RG6 vs RG6U cable

Discussion in 'DISH Network Support Forum' started by debbytcr, Sep 19, 2006.

  1. debbytcr

    debbytcr Thread Starter New Member

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    Can anyone tell me the difference between RG6 and RG6U coaxial cable?
    What is a good quality brand?

    Thanks
    TR
     
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  2. rcdallas

    rcdallas PIT MEMBER

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    If it is what I am thinking it is, RG6U is quad shield where as RG6 is shielded twice. We use CommScope.

    The main thing is that it's been swept tested to at least 2150 MHz. All of our stuff is rated to 3Ghz. Use direct burial for underground lines not enclosed in conduit.
     
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  3. iafirebuff

    iafirebuff SatelliteGuys Family

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    I thought RG-U was for burial, and Quad was RG6-QS? Maybe it that is just a brand specific thing?
     
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  4. Iceberg

    Iceberg The No Pain Train
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    Quad specifically says Quad on it

    I think IAFire is right. RG6U is burial
     
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  5. Mike500

    Mike500 Active SatelliteGuys Member

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    U in rg6u means "unbalanced," a charisteristic having to do with capacitorance and nothing to do with where the cable is to be used.
     
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  6. bhelms

    bhelms "Wannabe Retiree"
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    RG-6 is a generic term, and is best interpreted as "sort of like". The "slash" number is a type designation, and that suffix came from the original, now obsolete, military "slash sheets". So RG-6/(letter) meant something specific as to construction and specifications. Thus using just RG-6 essentially means that the cable in question somehow deviates from the original /U (or /A, /B, etc.) specification in some manner. /U actually means "multiple uses".

    Here is a link to some information on the numbering scheme:

    http://www.bluejeanscable.com/articles/rg6.htm

    See also this topic in Wikipedia for another explanation, then follow the "coaxial cable" link in that article to get to a specific listing of RG type cables. You'll note they are (almost) all /U...

    http://en.wikipedia.org/wiki/RG-6

    As Iceberg noted, quad shield is usually marked as such, and it is also designated as such, e.g., RG-6/UQ...

    EDIT - I agree with Mike500 that RG-6/U (and ALL coax for that matter) is unbalanced, but that is not what the /U means.
     
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    Last edited: Sep 19, 2006
  7. Roadwarrior

    Roadwarrior PIT MEMBER

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    That's interesting. So I guess it's ok that nearly every satellite system installation out there is ran with cheap cable? I know I can't afford Belden. I use Perfect Vision solid copper. It's about 40$/1000 ft. I suppose it's good enough for for this type of thing, considering the entire system is cheap and designed for economy rather than durability. For that matter, what, exactly, is the difference in 75 ohm RG-59 and 75-ohm RG-6? besides the 2150 mhz swept tested bs, what would happen if, for instance, you did run a dual tuner dvr with RG-59, that was only swept tested to 1800? The center conductor is the same size, but the dialectric shielding is slightly smaller.

    I have had to use existing cable in apartment installs that were wired with the 75 ohm -59 because the Apartment Management would not allow any holes to be drilled or any new cables to be ran. I'm not a big fan of the flat cables(seems to me those things are worse than the -59), so I just use what's there. Even on a 625 it seemed to work fine. Of course I havent kept track of that particular customer, and have no idea how the system is working today.

    What will happen?
     
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  8. webbydude

    webbydude SatelliteGuys Family

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    Funny...not that I have a piece of 59 to compare to 6, but I always thought the center conductors were NOT the same size. And yes, 6 is better insulated. Those two factors are what gives a better overall signal. In a lot of instances, you will start to have signal problems with 59....ESPECIALLY with longer cable runs. Impedence...resistance...whatever you want to call it.
     
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  9. bhelms

    bhelms "Wannabe Retiree"
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    We had a thread about this some time ago, and IIRC, it boiled down to "consumer grade" vs. "commercial grade". One common compromise is the quality of components used vs. system cost necessities. That shouldn't be any surprise to anyone given the highly competitive, low margin nature of the business these days. DBS installations are indeed "consumer grade" and cheaper materials are often used. Does that mean that they won't work? No, or else they couldn't be used. A lot of the added cost in premium products/services comes in terms of materials and techniques used to improve performance consistency and reliability in a variety of conditions. A DBS installer will use cheaper cable where the reliability of the system (or lack of it) won't impact more than one customer, whereas a CATV system installer will likely opt for the more expensive materials where reliability of the system will impact a greater number of subscribers.

    I think in many cases RG-59 would work just as well as RG-6. We tend to use the lower-loss cable since it's not much more expensive and readily available. That said, there are many "grades" of RG-6 for many different applications and the installer should choose wisely based on the intended service conditions and consequences of less-than-optimal system operation and reliability.

    In the example you gave, if the RG-59 would not work you would have known that right away. In general for shorter coax runs and expecially at lower frequencies RG-59 should do just fine...

    EDIT - For my own applications I sometimes use Belden 1189A for OTA and "RF" applications up to 1GHz. It's a lower-cost "quality" cable (I last paid $.11/ft I believe), but it has the quad shield that I personally prefer for RF applications where noise interference is likely, or when I run it near other conductors, like in conduit. Tho' I have never tried it, I'll bet it would work fine at DBS block-converted frequencies (~2150MHz) in shorter lengths. There is also 1190A that is similar but made for direct burial. For DBS frequencies I might use 1694A especially for longer runs where lowest loss is required. That cable is swept to 4.5GHz. All of these are RG-6/U types...

    EDIT AGAIN - The dielectric in the coax is probably the most important factor in the cable's performance. (Whether the center conductor is solid copper or copper-clad steel has little bearing on how well the cable passes RF due to "skin effect" and the steel type is actually stronger, but the solid copper will pass DC or 60Hz AC better to LNBs or preamps that need power.) The foam used in the dielectric sets the performance as well as the diameter, and the better foams cost more. If I understand the design challenges properly, ideally you would want almost pure air as the dielectric. The high performance foams are closed-cell types with a high air ratio. Air has the lowest possible dielectric constant ~1, and anything with a higher constant used in the space between the center conductor and the shield increases the capacitance per unit length, and that limits the frequency range of the cable.
     
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    Last edited: Sep 19, 2006
  10. Roadwarrior

    Roadwarrior PIT MEMBER

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    I'm sure some of the RG-59 does have a smaller center conductor. The 75-ohm that I see in alot of houses around here that was wired in during construction, has the same size center conductor as the RG-6 that I use. If it is smaller, then it's by a mere fraction.

    Now, I have heard that there is signal loss if you use RG-59. Is this something that happens over time? If I'm getting signals in the 100's on both sats when it's installed, how bad will the signal loss get? And why does it take time to lose the signal?

    I hope you dont think that I use existing RG-59 instead of running new. I'm talking mostly hypothetically, but like I said in my last post, it was either use the existing cable, or don't do the job.(Manager doesn't like that, the jobs MUST go in, no matter what). Since I rarely get chargebacks, and when I do there is no forthcoming information about what it is that had to be fixed or what job it was on, I just want to know what this customer is in for. If it was working like gangbusters when I left, am I to understand that major problems will develop with the signal? To the point that it eventually not even work?

    I'm not disagreeing with you, I just want to better understand what happens.


    Ok, bhelms types faster than me. Thanks for that info.
     
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  11. webbydude

    webbydude SatelliteGuys Family

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    Oh, not completely disagreeing. LOL

    And any installer that says he has "never used RG-59", is a liar. There just are too many instances...like the apartment example...where it is impossible to not use. It all comes down to risk. If you feel you can run the risk and have no choice, then yes...*ahem*...59 will get you by. It all comes down to a case by case situation.
     
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  12. Tom Bombadil

    Tom Bombadil Supporting Founder
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    More info on this topic can be found here:

    http://www.epanorama.net/documents/video/videocoax.html

    While RG-59 can have the same 18AWG center conductor as RG-6, usually it will have 20AWG. Hard to see a big difference unless you look closely.

    Shielding can vary considerably between brands and types, with a high quality Quad Shield being the best.

    The quality of the installation of the connectors is also important.

    I've run some simple comparisons of 6' to 75' coax cables, using a Dish receiver's signal strength indicator as a crude measuring tool. I've seen differences as great as 10 points between different cables, everything else in the system being the same. And I've seen RG-59 cables that outperformed RG-6 cables.

    I advise friends to get good quality cable from reputable brands. After all, the cost of RG-6 is a very low percentage of your whole satellite & A/V system. And good brands can be had for reasonable prices. Don't muck up your system and experience more channel drop-outs or rain fade to save $10 on coax.
     
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  13. Barry Erick

    Barry Erick Active SatelliteGuys Member

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    RG59 comes in several flavors, from those with very high signal loss and just one bare wire running instead of a braid that the better ones have. Those with a solid braid are excellent, but still nothing like the cheapest RG6. You have to see the specs for the exact cable you have to know exactly what you have.
     
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  14. Tom Bombadil

    Tom Bombadil Supporting Founder
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    Well, like I said in the post before yours, I have gotten higher signal strengths using some RG-59 cables than some RG-6. A good RG-6 is always better, but the best RG-59's are going to be better than the worst RG-6's.

    And there are times when certain types of RG-6 cables are better suited to specific applications. For example, one might think a quad-shield is always better, but it isn't. Here's why:

    http://www.audioholics.com/techtips/audioprinciples/interconnects/quadshieldcables.php

    If you want to play it safe and be sure you have a great coax, go with Belden 1694A. But there are others with similar performance.
     
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    Last edited: Sep 20, 2006
  15. bobrap

    bobrap Member

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    OK, for us not so tech savvy folks...will I see any difference between Radio Shack RG-6 and Belden 1694A?
     
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  16. bhelms

    bhelms "Wannabe Retiree"
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    Maybe. (Not the answer you were looking for, huh!) As others have said in this thread, cables are designed for specific purposes. As Tom further illustrated, in some cases a "quality" RG-59 can outperform a cheap RG-6, which points to the importance of materials and construction. At one time Radio Shack made their own cable in the US (Tandy Wire and Cable). I'm not sure if what they're selling is still made here or not, but I'm guessing it's now sourced off-shore and IMHO, those are not the highest quality cables. Belden 1694A is probably the best in the business (and priced accordingly!) so there is bound to be a performance difference. Whether or not you will "see" that will depend on additional factors. What frequencies are you planning to use it for, what length will you need, etc. I would suggest that for modest distances (< 100'?) at DBS frequencies you probably won't notice a difference. But as Tom mentioned, the price difference of that 100' of cable between the Belden and the RS types won't be significant, so if the Belden is available to you (order it on line) then why not spend a few $$ more to be sure you have the best possible performance? Otherwise it's penny wise and pound foolish...
     
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  17. bobrap

    bobrap Member

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    Thanks for the reply and you answer was what I expected...really. I'm trying to decide if adding another dish for 129 sat (I have a dish 1000) is worth the effort. If I do, I'm considering changing out all my cable runs (cables are about 9 yrs old), so I'm wanting to get the best possible signal.
     
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  18. chadzx11

    chadzx11 Active SatelliteGuys Member

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    not necessarily. Perfect Vision quad is labeled as

    "Perfect Vision RG-6 4"
     
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  19. debbytcr

    debbytcr Thread Starter New Member

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    I emailed belden and asked them the diff between RG6 and RG6\U and the tech wrote me back and said the U stood for universal and really had no meaning that there was no diff. I also asked about some Belden 6119 cable I had found a good price on explaining that I needed to make a run of approx 100 ft. He said the 6119 was good cable but for a long run he recomended Belden 1829 AC which has solid copper wire and is sweep tested to 3 GHZ. He said I would have less signal loss and should not have a problem

    This is fom the factory Tech.

    TR
     
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  20. Jared Twomey

    Jared Twomey Supporting Founder
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    i kinda got in on this late but here is my thought on it...

    They say to use RG6 because it is safe. There are some instances where rg59 will work fine. But if Dish told you to use rg59 if you wanted to.. you would have techs out there stringing it all over the place cause its cheaper.
    That is the same way with the "swept tested" rating on wire. Wire is swept tested up to a certain point... does that mean the wire can't handle freq higher than the quoted number... not at all... it just means it wasnt tested any higher.
    Thats why you'll find places were rg59 will work fine. Even though the wire doesnt say it's rated at 2Ghz... it is still passing the frequencies.
    Do i recommend using RG59 if its there?... hell no, unless you have no other choice.

    And alot of times you can hook up rg59 and your signal levels seem to be fine. The thing to watch for is the transponders that ride on the higher frequencies (the high even transponders if i remember right)... thats where you will start having loss first
     
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