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Had to undo my current grounding..

Discussion in 'DIRECTV Installation/MDU Discussion' started by JDubbs413, Oct 18, 2007.

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  1. JDubbs413

    JDubbs413 Icon

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    Sep 4, 2007
    I had my Zinwell WB68 grounded to the AC Unit outside of my house using the proper wire. However it created pixelation on all MPEG-4 channels. I undid the ground temporarily and the pixelation is gone. What should I do to get a grounded dish minus the pixelation?
     
  2. K4SMX

    K4SMX Hall Of Fame

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    I would say rather that you "connected" your WB68 to your air conditioner. How is your dish grounded? How is your grounding block grounded? Where is your WB68 in relation to the dish and the grounding block?
     
  3. JDubbs413

    JDubbs413 Icon

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    Sep 4, 2007
    Well the dish is on the roof and I assume the grounding wires for the dish itself run into the multiswitch. The multiswitch is on the outside of the house. I don't think there technically is a grounding block.
     
  4. K4SMX

    K4SMX Hall Of Fame

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    May 19, 2007
    This is the way I do it. I believe it's in accordance with the NEC. The "right" way is often inconvenient and time consuming, but at least it's not terribly expensive:

    #4 solid copper straight from the dish to an 8' ground rod.

    coax runs straight to a grounding block(s) at the same general location

    grounding block(s) bonded to the ground rod w/ #6 solid copper

    on to any multi-switch to be placed nearby, also bonded to the ground rod w/ #6

    separate #6 run from the grounding rod bonding point to nearby copper cold water pipe or preferably to the utility service ground

    I'll guarantee you there won't be any pixelation/switching issues with that installation with normal length runs of coax caused by improper grounding. (If they're long, you need a Sonora polarity locker, also grounded.)

    All of these materials are available at any Home Depot/Lowe's electrical department.
     
  5. AntAltMike

    AntAltMike Hall Of Fame

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    College...
    I've noticed that fewer and fewer of the members of the various DBS forums continue to contribute to threads involving grounding. Is there any thread in the archive that the Administration here might designate to be a sticky or reference thread?

    The NEC requires the mast to be grounded with 10 gauge copper, 8 gauge aluminium or 17 gauge copper clad steel wire. It doesn't have to be solid or insulated. It is to be connected to the building's ground electrode system. Starting with the 2002 code revision, you cannot satisfy that code requirement by connecting to a cold water pipe unless the connection is made within five feet of the point at which the cold water pipe enters the building.

    You may drive a ground rod to make a "better" mast ground, but last time I checked, it had to be 8 feet by 1/2" and had to be bonded to the building's ground electrode system with 6 gauge or larger copper wire, which also did not have to be solid or insulated.

    The individual coaxes outer conductors have to be grounded with a wire approximately equal to their current carrying capability as near as is possible to the point at which each enters the building. Generally, this condition is presumed to be satisfied with 12 gauge copper wire, even though most people doubt that it, in fact, is equal to the coax's current carrying capability.

    The NEC is a fire and safety code. It was not designed to serve as a "technical" ground to improve the performance of your electronic system. It is intended to reduce fire and shock hazards. The mast ground is there primarily to bleed off static discharge to reduce the liklihood that it will attract lightning. The outer conductor ground will shunt any high current surges to ground, so they will be less likely to cause fires or give shocks.

    The code grounding requirements cannot be met by connecting a ground wire to an air conditioner, nor to its shut-off or disconnect breaker or switch box, nor to any EMT conduit. I don't know how the connection you have resulted in what you have called pixelization. That term is used in these forums to describe different symptoms. Most likely, it served as a path for "noise" generated by the air conditioner to enter and disrupt your satellite system's operation. Obviously, you are better off without that connection.
     
  6. Coffey77

    Coffey77 Cutting Edge: ECHELON '07

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    Nov 12, 2006
    I'm heading to a grounding and bonding seminar next week, lots of fun. I"ll keep an ear open for info. ;)
     
  7. randyk47

    randyk47 Icon

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    Aug 21, 2006
    San Antonio, TX
    This whole grounding business is extremely confusing. My dish/grounding block are "grounded" but to a cold water pipe. My house literally sits on solid rock....well, solid limestone would be more accurate. Most places in my yard, which took numerous dump trucks loads of top soil to establish, you can't dig more than a foot. The idea of driving an 8' long grounding rod isn't/wasn't going to happen. Sure, there's a grounding rod by my main service. The house was two years old when I bought it and I haven't the faintest idea how long it is or how they installed it. The other problem is that it is completely on the other side of the house. Any notion of bonding a rod on the dish side of the house is pretty much totally out of the question even if I could get by the solid limestone problem. Answer might have been to install the dish on the side of the house above the main service and run the ground to the grounding rod there. Problem with that is that there's no LOS from that side of the house. I guess, strictly speaking, since I don't have a "perfect" grounding situation I should have gone with cable?
     
  8. raoul5788

    raoul5788 Guest

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    Here in CT your dish is required to be grounded to within 5' of the water service entrance.
     
  9. K4SMX

    K4SMX Hall Of Fame

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    May 19, 2007
    One of the possible reasons is that some members like to debate every point to death, and posters who understand the issue really don't have time for that. I'm in agreement with your comments above. What I posted above is a slightly "beefed up" version of the NEC which I personally use for roof-mounted antennas of any type. I am a firm believer in overkill, where grounding is involved. I prefer #4 coming down from the dish, since it's easily available at home improvement stores in 25' boxed lengths along with the split-U connectors to attain longer lengths. Half-inch copper strap is better, but not as readily available. At my current location, I have two pieces of #4 from the roof-mounted OTA antenna system to a multiple ground rod system. Am I perfectly safe from lightning? No. Is it better than doing nothing? Absolutely. While the NEC may not have been specifically designed to "improve the performance of your electronics system," following the NEC will certainly prevent degradation of that performance due to improper grounding procedures.
     
  10. davejacobson

    davejacobson Legend

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    Mar 14, 2005
    You dont need to drive a ground rod. Yor electrical service will have a grounding system the dish and cable MUST be grounded there.Your AC is not a valid ground.The only time you are permited to drive a ground rod is when your ground run is more than 20 ft. Then at least a #6 wire is run from that rod to the main electrical ground.The 20 ft rule is generally not inforced for the antenna/cable guys, but the run to the main electrical should be done. The #14 messenger can be used to ground the dish. And before anyone goes off on me this is wire is not big enough to carry any direct lightning strike. It is to reduce staic on the dish protecting the electronics from a static shock and reduce the likleyhood of a lighting strike. Plus its the code. Read up on the code in section 800 (chapter 8) in the 2005 NEC and reference any comments or disagreements from that.http://ecmweb.com/nec/electric_article_radio_television/
     
  11. armophob

    armophob Difficulty Concen........

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    I think this is what you are looking for...

    http://www.dbstalk.com/showthread.php?p=941620#post941620
     
  12. K4SMX

    K4SMX Hall Of Fame

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    May 19, 2007
    This is not an uncommon problem, and there have been specific procedures developed to deal with it. They involve, for example, the construction of a counterpoise ground system around the object to be grounded. I watched these installed by a professional lightning protection company in 3 different pump house locations here at my secondary location in the western NC mountains last summer. What they did was dig a trench that appeared to be about a foot deep all the way around the small 10' x 10' building and bury copper strap in it. Then they connected the copper down straps from the lightning rods to the counterpoise ground.

    You can similarly create a radial ground system by burying runs of copper strap or heavy gauge solid wire in several different directions away from the object to be grounded. These typically involve shorter, connected ground rods every 10' or so. I'm sure with a little research you can dig up the exact spec's for how it is recommended these two methods should be constructed. Believe me, this subject has been extensively studied for years and solutions developed for most soil conditions even to include chemical treatment of the soil. This last is obviously not something you would do to your yard, but to give an example of how thoroughly this has been studied since Marconi.
     
  13. K4SMX

    K4SMX Hall Of Fame

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    This is where minimum requirements that are frequently skirted can be improved upon by those willing to spend a little time and effort. I always install a ground rod (or other ground system) to a roof-mounted antenna and connect to the service ground w/ #6, no matter the distance. You don't need "permission" from anyone to install your own antenna ground, but it must be bonded to the service ground.
     
  14. donshan

    donshan Godfather

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    Jun 18, 2007

    I find it useful to use a digital volt ohm meter and measure the electrical resistance between the satellite/antenna system ground vs. the building's electrical ground system using one of the round ground holes at any 120 volt outlet. This resistance should be close to zero if both are correctly bonded back to the same service ground.

    I just ran a new pair of sat lines and an antenna cable to our BR and tested the resistance between the properly grounded antenna lead shield vs. the building electrical ground and was surprised to see a reading of 106 ohms. Checking back to the main sat/antenna ground clamp installed 8 years ago I discovered corrosion. After cleaning the ground wires and clamp at the main service ground, the bedroom reading came down to 0.3 ohms and passed a continuity check. Much better! Even when the wiring is correct it may not stay that way over the years.
     
  15. techrep

    techrep Hall Of Fame

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    Sep 15, 2007
    There is also a "grounding mat" which is about 2'x4' and can be buried 1' to 2' deep.
     
  16. donshan

    donshan Godfather

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    Jun 18, 2007
    In most of the US that gets adequate rainfall, especially east of he Mississippi grounding rods and the mat you suggest may work. However the soil must be damp for any ground rod/mat system to work. Completely dry sand or soil does not conduct electricity very well and shallow grounds are more susceptible. With many areas of the country experiencing droughts a ground needs to be deep enough to reach damp soil, thus the ground rods that are eight feet long.

    I live in a desert area that only gets 7 inches of rain a year and soil grounds can be ineffective because of high soil electrical resistance. The sure way is to run a ground rod back to the same ground the power company uses at the meter/panel.
     
  17. techrep

    techrep Hall Of Fame

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    All good points.

    I like 2 ground rods at the service panel and one at the dish, all connected.
    The mats are for extremely rocky ground where you just can't get a ground rod hammered in (short of blasting or a mining drill.) If I have to resort to the mat, I use two.
     
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