# Help With Tivo Bolt, Comcast and pixellating/tilling/gittering



## CzarQwerty (Nov 3, 2015)

I'm new to Tivo and to Comcast. I have a tivo bolt with a cablecard.
We are getting a lot of pixellating/tilling/gittering (whatever you like to call it) happening. On some channels it's every 15 seconds or so. On some channels we barely see it.
My signal strength on most channels range from 80 - 90%, usually hovering around 82%.
The SNR varies between 32 and 34, usually 32 Db.
From what I can tell, these are good numbers. Is that correct? Does that mean there is something wrong with the cablecard? is there some way to test the card?

Thank you for any advice!


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## Jed1 (Jun 18, 2013)

CzarQwerty said:


> I'm new to Tivo and to Comcast. I have a tivo bolt with a cablecard.
> We are getting a lot of pixellating/tilling/gittering (whatever you like to call it) happening. On some channels it's every 15 seconds or so. On some channels we barely see it.
> My signal strength on most channels range from 80 - 90%, usually hovering around 82%.
> The SNR varies between 32 and 34, usually 32 Db.
> ...


Nope 32dB for the SNR is to low. You are on the edge of the digital cliff. That number should be no less than 36dB. Call Comcast and get a tech sent to your house as there is something wrong with the signal. Can be bad F connector on the coax, bad coax wiring, bad or to many splitters, problem with the drop or tap outside your home.


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## CzarQwerty (Nov 3, 2015)

Thanks, there's only one splitter for the whole house, so I'll get a tech out to replace the run to the bolt.


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## CzarQwerty (Nov 3, 2015)

Thanks for the advice. A new line was run directly from the only splitter in the house to the bolt.
Now a lot of channels are fine. Channels 800-825 have 90%+ signal strength with SNR around 35-36.
But channels 830-850 have a 75% signal stength and SNR of 30. Then it goes back up again for channels 860+.
Any suggestions? Is it the splitter?

Thanks!


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## Jed1 (Jun 18, 2013)

CzarQwerty said:


> Thanks for the advice. A new line was run directly from the only splitter in the house to the bolt.
> Now a lot of channels are fine. Channels 800-825 have 90%+ signal strength with SNR around 35-36.
> But channels 830-850 have a 75% signal stength and SNR of 30. Then it goes back up again for channels 860+.
> Any suggestions? Is it the splitter?
> ...


Tune the TiVo to the channels that are failing. Go into the TiVo menu and then go to the settings and messages and then go to account and system info. From there select TiVo diagnostics and then write down the frequency the channel is on and what the signal strength and SNR is. Also note if there is any counts in the RS corrected and RS uncorrected column.
Do this for each problematic channel and report that data here. Most likely the group of channels that are problematic are all located in the same frequency spectrum.
You may have to get Comcast back out to troubleshoot. Splitters can be the problem if the channels are all in the higher frequency spectrum. If the splitter is old and rated for something in the 500Mhz or 600Mhz range will cause the channels in the 700Mhz to 865Mhz range to fail.
Putting a splitter that is rated for 5Mhz to 1000Mhz (1Ghz) will help.


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## CzarQwerty (Nov 3, 2015)

Thanks Jed1, the splitter that Comcast installed says 5-1005 mhz. It splits into 3, with 2 of the outputs saying -7 db, and the other saying -3.5 db. I switched the Tivo bolt line to the -3.5 db and that helped with some of the channels.

Here is the main channel that has problems after switching inputs:
Signal Strength: 80%
SNR: 32 dB
RS Uncorrected: 240
Freq: 759000 hz


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## Jed1 (Jun 18, 2013)

CzarQwerty said:


> Thanks Jed1, the splitter that Comcast installed says 5-1005 mhz. It splits into 3, with 2 of the outputs saying -7 db, and the other saying -3.5 db. I switched the Tivo bolt line to the -3.5 db and that helped with some of the channels.
> 
> Here is the main channel that has problems after switching inputs:
> Signal Strength: 80%
> ...


Is this the only channel that is having issues or is there more channels that are failing or have failed?
If this is happening in a specific frequency range or starting at a specific range and then everything above that range is failing then I can assume of few things to be wrong.
In order to trouble shoot you will need to have Comcast come back out to troubleshoot. The tech will have to look at the entire downstream frequency range to see where the signal loss is starting and ending at.

If it is a few channels in a specific range, especially in the 700Mhz range, then one issue can be ingress of Long Term Evolution (LTE4G cell phone service). The uplink/downlink for Verizon and At&T are operating in that range. If you have a cell tower with in a mile or two of your home then this maybe the trouble. Locating where the ingress is will be a bastard to find.

The second issue can be if you have the signal starting to roll off around 500 to 600Mhz and not recover all the way to 865Mhz. This will indicate that there is some older splitter or older coax cable inside the house. You can also have an issue of the drop coming into your home is starting to get weathered and starting to corrode inside.
One thing important to understand is that the signal does not travel through the center of the center conductor but along the out circumference of the center conductor. So even if you have a kink or the cable staples are to tight it can affect the signal and cause this issue.
Another thing is people who change the splitters and spin the splitter instead of tightening the F connector can damage the contact points inside the splitter and turn it into a piece of junk. 
Having a piece of coax that has a copper coated steel center conductor. This type of coax is cheaper but has more potential to have signal issues than solid copper conductor coax cable.
Cheaply made coax wiring can be another problem as it is made to less stringent standards. One issue to cheap cable is the dielectric that separates the center conductor from the braiding is to thin or uneven.
Water in the tap or moisture getting inside the coax can be a another problem.
Poorly installed or wore out F connectors also can attribute to this. If you cup the F connector with your hand or wiggle it and the signal recovers then the F connectors will need to be replaced.

The third thing is if the analyzer shows that the lower frequency channels have more signal power than the upper frequency channels. This is known as tilt as the signal power is not even across the whole downstream spectrum. This is mainly caused from the cascading of amplifiers in the distribution system outside your home. The automatic gain control in the amps is not working correctly and is not leveling out the signal at each amp. One of the amps close to your home can be failing or adjusted out of spec.
This is the main reason you should never use an amp in your home unless you can make sure that the amp is not amplifying the lower frequency channels at the expense of the upper frequency channels.

I know it is a pain but keep on Comcast to fix this. If you find other channels that are not working or are tiling and having audio dropouts, then note the frequency they are on and tell that to the CSR and note it on your trouble ticket. Make sure you show the tech the frequency of the channels that are failing. If he is a good tech this should help him locate the problem more easily.


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## GoodSpike (Dec 17, 2001)

Jed1 said:


> If it is a few channels in a specific range,


This reminded me of something from when I first went to the HDHR Prime. There were channels I could not get. Turned out Comcast had installed a physical filter on my line when I had limited basic (basically only about 30 channels, most of them broadcast or shopping networks). They had not come out to physically remove that filter. Since the broadcast channels included the HD versions, the filter didn't block a lot of the digital channels, but it did affect some.


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## Jed1 (Jun 18, 2013)

GoodSpike said:


> This reminded me of something from when I first went to the HDHR Prime. There were channels I could not get. Turned out Comcast had installed a physical filter on my line when I had limited basic (basically only about 30 channels, most of them broadcast or shopping networks). They had not come out to physically remove that filter. Since the broadcast channels included the HD versions, the filter didn't block a lot of the digital channels, but it did affect some.


Yes this was something that the cable companies deployed when they were still broadcasting analog TV signals. Since most bigger systems have ended analog TV support and are now fully encrypted so there is no need to use this method anymore.
The filters used to block out the channels from above 213Mhz to around 600Mhz. This would leave the channels above that come through but since they were digital most of them are encrypted.

I think the OP has mentioned he is new to Comcast so there should not be any filters on his feed. If there is then that is a glaring oversight by the tech as these filters are not hard to miss.
Comcast did replace the coax from the splitter to the Bolt but they may have to replace the drop coming to his house.


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## GoodSpike (Dec 17, 2001)

Jed1 said:


> I think the OP has mentioned he is new to Comcast so there should not be any filters on his feed. If there is *then that is a glaring oversight by the tech* as these filters are not hard to miss.


So in other words, it's extremely likely! 

Seriously, I don't remember how that was finally diagnosed on my house. It's been too long. But at some point Comcast should have rolled a truck to my house and they didn't, and then only later did it become a problem.


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## Jed1 (Jun 18, 2013)

GoodSpike said:


> So in other words, it's extremely likely!
> 
> Seriously, I don't remember how that was finally diagnosed on my house. It's been too long. But at some point Comcast should have rolled a truck to my house and they didn't, and then only later did it become a problem.


With Comcast anything is likely. Their system is so big and is made up of hundreds of old cable systems, you have to wonder how anything works properly.
Murphy's Law definitely applies with Comcast, "What can go wrong will go wrong".


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## GoodSpike (Dec 17, 2001)

Jed1 said:


> With Comcast anything is likely. Their system is so big and is made up of hundreds of old cable systems, you have to wonder how anything works properly.
> Murphy's Law definitely applies with Comcast, "What can go wrong will go wrong".


Where I used to live Comcast bought the system, and until they physically replaced the cables for the entire neighborhood even a light rain could make the TV service go out. And given that was Seattle, that was quite frequent!


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## CzarQwerty (Nov 3, 2015)

Thanks everyone. I'll keep track of other channels with issues and get comcast back out here.


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## CzarQwerty (Nov 3, 2015)

The line between the pole and my house is old and will be replaced. The signal coming into the house is weak.
Thanks for your help!


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