70 may be O.K. but just because signal is locked and you are getting picture doesn't mean you are getting the best picture quality.
What no one will tell you about HDTV...
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70 may be O.K. but just because signal is locked and you are getting picture doesn't mean you are getting the best picture quality.
It's the same "one man's opinion" cah-cah he's been peddling all along.Boy, I wish I could see what you posted jeff, but since you're on my ignore list im out of luck
Go back into hibernation!!!!!
Obviously, you didn't think it worth researching or you would have found what I did. You can see the additional posted links on the site, or better yet, do your own searches about digital signal, noise, signal-to-noise ratio, and artifacts. The definitions should open your eyes to the "digital" signal that we receive.
Don't take my word for it, look for yourselves.
Don't take my word for it, look for yourselves.
Yo, Jeff, you're just scientifically wrong. Consumer digital tuners (e.g. ATSC or satellite tuners) do not subtly degrade picture quality if they don't get all the bits. They block or skip the video. The effects are obvious, and anyone seeing them will notice. It's not a subtle "gee I thought my picture was OK, but now I realize it's a lot better".
The papers you link to are talking about encoding at the source, not decoding at the consumer set-top box or TV.
The effect you are seeing is psychological. You tell people that their picture should be a lot better now, and they think it is. Or you've adjusted some of the settings (e.g. changed their video settings on the TV).
You are spouting the same nonsense that people who sell Monster cables spout. That, somehow, they'll magically make a digital signal "better".
Well, DUH. How else did you think it worked? In the real world (unless you're talking quantum effects) everything is analog. All we do is encode digital information in analog signals, typically RF transmissions, via any number of encoding schemes. This is not news. This is engineering applied to physics.
again, DUH.
It's not really useful to talk about digital TV broadcasts as "analog" because you're just confusing things. When people say analog vs. digital they are talking about the encoding, not the carrier signal. Obviously the carrier is analog. However, digital encoding can transmit video/audio with much less bandwidth than analog encoding. That's why the FCC is sunsetting analog broadcasts, because that way they can conserve bandwidth and return some of the spectrum to other uses.
The papers you link to are talking about encoding at the source, not decoding at the consumer set-top box or TV.
The effect you are seeing is psychological. You tell people that their picture should be a lot better now, and they think it is. Or you've adjusted some of the settings (e.g. changed their video settings on the TV).
You are spouting the same nonsense that people who sell Monster cables spout. That, somehow, they'll magically make a digital signal "better".
Well, DUH. How else did you think it worked? In the real world (unless you're talking quantum effects) everything is analog. All we do is encode digital information in analog signals, typically RF transmissions, via any number of encoding schemes. This is not news. This is engineering applied to physics.
again, DUH.
It's not really useful to talk about digital TV broadcasts as "analog" because you're just confusing things. When people say analog vs. digital they are talking about the encoding, not the carrier signal. Obviously the carrier is analog. However, digital encoding can transmit video/audio with much less bandwidth than analog encoding. That's why the FCC is sunsetting analog broadcasts, because that way they can conserve bandwidth and return some of the spectrum to other uses.
I've scanned through your stuff. You are quite right that many people have simply not enabled HD in their setup, either by having the wrong connections between the STB and the TV, or by not configuring their TV and STB correctly, or (in the case of OTA) not setting up their ATSC tuner on the TV. That is a good call.
However all the stuff about signal strength and picture quality is quite misleading, as I've detailed above (and many others have too).
Because there's no forum or feedback on that website. It's a one way manifesto.
Well since obviously you smoked waaaaaaaayyyyy too much weed let's see if we can explain it again (although I doubt that will help). The below info is coming from someone who works with KU Band & C-Band dishes all the time so I am working with a signal from a source
As noted above
That is the ONLY way more signal will be better in some cases. It doesn't make the picture better. It has to do with FEC (Forward Error Correction). Again this is ONLY at the source. I have tuned my 2 C-Band dishes at pretty much every satellite that I can physically "see" here from Minnesota which is from AMC6 (72W) to AMC8 (137W) and the only channels I have issues with are ones with 7/8 FEC and that is due to the smaller dish I have so there is more room for error. Due to this, on some channels even though I have a 50 quality on the free to air box I still get pixelation. SO in that case (AND THAT CASE ONLY) yes more signal is better. But on 95% of the channels I can see on both C-Band and KU Band a 30 quality (the threshold on my receiver) and a 99 is the same. Picture does not look any different. Even on HD channels. As long as there is enough signal quality for the signal to be stable, the picture is the same. And this is on a 6 foot dish. I have seen a signal of a HD channel at 75 quality and 30 quality (on a 99 scale)...same picture. The fact that Dish/Direct is using much larger dishes, that point is moot. When they re-encode it and beam it back up, it doesn't matter if its a 60 signal or a 120 signal...its the same picture
Jeff
Why can't you just come to terms ,and admit you don't have a clue. Really,, suck it up already.
Why can't you just come to terms ,and admit you don't have a clue. Really,, suck it up already.
what's really funny to me, is there is so much response to this troll, but when someone asks a legitimate question, albeit it may be similar to something else already posted in the forums (maybe not in the HD, but somewhere else), thus may have been overlooked by the person submitting the question, several of you want to have a heart attack or aneurysm and attack the poor soul.
Signal strength and picture quality resolved...
The science confirms my claims. Granted, it was hard to find. Most things written about the subject are written in terms of upper performance limits rather than lower limits; of digital superiority over analog, not that it has the same obstacles to overcome.
Digital is described as more "robust" to the analog influences like ghosting and interference. More robust, not immune.
Prior to the advent of HDTV, we didn't have many choices of picture quality. We didn't need a very discriminating eye to see how superior digital was to analog. In the early days of satellite it was easy to align a dish. All you had to hit was one strong satellite. Early systems had less noise to deal with, also, and before long the digital myth became digital mantra - "Digital is all or nothing", "Signal strength won't effect picture quality", and a host of similar, but incorrect statements.
Today, we have not one strong satellite (119), but we've added 110 (weaker) and, with the advent of HDTV, have added not one but two much weaker satellites. The 129 and 118.7 are about 80% of the strength of 119/110.
Today, we put in much larger systems with multiple receivers, switches, and multi-sat dishes. Technology within our homes and neighborhoods has exploded and wireless technology is everywhere. Today, we put in systems that have much greater noise to overcome.
Multi-sat dishes continue to be a challenge for many technicians with the weak satellite peaking required for the HD.
These factors combine to cause a significant number of systems left with marginal HD signal, and resulting poor quality.
Here's some science for you.
In terms of digital receiver operating specifications, there are a couple of descriptive terms that I found particularly interesting.
The point that we call "signal lock" has a name. It actually has two, both very descriptive. It is called either, the "failure point" or FP by DVB standards, and the ATSC calls it the "Threshold of Visibility or TOV.
It has a definition, too. It is defined in a bit error rate and it is defined in number of corrupted transport packets per time frame.
Failure Point (FP) - In digital receiver reception (DVB-T), the failure point is defined as the lowest rate it is practical to observe requiring an observation interval of about 1.5 minutes, or an average of two correctable transport packets per ten seconds. ATSC defines the failure point as the threshold of visibility (TOV).
With digital receivers this is the beginning. We have a signal but we're only getting enough information for a corrupted picture.
We have to reach the QEF condition. What is the QEF condition? It is called the "Quasi-Error Free" condition. Another descriptive term with "Quasi" meaning "semi" or "Sort-of", error free condition.
With bit error rates we aren't required to remove all of the errors, there are awesome error correction measures in the digital receiver. We have to reduce the bit error rate to a manageable level.
QEF - Quasi Error Free The QEF point is the error rate where the reed solomon code reaches the limit of its correction ability for white noise degradation. Strictly, the QEF is defined as 1 uncorrectable transport packet per hour; or bit error ratio of 2E-4 after the Viterbi decoder for ATSC and DVB-T. For cable TV the system FEC is optimized for quasi error free operation at a threshold output error event rate of one error event per 15 minutes.
As you increase signal you reduce the bit error rate to where you have enough uncorrupted information to produce the "perfect" digital picture. (The QEF condition)
In Dish terms (old meter) lets say that the FP is 50. The QEF is definitely achieved by 70. (Of course, it is impossible to have one reading for everyone due to differences in systems.)
But, what if we stopped there at the QEF point? If we did, picture would be great until any additional noise or signal drop came along.
The amount of signal that you have, above the QEF point, is what is available to counteract weather and noise influences. If you're only a few points above the QEF, a small rain shower would put you under the QEF, and could compromise the picture even though you still have lock.
Now consider again the weak HD satellites. They don't have from 70 to 115 signal strength (45 points of signal strength) to overcome noise like 119 does. The HD satellites are not even capable of receiving as much noise fighting signal in the first place. They might have from 70 to 85 signal strength to work with, or 15 points. A storm only has to lower the signal by 16 points to dip below the QEF. If your signal isn't maxed, it won't take much at all to dip below the QEF! This is why it becomes CRITICAL to max the HD signals!
You may think this isn't a problem, but the poll suggests that over 20% of installers have experienced systems in the "below QEF" condition. That alone suggests that the potential of customers existing below QEF (especially now in terms of HD), is quite large indeed.
Due to the poor skills and understanding of some technicians, and other reasons mentioned above, many are left complaining about Dish's poor picture quality. My experience says that Dish quality is second, only slightly, to good OTA. I don't believe that there is any reason why people should be complaining about quality, unless they've checked everything else and when they ask if it could be their low signal strength, they are told "No."
All the science and references are here:
Signal and HD
And to all who contributed to the thread, thanks for playing!
:
The science confirms my claims. Granted, it was hard to find. Most things written about the subject are written in terms of upper performance limits rather than lower limits; of digital superiority over analog, not that it has the same obstacles to overcome.
Digital is described as more "robust" to the analog influences like ghosting and interference. More robust, not immune.
Prior to the advent of HDTV, we didn't have many choices of picture quality. We didn't need a very discriminating eye to see how superior digital was to analog. In the early days of satellite it was easy to align a dish. All you had to hit was one strong satellite. Early systems had less noise to deal with, also, and before long the digital myth became digital mantra - "Digital is all or nothing", "Signal strength won't effect picture quality", and a host of similar, but incorrect statements.
Today, we have not one strong satellite (119), but we've added 110 (weaker) and, with the advent of HDTV, have added not one but two much weaker satellites. The 129 and 118.7 are about 80% of the strength of 119/110.
Today, we put in much larger systems with multiple receivers, switches, and multi-sat dishes. Technology within our homes and neighborhoods has exploded and wireless technology is everywhere. Today, we put in systems that have much greater noise to overcome.
Multi-sat dishes continue to be a challenge for many technicians with the weak satellite peaking required for the HD.
These factors combine to cause a significant number of systems left with marginal HD signal, and resulting poor quality.
Here's some science for you.
In terms of digital receiver operating specifications, there are a couple of descriptive terms that I found particularly interesting.
The point that we call "signal lock" has a name. It actually has two, both very descriptive. It is called either, the "failure point" or FP by DVB standards, and the ATSC calls it the "Threshold of Visibility or TOV.
It has a definition, too. It is defined in a bit error rate and it is defined in number of corrupted transport packets per time frame.
Failure Point (FP) - In digital receiver reception (DVB-T), the failure point is defined as the lowest rate it is practical to observe requiring an observation interval of about 1.5 minutes, or an average of two correctable transport packets per ten seconds. ATSC defines the failure point as the threshold of visibility (TOV).
With digital receivers this is the beginning. We have a signal but we're only getting enough information for a corrupted picture.
We have to reach the QEF condition. What is the QEF condition? It is called the "Quasi-Error Free" condition. Another descriptive term with "Quasi" meaning "semi" or "Sort-of", error free condition.
With bit error rates we aren't required to remove all of the errors, there are awesome error correction measures in the digital receiver. We have to reduce the bit error rate to a manageable level.
QEF - Quasi Error Free The QEF point is the error rate where the reed solomon code reaches the limit of its correction ability for white noise degradation. Strictly, the QEF is defined as 1 uncorrectable transport packet per hour; or bit error ratio of 2E-4 after the Viterbi decoder for ATSC and DVB-T. For cable TV the system FEC is optimized for quasi error free operation at a threshold output error event rate of one error event per 15 minutes.
As you increase signal you reduce the bit error rate to where you have enough uncorrupted information to produce the "perfect" digital picture. (The QEF condition)
In Dish terms (old meter) lets say that the FP is 50. The QEF is definitely achieved by 70. (Of course, it is impossible to have one reading for everyone due to differences in systems.)
But, what if we stopped there at the QEF point? If we did, picture would be great until any additional noise or signal drop came along.
The amount of signal that you have, above the QEF point, is what is available to counteract weather and noise influences. If you're only a few points above the QEF, a small rain shower would put you under the QEF, and could compromise the picture even though you still have lock.
Now consider again the weak HD satellites. They don't have from 70 to 115 signal strength (45 points of signal strength) to overcome noise like 119 does. The HD satellites are not even capable of receiving as much noise fighting signal in the first place. They might have from 70 to 85 signal strength to work with, or 15 points. A storm only has to lower the signal by 16 points to dip below the QEF. If your signal isn't maxed, it won't take much at all to dip below the QEF! This is why it becomes CRITICAL to max the HD signals!
You may think this isn't a problem, but the poll suggests that over 20% of installers have experienced systems in the "below QEF" condition. That alone suggests that the potential of customers existing below QEF (especially now in terms of HD), is quite large indeed.
Due to the poor skills and understanding of some technicians, and other reasons mentioned above, many are left complaining about Dish's poor picture quality. My experience says that Dish quality is second, only slightly, to good OTA. I don't believe that there is any reason why people should be complaining about quality, unless they've checked everything else and when they ask if it could be their low signal strength, they are told "No."
All the science and references are here:
Signal and HD
And to all who contributed to the thread, thanks for playing!
:
Wow.. You had to search for 5 months to find an article that agrees with your logic. You are persistent.
I'm not going to say that its wrong or right. But I would like to see more sources as I found this definition on the very same web site you are using as a source.
Cliff Effect - When approaching the fringes of reception, analog TV pictures begin to degrade by becoming "snowy." By contrast, when in a weak digital signal area, a relatively small change in received power may cause the DTV picture to abruptly change from perfect to nothing; hence the name, "cliff effect."
The perfect or nothing kind of contradicts the other article, no? You may want to ask them to clarify.
I'm not going to say that its wrong or right. But I would like to see more sources as I found this definition on the very same web site you are using as a source.
Cliff Effect - When approaching the fringes of reception, analog TV pictures begin to degrade by becoming "snowy." By contrast, when in a weak digital signal area, a relatively small change in received power may cause the DTV picture to abruptly change from perfect to nothing; hence the name, "cliff effect."
The perfect or nothing kind of contradicts the other article, no? You may want to ask them to clarify.
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"and could compromise the picture even though you still have lock" - now give us explanation of the term "compromise the picture" in technical manner.
Of course I included the definition...
The science is all there on the website with links to all technical information. Of course I included the definition in the glossary, but, I'll help you and give you the references:
The rest and more is on the website.
The science is all there on the website with links to all technical information. Of course I included the definition in the glossary, but, I'll help you and give you the references:
"Results of RF measurements with DVB-T chip-set and comparison with ATSC performance" http://www.bbc.co.uk/rd/pubs/papers/pdffiles/crn-dvbtm.pdf
"Performance Comparison of ATSC 8-VSB and DVB-T COFDM Transmission Systems for Digital Television Terrestrial Broadcasting" http://paginas.fe.up.pt/~mandrade/tvd/2003/docs/DVB/ATSC/ICCE99paper.pdf
"Lab Report 98/01 Section 1: Australian Laboratory Testing of Modulation Systems" Lab Report 98/01 Section 1: Australian Laboratory Testing of Modulation Systems for DTTBThe rest and more is on the website.
I would love to...
Technically, it is described by bit error ratio, or corrupted transport packets/time ratio as mentioned above.
The picture is described in a number of ways. It can be blurry, grainy, blotchy, and lacking detail.
Unfortunately, the difference between objective measurements and subjective measurements, or the correlation between the two, is difficult.
It is so difficult, there is an entire government agency dedicated to figuring that out.
Video Quality Research Home Page
Technically, it is described by bit error ratio, or corrupted transport packets/time ratio as mentioned above.
The picture is described in a number of ways. It can be blurry, grainy, blotchy, and lacking detail.
Unfortunately, the difference between objective measurements and subjective measurements, or the correlation between the two, is difficult.
It is so difficult, there is an entire government agency dedicated to figuring that out.
Video Quality Research Home Page
Now, show me how missing packets could "blurry, grainy, blotchy, and lacking detail".
Step by step please.
Step by step please.
You included the definition in the glossary? Are you saying that is your website that you reference???
