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Mikel
voltage in cable coaxial

I was told by my cable company that I have "voltage" in my cable lines. One or more of the TVs in my home are not grounded properly and volts are ecaping my TV through the cable. This is causing interference in my TV reception and Internet (and who knows what else).
I have a home built in the 30s and I do not have a ground wire at this recepical. Will the GFCI help prevent this problem? Can I groung the outlet to a cold water line?

Ernie_Fergler
Re: voltage in cable coaxial
Mikel wrote:

I was told by my cable company that I have "voltage" in my cable lines. One or more of the TVs in my home are not grounded properly and volts are ecaping my TV through the cable. This is causing interference in my TV reception and Internet (and who knows what else).
I have a home built in the 30s and I do not have a ground wire at this recepical. Will the GFCI help prevent this problem? Can I groung the outlet to a cold water line?

I CAN'T BUY THAT...

canuk
Re: voltage in cable coaxial

Nope .... don't buy that.:confused:

First thing .... if the cord from the TV only has a two prong plug then you wouldn't be using the "ground" anyway .... simply the hot & neutral.

Second .... it's unlikely the TV is feeding any voltage from it's internal tuner into the cable.

No ... you shouldn't ground the receptacle to the cold water pipe.

JLMCDANIEL
Re: voltage in cable coaxial

If you have old outlets that are not keyed, that is both slots are the same size, you might try unplugging your TV, turn the plug over and plug it back in. And no an ungrounded GCFI outlet will not work.
Jack

Re: voltage in cable coaxial

Is your internet a dedicated line seperate from your tv?
I had a problem with interference also -the problem was that I branched of of my tv line to my cable modem.I seperated them and now they work fine.Its worth a try

canuk
Re: voltage in cable coaxial

Who knows what the set up is .... considering there are more than one TV's and a modem then it's guaranteed a splitter is being used somewhere.

These splitters are known to go bad and cause interference for TV signals.

There could be a signal drop which means an amplifier may be needed.

It could be simply poor connections done to the cables themselves.

There are two components here ... TV and Data ... usually for both to be affected usually means a poor connection of the actual cable feed.

If it's an outside connection on overhead lines there could be a corroded connection outside and the cable guy may not have felt like climbing a ladder to check.... same with under ground run lines.... poor connection at the outside box.

The cable could be run along fluorescent lights or something with a motor picking up strong EM/RF interference. For example ... I have a surround receiver with a cooling fan .... when the receiver was situated too close to the TV and when turned on .... the cooling fan would cause interference to the TV but wouldn't affect the cable modem.

I doubt it has anything to do with what was described by the original poster.

Lots of other possibilities.:)

Re: voltage in cable coaxial

I have had problems like you described before. I suggest start with either replacing the connectors if they are crimped on. Or if they are the twist on type try re terminating them. Just make sure the outer shield connects to the outer shell of the connector. Also make sure the center copper conductor does not come on contact with the outer shield. This is usually what cause the weak signal.The cable companies use a DBM meter that measures signal loss. a good technician can tell what cables are giving you the problems. If the technician is just a installer he usually does not know what he is measuring other then what is the minimum standard is required. Ask the cable company to send a technician that knows what he is doing. The one you had did not have a clue... good luck

Born2Wire
Re: voltage in cable coaxial

First thing I would look at are the actual ends on the wires. Their wiring system usually gets grounded the minute it reaches your property , typically found outside at the first splitter or conection block. As long as their ground is made , and all the wiring ends are well ,it will continue through-out. You talked to an idiot...

novausc
Re: voltage in cable coaxial

I'm surpised that all of you have been so quick to point the dog in the other direction. Voltage backfeeding off of a TV is quite common on older TVs in older homes. I worked for Time Warner Cable for 10 years and I've seen this quite a bit. It's usally caused by poor grounding of the TV (or electrical device, I've seen electric water heaters cause the issue too) and it grounds to cable instead. Electricity takes the quickest path to ground so if you have a poor ground lead in the TV and it shorts then it's going to ground to natural ground which is all the dead points in the case. Since you have no ground on the outlet, it has nowhere to go. The barrel splice that is soldered to the tuner is also grounded to this which means the braiding is the best point of discharge all the way to the cables groundblock. It will follow the brading all the way to the ground block, which should be installed at the same point the house is grounded to prevent a differential from building. usually the voltage becomes noticable if you have an ungrounded splitter somewhere in the mix. Disconnect the suspected tv's coax cable from the splitter and use a multimeter to test for voltage on the coax by putting negative on the center conductor and the positive on the coax connector. if you get a positive voltage(set for DC current) then you're grounding to the braiding. there are a few ways to correct the issue, 1 makes sure your ground on the main splitter at the grounding block is secure as well as the homes grounding spike, 2 install a voltage filter on the line before the TV(not sure where to buy these now, radio shack carried them 10 years ago but not anymore. Fry's Electronics has them.), 3 you can block the voltage if you clear the braiding from the connector, i dont recommend this as now you have unshielded cable but it will stop the voltage from traveling the distance. One thing to remember, never ground anything to anything that is not the homes central ground. you can build up a differential and cause way more trouble than you want, including death.

canuk
Re: voltage in cable coaxial
Quote:

if you have a poor ground lead in the TV and it shorts then it's going to ground to natural ground which is all the dead points in the case.

Interesting .... I have to admit years ago when I used to repair electronic equipment including TV's ..... never seen what you describe. Not quite sure what you are meaning by a ground lead inside the TV shorting ..... to what?

I've never seen a TV tuner block back feed voltage but i have seen tuner block malfunction changing impedance and loading down the cable input.

It would seem an easy troubleshooting proceedure would be disconnect the TV in question to see if the interferance problem clears.

Just a thought. :)

Re: voltage in cable coaxial
canuk wrote:

Interesting .... I have to admit years ago when I used to repair electronic equipment including TV's ..... never seen what you describe. Not quite sure what you are meaning by a ground lead inside the TV shorting ..... to what?

I've never seen a TV tuner block back feed voltage but i have seen tuner block malfunction changing impedance and loading down the cable input.

It would seem an easy troubleshooting proceedure would be disconnect the TV in question to see if the interferance problem clears.

Just a thought. :)

I agree with Canuk...I have a degree in electronics never seen a TV back feed into the cable. But I have seen voltage on a ground caused by someone using a ground for a neutral. I think disconnecting the TV to see if there is voltage on the coax would be a simple test. If there was still was no voltage after the TV was disconnected then I would stand corrected. I think the technician should have explained what could be the cause. This whole thing is strange. In 30 years I have never heard of that. But you never know:confused:

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