What no one will tell you about HDTV...

[highdefjeff]

What that means is that the ORIGINAL signal is what is important, what audio and video is being captured and the bit depth that it is captured at.

Data that is transmitted at the depth captured will either work or not work depending on some of the variables you are addressing but it will not lower the quality to another bit depth. Your data is either intact or not intact.

For example, you use a low quality HDMI cable and try to send a 1080p signal over that cable. Because the cable is not able to support the bandwidth required to stream that digital data adequately, you get NO picture, not a reduced quality picture.

On a DBS system, if your signal strength is low, you will get dropouts and other artifacts, or worse, Signal Lost and no picture/audio at all.

The behaviors you are describing are for analog signals, not digital.

Correct. And between dropouts and ARTIFACTs (artifacts aren't loss of picture are they?) is a compromised picture, a picture that doesn't "WOW" like it should.

There is a level of "good" HD and then there is "GREAT" HD.

I also updated the links to more pertinent information. Refresh all pages for new info!

HDTV Help!

 

[highdefjeff]

Here's more

Excerpt from following link:

"The FEC encoder takes preventive measures to protect the transport streams from errors caused by noise and interference in the transmission channel. It includes Reed-Solomon coding, outer interleaving, and convolutional coding. The modulator then converts the FEC protected transport packets into digital symbols that are suitable for transmission in the terrestrial channels. This involves QAM and OFDM in DVB-T and ISDB-T systems, or PAM and VSB in ATSC-T. The final stage is the upper converter, which converts the modulated digital signal into the appropriate RF channel. The sequence of operations in the receiver side is a reverse order of the operations in the transmitter side."

TechOnline | Digital Television Terrestrial Broadcasting Primer

So, the signal IS converted to an RF signal, eh?

 

[8bitbytes]

So, the signal IS converted to an RF signal, eh?

That is where your signal strength is coming from, yes, but, that translates back into a digital signal that is either sufficient for a picture or not.

If you are equating WOW! with a lack of digital artifacts, then you need to look at the signal processing circuitry and not necessarily signal strength. My picture is WOW! all the time, but occasionally I may see a slight localized pixelation in a spot or two or some macroblocking very briefly in a few frames but the picture is still WOW!

Maybe you need to define what you mean by WOW! because what you are trying to say is not clear at all.

 

[AllieVi]

The proof of the pudding is a bit error rate test. I don't accept the claim that errors don't occur just because the signal is locked. The real question is how many errors are there and do different configurations affect the numbers.

 

[SatinKzo]

Now I'm confused. It went from a lower signal lock means less quality pic, to artifacts, blocking and anomolies in the picture (which at time have nothing to do with signal strength).

Like 8bit says, what type of WOW are we talking? Flawless encoding, transmission, decoding, display or are you still saying that increasing signal strength automatically increases PQ?

 

[lakebum431]

I think the OP is grasping at straws to try to find something that makes his statements sound less ridiculous.

 

[Hemi 6.1]

What is the point of this thread? If a signal is peaked its peaked. Done!!! Most of what I've heard is complete BS. HD is only going to be as good as your equipment would let it. A singnal strength in the 70's verses one in the 90's is not going to make any difference what so ever when it comes to satellites digital signal. Sorry but I'm not buying that for one minute.Voltage drop I would say is possible, Over 100 feet.But what's not making any sence is you get what you get with your signal. How can an amp,improve a signal to your dish?It can't. You can't mount an amp. in thin air. .All it can do is bring back lost voltage from the dish to your receiver. If your dish is peaked its Peaked.

 

[8bitbytes]

The proof of the pudding is a bit error rate test. I don't accept the claim that errors don't occur just because the signal is locked. The real question is how many errors are there and do different configurations affect the numbers.

Nobody said errors don't occur. Of course they do. Even at 100% signal strength - that's just the signal, not the original source.

IF you examine your picture frame by frame WITHOUT any signal processing then you might be able to see something less than the mystical WOW! but is real life applications, you will not see any difference between an image from a 70% signal and a 100% signal. I can turn my OTA antenna on my computer right NOW and capture all the data you want and my picture is still the same, 1920 x 1080 @ 19.2 mbps. I can vary the snr from 21 to 31db and the picture is still the same.

Now, is it important to get the strongest signal possible? Of course! Is the signal strength to blame if your Vizio doesn't look as good as my Bravia XBR3? No.

 

[KAB]

"WOW" turned upside down is..."MOM", your son is spending way too much time on the internet!

 

[highdefjeff]

I agree, if it is peaked...no problem

What is the point of this thread? If a signal is peaked its peaked. Done!!! Most of what I've heard is complete BS. HD is only going to be as good as your equipment would let it. A singnal strength in the 70's verses one in the 90's is not going to make any difference what so ever when it comes to satellites digital signal. Sorry but I'm not buying that for one minute.Voltage drop I would say is possible, Over 100 feet.But what's not making any sence is you get what you get with your signal. How can an amp,improve a signal to your dish?It can't. You can't mount an amp. in thin air. .All it can do is bring back lost voltage from the dish to your receiver. If your dish is peaked its Peaked.

I'm talking about marginal signal, not peaked dishes.
I'm talking about watching that marginal signal that gives you intermittent areas of pixelation even though the signal is locked. Haven't you been to a house where the receiver is very slow to respond on channel changes, then checked the signal, to find it was low? After repeaking the dish, the receiver now works at the normal time interval for a channel change?

I'm talking about poor quality signal with OTA. Signal to noise ratio, and other error causing agents.

As far as voltage, I am referring to a receiver that is not back-feeding the proper voltage (under) but still is working. One that when you test voltage, you would replace it. It would not be so low as to be completely dead.

If all you do is install, you'll never see this. When you go to find out what's wrong with a system, you might find this.

This is an effect that requires attention to detail to see, and having seen many renditions of HDTV.

If you haven't checked the image quality of the HD set before setting about to correct whatever problem you've been sent to fix, you won't see it.

This is the smallest detail of great HDTV. It is the last consideration if you've tried everything else. (In satellite, if you've truly peaked the dish, you won't see this unless you're troubleshooting someone else's work.
With OTA you need to use a meter for the best point, and always (my opinion) add a signal amplifier/improver.)

I went to somewhere around 600 service calls from May 2006 through January 2007. Only one call was about picture quality. (They had gotten spoiled and thought there was a problem with the SD on their big TV.) What was astonishing was that of all those who had Dish HD installed, only 4 customers where watching HD. NONE of those calls where about picture quality, yet when I went to fix signal issues or whatever, I checked the HD because I LOVE HD! The highest percentage of them where watching the default Enhanced Definition of the HD receivers. Having seen and dealt with 100's of HDTV's, I want them all to look as good as the best ones, and a person can be watching HD that is not as good it could be, if some of the mentioned conditions exist (too low of voltage back-feed, marginally pointed dish, or poor (signal to noise) quality signal .

 

[Foxbat]

With OTA you need to use a meter for the best point, and always (my opinion) add a signal amplifier/improver.)

Using an analog meter for OTA tuning means you may have the strongest signal, but if that signal is being contaminated with reflected signals, it will produce sub-standard digital reception. Likewise, always adding a signal amplifier can take a strong signal and by applying a fixed level of amplification, create a signal that overloads the front end of the OTA tuner, again creating the opposite effect than you want.

Signal Improver? You mean like those metalized plastic stickers you stick in a cell phone that claim to let you make phone calls from inside an elevator? Or are you referring to some other SPAM-happy device that prey on peoples' misunderstanding of ATSC? Like an HDTV antenna? Here's a clue: Garbage In, Garbage Out. If your antenna is not aimed to provide a signal with the fewest errors (usually by peaking with the TV's or STB's signal quality meter, adding noise by amplification is not the answer.

Now, if you're doing an installation 30-80 miles from the transmitters, an antenna-mounted pre-amplifier will boost the signal strength of whatever the antenna can pick up, overcoming the signal loss that will occur in the RG-6 downlead. In that case, a pre-amp is a good idea. But you can't make a blanket statement like "always add a signal amplifier".

Wow! Where did that come from?

 

[lakebum431]

and always (my opinion) add a signal amplifier/improver.)

You know what they say about opinions. They are like ***holes, everyone has one, yours just stinks more than mine.

 

[highdefjeff]

That is where your signal strength is coming from, yes, but, that translates back into a digital signal that is either sufficient for a picture or not.

If you are equating WOW! with a lack of digital artifacts, then you need to look at the signal processing circuitry and not necessarily signal strength. My picture is WOW! all the time, but occasionally I may see a slight localized pixelation in a spot or two or some macroblocking very briefly in a few frames but the picture is still WOW!

Maybe you need to define what you mean by WOW! because what you are trying to say is not clear at all.

It is a small but noticeable difference in detail (lack of). I don't know how better to describe it, but it happens. Haven't you seen differences in HD? You probably have seen the ones that grab you as soon as you turn it on, and others that aren't so good? You probably attributed that to the difference in TV's, brand, 720 vs. 1080, etc. This is the "amount" of difference I'm talking about, but, it's not always the TV or brand. I am certain that installation is overall way more important than 720 vs. 1080.
You may have not seen it or noticed it or even considered the possibility, but realize that 6 million people out there THINK they're watching HD and aren't. (Not because of the above mentioned issues, but because of perception and confusion.)

Hopefully, technicians will take it upon themselves to dig for answers and help the digital transition happen!

 

[highdefjeff]

In the context of marginal or poor quality signal

Using an analog meter for OTA tuning means you may have the strongest signal, but if that signal is being contaminated with reflected signals, it will produce sub-standard digital reception. Likewise, always adding a signal amplifier can take a strong signal and by applying a fixed level of amplification, create a signal that overloads the front end of the OTA tuner, again creating the opposite effect than you want.

Signal Improver? You mean like those metalized plastic stickers you stick in a cell phone that claim to let you make phone calls from inside an elevator? Or are you referring to some other SPAM-happy device that prey on peoples' misunderstanding of ATSC? Like an HDTV antenna? Here's a clue: Garbage In, Garbage Out. If your antenna is not aimed to provide a signal with the fewest errors (usually by peaking with the TV's or STB's signal quality meter, adding noise by amplification is not the answer.

Now, if you're doing an installation 30-80 miles from the transmitters, an antenna-mounted pre-amplifier will boost the signal strength of whatever the antenna can pick up, overcoming the signal loss that will occur in the RG-6 downlead. In that case, a pre-amp is a good idea. But you can't make a blanket statement like "always add a signal amplifier".

Wow! Where did that come from?

In the context of marginal signal or poor signal quality, always add a signal amplifier or improver to increase or clean up the signal.

I always say that if it is not broken, don't fix it.

 

[highdefjeff]

Of those who voted...

And if I where a betting man, for those who voted, I would say these things:

The ones who voted "I have" are probably some of the best technicians out there.
I'd bet they are troubleshooters or "Top" guys in their organizations.
I'd also bet they have high attention to detail skills and take pride in their work.

 

[Hemi 6.1]

And if I where a betting man, for those who voted, I would say these things:

The ones who voted "I have" are probably some of the best technicians out there.
I'd bet they are troubleshooters or "Top" guys in their organizations.
I'd also bet they have high attention to detail skills and take pride in their work.

Thats your Opinion. I don't talk people into buying crap they don't need for an install. Its a waste of everyones money. Taking pride in you work also means doing the job right without the BS extras.I 'd like to know what makes you think you can judge anyones work here? Just because you think your right don't make it so. Sorry.If I wouldn't do it to my own house ,I sure as %ell would't do it to anyone elses.I think every Installer here takes a lot of pride in their work.They are here learning and giving info,spending free time to do this. The ones that aren't on the Satellites guys website are the ones that are there just for the pay check.

 

[Hemi 6.1]

I've learned more here about satellite tv in the few months I've been here,then in the last 15 years. I give a thumbs up to all Installers on Satellite Guys. And a thumbs up to ALL of its members.:up:up

 

[digiblur]

Plain and simple... better signal strength than a lower signal strength that is locked and working does not obtain a better picture.

Now it does make a difference during a rain storm or something but then the lower signal isn't locked though, so that throws it out. But that's not what we are talking about.

 

[John Kotches]

The proof of the pudding is a bit error rate test. I don't accept the claim that errors don't occur just because the signal is locked. The real question is how many errors are there and do different configurations affect the numbers.

And this is why they have Reed Solomon Code; Interleaving and checksums. So that they can detect and correct bit errors. Depending on what level of checksums they are using; it is possible to recoup from multi-bit errors.

Cheers,

 

[highdefjeff]

All of the extensive work put into Reed Solomon and other related functions are to reduce errors, recover or reproduce digital information. Why? Because digital signal is prone to error and if they didn't, we'd all have crappy picture.

And if your signal is marginal, or corrupted, you can experience a good picture instead of a great one, even in the digital world.