SKY Picture quality on PLasma TV

pablo21

Steady now Lad's and Lassies, its just a discussion here, no need to take anybodys head off!

I've tried two different sky box's but neither have anything more than scart and RF connectivity.

I'm sitting the same distance from the TV as I always have, Its roughly 3-4 metres from the telly. Thats the farthest I can get from it in my sitting room! Wouldnt that be fairly standard in an average size house? Thats not belittling your point poster but that is as far as I can comfortably get from it.

I know the difference between a good picture and a bad picture and the picture from sky is bad. The picture on component dvd is very good. Those are the facts.

The information I have gleaned from this thread is that its quiet likely that sky broadcast quality is crap but the only options available to me to improve on that is upgrade to HD or try a high quality SCART Cable.

Many thanks for all your inputs.

Idleater

pablo21 wrote:

The information I have gleaned from this thread is that its quiet likely that sky broadcast quality is crap but the only options available to me to improve on that is upgrade to HD or try a high quality SCART Cable.

No problem, and I hope you do resolve your issue somewhat with a good scart cable.

andy1249 wrote:

If you think for one minute that an analog cable is more tolerant of noise than a Digital one then its your knowledge of Digital that is sadly lacking , what the hell do you think this whole digital revolution is about anyways !!

Since my knowledge is completely lacking, and I have no idea what I am talking about, but you are so right, I suggest you read up on the differences between various connection methods for transferring video.

Here is a good article to get you started.

For example:

First, there is no reason why any perceptible degradation of an analog component video signal should occur even over rather substantial distances; the maximum runs in home theater installations do not present a challenge for analog cabling built to professional standards. Second, it is a flawed assumption to suppose that digital signal handling is always error-free. DVI and HDMI signals aren't subject to error correction; once information is lost, it's lost for good.

and

The argument often made for the DVI or HDMI signal formats is the "pure digital" argument--that by taking a digital recording, and rendering it straight into digital form as a DVI or HDMI signal, and then delivering that digital signal straight to the display, there is a sort of a perfect no-loss-and-no-alteration-of-information signal chain. If the display itself is a native digital display (e.g. an LCD or Plasma display), the argument goes, the signal never has to undergo digital-to-analog conversion and therefore is less altered along the way.
That might be true, were it not for the fact that digital signals are encoded in different ways and have to be converted, and that these signals have to be scaled and processed to be displayed. Consequently, there are always conversions going on, and these conversions aren't always easy going. "Digital to digital" conversion is no more a guarantee of signal quality than "digital to analog," and in practice may be substantially worse. Whether it's better or worse will depend upon the circuitry involved.

and

Analog component video is an extremely robust signal type, without any need for boosters, relays or other special equipment, up to 200 feet without any signal quality issues at all.
DVI and HDMI, unfortunately, are not so robust. The problem here is the same as the virtue of analog component: tight control over impedance. When the professional video industry went to digital signals, it settled upon a standard--SDI, serial digital video--which was designed to be run in coaxial cables, where impedance can be controlled very tightly, and consequently, uncompressed, full-blown HD signals can be run hundreds of feet with no loss of information in SDI. For reasons known only to the designers of the DVI and HDMI standards, this very sound design principle was ignored; instead of coaxial cable, the DVI and HDMI signals are run balanced, through twisted-pair cable. The best twisted pair cables control impedance to about +/- 10%. When a digital signal is run through a cable, the edges of the bits (represented by sudden transitions in voltage) round off, and the rounding increases dramatically with distance. Meanwhile, poor control over impedance results in signal reflections--portions of the signal bounce off of the display end of the line, propagate back down the cable, and return, interfering with later information in the same bitstream. At some point, the data become unrecoverable, and with no error correction available, there's no way to restore the lost information.
DVI and HDMI connections, for this reason, are subject to the "digital cliff" phenomenon.

L.

andy1249

Nereid ,

Thats all sensationalist technophobic garbage ,typical of that particular forum , the fact is that digital is the only way to ensure an unaltered path for any signal from point A to point B.

I suggest you read some engineering text or at the very least some properly supported electronic theory !

Any one of these should do you to start with !!

http://www.amazon.com/s/ref=br_ss_hs/102-2389466-6402516?platform=gurupa&url=index%3Dblended&keywords=principles+of+digital&Go.x=8&Go.y=12

When a digital signal is run through a cable, the edges of the bits (represented by sudden transitions in voltage) round off, and the rounding increases dramatically with distance. Meanwhile, poor control over impedance results in signal reflections--portions of the signal bounce off of the display end of the line, propagate back down the cable, and return, interfering with later information in the same bitstream. At some point, the data become unrecoverable, and with no error correction available, there's no way to restore the lost information.
DVI and HDMI connections, for this reason, are subject to the "digital cliff" phenomenon.

This last piece of text for example , shows a marked misunderstanding of how digital works and is applying analog signal loss principles to a digital signal.
Digital signals are encoded analog signals and as such the " rounding " of the edges matters little , all that has to be done is for the code to make it from one end to the other , this is why digital is so robust , it survives all the rounding of the edges , the reflections , etc. and rebuilds the analog signal at the recieving end from the transmitted code with no loss , regardless of the conditions of the line.
The cliff phenomena , rather than being a bad thing is a good thing , in that a digital line either works , at full quality , or doesnt work at all full stop , there are no degrees of quality in terms of the cable , its either good or its not !! full stop !!

I personally have had real and significant problems with bad analog cable , scarts in particular are dreadful in this respect , the quality and resulting noise can be terrible. So that article to me is ridiculous , as for component , while thats a lot better , it can still suck with cheap cable.

andy1249

For reasons known only to the designers of the DVI and HDMI standards, this very sound design principle was ignored; instead of coaxial cable, the DVI and HDMI signals are run balanced, through twisted-pair cable.

Just to add , a twisted pair cable in a balanced line configuration has one of the best noise immunities available , see link below for basic details , the math can be found in the books above , its neater and more efficient for home use than most cables

http://en.wikipedia.org/wiki/Balanced_line