S-Video ground pins commoned

Discussion in 'Cables & Switches' started by Gazz, Mar 13, 2006.

  1. Gazz

    Gazz
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    Hi all,
    I'm currently running a composite video feed from a Sky+ box to a 29" TV in a different room through a number of walls and under floors. The cable is a twin core + screen low loss video cable (one core not used). I'm shortly going to purchase a plasma TV.
    Now, I'd like to feed the plasma an S-vid signal, but running a new cable now everything's decorated is a bit of a prob, so I was toying with the idea of trying to use the existing cable run for an S-vid signal.
    Can any of you let me know if it's possible to use the two cores for the Chroma and Lumi +ve signals but short pins 3 and 4 and use the cable screen as a common Chroma/Lumi ground? Or am I being hopelessly optimistic and it'll render the picture no better than composite (or indeed not work at all)?
    Thanks for your collective expertees.
    Gary
     
  2. stevelup

    stevelup
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    Hi

    If it's two core + a single overall screen, it can't be coaxial - therefore it can't by definition be video cable?

    What you are proposiing will work - the screens are usually commoned at the device end anyway - I'm just puzzled as to what your cable is.

    Steve
     
  3. Gazz

    Gazz
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    Ah - yes, I see your point - two parallel cores wouldn't be coaxial, would they. And, oops again, I meant to say that it was low loss audio cable (the sort of thing used as high performance microphone cable when running balanced (or indeed unbalanced) signals to XLR connectors). That'll teach me to dash off a thread at the end of the day without checking it.
    I'm glad to hear that connecting the one screen to both ground pins will work though - that'll save a lot of time. Of course, I'm making a leap of faith that the cable is of suitable impedance and interference rejection for an S-video signal, but it's currently carrying a composite video signal on one core and the screen with no noticeable softening of the picture at the receiving end so it would seem hopeful.
    Worth a bash, do you think?
     
  4. stevelup

    stevelup
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    If it's working OK now carrying composite, I can't see any reason why it won't work for s-video.

    Give it a go!

    Steve
     
  5. Gazz

    Gazz
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    Great news (insert little smiley dancing a jig).
    Thanks for that Steve - sounds like I can avoid ripping out plasterboard and flooring and stay on good terms with the wife.
     

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