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LNB - how do i check if faulty?

Discussion in 'Satellite TV, Sky TV & FreeSat' started by Trick, Aug 8, 2004.

  1. Trick

    Trick
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    Happily watching sattv this morning, then went outside for a bit, came back in and the sat is now displaying "no satelite signal received".

    Box is ok, cause i tried it on a friends dish. So i presume my dish is faulty - but what actually fails? i have seen some people mention the lnb - whatever that is - how do i check if that has failed?

    surely it cant be my dish being out of line cause its a solid installation and ive been happily watching it....
     
  2. WScarlet

    WScarlet
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    Well i had a similar problem a couple of months back when we had strong winds today we are having strong winds, the LNB is the thing at the point of your dish that collects the signal and puts it down your cable into your box, only thing i can really say is check that your LNB hasn't been blown off the pole or anythink that doesn't look right as thats what happened to mine :/
     
  3. Chris Muriel

    Chris Muriel
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    LNB stands for Low Noise Block (down)Converter; on standard $ky systems it is actually an LNBF (LNB with integral Feedhorn).
    The feedhorn "illuminates the dish" - has to pick up the satellite signals that the dish received. The satellite beams your channels down in Ku band - 10.9 to 12.7 GHz.
    The LNBF downconverts these difficult frequencies in to the range 950-2100 MHz or so - the IF or Intermediate Frequency. This is what feeds the F-type socket on your digibox.
    You may have a faulty LNBF ; you could just as easily have a misaligned dish - it could have physically moved due to wind or being knocked by a window cleaner's ladder.
    It also possibly that the dish hasn't moved but the LNBF or its clamp has moved .
    See http://www.netcentral.co.uk/satcure/lnb.htm

    and http://www.satcure.co.uk/tech/

    Chris Muriel, Manchester.
     
  4. Trick

    Trick
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    cheers
     
  5. STOWITBELOW

    STOWITBELOW
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    Trick, Lnbs come in several flavours, they are the bit on the end of the arm that picks up the signal collected from the dish. If it's a duel Lnb it is in fact 2 in one & these are usualy fitted. (quads are fitted to + set ups) Perhaps trying the 2nd connection may help identify the fault as either alignment or Lnb failure. They do fail, & are replaced fairly 'often' if there is a poor signal, & the dish is pointing in the correct direction. I don't know if they just fail, but certainly deteriorate. Also dont rule out cable failure. It could have become disconnected, but that should be easy to spot.
     
  6. Trick

    Trick
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    turned the box on today and its working again..hmmmm
    Ive got a sat guy coming to check it today...
     
  7. JamesE

    JamesE
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    Most commom fault is an F-plug problem - you only have to look at them and they can fall off. Try pulling on the cable and if it comes out of the F-plug then remake the end.
     
  8. GGTVBD

    GGTVBD
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    Cobblers! :laugh: :devil:

    A. Dork
     
  9. Fernsehman

    Fernsehman
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    Duel? Don't try to confuse the beginners. The correct term is "twin-output LNB" and it has nothing to do with sword fighting. ;)
     

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