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Internet uploading causes TV pixelation & sound stutter

Contributor

Internet uploading causes TV pixelation & sound stutter

For years I've experienced pixelation issues on our TVs, whether they be DTAs or HD DVRs. The time came that I replaced all the cabling in the house and cleaned up all the splitters and such. I had hoped this would resolve the issue but sadly it did not. Only recently did I finally discover the culprit. I noticed that uploading on the internet was when the pixelation would occur. Unfortunately, I can't for the life of me figure out how to fix the issue.

 

I've gone so far as to replace both the recently installed RCA 2 way and PCT-MA2-8P amp splitter with an Antronix 2 way splitter to feed the SurfBoard SB6121 and PPC Evolution 9 way splitter to feed the cable boxes. (also tried using the passive line too, which works fine, but made no difference to pixelation issue) I was hoping swapping the splitters out to Comcast recommended equipment would solve the issue, but alas, still suffering.

 

My modem upstream power levels hover around 43-45 dBmV

 

Why oh why is uploading causing major pixelation on all the cable boxes? This has got me stumped!

Official Employee

Re: Internet uploading causes TV pixelation & sound stutter

Have you tried swapping the modem or replacing the router? What device are you uploading to?
Since you've narrowed it down that's where to focus attention

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Contributor

Re: Internet uploading causes TV pixelation & sound stutter

That's what I'm starting to wonder since I've gone through so many things. I'm using a Netgear WNDR3700 router and that, along with my modem, were purchased at the same time (Dec 2013).

 

It seems to happen with any kind of uploading. I can create the problem when doing a speed test where at the tail end of the upload test the TVs will experience a brief moment of pixelation. If I do extended uploads, such as large FTP files, it'll do it the whole time. I've even tried limiting the upload speeds with absolutely no imporovement. Somewhere there's upstream interference happening and I'd hate to have to buy a new modem and/or router.

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Maybe go by the Comcast Store and pick up a router to 'borrow' to test a different piece of hardware.

 

It's a bizarre set of issues you've got. It borders on near impossible.

 

Are you running stock firmware on your Netgear?

 

-KP

Official Employee

Re: Internet uploading causes TV pixelation & sound stutter

Hi ca2kjet,

 

I was able to check your line levels using the email address you have registered with the Forums. I don't see anything that would cause the problems you are having. FWIW, I agree with ComcastAndrew and believe the issue is with the actual equipment. Were you able to swap either piece to see if there were any changes? 


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Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Still investigating the issue. Unfortunately I haven't had the opportunity to swap anything out but I'm starting to think it's with the modem. The one thing I haven't taken note of yet is if there's any difference in upstream signals during uploading.

Official Employee

Re: Internet uploading causes TV pixelation & sound stutter

Ok, well no rush, whenever you have a moment to do so, please follow up with us to let us know how everything is working after swapping stuff on your end. Thanks. 


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Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

If that really is happening, I'd probably try to login to the Modem Admin page (probably 192.168.100.1 ?) and see what channel frequency's are being used.  I suppose that there could be some overlap or somesuch, but it sure is a bizarre thing.

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter

If it helps, I've posted my modem signal info as of this morning.

modem-info.jpg

 

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Well, your signals levels look good.

 

I'm a little surprised that your downstream frequencies are in the 500mHz range.

Mine are up in the 600mHz's.

It might just be your local system.

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 627000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK d11_m_5345_performance2_c01.cm
Security Enabled BPI+

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 77 627000000 Hz -5.2 dBmV 43.9 dB 0 0
2 Locked QAM256 73 603000000 Hz -4.7 dBmV 43.9 dB 0 0
3 Locked QAM256 74 609000000 Hz -5.3 dBmV 43.9 dB 0 0
4 Locked QAM256 75 615000000 Hz -4.8 dBmV 40.8 dB 0 0
5 Locked QAM256 76 621000000 Hz -5.3 dBmV 41.9 dB 0 0
6 Locked QAM256 78 633000000 Hz -5.0 dBmV 42.5 dB 0 0
7 Locked QAM256 79 639000000 Hz -5.4 dBmV 42.5 dB 0 0
8 Locked QAM256 80 645000000 Hz -5.3 dBmV 43.7 dB 0 0

 

Total Correctables Total Uncorrectables
0 0

 

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 6 5120 Ksym/sec 29600000 Hz 53.0 dBmV
2 Locked ATDMA 5 5120 Ksym/sec 36100000 Hz 53.0 dBmV
3 Locked ATDMA 7 5120 Ksym/sec 23000000 Hz 53.0 dBmV
4 Locked ATDMA 8 5120 Ksym/sec 16500000 Hz 53.0 dBmV
CM IP Address Duration Expires
  D: 24896 H: 02 M: 38 S: 16

Sat Nov 11 08:41:29 2017

 

I would probably go by the Comcast store and borrow a modem to see if different hardware improves the situation.

 

-KP

Official Employee

Re: Internet uploading causes TV pixelation & sound stutter


ca2kjet wrote:

If it helps, I've posted my modem signal info as of this morning.

modem-info.jpg

 


Levels are great, no issues there. You do have an older modem though.


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Official Employee

Re: Internet uploading causes TV pixelation & sound stutter


kpeters59 wrote:

Well, your signals levels look good.

 

I'm a little surprised that your downstream frequencies are in the 500mHz range.

Mine are up in the 600mHz's.

It might just be your local system.

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 627000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK d11_m_5345_performance2_c01.cm
Security Enabled BPI+

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 77 627000000 Hz -5.2 dBmV 43.9 dB 0 0
2 Locked QAM256 73 603000000 Hz -4.7 dBmV 43.9 dB 0 0
3 Locked QAM256 74 609000000 Hz -5.3 dBmV 43.9 dB 0 0
4 Locked QAM256 75 615000000 Hz -4.8 dBmV 40.8 dB 0 0
5 Locked QAM256 76 621000000 Hz -5.3 dBmV 41.9 dB 0 0
6 Locked QAM256 78 633000000 Hz -5.0 dBmV 42.5 dB 0 0
7 Locked QAM256 79 639000000 Hz -5.4 dBmV 42.5 dB 0 0
8 Locked QAM256 80 645000000 Hz -5.3 dBmV 43.7 dB 0 0

 

Total Correctables Total Uncorrectables
0 0

 

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 6 5120 Ksym/sec 29600000 Hz 53.0 dBmV
2 Locked ATDMA 5 5120 Ksym/sec 36100000 Hz 53.0 dBmV
3 Locked ATDMA 7 5120 Ksym/sec 23000000 Hz 53.0 dBmV
4 Locked ATDMA 8 5120 Ksym/sec 16500000 Hz 53.0 dBmV
CM IP Address Duration Expires
  D: 24896 H: 02 M: 38 S: 16

Sat Nov 11 08:41:29 2017

 

I would probably go by the Comcast store and borrow a modem to see if different hardware improves the situation.

 

-KP


KP

Your display isn't accurate, you actually have 24 downstream channels ranging from 513 to 675 MHz. An FYI, your upstream is too high, same as on your dvr ( even higher).


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Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

I'm aware that my signal levels don't seem optimum.  We put a meter at the MDU and it seems fine there.  It's a fairly short drop (with RG11) to the house. and a single (4 way) splitter. 

 

Since it works fine and all speed tests are typically above subscribed speeds (and my TiVo picture doesn't pixelate!) I don't worry about it too much.

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter


ComcastAndrew wrote:

You do have an older modem though.


Just as an FYI, I'm not leasing it but don't have a problem upgrading it if that's the case. What's the latest recommended modem for my setup?

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Hello ca2kjet,

 

Unfortunately I do not have a specific modem that I can suggest for you as the all have their own pro's and con's. You can always go to your nearest service center to get one of our latest models or we may be able to have one shipped out to you. Just let us know how you want to proceed.




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Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Just wanted to update anyone following this...

 

As I've investigated this issue, I have often times power cycled the modem. I think I resolve the issue only to find that after a day or two, the issue returns and uploading again causes pixelation on the TVs.

 

This makes me wonder if the modem is having a physical problem. It's almost like after running for a bit, the modem is working too hard to push upstream, even though it doesn't need to, thus flooding the line. I know it's not an environmental heat issue because it's in a cool, dry location in its own open space.

 

I watched the modem config during uploading a bunch of website files via FTP (which was causing major pixelation during the whole upload process) and nothing changed with regard to signal strengths.

 

At this point, I really think the modem is the culprit. I'm going to go ahead and replace it with something newer... I shall return when I have more info to provide.

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Just throwing this out there (again).  You could get a modem from Comcast (for free) and try it and see if it fixes it.

 

If you return it to Comcast prtetty quickly, they (most likely) won't charge you at all...

 

You probably could get them to mail it to you, too...

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter


kpeters59 wrote:

Just throwing this out there (again).  You could get a modem from Comcast (for free) and try it and see if it fixes it.

 

If you return it to Comcast prtetty quickly, they (most likely) won't charge you at all...

 

You probably could get them to mail it to you, too...

 

-KP


Wouldn't they require me to start "leasing" the modem? I'd rather not open that can of worms again... After buying what I have now, it was a nightmare to get Comcast to stop charging our account. That was even after multiple times of informing them our previous modem had been returned to our local facility.

 

Anyways, I've already looked into some different models and have made a purchase. Should be getting it tomorrow... worse case, if problem still exists, I return it...

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Yes.

 

But if you take it back real quick, they won't charge you...did I already say that?

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter

One last test before changing any equipment around... I decided to plug a laptop directly into the modem. Did a simple internet speed test and during the upload part, sure enough, instant pixelation. So that absolutely narrows it down to the modem. If a new one doesn't resolve this issue, I'll have to get Comcast involved.

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter

Hello ca2kjet,

 

Were you able to get your new modem installed?




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Contributor

Re: Internet uploading causes TV pixelation & sound stutter


ComcastMichaelP wrote:

Hello ca2kjet,

 

Were you able to get your new modem installed?


New modem was installed this evening. Have been throwing everything at it to see if I could cause pixelation and so far, nothing. Hopefully I'm not jinxing myself, but it looks like it was the modem after all. Smiley Happy

Official Employee

Re: Internet uploading causes TV pixelation & sound stutter

Hi ca2kjet,

 

Thanks for following up and letting us know everything appears to be working ok for now. If you begin to experience any more issues, please feel free to reach out to us. 


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