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B-Band Converter Location in Wiring Layout

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by sbellner, Jan 16, 2011.

  1. sbellner

    sbellner New Member

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    May 23, 2009
    Longview, TX
    Does it make any difference how closely the B-band converter is located to the DVR? I have a D* HR-22/100, and would like to relocate them from the back of the receiver (the rat's nest) to a hidden location in the wiring run.
     
  2. Wisegoat

    Wisegoat Icon

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    Aug 16, 2006
    I have mine at the multiswitch with no issues. Just make sure you have them facing the correct direction. The small piece of coax hanging off the BBC needs to be facing your receivers. If you do it the other way, they won't work. You will have to make/buy some small jumpers to go from the switch to the BBC; that is what I did.
     
  3. dsw2112

    dsw2112 Always Searching

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    Jun 12, 2009
    The "difference" is the db loss you'll introduce into your system. The farther the BBC is from the receiver the more loss you will incur (in most cases by moving the BBC farther away you'll add more than 50% extra loss.) The "ideal" solution to rid yourself of the BBC's would be to switch to SWM; in addition to the BBC's going "bye bye" would be the addition of automatic gain control (AGC) which will help fight rain fade.
     
  4. sptrout

    sptrout AllStar

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    Dec 29, 2006
    Spring, TX
    The other posters have posted the correct way(s), but if you want an example of how not to do it, but still works:)..... My converter is in the attic above my TV location, so there is at least 20' of cable between the HR22 and the converter, plus I have to use a diplexer configuration to get my OTA signal down one of the two cable drops. With all that stuff, I still see 90's on the signal strength readings and all works fine including OTA. As I said, not what I would prefer if I was starting from the beginning, but it is what I ended-up with.
     
  5. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Dec 9, 2006
    You've done well to take most of my post. To the OP, 5 -10' isn't going to make much of a difference, which may be enough to sort out your rat's nest. Maybe 30-50' isn't a good idea as mentioned ^.
     
  6. BattleScott

    BattleScott Hall Of Fame

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    Aug 28, 2006
    Just curious, what "loss" would be increased based on the distance between the tuner and the BBC? I would think the insertion loss would be pretty much the same no matter where along the coax run the device is located. As long as the device isn't exposed to the elements, I would think it's relative position is not important.
     
  7. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    The loss at 250-750 MHz is 3-5.5 dB/100' and the output of the BBC changes these to 1650-2150 MHz, with the loss 7-10 dB/100'.

    [​IMG]
     
  8. BattleScott

    BattleScott Hall Of Fame

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    OK got it. But other signals are already running at those higher frequencies and the system is desinged with enough headroom to compensate for the 7-10dB loss. In theory, moving the BBC all the way to the end of the max 125' shouldn't create any performance issues or else the same issues would be present on the signals that are not converted, correct?
     
  9. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    With the bulk of HD in the 250-750 range, these would be impacted, "but" you are correct that the higher range is used also. These "used to be" the Spaceway spots, so they came at higher levels from the SATs. Since then one of the 103s is using them "I think".
    Is this a "game changer?", no.
    Is this how DirecTV intended them to be used? No again.

    I guess I'm just trying to inform those that want to do this, what the trade offs "could be". ;)
     
  10. dsw2112

    dsw2112 Always Searching

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    Jun 12, 2009
    Yep, and since HD is what suffers rainfade first it makes sense to alert someone of the tradeoff involved.
     
  11. sbellner

    sbellner New Member

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    May 23, 2009
    Longview, TX
    I was going to put them at the multiswitch, but as noted, one needs the "male" equivalent of a barrel connector to connect them directly to the multiswitch, unless you want to connect them backwards. I have moved and labeled all my wiring inside, and I thought locating them at the multiswitch would be a good "out of sight, out of mind" solution. But I ended up moving them from behind the receiver to the the joists in the basement. For all the rooms in the house except the Family Room, I have a home run directly to the multiswitch. But for the Family room, I have a spot where I have several pre-wired wall drops converging to one location. I can then just jumper over to the appropriate pair based on how my wife wants the room layed out. I've got sat connections in every corner of the room, and the longest run is probably about 30'. So far no problem with signal loss, but every time I disconnect one of the inputs, I have to reset the receiver. I've got the same setup with the ethernet.

    The rat's nest is looking better, but I've still got some work to do. It's a never-ending task.
     
  12. TomCat

    TomCat Broadcast Engineer

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    Speaking as a former CATV design engineer, that is absolutely correct. The difference in level at input to the receiver would be maybe 2.5 dB, maybe 3 or 4 dB max, which is fairly insignificant (this from subtracting what would be the loss for 125 ft at the frequencies after conversion from what they would be before conversion). For a shorter run, even less significant. Digital distribution can actually tolerate larger signal losses than analog distribution ever could.

    The danger might be at the input to the BBC, which would be higher if placed earlier in the distribution, such as at the LNBF or switch, as that might actually overload the BBC and cause it to create distortion which can increase intersymbol interference which can reduce the signal quality level, possibly significantly. That said, my best guess is that it would not, and probably has the headroom to accommodate that.

    Obviously, the BBC is designed to see optimal signals and put out optimal signals if placed near the receiver, but this sort of usage is probably going to work just fine. If not, well then don't do it. Case closed.
     

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