How do satelite Dishes Work

Discussion in 'TV & Satellite' started by Enodreven, Sep 5, 2007.

  1. Enodreven

    Enodreven Deleted User

    Hi,

    Just wondering does anyone know exactly how the actual dish functions, the reason I am asking is rather than taking a very large dish with you if you were visiting southern Spain could you modify your existing:-

    (1) Would it be possible to make a clip on arrangement to enlarge say a 60cm dish

    (2) If it is possible does that have to be made of metal ??

    (3) Would the LNB arm need to be altered

    (4) Do they allready make a clip on attachment
     
  2. scotjimland

    scotjimland Funster Life Member

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    Hi

    (1) Very difficult , the dish focuses the beam onto the LNB
    (2) Doesn't need to be metal
    (3) Yes, see (1)
    (4) Not to my knowledge

    A 60 cm. dish is more than adequate for southern Spain, you will get the Astra southern beam, to get the northern beam you would need at least a 1.5mt or larger dish.. not very practical.

    Jim
     
  3. johnsandywhite

    johnsandywhite Read Only Funster

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    The Dish concentrates the beam to the LNB.

    1. Not really possible. But NOT impossible.

    2. No. But should not be TOO reflective a material so as not to burn out the LNB.

    3. The LNB should already be positioned to the centre of the dish.

    4. Not that I have ever heard of.

    :Cool: What you need is one of those dishes that fold down like a Fan. They use similar ones on expeditions and in Army communicatons. :Wink:
     
  4. Enodreven

    Enodreven Deleted User

    Hi, Thanks everyone for the info so far .

    Do you know if its more effective to mount the LNB centraly over the dish or on an arm from the edge, the reason i am asking is that the Mulitmo dish has the LNB mounted centrally over what is a very small dish and the blurb states it acts like a dish a lot larger ? does anyone know if this is true ?

    Hi, John, do you know who makes those large fan like dishes ?

    Brian
     
  5. johnsandywhite

    johnsandywhite Read Only Funster

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    Hi Brian

    As far as I know. There are (as you mention), different ways of mounting an LNB. In the dish centre and on an arm centered to the maximum signal from the dish. They use 2 different types of LNB. Effectively the Multimo has a reversed LNB to pick up the signal. A Kathrien uses a side mounted LNB within the dish and uses a completely different way of concentrating the signal to the LNB. Some dishes are elliptical from top to bottom (usual) and the Sky dish is elliptical from side to side. The Sky dish uses a different LNB because of this.

    I'm sorry I have never tried to find out who produces the Fan dishes. Which BTW can be made of clear Plastic.
     
  6. Enodreven

    Enodreven Deleted User

    Hi, John

    Thanks for the info, I have just been looking at Maplins web site and they have a 45cm square dish with LNB built-in and state that it operates like a 65cm dish, having read a bit further and using Pythagoras theorem (i never could spell) it would appear this 45cm square is at least 65cm across so no wonder it works like a 65cm dish.

    http://www.maplin.co.uk/module.aspx?ModuleNo=220124&doy=5m9#overview

    But the strange thing is that the LNB appears to be set back into the bowl of the square dish with what appears to be a plastic cover over the whole thing, I supose that is what you were saying they must be using a different type of LNB

    Interesting subject ?

    Thanks
    Brian
     
  7. johnsandywhite

    johnsandywhite Read Only Funster

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    Hi Brain. Yes, we have a Kathrien which actually works as a Diamond from top to bottom. Because of this it equates to a 65cm dish.
     
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