Proper grounding of cable TV - AVS Forum
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post #1 of 13 Old 07-11-2007, 06:47 AM - Thread Starter
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Okay, a brief description of my problem. I've had lines of intereference on several channels for some time now. Had cable tech hook a line directly from the side of the house where their line comes. Bypassing all other lines and splitters, and going to one TV. Problem still exists. Which immediately makes me think it's in the signal from the cable co. But then I was thinking about how the interference seems to change in intensity over time. Which makes me think it could be something getting into my line. The only thing that remains a constant from when we hooked one line directly and the way it was, is the ground block.

Right now it looks like they have that ground wire coming from a block to a rod in the ground. I'm thinking this is the same rod the house electicity is grounded too, but I'm not sure. If true then I'm thinking my electricity is causing this problem. Is there a way to seperate the cable TV ground so it's by itself ? Or is it required to be grounded a certain way ? What should I look at to make sure everything is grounded correctly ?

I'm supposed to have a TW tech get back to me and I of course will zero in on my ground to make sure it's okay.
As always, I am so grateful for the info people try to give.
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post #2 of 13 Old 07-11-2007, 08:10 AM
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It should be the same ground as your house. Isolating the grounds permits a potential difference than can account for the problems.

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post #3 of 13 Old 07-11-2007, 08:49 AM
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If you feel adventurous, you can try running a new ground wire to a cold water pipe in the basement. Or, ground to a block in your electrical panel. But I would wait to see what the TW tech has to say first.

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post #4 of 13 Old 07-11-2007, 10:57 AM
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The Cable TV ground should always be bonded to the same ground as the house electrical system. Any additional grounds (like stakes or cold-water pipes) are just extras.

Ken English, Sr. Engineer, KSL-TV.
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post #5 of 13 Old 07-11-2007, 11:20 AM - Thread Starter
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Okay, I've looked at the ground situation at my house. It looks like both the Cable TV and Electricity is grounded to the same rod driven into the land. Does this sound right ? Does the electricity of the home usually use these rods in the ground ? I'm assuming yes. I noticed the bracket used to ground the wire to the rod is extremely loose but still around the rod. Like you can pull it straight up and off the rod with no effort. This looks like the electric ground. Does this need to be tightened good to the rod ? Can this looseness be the cause of interference ? Below this bracket is another bracket that seems to be where the cable ground wire comes to the rod. Here I notice some exposed wire that seems to come from the coax itself, like the copper from within the coax. This is a different wire than the ground wire. I'm assuming the coax part needs to be grounded there. Does the exposed wire sound right ?

Thanks for everyones thoughts. I'm definitely gonna have this ground thing redone. The rod and brackets just seem very old looking.
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post #6 of 13 Old 07-11-2007, 02:47 PM
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If the ground wire for the house power is loose, then the cable tv line is carrying some the current from the house's breaker panel (the amount depends on how much of an unbalance there is between circuits at the moment) back to the pole. Usually, the power poles have a very good ground on them (bare copper wire spiralled all around the pole and on it's base, underground) and CATV is grounded to that. So, a bad ground at your house means the excess current will flow toward the pole, via whatever means is connected....Cable TV shield, phone wire, etc.

Be very careful fixing it, or call an electrician to fix it. Either way, it needs repair.

Ken English, Sr. Engineer, KSL-TV.
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post #7 of 13 Old 07-11-2007, 02:53 PM
 
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Yes the grounds should be the same as the others here have said. Just have the TW 'tech' replace the drop from the pole to the GB. You never said if you had aerial or UG service.
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post #8 of 13 Old 07-11-2007, 04:22 PM - Thread Starter
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I'm unclear on what you mean aireal or UG. So it sounds like I have a problem here ? Both the electric and cable TV ground wires are connected to the rod in the ground. But each has it's own bracket ( a doughnut like bracket fit around the rod). So the wire is on the rod via this bracket. But this bracket is extremely loose. It has screws to tighten it all around the rod. The way it is now you can easily slip it off the top of the rod with no problem.

Now the wire IS hooked to this bracket and it IS on the rod. As long as this is connecting should there be a problem ? Or does the looseness of this bracket cause a problem ?

Thanks again for any info.
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post #9 of 13 Old 07-11-2007, 04:25 PM
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Quote:
Originally Posted by tuna-head View Post

Now the wire IS hooked to this bracket and it IS on the rod. As long as this is connecting should there be a problem ? Or does the looseness of this bracket cause a problem ?

Yes, the looseness is an issue. That will increase the resistance in the ground path at that point and change the balance of any current flow through the various ground paths. If that path is not the lowest impedance in the house/system, it cannot do its job properly.

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post #10 of 13 Old 07-12-2007, 06:20 AM
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Quote:
Originally Posted by tuna-head View Post

I'm unclear on what you mean aireal or UG.

Aerial means overhead (up in the air between a pole and your house) and UG means underground (buried in the ground between your house and a pedestal in the ground).

CIAO!

Ed N.
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post #11 of 13 Old 07-12-2007, 07:25 AM - Thread Starter
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Thanks guys. As I wait for the tech I'm wondering if there is anything safe I can do to test whether this ground thing is causing my interference. I'm not an expert and don;t want to blow up my house or myself

I was thinking about simply trying to screw down the loose bracket with a screwdriver. Would I electrocute myself ?

And then I was wondering what would happen if I briefly pulled the bracket up and off the rod, so i could see if this made a difference on my interference.

I'm just a bit impatient waiting for TW to get back to me. When I have a thought in my mind I want to scratch it. Though I don't want to cause harm.

Thanks again.
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post #12 of 13 Old 07-14-2007, 07:32 AM
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I'd ask the power company to come out. It's a quick fix for them, and they have the proper tools (and rubber gloves) to fix it.

Ken English, Sr. Engineer, KSL-TV.
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post #13 of 13 Old 07-15-2007, 12:43 PM
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all grounds phone,electrical, cable and antenna should be in one place the rod connected to your
service box or you will have the potential to set up a ground loop and yes that ground clamp should be tight.
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