vod pixelation
hobobluz
Enthusiast - Level 2

I was having pixelation on my video on demand. My fios was installed in the last month. In attempting to solve the problem, I ran a coax cable from the outside box direct to the mrdvr. Same problem. I then tried to reconnect the original cable to the outside box but couldn't because the cable tie was too tight, not giving me enough slack. I cut that tie, and another one about 6 inches away that was holding about 5 cables/wires, so I could have enough slack to reconnect.  Both of these ties were so tight, they were severely pinching the cables/wires. Long story short, I again tried on demand AND IT WAS PERFECT.

Now, the only thing I  did was disconnect and reconnect the coax to the outside box, and cut to remove two cable ties.

I am thinking maybe the tightly pulled ties were causing cross talk in the bundle, or maybe they were actually shorting something inside of the wires. In any event, if anyone is having pixelation problems, I would recommend seeing if the ties are pulled up too tightly.

Anyone else have this issue and if so how was it resolved.

hobobluz.

1 Solution

Correct answers
Re: vod pixelation
Keyboards
Master - Level 3

The problem was most likely the cable ties (as you surmised, but not due to cross talk).  If the cable itself is pinched (in other words a change in the distance between the center conductor and shield) it can have a frequency dependent impedance problem that would show up at higher frequencies.  VOD being delivered over MoCA is at frequencies above 1 GHz and most susceptable to impedance discontinuities.

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Re: vod pixelation
GaryDoug
Specialist - Level 1

Vewwy intewesting.......

You said you were still having problems after disconnecting the original coax. That should rule out any problem with that cable.

Is the splitter anywhere near the offending cable ties? If you were having problems only with VOD, I would have checked the coax to the router. What are the "... 5 cables/wires.." that you referenced?

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Re: vod pixelation
hobobluz
Enthusiast - Level 2

The splitter is about 12 feet from the outside box, and about 8 feet from the mrdvr.  The tech replaced the old with a new 1ghz splitter. In the bundle are the wire that comes from the street, the coax that feeds the house, the white (fios?) cable, ground wire, phone wire.

hobobluz

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Re: vod pixelation
Keyboards
Master - Level 3

The problem was most likely the cable ties (as you surmised, but not due to cross talk).  If the cable itself is pinched (in other words a change in the distance between the center conductor and shield) it can have a frequency dependent impedance problem that would show up at higher frequencies.  VOD being delivered over MoCA is at frequencies above 1 GHz and most susceptable to impedance discontinuities.

Re: vod pixelation
GaryDoug
Specialist - Level 1

Wow!! Check out the brain on Keyboards! What a great call.

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Re: vod pixelation
hobobluz
Enthusiast - Level 2

Thanks. That pinching makes more sense. I've searched this problem and see others with the same issue. Maybe the techs/installers should be make aware of this? You would think they are, but obviously not so.

Thanks again.

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Re: vod pixelation
GaryDoug
Specialist - Level 1

The pinching of the coax makes perfect sense. so much that I decided to do an experiment (what engineers do with too much extra time on their hands). I used a small portable bench vice, a 2" square piece of 1/4" steel, and a 1/4" diameter steel rod. I sandwiched a 6' RG6 jumper (ran from my splitter behind a TV to a dvr box) between the plate and the rod and began to apply pressure by tightening the vise. All the while viewing the SNR of a selected 850 mhz channel on the TV screen. No matter how much I tightened the vise, the SNR never changed, until the cable finally shorted, putting the SNR at 0. I really expected more convincing results. Perhaps the cable insulation is different from yours. I then released the vise, leaving a seriously deformed cable (but back to normal SNR) and proceeded to twist, fold, and turn it while again viewing the screen. Still nothing. Then just before giving up, I twisted the cable mercilessly while pulling on it at each side of the pinched area. Bingo....the SNR dropped from 37 to 32 and stayed there. The reception on the TV changed to a jumbled mess of pixels. After examining the cable, I determined what had happened was that the shield had separated from itself at the damaged area leaving effectively about 3' of unshielded coax going to the TV. If this is what has happened to yours, it will still have a defect waiting to return. I suggest replacing it.

Re: vod pixelation
prisaz
Legend

I could never find a cable stretcher that would work without causing damage. If someone could just make one that works. COOL TEST!

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Re: vod pixelation
papalee1
Newbie
I may not know a lot about FiOS, but I find it odd that vod is streamed through a router. I was having pixelation issues while watching a movie I purchased on vod. After searching through this forum I decided to try a simple, quick fix and reset the router. It worked. Pixelation stayed away the rest of the movie. I guess I'm wondering why is it that vod is streamed through the router and not just directly through the cable itself, which also confuses me as it is not a fiber optic cable. Just where does the actual physical fiber optics of FiOS begin and end when it comes to residential service? I was a Directv customer for almost ten years before switching over to FiOS and, I must say, the vod via sattelite was crystal clear.
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Re: vod pixelation
jackmcgann
Specialist - Level 1

@papalee wrote:
 Just where does the actual physical fiber optics of FiOS begin and end when it comes to residential service?


Technically, it ends at the ONT. Most (all?) ONT's are attached to the premises, either at an indoor or outdoor location.

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