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Complete newbie questions

  • 28-01-2018 12:40pm
    #1
    Briain O Loinsigh
    Registered Users, Registered Users 2 Posts: 175 ✭✭


    Hello , just put up a satellite yesterday for the first time and have a couple of questions if someone could help.
    60cm satellite ,quad lnb ,Astra 28.

    I have the dish going straight into a freesat television, from a quad lnb.

    I ran a double cable to the sat, so I was going to run the other cable to a new freesat tuner. Does the lnb need power running from every source or would a freesat tuner be able to power the lnb on its own.
    I ask because I notice that there is an option to power the lnb on my television , I'd prefer not to have the tv powering the lnb if possible.

    Also can a cable from a satellite be split internally in the house ? , I'm getting 100 % quality and 92 % strength,
    Thanks.


Comments

  • #2
    Avns1s
    Registered Users, Registered Users 2 Posts: 3,423 ✭✭✭Avns1s


    A cable must run from one of the connections on the LNB direct to each sat tuner, be it a satellite box (some have 2 tuners requiring 2 cables for full functionality) or tv. You can not split that cable between LNB and Tuner.
    Each tuner must have the option to power the LNB turned to "on". This is the way the tuner and LNB selects a particular frequency.

    Hope this helps.


  • #3
    Briain O Loinsigh
    Registered Users, Registered Users 2 Posts: 175 ✭✭Briain O Loinsigh


    Avns1s wrote: »
    A cable must run from one of the connections on the LNB direct to each sat tuner, be it a satellite box (some have 2 tuners requiring 2 cables for full functionality) or tv. You can not split that cable between LNB and Tuner.
    Each tuner must have the option to power the LNB turned to "on". This is the way the tuner and LNB selects a particular frequency.

    Hope this helps.

    More than helpful , thanks a million.


  • #4
    Gerry Wicklow
    Registered Users, Registered Users 2 Posts: 4,568 ✭✭✭Gerry Wicklow


    Satellite TV uses 4 different frequency bands, low horizontal, low vertical, high horizontal and high vertical. Satellite tuners send a control voltage to the LNB to control which band it is looking at. For this reason each tuner must be wired directly to each LNB port otherwise you would have a conflict for control. This is also why you need two tuners (+cables and LNB ports) to be able to watch one channel while recording another.


  • #5
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    Johnboy1951 wrote: »
    ... That is as I understand it, but am open to correction.

    You're wrong, in the case of a quad LNB as mentioned in the OP anyway. It's already been pointed out how each tuner needs to power its own LNB.

    Your version could apply if using a splitter to, say, feed a twin tuner box from a single LNB output.


  • #6
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    Gerry Wicklow wrote: »
    Satellite TV uses 4 different frequency bands, low horizontal, low vertical, high horizontal and high vertical.

    It's only 2 frequency bands, as received from the satellite: at the receiver after down-conversion at the LNB, they overlap a lot.

    It's the re-use of frequencies across the 2 polarisations along with tuner bandwidth needing this downconversion by 2 factors (causing the overlap) that requires each tuner to have its own feed in the 1st place.


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  • #7
    Gerry Wicklow
    Registered Users, Registered Users 2 Posts: 4,568 ✭✭✭Gerry Wicklow


    Thurston? wrote: »
    It's only 2 frequency bands, as received from the satellite: at the receiver after down-conversion at the LNB, they overlap a lot.

    It's the re-use of frequencies across the 2 polarisations along with tuner bandwidth needing this downconversion by 2 factors (causing the overlap) that requires each tuner to have its own feed in the 1st place.

    Ok I was over simplifying for the sake of clarity :o


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