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NTSC (480i) on Sky

  • 04-04-2010 5:38pm
    #1
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭


    Was flicking around on the parents digibox and noticed that on a couple of channels (US based religious stuff*) the picture (including the search/scan banner) went all B&W

    The digibox is an aincent Panasonic and the TV was an even more aincent Samsung fed via an RF connection

    Do some channels on 28E broadcast in 480i and do some digiboxes attempt to output this as an NTSC signal.

    Incidently the audio on some of these channels was shockingly bad (virtually unintelligable). Does anyone actually watch this stuff ?

    * Yes I was bored


Comments

  • #2
    pa990
    Registered Users, Registered Users 2 Posts: 3,883 ✭✭✭pa990


    had that prob with a digi box years ago.. The video card packed up less than a year later.
    It might be a sign of the box on its way out


  • #3
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    The channels in question are 593 ("Faith") and 594 (KICC)

    Have also tried running an old JVC from the box in question results even stranger

    Picture colour on these channels but goes into B&W if I switch the TV itself to a terrestrial channel and then back to satellite.

    Only way to get it back into colour is to is to switch the TV to a terrestrial channel again or to switch the digibox to a channel other than 593 or 594 :confused:

    It crossed my mind that there may be some kind of chroma carrier instability issue but why should it be only apparent on two channels ?


  • #4
    Antenna
    Registered Users, Registered Users 2 Posts: 2,360 ✭✭✭Antenna


    Mike 1972 wrote: »
    Was flicking around on the parents digibox and noticed that on a couple of channels (US based religious stuff*) the picture (including the search/scan banner) went all B&W

    The digibox is an aincent Panasonic and the TV was an even more aincent Samsung fed via an RF connection

    Do some channels on 28E broadcast in 480i and do some digiboxes attempt to output this as an NTSC signal.

    Incidently the audio on some of these channels was shockingly bad (virtually unintelligable). Does anyone actually watch this stuff ?

    * Yes I was bored


    Only came across this thread a few days ago.

    Checked those channels and they were the normal '576i' (or '625 line' in analogue speak) - this on a FTA receiver set to output in the native format .

    Its possible they were temporarily 480i (525 line/60Hz field) for some reason?

    Any on-screen menus of the TV would be vertically stretched from the usual if it were displaying a 480i/'525 line' picture instead of the usual 576i/625line. This is the case with TVs I use.

    Also you are probably well aware of interference caused by harmonics of the line scan in CRT TVs to nearby LW/MW radio reception.
    With 625 line - theres a 2kHz whistle on RTE 252LW (16th TV line harmonic on 250kHz)
    However with the american 525 line (480i) displayed its a much lower frequency drone sound interference on RTE 252LW!


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