Multiple LNB satellite dish

A dish and feed array designed to receive two or three spaced apart satellites will have two or three feeds, each with an LNB. The feeds need to be spaced apart to suit the satellite azimuth and elevation pointing angle differences.

The dish acts as a mirror and forms an inverted and reversed image of the many satellites in a curved line in the focal region. If you are looking due south the satellites in the sky form a curved line with the highest satellite at the top. In such a case you would set your central feed aimed at the due south satellite. The outer feeds would be slightly higher up. The left feed would work to the right satellite and vice-versa.

Many dishes have pre-made fixed LNB spacings. This assumes that the dishes will be used in the US and for the reception of satellites spaced say 9 deg apart. The entire antenna (dish and LNBs) may be rotated to set the polarisation/skew angle. Optimise this for the central satellite.

General purpose multi-LNB antennas may have perhaps 5 feeds. The central LNB/feed will be set first and then the outer ones individually. Each LNB/feed needs to be adjusted, up/down and sideways and in rotation also to set the polarisation angle.

This figure shows a view of the sky with the various satellites represented by the red dots. Note the top three satellites and the corresponding triple LNB feed array below.

This triple multi LNB dish feed needs to be tilted anticlockwise if used to receive from three satellites in the south east. If used for satellites due south then it needs to be used upright, as illustrated. If used for satellites towards the south west then the feed array should be tilted in a clockwise direction. Note that in this above design the distances between the feeds is fixed, so this unit is suitable for its intended dish focal length only. It is not suitable for use with dishes of longer or shorter focal lengths.

For the enthusiast it is possible to use a fully adjustable multi-LNB arrangement with perhaps as many and 5 LNB/feeds. In this case set the pointing for the central feed first and then adjust the outer feeds individually. Up/down and sideways movements are needed to find the satellites and then individual rotation to set the polarization/skew angles. This fully adjustable design is suitable for a dishes with a variety of sizes and focal lengths.

If all the satellites are away sideways from south, for example in a generally south west direction, the the feeds will all be in a sloping line going down towards the south west.

As an example. You are on longitude 90 west and you want to point to satellites at 110 and 119 west. These satellites are further to the west than you are, so the satellites will be in a sloping line going downwards towards the south west. See the right hand half of the figure to the top right.

In some cases the individual LNBs may be rotated to individually to set the polarisation/skew angles correctly. In some cases the dual or triple feed assembly is not adjustable and also fixed relative to the dish and the entire dish and feed array must be rotated to set the average polarisation angle correctly. The tilt makes the feed array line up with the sloping line of satellites in the upper diagram.

DirecTV DIRECTV 21-Tuner SWM LNB for Slimline Dishes (3D2LNB)
Speakers (DirecTV)
  • To be used to pick up high definition local channel programming from DIRECTV
  • Built-in SWM Multiswitch gives a single wire to feed multiple receivers.
  • Will feed 21 tuners.
2016 Directv Swm 3 Dish Kaku Slimline 13 Tuner Last Test Come 100 Ft Wire Black w/ End Ppc Fitting Xl Plus 10'' pc toy table, Signal Finder Full Hd Cable
CE (directv & adrielectronics)
  • DIRECTV HD Slimline Dish SWM 3 LNB Satellite Dish with (( FREE PC TABLE TOY 10TOUCH SCREEN)). (1 Output 13 tuner LNB & SWM ,splitter 4 way for multiple SWM receivers)...
  • complet dish kaku sliline pwer 21 volt ,100 ft wire cable with ppc fitting xl plus 6 feet wire rg6
  • 1 hdm wire 1 rg6 flat wire ,2 barrels 1 signal finder, 1 bubble to align plus 1 free directv remote control,IS hard to believe but it comes with everything you see...
  • great kit for house ,camping ,rv truck Works best if used with H20,H21,H24,HR21 and HR20 ,HR21 AND HR22,HR23,HR24 High Def receivers and the H25 newer receiver...
  • Note : Is not swm 5 Also this kit come with a directv antenna installation LINK IF YOU NEED plus 1 full page diagrame to easy understand NOTE:COME W/LONG MAST PLUS...

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