Loss of H polarisation channels

Discussion in 'Satellite TV, Sky TV & FreeSat' started by haribosmum, Feb 2, 2009.

  1. haribosmum

    haribosmum
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    hi all, 1st post so hope this is in the right place. I've been searching for help and keep coming back to this forum so decided to post myself!

    Last week my sky+ lost certain channels BBC1 East (E) and (W), More 4, E4, E4+1 and possibly more, but they're the only ones I've found. I've followed the advice on LNB reset, s/w upgrade and it's had no effect. Went to find the frequencies to add channel and have found that when the polarisation is set to H the error is No Signal Found (and all the above require H not V).

    Does that mean the problem is with the dish rather than the digibox? We've had sky+ for 15mths now so out of warranty and rather than paying the standard £65 I'd be more interested in finding someone local to do it. But want to sound as if I know what I'm talking about! Any advice?
     
  2. Stevenage Neil

    Stevenage Neil
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    Have you tried swapping the LNB input cables on the back of the Sky box, (disconnect the power first)?

    If you can then receive your missing channels your LNB is most likely at fault.

    Neil
     
  3. haribosmum

    haribosmum
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    Hi, yes I swapped the two cables on the back and made sure they were both done up tightly. It made no difference. I haven't looked at the cables outside though, could it be something simple that one of them is loose?
    I don't fancy having a close look in the snow (problem predates the snow though)!

    Thanks.
     
  4. Trollslayer

    Trollslayer
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    It is mostly likely the horizontal polarising filter in the LNB.
     
  5. Stevenage Neil

    Stevenage Neil
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    If you have swapped the cables and things are just the same then it is either a catastrophic LNB failure on all outputs, or your Sky box is not sending out the correct switching voltage, (V to H).

    Just to be certain try a complete power down of the Sky box again.
     
  6. haribosmum

    haribosmum
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    we had this fixed by sky today, it was the LNB that needed replacing. luckily we didn't have to pay the standard fee (£65) as spoke to someone nice in cancellations.
     
  7. SamRadford

    SamRadford
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    Glad you got it fixed painlessly. :)

    Just for technical accuracy, there's no such filter. An LNB has two stub antennas at 90 degrees; one for V and one for H polarisation. The LNB switches to the H antenna when 18 volts is applied and V when 13 volts is applied.
     

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