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Cable Splitting Questions

Discussion in 'Playback Devices' started by Jason Charlton, Jul 5, 2006.

  1. Jason Charlton

    Jason Charlton Ambassador

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    Hi all,

    I just moved into a new house and discovered how wacky the cable wiring really is. I want to redistribute the cable signal, but had a few questions about the best way to approach it so that the signal doesn't degrade too much.

    Currently, the outside cable goes into a 3-way splitter (also outside). The outputs are marked "-7dB", "-7dB", and "-3.5dB".

    Do the numbers indicate the relative strength of each output signal?

    Is the signal from the "-3.5dB" output twice as strong as the "-7dB" outputs?

    Realistically, how many times could I split each of the outputs without degrading the signal too much and introducing a lot of interference?

    What kind of splitters should I get to distribute the signal (i.e. is there something special I should look for)?

    Generally speaking, is it better to use one 3-Way splitter rather than two 2-way splitters, or does it even make a difference?

    Thanks for your help and insight.

    -Jason
     
  2. Brian^K

    Brian^K Supporting Actor

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    A few unshakeable truths. The greatest weaknesses in any cable system can be found at the connections. Unfortunately, the very best connection technology tends not to be sold at the electronics stores. I've seen some high-quality splitters sold at Lowes, but even the best of them cannot hold a candle to the splitters that Comcast installs. I sure wish I knew where to buy those splitters. (I cannot find them online.) More than splitters, though -- the actual connectors are critical as well, and again, the cables and replacement connectors sold at electronics stores and Home Depot are all flash/no substance. Once you've held good splitters and good connectors in your hand, you know what they feel like, and you easily understand why the gold colored crap they sell to us retail customers is such a con.

    Realistically, the cable company can assert that anything more than one split in the cable degrades the signal so much that you cannot expect good signal. There is no reason to expect the cable company to serve, for example, four devices in your home. In practice, folks can generally serve three or four cable boxes and a cable modem no problem, but understand that that's substantially stretching the signal that the cable companies generally provide customers, and so you could very-well experience degredation going that far.

    Regarding the 3-way versus 2-2-way question: It depends. All other variables held constant, the 2-2-way will be better for the solo device hanging off the first 2-way, but generally the best overall solution is the fewest connections, so that means the 3-way will be better. However, a 3-way splitter could be the source of signal issues you have, as I alluded to, above.

    I avoid lots of issues by having my own signal booster. It sits at the point where the cable signal enters my home. I've got a three-way splitter after that. One of those lines has a two-way splitter, one line of which server my backup TiVo, which is a pretty low priority device for me, and the other line gets split between my basement/exercise room television and my kitchen television, i.e., the least important devices in my home. One of the two other lines from the original three-way splitter goes directly to my cable modem. The other gets split between my HDTV receiver and my primary TiVo, i.e., the three most important devices in my home.
     
  3. Jason Charlton

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    Thanks for the input. I think my plan will be to take the stronger of the three lines (-3.5dB) and split that 3 ways - reserving the stronger of those resulting signals to the basement HD theater (the only location with a digital cable box). The other two main lines will be split at most one time each since they are presumably weaker to begin with. I found a 3-way splitter online at partsexpress.com that seems to offer the same signal loss as the one that Comcast installed outside my house. We'll see how well it works in practice.

    -Jason
     
  4. David Norman

    David Norman Producer
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    I agree with most of what Brian said about connectors, etc.

    As far as how many splits you can use, that basically depends of the strength and quality of the signal at the beginning of the loop. The cable complany is SUPPOSED to have a certain minimum strength, but this what is optimal can be a bit hard to define and since testing meters are expensive it's not always the easiest information to get.

    If you have a good strong/clean signal then you could possibly get up to 8 decent signals out of an unamplified line. If you are closer to the Minimum, you may not be able to get more than one true signal and you may need a good amplifier/distribution amp to get a good signal. All amps are definately not created equally and getting a good one at Radio shack or Lowes can be difficult.

    This website has a lot of basic information and the guy who runs it has a pretty solid reputation for using quality equipment and does a lot of Web/Ebay sales. Electroline amps are generally pretty strong and are commonly used by the CableCo's themselves.

    http://www.cabletvamps.com/
     
  5. Brian^K

    Brian^K Supporting Actor

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    Just a note: Rated signal loss doesn't tell the whole story. Comcast's own equipment simply has better fidelity than the crap they sell at retail stores. Sucks, I know.
     

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