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Thread: Splitters and amplifiers

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    Splitters and amplifiers

    Just a quick question. I have a high quality [2ghz] 1 to 2 splitter. Can I use the 2 out ports for my dtv antenna cable and my 12vdc amp and run the in port to my 8 way splitter up in the attic? I used the same setup for my 2 dtv antennas and it worked fine.

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    I will allow this thread but this is an electrical forum. You may have better luck in a TV or antenna forum.

    Someone here may know the answer
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



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    What you're proposing will probably meet your needs. A 2-way resistive spliter will have 6dB loss and an 8-way will have 18dB loss (6dB for every doubling in splits). The amplifier should make up for the loss in the splitters in order to maintain the signal-to-noise ratio (S/N).
    If you're relatively far from the DTV transmitters, it may be better to put the amplifier first before any splitting so you don't lose S/N. If you're closer to transmitters and have a strong signal, putting the 2-way splitter first could prevent overload and IM distortion in the amplifier. Too much gain in the amplifier can cause the same problem. Also low cost amplifiers will likely have lower IP3 specs and have less headroom before distortion occurs.
    Last edited by synchro; 05-23-19 at 01:22 PM.

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    Some splitters incorporate what are known as directional couplers. As a result they cannot be used in the opposite direction to the one labelled. Others (such as ones designed for use with bi-directional cable) are symmetric.
    If a splitter specifies a high degree of isolation between "outputs" it cannot be used in reverse.
    Resistive splitters are inherently symmetric.

    Sent from my XT1585 using Tapatalk

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    Good point, and that's why I included the word "resistive" the first time I mentioned splitters and their loss values.
    Directional couplers are significantly more expensive and more limited in bandwidth, especially for tighter coupling values. And they will be physically larger if they have to cover lower frequencies.
    Even though the OP mentioned a high quality 6dB splitter, it most likely is not directional if it was for cable or DTV with a cheap F connector. The poorly controlled reflection coefficients of those connectors would significantly degrade the directivity of a good directional coupler.
    Last edited by synchro; 05-23-19 at 01:54 PM.

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    Thank you for the information, the replies have been very helpful. And please know I was reading this thread https://forums.mikeholt.com/showthread.php?t=104278 that's the reason I posted here

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    It sounds like you need to make sure the splitter has what's called D.C Pass-through.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    Quote Originally Posted by LarryFine View Post
    It sounds like you need to make sure the splitter has what's called D.C Pass-through.

    And some splitters have DC passthrough only for certain port combinations. This allows you to avoid sending DC to a unit which cannot handle it (e.g. a parallel coil input filter or a transformer.)

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    Quote Originally Posted by Bkln38 View Post
    Just a quick question. I have a high quality [2ghz] 1 to 2 splitter. Can I use the 2 out ports for my dtv antenna cable and my 12vdc amp and run the in port to my 8 way splitter up in the attic? I used the same setup for my 2 dtv antennas and it worked fine.
    No idea what you are talking about. It sounds like you want to use the splitter as a power inserter to put 12vdc along with the dish signal on the cable going up to the attic? Is the 8 way amplified maybe??

    Not all splitters are power passing. However most sold to the satellite industry are. Power passing will be indicated on the case or label if it is. You would be better off with an actual power inserter- looks like a 2 way but doesn't have the -3.5db loss.

    -Hal

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