# Need Help with HDMI signal loss/interference



## Marsh Marlowe

Hey everyone, new to the forum. I did a quick search and couldn't find a problem exactly like mine, but please forgive me if this has already been addressed.

I moved into my home about 2 years ago. The previous owner of the home had a pair of HDMI cables run through the wall above the fireplace and installed an electrical 120V wall outlet behind where his TV was mounted to the wall. There are also speaker wires for center, left, and right speakers, which are connected and working. The HDMI cables look to be of high quality, though maybe a bit dated. They're Rocketfish brand with thick insulation and gold plated connectors. I'm estimating the cables to be, at most, 30' long. I've been having some signal issues using these cables... here's what's going on:

When I connect my DirecTV DVR Receiver to either of the HDMI cables, I get a grainy, pixelated picture. When I connect the smaller client DirecTV box to either of the cables, I get a much better quality picture, with only the occasional floating "red specks" on an otherwise dark image. No other notable distortion, definitely not something I can't deal with.

When I connect my XBOX 360 to either of HDMI cables, I get a great picture, but like with the client box, I get faint occasional red specks on dark images. When I connect my PS3 to either of the HDMI cables, I get a clipping image. The PS3 has given the worst picture out of all the HDMI signal sources I've tried.

So, I ordered a cheap passive "signal booster" off eBay. When I use the signal booster inline with the PS3, the clipping is eliminated, but I still get an occasional grainy image.

So, it seems that some of these signal sources (XBOX, DirecTV client box) have stronger signals and are able to overcome whatever interference may be present. 

So a few questions-

Would a powered HDMI signal booster be worth a try?

What could be causing the signal interference? I don't know how the wires are running behind the wall, or how close the HDMI cables are to the 120V wiring/speaker wires. Can 120V wiring/speakers wires cause signal interference with HDMI cables?

The HDMI cables are directional cables (at least that's how they're labeled). The previous owner of the home somehow went to all the trouble of running these cables behind the wall, and they're backwards... :rolleyesno: The source side exits the wall behind the TV, and the Display side exits the wall behind the entertainment center. Does this even matter?

My last resort is tear out the drywall and replace or reposition the cables behind the wall. For obvious reasons, I'd like to avoid doing this if possible. I've tried pulling on the cables to see if I could possibly pull new cables through, but it seems they are now part of the structure of the home because they aren't budging a bit.

Thanks for any input!


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## NBPk402

Marsh Marlowe said:


> Hey everyone, new to the forum. I did a quick search and couldn't find a problem exactly like mine, but please forgive me if this has already been addressed.
> 
> I moved into my home about 2 years ago. The previous owner of the home had a pair of HDMI cables run through the wall above the fireplace and installed an electrical 120V wall outlet behind where his TV was mounted to the wall. The HDMI cables look to be of high quality, though maybe a bit dated. They're Rocketfish brand with thick insulation and gold plated connectors. I'm estimating the cables to be, at most, 30' long. I've been having some signal issues using these cables... here's what's going on:
> 
> When I connect my DirecTV DVR Receiver to either of the HDMI cables, I get a grainy, pixelated picture. When I connect the smaller client DirecTV box to either of the cables, I get a much better quality picture, with only the occasional floating "red specks" on an otherwise dark image. No other notable distortion, definitely not something I can't deal with.
> 
> When I connect my XBOX 360 to either of HDMI cables, I get a great picture, but like with the client box, I get faint occasional red specks on dark images. When I connect my PS3 to either of the HDMI cables, I get a clipping image. The PS3 has given the worst picture out of all the HDMI signal sources I've tried.
> 
> So, I ordered a cheap passive "signal booster" off eBay. When I use the signal booster inline with the PS3, the clipping is eliminated, but I still get an occasional grainy image.
> 
> So, it seems that some of these signal sources (XBOX, DirecTV client box) have stronger signals and are able to overcome whatever interference may be present.
> 
> So a few questions-
> 
> Would a powered HDMI signal booster be worth a try?
> 
> What could be causing the signal interference? I don't know how the wires are running behind the wall, or how close the HDMI cables are to the 120V wiring. Can 120V wiring cause signal interference with HDMI cables?
> 
> The HDMI cables are directional cables (at least that's how they're labeled). The previous owner of the home somehow went to all the trouble of running these cables behind the wall, and they're backwards... :rolleyesno: The source side exits the wall behind the TV, and the Display side exits the wall behind the entertainment center. Does this even matter?
> 
> My last resort is tear out the drywall and replace or reposition the cables behind the wall. For obvious reasons, I'd like to avoid doing this if possible. I've tried pulling on the cables to see if I could possibly pull new cables through, but it seems they are now part of the structure of the home because they aren't budging a bit.
> 
> Thanks for any input!


Are you using the same quality cable for all the sources? I am wondering if part of your problem might be the cable running backwards. I run the Redmere cables and if I recall correctly they would not even work backwards. Anytime you have a power cable it should be at least 12" away (preferably farther), and if you have to cross one it should be at 90 degrees to the other cable. 

Is it possible to run a new hdmi cable and conceal it without tearing up your walls? An example would be to run it in the wall where it is now, and exit behind your mouldings. At that point you could run it behind the mouldings to your source location. If you do this just be careful where you nail the moulding! 

I would try this first to make sure it is the 30' long cable or some other cable... 

1: Take a source and hook it up directly to your tv, and see if it still causes the problem. If it doesn't then you eliminated that source and that sources cable. Once you have tested all the cables you will know if the in wall cable is the problem. 

2: It is possible that just switching the direction of the cable will solve the problem. To test it I would plug the source in where the tv is and then plug the tv in where the source normally is... If you still have the problem then I would say it is the cable.


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## Marsh Marlowe

Thanks for the reply.

Sorry, I should have stated in the original post that I have hooked up all the sources directly to the TV using different cables, and don't have any signal issues. The 2 cables running behind the wall are identical to each other. 

In order to plug in the source where the TV is, and the TV where the source is, I'd have to remove the TV from the wall above the fireplace and place it on the other side of the room. Definitely worth a shot, but it would take some doing, and if it turns out the signal quality is now perfect with cables now in the "right" direction, I'd still have the original problem... I can't change the orientation of the cables without removing drywall... they are stuck 

I will look into other ways of running the cables with them still being concealed. Thanks again for your input and quick response :T


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## NBPk402

Marsh Marlowe said:


> Thanks for the reply.
> 
> Sorry, I should have stated in the original post that I have hooked up all the sources directly to the TV using different cables, and don't have any signal issues. The 2 cables running behind the wall are identical to each other.
> 
> In order to plug in the source where the TV is, and the TV where the source is, I'd have to remove the TV from the wall above the fireplace and place it on the other side of the room. Definitely worth a shot, but it would take some doing, and if it turns out the signal quality is now perfect with cables now in the "right" direction, I'd still have the original problem... I can't change the orientation of the cables without removing drywall... they are stuck
> 
> I will look into other ways of running the cables with them still being concealed. Thanks again for your input and quick response :T


If you don't mind spending around $40... Go to Monoprice.com and get the Redmere cable and just run the new cable (test it out first to make sure, but I think it will solve the problem). I would get some string and run it along the area you are going to run new cable just to make sure you will have enough. Another option is to run 2 cat 5 cables and then run the cat5 converters but I think it will cost you more to go that way.


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## Marsh Marlowe

I checked out the Redmere cables. So these cables are thinner and easier to run I take it?

I was not aware that running cat 5 cables was an option. I'll have to look into this as well.


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## NBPk402

Marsh Marlowe said:


> I checked out the Redmere cables. So these cables are thinner and easier to run I take it?
> 
> I was not aware that running cat 5 cables was an option. I'll have to look into this as well.


Yes and Monoprice has a lifetime warranty on them. If you order check out their overnight delivery price... For me it was cheaper than their normal rate. :T


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## gazoink

ellisr63 said:


> Are you using the same quality cable for all the sources? I am wondering if part of your problem might be the cable running backwards. I run the Redmere cables and if I recall correctly they would not even work backwards.


Active cables won't work backwards at all. If they are passive, reversing won't help.


ellisr63 said:


> Anytime you have a power cable it should be at least 12" away (preferably farther), and if you have to cross one it should be at 90 degrees to the other cable.


 A common misconception. The electric and magnetic field around a paired power run is nearly all cancelled by the fact there's a pair. If the pair is in conduit, the E and H fields are effectively shielded from anything near by. Unless you try to run an audio line in the same conduit with power, or a microphone line next to power, there's no issue, certainly nothing that would require 12".



ellisr63 said:


> If you don't mind spending around $40... Go to Monoprice.com and get the Redmere cable and just run the new cable (test it out first to make sure, but I think it will solve the problem). I would get some string and run it along the area you are going to run new cable just to make sure you will have enough. Another option is to run 2 cat 5 cables and then run the cat5 converters but I think it will cost you more to go that way.


Yes, Redmere cables are thinner. They are also more fragile both physically and electrically. I've had them fail several times. The warranty doesn't mean much if you have to re-pull cables through walls. Otherwise they are fine. A good Cat5 extender system is a much preferred option for 30' runs and greater. Somewhat more expensive, but the cable is less fragile, and length isn't a limit up to 150'. I use Wyrestorm extenders, single Cat5 for HDMI 1.4.
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## Marsh Marlowe

Interesting. That makes me wonder if it's not interference causing the issue, but the cables themselves are damaged in some way. I don't believe the cables have been run through a conduit mainly because if they were, the cables would move freely when I pull on them (I think).

So what about a signal amplifier? Worth a try, or no?


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## gazoink

Marsh Marlowe said:


> Interesting. That makes me wonder if it's not interference causing the issue, but the cables themselves are damaged in some way. I don't believe the cables have been run through a conduit mainly because if they were, the cables would move freely when I pull on them (I think).
> 
> So what about a signal amplifier? Worth a try, or no?


For it to be interference from a power run, the cable would have to run in parallel for some distance with a single AC conductor, not a hot and cold pair. That's possible, but not common. 

The cables should work without a signal amp. If they don't, an amplifier won't help, at least reliably. I've never run into an HDMI issue that could be solved by adding something to a cable that wasn't working. It's always been a cable replacement.


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## gazoink

You might just try a new cable without running it in the wall. There's an outside chance you might have a grounding issue between the TV and AVR. If the new cable works you can run it elegantly after you try it.


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## NBPk402

gazoink said:


> Active cables won't work backwards at all. If they are passive, reversing won't help.
> A common misconception.


I understand that... Can you explain why his cables are marked with source on one end are hooked up backwards and still work?


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## gazoink

ellisr63 said:


> I understand that... Can you explain why his cables are marked with source on one end are hooked up backwards and still work?


No I can't, by they aren't really working are they? If they were he wouldn't be here asking questions.


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