Why does my house have dual coaxial lines?

Discussion in 'Apple TV and Home Theater' started by Undecided, Feb 7, 2015.

  1. Undecided macrumors 6502a

    Mar 4, 2005
    Maybe I should post this in something like an xfinity forum, but I'm guessing someone around here can explain this.

    From the street, my house has a pair of coaxial cables (they are as a pair, side by side - the cross section of the dual cable is like a figure 8).

    Then, in my house, I have two such pairs - one pair goes to my living room (which then has two F connectors) and one pair goes upstairs to the master bedroom (again with two F connectors).

    So, where the street meets my house, basically I have the one pair from the street that must link to the two pairs inside the house.

    First of all, why are they pairs of cable? I though cable TV (and now internet) all goes on one cable.

    Second, anything clever I can do to take advantage of this?

    I am dealing with this because I'm switching from AT&T U-verse to Comcast (internet only), so one thing I plan on doing is keeping U-verse on one cable line in the house while hooking Comcast up to the other, until I am satisfied that I got Comcast working.

    Third, I assume if I wanted both the living room and upstairs hooked up to the cable line coming in I would just use a splitter, to attach the two internal lines with the single external cable line? (I realize that would be for TV, not internet...)
  2. DM in MD macrumors newbie

    Feb 7, 2015
    How long has that cable been there? We got cable TV at my house 30+ years ago. The coax was doubled as you describe. That's because the cable box had an A/B switch. IIRC the premium channels were on the B side.

    Comcast eventually bought the last successor to our original cable provider, and then delivered the signal on just one of the pair. FYI, I could never get Comcast internet to stay synched. I think that 30-year-old coax from my house to the pole to wherever was fine for analog, but had sufficiently degraded over time so that a digital signal was problematic, although the TV worked fine. Needless to say Comcast was not about to rewire the neighborhood. My DSL was OK, but then FIOS came to the rescue!

    Good luck.
  3. Undecided, Feb 7, 2015
    Last edited: Feb 8, 2015

    Undecided thread starter macrumors 6502a

    Mar 4, 2005
    I'm not sure when the cable was laid but the place was built 20 years ago.

    I think you're right - one is just not used. <shrug> weird.

    One other trick I did was take one cable from each of the pairs inside the house, and linked them together, so I had a cable going from the living room to the master bedroom upstairs. I figured if the lines are going to be used, maybe I can put an antenna upstairs, connected to the tv via the cable in the walls, and get a better signal.
  4. brentsg macrumors 68040

    Oct 15, 2008
    Sometimes cable companies that provide primary voice services (ie phone intended as primary use by FCC rules) will run from dedicated equipment in the providers head end. If this is the case it may appear as separate coax facilities from the Internet/television coax in a home or business.
  5. Lord Hamsa macrumors 6502a

    Jul 16, 2013
    If a previous owner had DirecTV, that uses dual coax with a dual-LNB dish where one LNB points always to the odd transponders and the other to the even transponders. With a single LNB system, multiple units in the house (or multiple tuners on a DVR) could only have different channel simultaneously if they were in the same transponder group.
  6. HobeSoundDarryl, Feb 8, 2015
    Last edited: Feb 8, 2015

    HobeSoundDarryl macrumors 604


    Feb 8, 2004
    Hobe Sound, FL (20 miles north of Palm Beach)
    While this sounds like an old way of cable wiring, dual runs (of new cable) can be very useful. My advice to anyone building a home today is to run at least dual runs to every outlet from a central "hub".

    Dual runs give you wired options for networking over cable. For example, if you have a box at your primary TV that can output a copy of it's signal on a "cable out" jack, it means you could route that same signal to any other location in that new home. How that's more commonly approached today is via wireless connections through separate boxes BUT each of those separate boxes tend to have a lease fee.

    A dual run like this could also be split back at the "hub" and sent to more than just one other TV in the house. Any unencrypted television (like basic cable in many areas or over-the-air from an antenna) could send either the same or unique (channel) signals to more than 1 TV in the house.

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5 February 7, 2015