Satellite dish

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Image:Antenne-toroidale.jpg Image:Satellite dish 1.jpg

A satellite dish is a type of parabolic antenna designed with the specific purpose of transmitting signals to and/or receiving from satellites. A satellite dish is a particular type of microwave antenna. Satellite dishes come in varying sizes and designs, and are most commonly used to receive satellite television.

Modern dishes intended for home television use are generally 45.72 cm (18") to 80 cm (31") in diameter, and are fixed in one position. This type of system is referred to as direct broadcast satellite or DBS. Systems commonly used with communications satellites for Ku-band free-to-air and ethnic broadcast reception use a slightly larger antenna, typically about one metre in size. Older types of home satellite dishes, called television receive-only or TVRO, were several metres/feet in diameter and had motors which could position the dish to receive signals from several different satellites (polar mount).

A common misconception is that the LNBF (low-noise block/feedhorn), the device at the front of the dish, receives the signal directly from the atmosphere. See, for instance, this BBC News 24 countdown [1] that shows a "red data stream" being received by the LNBF directly instead of being beamed to the dish, which because of its parabolic shape will collect the signal into a smaller area and deliver it to the LNBF.

Contents

Types

Use

  • Individual dishes serving one dwelling: Direct To Home (DTH).
  • Collective dishes, shared by several dwellings: Satellite Master Antenna Television (SMATV).

Design

DTH installation

One has to see the satellites' footprints for one's country. One may look for FTA channels in every satellite. The satellites one can receive in a concrete location depends on one's dish size, LNB, and geographical surrounding (houses, mountains, local interference, and similar).

The satellite dish pointing angles are azimuth and elevation. One may use a program that uses one's geographic coordinates, town, zone name, or ZIP/postal code to calculate azimuth and elevation for the satellite.

Azimuth is the side to side angle. By definition north is 0 or 360 deg, east is 90, south is 180, and west is 270. You can use a magnetic compass, maps, the sun, the north pole start, and some GPS receivers that show a view of the sky with sun and moon marked.

Elevation is the up-down angle. One can easily set up elevation, using a scale marked on the mount bracket or use an inclinometer.

Note that you find a satellite by pre-setting the elevation accuratelty and then swinging the whole antenna boldly in azimuth till the signal locks up in the sat finder meter or your receiver signal meter.

A satellite installation kit normally includes:

For complete installation one also needs:

  • At least, two pair of F connectors and F connector T adapter with 3 female ends (for derivation point for television sets in different locations at home). Satellite socket.
  • Coaxial cable.
  • Mount (for the wall or balcony).
  • Sat finder meter.

See also

External links

de:Parabolantenne (TV) es:Antena parabólica nl:Schotelantenne no:Parabolantenne pl:Antena_satelitarna

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