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Discussion Starter · #1 ·
Hi all,

I am in the process of retrofitting my 1940's home with structured wiring. I went to the local networking store and they said that if I go with shielded RG6 I need to make sure that the shielding is grounded for it to do any good. This makes some sense to me, but the guys at the store didn't seem to know where/how to ground the shielding. I am planning on using a leviton media enclosure with a two way spliiter off the utlity, one side to cable modem and one to video amp, and then from the video amp to a 6 way splitter and from the splitter to my drops. Where/how do I ground my cable so the shielding works???


Edward
 

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By code, at the point where your CATV service enters the house there should be a "ground block", installed by the Cable company, which will be connected by copper wire to the house electrical service entrance ground rod, if nearby, or possibly alternatively the meter box or a metal cold water pipe. That establishes the safety ground for the CATV run into the house.


All devices that use coaxial cable with "F" connectors downstream of that are connected to that ground through the coaxial cable shield and outer shell of the connectors. That is sufficient for most purposes as both a safety measure against stray current (e.g. induced by nearby lightning strikes) and small signal shielding (preventing induced hum or interference from normal nearby sources).


That having been said, it would be a good idea to connect the media enclosure box to the same house ground point with a separate #8 (or heavier gauge) ground wire. Then any device in the enclosure can be grounded to it either by mounting it with screws or using short jumper wires. CATV splitters usually have a small screw at one corner for this purpose. This will provide a lower resistance path to ground for induced surges and may further protect any connected equipment such as your distribution amplifier.


Finally of course use surge protectors on not only AC power cords and phone lines, but at least on the incoming CATV feed line. The block they put outside is supposed to also offer surge protection, but a second one where the CATV line comes into the media enclosure is good insurance.


Mike
 

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Quote:
if I go with shielded RG6 I need to make sure that the shielding is grounded for it to do any good
RG6 is coax cable, coax is inherently sheilded...you can't have unsheilded coax.

The sheild will be connected to ground at the RF tap on the pole, this is an unbalanced circuit that requires the sheild to be the return path. If the sheild is not connected to anything, you will not get any signal.
 

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If it isn't grounded at the same place the electrical service is grounded though, you get extra signal, commonly known as ground loop hum.
 

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Discussion Starter · #5 ·
So in RG6 the "shield" is the signal ground? And the different levels of shielding imply different construction of the signal ground? The guys at the store implied that the shielding and signal grounds were separate conductors. Is this not true?
 

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Quote:
So in RG6 the "shield" is the signal ground?
Yes.

Quote:
The guys at the store implied that the shielding and signal grounds were separate conductors. Is this not true?
No, it's not true.
 
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