Does dish signal strength affect picture quality?

[andyg]

Hello guys,

I've been puzzled by this recently. Does the dish signal strength actually directly correlate with picture quality that you get?
Or is the dish signal strength just a matter of reliability of signal (say more stable during certain weather), but not the actual quality of picture?

I am getting signal strength of between 51 - 68 on my dish network system. I never received any pixelated images even when it was slightly raining (I have not tested it yet with heavy rain). However, sometimes when I watch certain programming, especially sports like hockey, the screen appears to be a little fuzzy or have grains on it or basically not sharp enough when the images are moving, not when the picture is steady focused on one player let's say. It is hard to see the puck moving around the ice sometimes even.

So is it because of my signal strength that I am getting from my dish, or does the signal strength not affect picture quality at all?
One guy I heard said that it does affect picture quality, another one I heard saying that nope..since it is digital signal you either get it or not (if it was something wrong wit it, you would get pixelation)...anyway please let me know your ideas.

thanks,
andy

 

[Jared Twomey]

nope... signal strength shouldnt effect the picture at all. It is a digital stream that is being sent down, so you either have it or you don't.
the only thing you would see is the pixelating if it started to loose signal while you are watching it.
the fuzzyness is probably the channel being compressed too much, but i'm sure someone will chime in with a more acurate explanation of the degraded picture

 

[JimK2]

The range of good picture and no picture is very narrow with macro blocking and pixilation between the two. I had the experience of weak signal and when the evening fog would slowly roll it would be a good picture, then extreme macro blocking, pixilation and then no picture.

 

[andyg]

The range of good picture and no picture is very narrow with macro blocking and pixilation between the two. I had the experience of weak signal and when the evening fog would slowly roll it would be a good picture, then extreme macro blocking, pixilation and then no picture.

do you have pictures of what macroblocking and pixelation looks like on TV?
Also..are "motion artifacts" another possible "side effect"?

thanks

 

[andyg]

nope... signal strength shouldnt effect the picture at all. It is a digital stream that is being sent down, so you either have it or you don't.
the only thing you would see is the pixelating if it started to loose signal while you are watching it.
the fuzzyness is probably the channel being compressed too much, but i'm sure someone will chime in with a more acurate explanation of the degraded picture

that's what I was thinking too..but wanted somebody like you to confirm it. I also noticed, although I am not 100% sure, that it happens more or less on one of my TVs, the other TVs do not have that problem picture that I described, or maybe I just have not noticed it yet, since I mostly watch the first TV that is having problems.

 

[fhsucade07]

The range of good picture and no picture is very narrow with macro blocking and pixilation between the two. I had the experience of weak signal and when the evening fog would slowly roll it would be a good picture, then extreme macro blocking, pixilation and then no picture.

Ditto. I ordered the Charlotte locals (from Northeast Georgia) toward the beginning of the football season figuring I would get to see a couple of different NFL games (mainly the Panthers). Ironically, my CBS (NPS Atlanta) and the Charlotte CBS are usually showing the same game unless one is carrying the Falcons or Panthers when they are playing an AFC team. Regardless, with the drought of rain we have experienced, I had perfect picture quality with a signal that ranged between 41 - 50. However, when the clouds slowly came in (whether they had rain or not), it would quickly give an extreme pixilation and, in a matter of what seemed like seconds, there would be no picture at all. Two years earlier, I had Cincinatti with a signal strength of about 60 - 63 and even when it rained, I rarely lost signal.

The only thing I have ever really experienced (with my service) that has knocked everything out for the course of several hours has been an ice storm. Even when we have had snow in the area (9 inches one morning last February), it didn't knock the DISH out. Of course, I generally have a signal strength of about 100 -- the lowest signal will come from a market I have "moved" to.

Cade

 

[vegassatellite]

Nearly all digital transmissions use a means of fixing missing data using a scheme called FEC (Forward Error Correction). What this means is that there is extra information supplied that tells the receiver what to display in place of missing bits of data such as pixels. If you are looking at a sports announcer in a red jacket, there might be several shades of red throughout the image of the jacket for things like shadows, lighting, etc. However, there will also be data that says if any pixels are missing in the grids where the jacket is shown onscreen to just replace them with a particular generic red color sent in the FEC data stream. Obviously, a few lost pixels would still yield a good looking reproduction of the sportcaster's jacket. However, many of these pixels get lost and the jacket appears blotchy and more "squarish" as entire sections of the missing pixels are replaced by the generic red from the FEC stream. In the worst circumstances, you will see the grids themselves and eventually the picture will drop out. The audio information will be lost and you will hear squawks, etc.

The signal doesn't necessarily have to be stronger, but it needs to be clean. Digital signals are more affected by quality of signal as opposed to quantity of signal. Things like kinked cables can affect sync timings, cause data to be reflected back instead of staying on course through the wire, etc. The onscreen meter is not a raw quantity measurement but a blend of measurements of the Bit:Error Ratios, Carrier:Noise ratios, raw signal level, etc. A problem in any of those can result in a weak number. A technician with a good meter like a Super Buddy (many techs don't carry one), can check the signal for things like error counts, etc. Beyond a set amount and you would have a problem.

You might try swapping receivers to see if you have blocking with that receiver in a different rooms.

As far as "grain" goes, that is an analog problem and is most commonly associated with poor connection between receiver and TV. If you watch your satellite feed by tuning your TV to 3 or 4, try a different coax between the TV and receiver or better yet go with a composite (yellow-red-white) connection or S-video (s-video+red+white).

 

[andyg]

is there any difference whether the dish is mounted on the roof or on the side wall of the house?
do the dishes mounted on root have better signal or not necessarily?

 

[RandallA]

is there any difference whether the dish is mounted on the roof or on the side wall of the house?
do the dishes mounted on root have better signal or not necessarily?

You can mount it on the ground if you can get signal there, you won't get a better signal by going on the roof or on a high tower.

 

[vegassatellite]

The satellites are some 23,000 miles out in space. Moving your dish ten feet closer to that is insignificant. As long as your view is unobstructed and the dish is fully aligned, you should be fine. If you want more signal and better carrierise ratios, you can buy a larger dish.

 

[andyg]

The satellites are some 23,000 miles out in space. Moving your dish ten feet closer to that is insignificant. As long as your view is unobstructed and the dish is fully aligned, you should be fine. If you want more signal and better carrierise ratios, you can buy a larger dish.

where can I buy a larger dish other than from dish network? And after buying can I make it to work with Dish network? is there any link here on how to set it up.
thanks

 

[RandallA]

Both the 24'' or 30'' dish are bigger than the Dish Network D500. Look for a Winegard with a D shape LNB holder.

I just read your first post and I doubt that a bigger dish will fix your problem. If you're getting signals in the upper 50s and lower 60s, the problem is not with your dish. What type of TV do you have? I have a LCD 720p and if I set the receiver to 1080i the banner scrolling at the bottom of Espn is unreadable. I set the receiver to 720p and I can read them again. My problem is that I like how 1080i looks better.

 

[andyg]

Both the 24'' or 30'' dish are bigger than the Dish Network D500. Look for a Winegard with a D shape LNB holder.

I just read your first post and I doubt that a bigger dish will fix your problem. If you're getting signals in the upper 50s and lower 60s, the problem is not with your dish. What type of TV do you have? I have a LCD 720p and if I set the receiver to 1080i the banner scrolling at the bottom of Espn is unreadable. I set the receiver to 720p and I can read them again. My problem is that I like how 1080i looks better.

i have pretty old CRT's..the largest is like 27'

 

[highdefjeff]

Digital picture quality does vary due to signal

You say: (vegassatellite)

"Digital signals are more affected by quality of signal as opposed to quantity of signal."

First, quality of the signal is a function of quantity of signal. Performance related to signal and picture quality, in short, is signal-to-noise ratio and the resulting bit error rates. The two cannot be separated as to which one "more" affects digital signals.

Your statement, "The signal doesn't necessarily have to be stronger, but it needs to be clean.", is somewhat correct. Signal-to-noise ratio is the ratio of the amount of signal to the amount of noise in the system.

Noise is the enemy of signal. You can improve (lessen) the noise in the system, or you can increase the signal - both will increase your signal-to-noise ratio and performance.

The problem is that there is very little that a technician can do to reduce noise. Most of the noise in a system is completely out of the reach of what a technicians can affect.

I can think of two ways a technician can reduce noise but there may be more.

1. You can reduce noise if there are poor connections. You can tighten them and replace any improper fittings.

2. You can reduce noise by properly grounding a system. (It is now more important than ever to ground satellite systems!)

Those two things are extremely important, but typically represent a small fraction of the total system noise. By comparison, small increases in signal level result in greatly reduced bit error rates.

The most important thing a technician can do is to peak the satellite signals.

Specifically with Dish, the "weak" HD satellite signals need to be peaked. (129, 118.7) These signals start out weaker so it is much more important that they are peaked.

And you say,

"As far as "grain" goes, that is an analog problem and is most commonly associated with poor connection between receiver and TV."

but in digital tv, specifically HDTV, graininess can be observed with improperly adjusted tv enhancement and picture controls.

Digital picture quality can be impaired due to low signal!

When someone complains of the picture quality of their HD, and they have used the right cables, set the correct receiver and TV settings, and calibrated their TV, check the signal level.

And if a customer asks if their poor picture quality could be due to low signal, the correct answer is "yes".