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Internet uploading causes TV pixelation & sound stutter (continued)

Contributor

Internet uploading causes TV pixelation & sound stutter (continued)

This is a followup to this thread: http://forums.xfinity.com/t5/Non-X1-Service/Internet-uploading-causes-TV-pixelation-amp-sound-stutte...

 

I just discovered that there appear to be some TV channels that are still pixelating during internet uploads (ex. 830 FXHD). While the issue isn't as extreme as before it's still happening. My only guess is my new modem is operating with different upload frequencies so most channels that were experiencing this issue before are fine. There's clearly something wrong somewhere down the line that's allowing upstreams to back feed into the downstream signal and I doubt it's from within the house since I've literally replaced everything.

 

This is such a bummer...  I'm out of stuff to fix / replace / config. Not sure where to go from here...

 

I've included a recent shot of the modem power levels.

modem-check.png
Official Employee

Re: Internet uploading causes TV pixelation & sound stutter (continued)

Hi @ca2kjet. I can assist with checking the diagnostics to your modem and from your local Node/Plant area, so we can continue to work toward getting this resolved for you. Please send me a private message and include your full name, service address, and account number so I can access your account. 

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Contributor

Internet uploading causes TV pixelation & sound stutter (3rd time)

So here we are, again, for the third time... uploading anything causes pixelation/stutter on all the HD cable boxes in the house.

 

Reference previous threads:

https://forums.xfinity.com/t5/Non-X1-Service/Internet-uploading-causes-TV-pixelation-amp-sound-stutt...

https://forums.xfinity.com/t5/Non-X1-Service/Internet-uploading-causes-TV-pixelation-amp-sound-stutt...

 

At this point, I know for a fact it's not on my end since Comcast discovered something wrong on their end, told me they corrected it and everything was great for about a month. Now I'm back in the same boat again. What is going on!? Did Comcast revert their system back? Can someone please escalate this so it gets permanently fixed?

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Could someone from Comcast please look into this issue? This needs to be corrected. It's at the point that browsing "heavy" websites is causing pixelation on many HD channels. I can't keep dealing with this...

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

It's still bizarro world...

 

Can you log in to your modem and see what channels are being used on it?

 

It'll likely be starting around 513mHz.

 

Then, try to do an 'inventory' of what channels are affected.  Maybe there's some 'harmonic frequency' issue or some such that's causing it.

 

Have you consodered switching your DVR/  Maybe try TiVo?

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

This is an issue that appears on every device in the house. Doesn't matter if it's an HD DVR or HD DTA. We received an automated call from Comcast when I brought this up back in December that said they "found the problem on their end and corrected it". No details beyond that and everything appeared to be fine for a while. It's like the issue has crept back.

 

I know it's affecting channels 821, 825, 830, 840, 841, most of the 850s (sports channels)... I've seen it on 862, 872, there's probably many more that I haven't checked yet. I checked 785, no issues... checked 907, and few other higher channels, no issues. Looks like channels 802 through 810 are fine.  From what I can tell, it seems like every channel from ~815 through 900 are affected.

 

You can reference my previous specs of the new modem here: https://forums.xfinity.com/t5/Non-X1-Service/Internet-uploading-causes-TV-pixelation-amp-sound-stutt...

 

This is as of this morning...current-specs.png

 

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Since you've replaced the modem, that leaves the coax and the splitters to consider.

 

The Data channels shouldn't be overlapping the TV channels, but they could be, I guess.

 

Depending on which box you're using, there's a 'service menu' that can be accessed to tell you what frequencies the tuned channel is on, too...

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

It's not on my end though, wish it were... I've already ruled everything out (details are in the first thread I started). I got so fed up with this issue over the years trying to determine the reason it was happening that last Spring I pulled out all the cable lines in the house right to the outside tap, replaced, rerouted and consolidated to a new DMARC and used industry recommended config and brands. I even tried two separate splitter brands (not the cheap stuff) during my initial research.

 

As noted, Comcast did do something on their end that appeared to have corrected the problem but apparently wasn't a permanent fix. All I know is that the upstream signal is interfering with the downstream signal and the severity of that interference continues to increase day by day.

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

This is getting ridiculous. Comcast, any chance someone can check out the lines that are coming to the house?

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

It doesn't make any sense to me that it's the 'lines' outside the house.  Maybe inside.  Or the equipment inside.  What cable box(es) are you using?  Is it an X1?  Is the entire house X1?  Is the house wiring RG6?

 

-KP

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

I have scoured the internet for anything that I could find. That link you posted I have come across in the past, and for that person it was just a bad splitter.

 

My issue affects all Comcast cable boxes in the house, DVR HD and DTA HD boxes. I do not have the X1 platform.

 

This issue has been happening for a few years now. Last Spring, the following was done to try and finally solve it because it just kept getting worse:

 

  • All cable lines replaced, all RG6, (all rerouted for better paths, reduced length, away from electrical cables, etc)
  • Removed 3 way splitter at exterior tap, now that just goes directly to the new DMARC location
  • Removed other splitters inside the house from over the years (I think I removed 3 of them)
  • Replaced cable modem with brand new model
  • Tried 2 different splitters to split incoming tap to cable modem and TV amp
  • Tried 2 different amps for TV feeds (total of 4 TV lines for inside house)
  • Current splitter and amp are both Comcast recommended brand/products
  • Tried running cable modem without the initial split and through amp's cable modem port, no difference
  • To rule out amp, tried running a single TV and modem from 2 way splitter, directly connected a laptop to the modem to rule out my network environment, still same issue

For all I know, it could be a simple issue at the pole ever since my neighbor switched to FIOS a few years back and their old Comcast tap was never properly capped. There is absolutely no way the issue is on my end though. That leaves... outside tap to pole, main line to node, trunk line all the way up to the actual head end. Since Comcast already made a change on their end that recently "solved" the issue, but only temporarily, I'd say it's on their side.

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Have you tried an attenuator on either the modem or the cable box(es) leg?

 

Depending on which cable box you have, there's usually a 'diagnostic screen' you can (figure out how to ) pull up and see the signal levels on the box.  Too high of an upstream signal is most likley the cause.

 

Although MoCA needs splitters with low port isolation, since you're (apparently) not using MoCA, you could probably consider splitters with a higher port isolation.

 

What about putting the modem on one leg of a 2-way splitter and all the TV's on a 2nd splitter off of the 2nd leg?

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)


@kpeters59 wrote:

Have you tried an attenuator on either the modem or the cable box(es) leg?

 

Not a pure attenuator pad, but the outside tap is split, reducing the power already and there were tons of splitters upon splitters on the old setup, I'm surprised anything worked. Originally, there was a 3 way splitter outside the house, then the modem was on another 3 way splitter and then there were two more splitters in the house. Modem probably had the signal knocked down ~10db and this issue existed back then.

 

Depending on which cable box you have, there's usually a 'diagnostic screen' you can (figure out how to ) pull up and see the signal levels on the box.  Too high of an upstream signal is most likley the cause.

 

Downstream/Upstream signals posted earlier in this thread (all appear within spec)

 

Although MoCA needs splitters with low port isolation, since you're (apparently) not using MoCA, you could probably consider splitters with a higher port isolation.

 

Currently using a PPC Evo 9 way splitter for TVs and an Antronix 2 way splitter for tap split between modem and PPC Evo 9. I have also tried other splitters and amps.

 

What about putting the modem on one leg of a 2-way splitter and all the TV's on a 2nd splitter off of the 2nd leg?

 

That's the current setup. I have tried doing it with and without. Outside tap is split with Antronix 2 way splitter with one leg to the modem and the other to the PPC Evo 9 way for the TVs.

 

-KP


 

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

That diagnostic screen was from the modem.  It IS within specs, but on the higher side.

 

I was talking about the cable box.  They have diagnostics screens as well.

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

My apologies for the misunderstanding.

 

Now I'm left scratching my head... I just tested and no channels that I can find are exhibiting the pixelation issue. Did Comcast sneak in a fix this morning???

 

I'll have to keep an eye on this and if the issue pops up I'll note the diag details. For what it's worth, here's some diag info that I just pulled:

 

Channel that wasn't showing issues: 802
Freq: 357
Power Level: Between 5.5 and 5.8
Signal-to-noise: 42

On a channel that was previously having issues: 854
Freq: 63
Power Level: Between 3.6 and 4.2
Signal-to-noise: 40 to 41

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Got hit with power outages two times in a row over the last week. Before the power outage, the issue was not occurring. Well, it's back. Cable modem specs remain the same as before. 

 

Channel 802 previously had a power level of 5.5 to 5.8 and no issues. Today, the power level is up to 13!

Channel 854 previously had a power level of 3.6 to 4.2 and no issues. Today, the power level is up to 10!

 

There's the problem! Comcast is pumping too high of a power level to my house! No wonder I keep having issues. I guess the last few times I've complained they simply padded the feed to drop the signal.

 

Should I keep bugging Comcast about this??? This is getting annoying that the levels end up getting "reset" back to high. Should I just slap in an attenuator before the PPC Evo 9 way splitter to the TVs? Would an attenuator even solve this problem? If so, what type?

 

I'm amazed this issue occurred even when we had a bunch of a splitters throughout the house. I've looked at various channels and their power levels are all up in the low 10s. So power levels appear to be 7-8 dBmv too high.

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

You'd do just fine with a signal level as low as -5dB.

 

Maybe get some attenuators off Ebay or something and pad it down 6 or 9 dB or something and see if it goes away forever?

 

-KP

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

However, the signal level shouldn't be fluxuating that much.

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

It's probably always been high and never realized it. My guess is Comcast changed it for my house the last few times I complained and somehow that setting keeps getting reverted back to the "normal" high strength. I'm probably better off just doing the attenuator as a semi-permanent fix on my end. Question though, should this be placed after the split of the modem/TV lines and before the whole house TV splitter or somewhere else? Would this attentuator do what I'm looking for? http://a.co/i3NOwLB

Regular Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

I'd guess it depends on whether ALL the TV's have signal level that high or not.  If they're all that high, put it at the input to the 1st splitter.  Otherwise, put one at each cable box.

 

-KP

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

I feel like I'm going in ciricles, the issue isn't occuring now and the power levels are still the same. I'm so confused...

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

I don't know what's going on. The problem has returned and there's no noticable difference with the tuner specs from before. Some cable boxes have a signal as high as 10dB while one has a -3dB but they're ALL showing the pixelation issue. I'm at my wits end with this...

 

FYI... even posting this reply caused a moment of pixelation... wow...

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

No one seems to be able to resolve this issue... even after having a tech come out.

 

He commented that I shouldn't be using an amp splitter. Ok, fine. Swapped out with a non amp 4 way splitter off a 2 way split for modem as recommended. He installed a "device" that he said blocks upstream signals. After checking what he installed, all it was was a MoCA filter.

 

After our cable gets disconnected and then reconnected, the issue appears to be gone. Eventually, over a couple of a weeks (maybe sooner, maybe longer) the issue returns and gets worse and worse. The issue even happens when NO upstreaming is going on. I can do upstreaming and cause our problematic channels to literally grind to a halt.

 

From my own diagnosis of things thus far, I now know the issue occurs with channels that are on the 69 through 85 frequency, 69 being the the most affected. Everything is in spec as far as power levels and signal-to-noise on the problem channels. So what's on with the 69-85 freq that's causing this issue??????

 

No one can seem to figure out what the problem is and actually fix it. I'd rather not leave Comcast, but it's almost come to that point...

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

For kicks, since the issue was non-stop, I went and disconnected the coax cable from the cable modem. Issue stopped instantly. Re-connected the coax and everything is back to normal, working perfectly. This confirms that the internet IS the source of the interference on the TV side and that something is compounding somewhere on the signal. I may have to resort to installing a timer on the outlet and hard resetting it every day at like 3 AM or something... ugh...

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

I discovered a wallplate in the house that had a horribly done screw-on crimp. Went ahead and replaced with a proper compression crimp. Monitored for a few weeks and thought I finally found the culprit.

 

So we decided to go ahead and get Triple Play thus moving our phones over to Comcast. Got a brand new voice capable modem and upgraded our main box to the X1 platform while we were at it. All was well... and then, today, during some heavy uploading I come to find out that the pixelation issue IS STILL HAPPENING.

 

I give up... this is never going to get resolved and at this point I'm just venting and documenting notes.

 

It comes down to this;

 

  • Over time, upstreaming is building interference on the line. It appears to be happening on any channel that sits around a freq of 57 through 85.
  • Heavy upstream traffic can bring about this interference faster (i.e. maxing out upload bandwidth).
  • Disconnecting the coax from the modem instantly clears whatever is building on the line.
  • A tech can't see the issue unless I leave the pixelation happening. Since it could be days for a tech to come out, the TV would be unwatchable. Then when the tech shows up they disconnect things to check stuff out and "fix" it. But it may take days before seeing pixelation again so the issue ISN'T fixed.
  • It is NOT on my end. The tech who came out to "install" our new modem even noted that splitters, equipment and setup was proper.
  • Trying to explain over the phone to Comcast that someone needs to come out and check the lines at the pole, etc has been impossible because they want to have a tech come out and check my service. They do that. Reset the connection and "fix" it. So it never goes anywhere. Hence why this issue is never going to get resolved.

I'll probably move my internet and phone over to Verizon at some point. I just can't keep wasting anymore time on this.

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Modem details: Switchable upstream filters for 42 MHz or 85MHz operation.

 

Aha! So why are my modems (on my 3rd model at this point) trying to upstream between 42-85 Mhz? I have TV channels that operate on that freq and upstream is interfering with them. Does anyone make a 43-85mhz filter to block that range? I really don't understand why the modem is trying to broadcast on that spectrum when all the upstream bonded channels are currently below 42 Mhz. Can I stop the modem from using anything over 42???

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Anyone from Comcast know why there'd be interference from upstreaming in the 42-85 Mhz range when my modem shows locked channels below the 42 Mhz range? I shouldn't even be transmitting outside of 42 Mhz.

 

My pixelation problem "builds" over time the more I upstream. It only affects TV channels that sit 85 Mhz and below.

 

If the channels that sit in the upstream spectrum were moved I bet I'd never see this issue again. This is so very strange...

 

 

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Just found this tidbit of info online;

 

"This all sounds very nice and at this point you could ask why not everyone is using this extra capacity yet. When you have a modem that supports this feature (check capability TLV5.20), the CMTS obviously has to be configured accordingly. That's not that hard to do, the real obstacle is that the network has to be equipped for this frequency boost as well. This means that its components (such as diplex filters, network termination units,... ) have to be suited to work with this extended frequency range. And often that means a substantial network upgrade!

When these issues are tackled, it has to be taken into account that some legacy customer premise equipment (TVs, STBs) may take the 54-85MHz band as input (used to hold TV-channels). Bad in-house splitters could lead to high upstream power going to these devices with possible failures and disturbances as a consequence."

 

There is NO way the issue I'm having is on my end. Comcast, please look into this! Is there old equipment at the pole in my neighborhood that's causing this "input" from the upstreaming? Something configured wrong?

 

I'm trying to give you guys as much help tracking down this issue as I can...

Contributor

Re: Internet uploading causes TV pixelation & sound stutter (3rd time)

Comcast, I've found the problem now it's up to you to fix it! I'm getting "reflections" caused by high upstreaming above 54 Mhz. Anyone happen to sell a 54-85mhz filter???

 

"Harmonic distortion or similar issues caused by a powerful upstream signal above 54 MHz in the tuner may also contribute to the problem."

 

"The upstream transmit signal from an 85 MHz cable modem is potentially quite powerful. Therefore, the transmitted signal will generate reflections within each splitter that it crosses. That reflected energy travels back through the rest of the home network and can cause a device's AGC circuit to attenuate the entire downstream signal and create video problems."

 

"The problem of unexpected reflected energy in the downstream tuner's receive band is not limited to the home where a new 85 MHz modem is deployed. When a signal is sent from one home into a port on a tap, reflections are generated in the splitter circuitry within the tap. Therefore, another home that shares a tap's internal splitter can receive a high level of reflected energy. In testing, reflections with as little as 24 dB of loss were seen."

Contributor

High upstream causes interference with TV

I'm starting a new thread under the internet category because I'm not sure where my issue lies as far what area covers this. After over a year of trying to track down what is happening I've finally discovered the root issue. However, I need Comcast to figure what's actually causing it on their end.

 

For past reference: https://forums.xfinity.com/t5/Non-X1-Service/Internet-uploading-causes-TV-pixelation-amp-sound-stutt...

 

During high upstreaming, I'm getting "reflections" in the 42-85 mhz spectrum which causes major pixelation on any TV channels that are broadcasting within that same spectrum. This "reflection" issue compounds and is only resolved by physically disconnecting the coax cable from the cable modem and plugging it right back in. Eventually, after enough heavy upstreaming the problem returns and pixelation gets worse and worse. My modem is locked on channels below 42 mhz so I have no idea why there would be any upstreaming in the higher range.

 

I'd like someone from Comcast (from an engineering standpoint) to determine why this upstream interference is happening. It may just be the splitter at the pole where my tap connects to or it may be further up the line, but I guarantee at this point it's not on my side. Not after replacing literally everything on my end and even having a tech come out and look over the issue. Someone please bump this up the line so the right people can work on this!