive signals directly from the atmosphere. For example, a downlink BBC shows "red flag" received by the LNBF directly instead sent to a satellite dish, but because of the parabolic shape will collect the signal into a smaller area and deliver it to the LNBF.


Motorized parabole

A satellite antenna mounted on a post and driven by servo or stepper motors can be controlled and rotated forward to position the satellite in the sky. Parabola popular motor is divided into three standards: DiSEqC, USALS, and 36v positioners. Many receivers support all of these standards.
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