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Sky digital and 100hz TV's

Discussion in 'TVs' started by audiop, Dec 17, 2004.

  1. audiop

    audiop
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    I have just bought a JVC 100hz TV in the hope of experiencing excellent flicker free images and am disappointed to find that the picture (which is sky digital derived) is very poor, there is very obvious pixellation and poor definition. After researching the issue on the web I have read that 100hz TV's are incompatible with Sky digital. Can anyone give me more info on this or point me towards a useful solution - I am considering returning the TV and asking to exchange it for a 50hz model.

    Thanks

    Audiop
     
  2. spocktra

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    It all comes down to source material. 100 htz tvs look great with dvd and a GOOD sky signal .However when the feed loses quality it is shown for what it is.If you cant live with this failing swap it for a good 50htz but i would suggest viewing before as 32"50htz can lose definition.
     
  3. w3dal

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    My 32" Sony 100hz TV gives excellent results from Sky Digital.

    I would never go back to a 50hz TV
     
  4. asdff

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    wat jvc is this?
     
  5. Nick_UK

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    100Hz TV's work by storing one frame of a TV picture in memory, and reading it back twice. If the manufacturer skimps by putting in insufficient memory, or cheap digital-to-analogue converters, the result is pixellated pictures, and bad grey scales. It doesn't matter what the source is.
     
  6. audiop

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    Its an AV32X47HK
     
  7. audiop

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    What can be done to improve the signal quality - would a larger dish than the standard mini-dish improve things ? We live in Devon and I was told that this is not the best part of the UK for signal quality and whereas in other parts of the UK a mini dish suffices, a larger dish is needed here for a top quality picture.
     
  8. Alan D

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    Have you done a signal test on your Sky set up?
    Services (3rd green button at top of remote)
    > System Setup
    > Signal Test
    You get a "signal strength" reading and a "signal quality" reading. If both are below halfway, then it may be the cause of your problems. You could get a Sky engineer to check your dish alignment, but this may be a waste of money - especially if you live in a "difficult area" for Sky. Otherwise worth enquiring about a larger dish (I don't know if Sky do this directly, but a local dealer may help).
    100Hz TVs may be a little more susceptable to weaker signals, but they are really showing up the deficiencies of the signal.
     
  9. spocktra

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    Sky will not provide a larger dish because you would be able to receive channels not controlled by their monopoly.
     
  10. audiop

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    Signal strength and quality both around 50 %.
     
  11. Alan D

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    Maybe the Sky signal isn't the real issue here.
    This is a very basic point (and apologies if it's too obvious), but I assume you are using RGB output from your digibox and feeding into one of the RGB enabled Scarts on the JVC?
    Assuming you are watching an RGB signal - maybe you should explore the settings on the JVC, making sure that e.g. any noise reduction function is either turned down or off. Also ensure picture settings are not too "extreme". These things often come out of the factory with 100% contrast - when approx 50% will give an instantly more natural picture.
    Too much picture processing and too high a contrast setting will also accentuate any pixellation and picture imperfections.
     
  12. Kier

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    The problem isn't the signal quality, it's the data compression. If you've ever played around with JPEG saving on your computer you can see what's going on. When you set the JPEG compression to its lowest level (low compression, high quality) then the resulting image is almost indistinguishable from the original. However, if you drag the quality/compression slider all the way down the image gradually turns to crap but the file size is tiny.

    This is the problem with Sky Digital - the compression is way too aggressive on most channels carried by Sky, resulting in blocky, pixelated images that fall apart completely when the delta information (this is the amount of information that changes between one frame of video and the next) is at a high rate.

    Therefore, it doesn't matter if you have the most expensive TV available and you're using the radio telescope at Jodrell Bank as your minidish, pictures from Sky will still look like crap.

    As a wise friend of mine once said, You can't polish a turd.

    Unfortunately.
     
  13. audiop

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    Thanks to all of you who have replied to this thread - I originally thought it was the TV at fault - however this TV has had such good reviews that assumed something else must be wrong i didn't notice the problem so much on my old panasonic 28" 4:3 set.

    Yes turning all the processing down does help, it does leave me with a very soft image, but thats better than viewing people that look like plastic dummies !
     
  14. audiop

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    Yes I have turned all the settings down and it does help, reducing the sharpness to approx 25% makes a big difference. I assume that features such as JVC's digipure pro and noise reduction are useless with the sky ?
     
  15. spocktra

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    I have yet to see a 100htz that doesnt have SOME kind of digital noise caused by skys poor feed.
     
  16. Cynthia 7

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    When we first had Sky analogue our picture was unwatchable although the dish was mounted on a high pole in the garden. Sky installed it and the more senior of the two men that came said we would need a larger dish although we were really not meant to have it in this area (East Sussex). Because it was out of sight and surrounded by bushes and trees he said no-one would know. We had to pay extra for this but the picture was excellent after. Now we have Sky digital with normal size dish and initially had a bad picture until one tree had to be cut down and others had branches removed. The Sky digital installer said that both signals had to be at least 50% or the picture would be poor with constant or intermittent pixellation.

    I hope it improves for you Audiop.

    I had read that some people have used the large dish with Sky digital and it has solved their picture problems. Probably not a cheap option though to get a contractor in to change this.
     
  17. Pwaaz

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    We had our nw 32" PD50 delivered last night, and the picture from Sky feed is rubbish. I can't watch it, as I'm too entranced by all the shimmering and pixelling to watch the programme! We live in Devon, and checked signal strength last night, it was 50% for both readings. Is it true that a bigger dish would improve things? The Panasonic guy is coming round tonight to check it (and another problem I noticed with the picture from DVD), although they say it would be better from a Freeview feed, I think he's bringing a freeview box to prove to me that this TV is good! Will let you know...
     
  18. Pwaaz

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    The engineer came, and agreed there is a problem with the picture from DVD. Regarding the shimmering, he said this is the nature of a highly processed picture (in which case, what's the point of all this processing?). He said he could bring another set out to see if it's from a better batch, or I could maybe look at another model (TX40) which has a less processed picture. I think all this scanning and processing is emperor's new clothes stuff...
     
  19. red16v

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    I thoroughly recommend the Toshiba 32ZP48 - fed with a Freeview signal. regards, yt.
     
  20. fire boy

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    I just bought the 36" pd50 and my sky+ picture was pants even with !00% signal strenth and 50% but after some contrast and picture tweeks its now a LOT better.
    If using sky+ try check the box is set to RGB and not PAL

    hpor this helps
     
  21. Pwaaz

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    Thanks for that Fire Boy, engineer brought out another set, which over the last week has had a much better picture, sometimes scarily clear when on a good channel. Last 2 days its been pants again, so we will call him back. the man at the Panny shop said they have had some problems with the PD50 pictures and have promised to get everything sorted...
     
  22. mcguire76

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    So can anybody recomend a 32" tv that will give a good picture from Sky+? My current tv is a 28" Toshiba 4:3 which gives a stunning picture with no visible defects, I doubt I that I'de be willing to put up with any visible defects on a brand new tv! :cool: I take it the new Pixel Plus 2 tv's have problems with Sky aswell?
    Cheers........Mark
     
  23. Nick_UK

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    Just a couple of comments :

    Signal strength on Sky is relatively unimportant, but signal quality is. Signal quality is merely the number of errors encountered during processing, and processing errors do result in pixellated pictures.

    Many people who complain about poor quality pictures on Sky and Freeview, are turning the sharpness up way too high on their TV's. The pictures provided by digital TV will always be slightly softer than those seen on analogue TV, and trying to improve the definition of digital TV with the sharpness control will invariably make the picture worse. Increasing the size of any screen will accentuate any shortcomings of the picture content.
     

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