# Electrical Pixelation



## kbmb (Jun 22, 2004)

I have a bizarre pixelation that I'm wondering if some of the people on here can assist with.

Comcast Cable
Roamio Plus - plugged into a basic APC UPS

We have a box fan plugged into a separate outlet. I started to notice that when we turn the fan on or off, we get pixelation on our Tivo. I've tested by turning it on and off multiple times. Doesn't happen while it's on....just the process of on/off. I've even watched the diagnostics, and the RS Corrected and Uncorrected jump all over the place.....even reset to zero. During the on/off tests I've seen the signal jump from 99% to 59%.

I've moved the fan around to different outlets in the house, does it everywhere. Tried a pedestal fan.....same thing. Turning on/off a window AC doesn't do anything to the picture.

It's not really a problem as it is just something I noticed. Hoping some of the smart electrical/cable people on here might be able to tell me what's happening. Is it a problem in the electrical wiring? House relatively new...1989. 

Thanks for any help.

EDIT: also have a Roamio Basic upstairs. Same thing happens with turning the fan on/off. 

EDIT2: the pixelation is recorded, so it's not just on the tv. 

-Kevin


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## thefisch (Jul 25, 2015)

If it is happening all over the house then it could be a ground or interference issue somewhere. Do you have a TV connected with just coax (no tivo)? If so, do you see any static or signal issues with the same on/off test?

I would attempt to isolate the issue by disconnecting all coax leads and then testing as you connect each one. Try some direct connections from the main lead to the tivo with loose wire down the hall rather than using existing wiring. Also, remove any coax you have going through surge protectors.


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## KillerBeagle (Sep 3, 2015)

What is the duration of this pixellation? The nearly instantaneous time of changing the switch position, or the whole time the fan is spinning up?
A cheap switch can create a lot of electromagnetic noise across the frequency spectrum, which could be picked up by poorly shielded or ungrounded cables. 
If you plug the fan into a switched outlet, and turn it on and off via the wall switch, do you see the same thing?


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## kbmb (Jun 22, 2004)

Thank you both for your replies.



thefisch said:


> If it is happening all over the house then it could be a ground or interference issue somewhere. Do you have a TV connected with just coax (no tivo)? If so, do you see any static or signal issues with the same on/off test?
> 
> I would attempt to isolate the issue by disconnecting all coax leads and then testing as you connect each one. Try some direct connections from the main lead to the tivo with loose wire down the hall rather than using existing wiring. Also, remove any coax you have going through surge protectors.


I'll have to try this, although I don't think plugging the coax into the TV will give me anything since Comcast moved away from clear channels.

I do note that this does not happen while playing back something recorded.....so looks like it is affecting the coax signal from Comcast.



KillerBeagle said:


> What is the duration of this pixellation? The nearly instantaneous time of changing the switch position, or the whole time the fan is spinning up?
> A cheap switch can create a lot of electromagnetic noise across the frequency spectrum, which could be picked up by poorly shielded or ungrounded cables.
> If you plug the fan into a switched outlet, and turn it on and off via the wall switch, do you see the same thing?


The pixelation only happens when turning the knob of the fan on/off. It pixelates for a sec and then goes away. No pixelation while the fan it running.

I did plug the fan into a switched outlet. Turned it on and off via the switch and could NOT get it to pixelate. However, if I leave the wall switch on and turn the knob on the fan on/off, I get the pixelation while plugged into the switch.

-Kevin


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## thefisch (Jul 25, 2015)

Since you have an APC UPS, unplug it from the wall so the roamio plus can run on battery and then retrest. If the problem still occurs, then it's obviously not due to a power surge on the electrical lines to the outlets. Then you can focus on cable interference. Since house is older it may have lines with thinner insulation compared to what's available in recent years.

Since you don't get channels without a box, try a long cox run from the source without any splitters. Then try the long run with the splitte with no other coax runs connected other than the source. then start adding rooms to the splitter one by one till you find the problem line. If you don't have a long test cable to use it will be harder to test the splitter and the source, but you can still test the room lines in case that's where the issue is. In wall problems can be a nightmare to diagnose. Hopefully if you find the line it would be to a room where you don't need cable.


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## kbmb (Jun 22, 2004)

thefisch said:


> Since you have an APC UPS, unplug it from the wall so the roamio plus can run on battery and then retrest. If the problem still occurs, then it's obviously not due to a power surge on the electrical lines to the outlets. Then you can focus on cable interference. Since house is older it may have lines with thinner insulation compared to what's available in recent years.
> 
> Since you don't get channels without a box, try a long cox run from the source without any splitters. Then try the long run with the splitte with no other coax runs connected other than the source. then start adding rooms to the splitter one by one till you find the problem line. If you don't have a long test cable to use it will be harder to test the splitter and the source, but you can still test the room lines in case that's where the issue is. In wall problems can be a nightmare to diagnose. Hopefully if you find the line it would be to a room where you don't need cable.


Had the TV and Tivo plugged into the APC and unplugged it from the wall. Problem still occurs. So looking like it's coax related.

I'll have to try the coax stuff this weekend and see.

I'm guessing since this only really happens with this specific case of turning a fan on/off that nothing really needs to be fixed?

I'd love to be able to pay someone to rerun all the lines in the house....but that's pricey.

-Kevin


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## thefisch (Jul 25, 2015)

There is no need to rerun coax for the whole house. If it is outside then your cable company should cover that. If it is inside, it could be one bad line that you can simply disconnect if not in use or if needed then run only one new line. Or it could just be a simple splitter replacement.

Interference is mostly a nuisance, but you'd want to be sure you have your coax lines going through surge protectors to make sure your devices are protected just in case.


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## kbmb (Jun 22, 2004)

thefisch said:


> There is no need to rerun coax for the whole house. If it is outside then your cable company should cover that. If it is inside, it could be one bad line that you can simply disconnect if not in use or if needed then run only one new line. Or it could just be a simple splitter replacement.
> 
> Interference is mostly a nuisance, but you'd want to be sure you have your coax lines going through surge protectors to make sure your devices are protected just in case.


Thanks for the help. I'll update when I know more.

-Kevin


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## kbmb (Jun 22, 2004)

thefisch said:


> There is no need to rerun coax for the whole house. If it is outside then your cable company should cover that. If it is inside, it could be one bad line that you can simply disconnect if not in use or if needed then run only one new line. Or it could just be a simple splitter replacement.
> 
> Interference is mostly a nuisance, but you'd want to be sure you have your coax lines going through surge protectors to make sure your devices are protected just in case.


Also, I'm guessing that this interference it pretty early in the run since it affects both the downstairs and upstairs TVs?

My setup is:

Cable line from outside goes into a 3 way splitter.

Split 1: directly to cable modem (on first floor)
Split 2: directly to downstairs TV (on first floor)
Split 3: directly to upstairs TV (on second floor)

So all the runs are straight runs from the initial split.

-Kevin


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## jonw747 (Aug 2, 2015)

Sounds like a grounding problem. The surge the fan is creating is causing the ground potential of either the TiVo or the Coax to change, but not both at the same time.

Did you say you tried connecting the TiVo directly to the wall without the UPS? 

You might also see if you can verify if the Cable is grounded somewhere near where it enters the house. It's possible there's a ground wire and it's become damaged.


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## kbmb (Jun 22, 2004)

jonw747 said:


> Sounds like a grounding problem. The surge the fan is creating is causing the ground potential of either the TiVo or the Coax to change, but not both at the same time.
> 
> Did you say you tried connecting the TiVo directly to the wall without the UPS?
> 
> You might also see if you can verify if the Cable is grounded somewhere near where it enters the house. It's possible there's a ground wire and it's become damaged.


No, I did not try connecting the Tivo directly to the wall. It's plugged into a UPS. I unplugged the UPS so the Tivo was running on battery and it DID have the issue.

I'll have to check to see if the line coming into the house is still grounded.

-Kevin


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## kbmb (Jun 22, 2004)

jonw747 said:


> Sounds like a grounding problem. The surge the fan is creating is causing the ground potential of either the TiVo or the Coax to change, but not both at the same time.
> 
> Did you say you tried connecting the TiVo directly to the wall without the UPS?
> 
> *You might also see if you can verify if the Cable is grounded somewhere near where it enters the house. It's possible there's a ground wire and it's become damaged.*


Checked outside......cable from underground line comes up and connects to cable entering house. Cable from underground has a metal clamp holder with a wire connected. Wire runs back to a clamp on the electric meter metal pole running into the ground.

-Kevin


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## kbmb (Jun 22, 2004)

thefisch said:


> Interference is mostly a nuisance, but you'd want to be sure you have your coax lines going through surge protectors to make sure your devices are protected just in case.


Do you recommend running the coax into surge protectors at each outlet? Or early in the run to cover all?

-Kevin


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## thefisch (Jul 25, 2015)

kbmb said:


> No, I did not try connecting the Tivo directly to the wall. It's plugged into a UPS. I unplugged the UPS so the Tivo was running on battery and it didn't have the issue.
> 
> I'll have to check to see if the line coming into the house is still grounded.
> 
> -Kevin


Wait a second, so the interference did *NOT *occur when the UPS was unplugged and the tivo was running on battery? Then the issue would not be with the cable lines. It would be electrical interference.



kbmb said:


> Also, I'm guessing that this interference it pretty early in the run since it affects both the downstairs and upstairs TVs?
> 
> My setup is:
> 
> ...


Interference issues can effect any place along the cable run since the interference can travel back down the line to the splitter. So it is hard to pinpoint the location issue until you start testing individual lines one at a time while the others are disconnected.

Are you sure you only have 3 lines? My inlaws home was built in the 80's and their outside line was split into two lines. One line went upstairs and was split again to feed the upstairs rooms. While you may only use 3 lines, there could be more. Just saying. If you only have 3 coax outlets in the whole house, then that's it. Or if the other lines are not currently connected and you can see their leads at your panel.

Also, do you know what kind of cable is running in the walls? There should be an RG designation printed on the lines.



kbmb said:


> Do you recommend running the coax into surge protectors at each outlet? Or early in the run to cover all?
> 
> -Kevin


I would do it at each connected device. You don't know where the issue is along the lines.



kbmb said:


> Checked outside......cable from underground line comes up and connects to cable entering house. Cable from underground has a metal clamp holder with a wire connected. Wire runs back to a clamp on the electric meter metal pole running into the ground.
> 
> -Kevin


Sounds like you're grounded on the outside.


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## kbmb (Jun 22, 2004)

thefisch said:


> Wait a second, so the interference did *NOT *occur when the UPS was unplugged and the tivo was running on battery? Then the issue would not be with the cable lines. It would be electrical interference.
> 
> Interference issues can effect any place along the cable run since the interference can travel back down the line to the splitter. So it is hard to pinpoint the location issue until you start testing individual lines one at a time while the others are disconnected.
> 
> ...


Sorry....mistyped. Updated my previous post. YES the issue occurred while running on UPS power.

Pretty sure only 3 lines. I can see the line coming in from outside run through the garage into the basement. That's where it's split. The lines to the cable modem and 1st floor tv are single lines. The line to the upstairs is not a single line.....no splitters....but does have coax connector in 2 places I believe. You know.....the connector to join to coax lines together?

Pretty sure it RG5...that's the standard correct. Think its the thicker RG6 as the run from the pole (underground) to the house. The connector I think sizes it down to RG5 for the house run.

Thanks again for all your insight.

-Kevin


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## jonw747 (Aug 2, 2015)

kbmb said:


> No, I did not try connecting the Tivo directly to the wall. It's plugged into a UPS. I unplugged the UPS so the Tivo was running on battery and it DID have the issue.
> 
> I'll have to check to see if the line coming into the house is still grounded.
> 
> -Kevin


Ahh, then by all means see what happens with the UPS out of the picture so we can rule that out as contributing to the problem.

Also have you ever seen anything like this when turning on something else with a motor other than the fan? It's possible the fan is doing something beyond drawing a lot of inductive current on start up. It may be defective.


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## kbmb (Jun 22, 2004)

jonw747 said:


> Ahh, then by all means see what happens with the UPS out of the picture so we can rule that out as contributing to the problem.
> 
> Also have you ever seen anything like this when turning on something else with a motor other than the fan? It's possible the fan is doing something beyond drawing a lot of inductive current on start up. It may be defective.


So unplugged the Tivo from the UPS and plugged directly into wall...still had the issue.

Why am I always nervous about unplugging a Tivo thinking it won't come back 

-Kevin


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## jonw747 (Aug 2, 2015)

kbmb said:


> So unplugged the Tivo from the UPS and plugged directly into wall...still had the issue.
> 
> Why am I always nervous about unplugging a Tivo thinking it won't come back
> 
> -Kevin


Does anything else besides the fan cause the issue? Fridge turning on? Vacuum cleaner? etc?

Because the answer may be to replace the fan ...


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## kbmb (Jun 22, 2004)

jonw747 said:


> Does anything else besides the fan cause the issue? Fridge turning on? Vacuum cleaner? etc?
> 
> Because the answer may be to replace the fan ...


Haven't found anything else yet. I've tried however, 2 different box fans and a pedestal fan.....all have the issue, however, I'm sure all have a similar motor.

We have a window A/C plugged into the same outlet as the fan and so far turning that on/off doesn't affect the TV.

It's just weird that I finally noticed it last night when my wife turned the fan off. Has my curiosity peaked more than anything else.

-Kevin


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## MikeBear (May 21, 2015)

Just replace the BOX FAN already!

For gosh sake, you can buy them for like $12 all day long! Or find a good filtered power strip like this one: http://www.amazon.com/Tripp-Lite-Is...8&qid=1442433929&sr=8-2&keywords=ISOBAR4ULTRA

VHF channels are especially sensitive to electrical interference, and it can even be worse if you are using an amplified antenna. I had to replace my Dell laptop power brick because it caused the same interference YOU are seeing with your fan. I also had to unplug a Harbor Freight $20 power tender charger that was on a battery in my garage, over 100 FEET away!

Once I did that, the issue went away.

P.S. all my equipment is plugged into a set of UPS's, and I still had the electrical issue. It's broadcasting through the air to my basic Roamio that's antenna only

P.P.S DIG UP the ground wire, and make sure it hasn't become disconnected from the house ground rod wire.


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## kbmb (Jun 22, 2004)

MikeBear said:


> Just replace the BOX FAN already!
> 
> For gosh sake, you can buy them for like $12 all day long! Or find a good filtered power strip like this one: http://www.amazon.com/Tripp-Lite-Is...8&qid=1442433929&sr=8-2&keywords=ISOBAR4ULTRA
> 
> ...


I've tried it with 2 different brand box fans, as well as 2 different pedestal fans. They all do it.

It's more my curiosity of what is happening and why. I could go buy 50 box fans and I'm betting each one will do the same thing. So what's the point?

-Kevin


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## jonw747 (Aug 2, 2015)

kbmb said:


> Haven't found anything else yet. I've tried however, 2 different box fans and a pedestal fan.....all have the issue, however, I'm sure all have a similar motor.
> 
> We have a window A/C plugged into the same outlet as the fan and so far turning that on/off doesn't affect the TV.
> 
> ...


No, that's good. The idea was to make sure the fan wasn't damaged. You may want to start reading up on ground loops and how to test if you have a ground issue or a loop.

For instance, one of the classic problems is a house designed with multiple grounding points. For instance, if the coax traces its earth ground to a ground spike on one side of the house, and the fan traces its earth ground to a water pipe on the other side, that's bad.


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## BobCamp1 (May 15, 2002)

My suggestion would be to buy better quality fans. Grounding has absolutely nothing to do with it. Not a thing. And I really don't want to start that debate, except that almost nobody has any clue about how this stuff really works. The system will have less noise if it's not grounded, but since that violates code for safety reasons that's not really an option.

The noise is being transmitted over the air. Your UPS experiment proved that. The fan may also be using your house's power wiring as an antenna to saturate your house with electrical noise. 

You can make sure that all unused cable lines and RF connectors are terminated with 75 ohm terminators, and that all used cable connections are in good shape and tightened. Take out the wall jacks and make sure the cable connectors behind them are also in good shape. If they are, you can probably just redo the connectors on all the cables. Otherwise you're talking about a full house cable rewire -- there's probably a 3" or greater gap in the shielding of your cable system somewhere.

But I'd just get a better fan first. Because despite all these precautions, a low quality AC motor will still interfere with your picture. My bowl mixer and blender interfere with my reception (I have FIOS). I suspect the cable line going to my bedroom is letting the noise in, but since it's stapled to the stud and buried inside a wall it's not getting fixed.


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## L David Matheny (Jan 29, 2011)

BobCamp1 said:


> My suggestion would be to buy better quality fans. Grounding has absolutely nothing to do with it. Not a thing. And I really don't want to start that debate, except that almost nobody has any clue about how this stuff really works. The system will have less noise if it's not grounded, but since that violates code for safety reasons that's not really an option.
> 
> The noise is being transmitted over the air. Your UPS experiment proved that. The fan may also be using your house's power wiring as an antenna to saturate your house with electrical noise.
> 
> ...


OP could try putting one of those clamp-on ferrite chokes on the fan's power cord, at the end next to the fan I guess. I don't know whether it would help, but it would be an interesting thing to try.


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## kbmb (Jun 22, 2004)

BobCamp1 said:


> My suggestion would be to buy better quality fans. Grounding has absolutely nothing to do with it. Not a thing. And I really don't want to start that debate, except that almost nobody has any clue about how this stuff really works. The system will have less noise if it's not grounded, but since that violates code for safety reasons that's not really an option.
> 
> The noise is being transmitted over the air. Your UPS experiment proved that. The fan may also be using your house's power wiring as an antenna to saturate your house with electrical noise.
> 
> ...


Curious......if I plugged the Tivo and TV into a UPS and unplugged it from the wall....and plugged the fan into a different UPS and unplugged it from the wall....you are saying I would still get the pixelation?

*EDIT: Interesting.....I actually tried it both ways.*

First just having the fan plugged into a different UPS and having it unplugged from the wall - still got the pixelation.

Second still having the fan in the UPS and unplugging the UPS the Tivo and TV are on (making everything run on battery power) - still got the pixelation.

You are correct....I don't understand any of it  But then again....this whole thing is more my curiosity....since honestly, it's not like I'm sitting here on a normal day turning fans on and off 

-Kevin


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## ggieseke (May 30, 2008)

If you got pixelation with both units unplugged it's RF interference.

Wrap the fan or the TiVo with grounded aluminum foil.


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## BobCamp1 (May 15, 2002)

ggieseke said:


> If you got pixelation with both units unplugged it's RF interference.
> 
> Wrap the fan or the TiVo with grounded aluminum foil.


It should not be grounded! Look here about 1/3 down on the page:

http://www.electro-elite.com/electricaltheory2.htm

Grounding it will just attach an antenna to an imperfect Faraday cage, which will have unpredictable results.

He can't wrap the Tivo in foil, as the heat won't escape. Plus that would be pointless, as the interfering signal is inside the cable.

He could poke holes the diameter of a pencil in the foil then wrap that around the fan, but that'll look silly. Just buy a nicer fan. It might be trial and error, so save your receipts.


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## jonw747 (Aug 2, 2015)

Technically the article just mentions that a Faraday cage can work ungrounded. They also work grounded.

Anyway, ferrite cores on all cords going in to the TiVo may help - that is if they don't already have them.


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