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Freesat To Multiple Rooms With Octo LNB

Discussion in 'Audio Visual' started by *Dan*, 12 Oct 2020.

  1. *Dan*

    *Dan*

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    I currently have an octo LNB connected to the satellite dish and I Currently have two rooms upstairs wired into the LNB with WEBRO WF-100 cable (shotgun) to provide two signals for each TV. I have two more pairs of outputs left on the LNB which I plan to use for the kitchen and lounge but before I proceed with the bigger job compared to wiring upstairs I wanted to check if there is any easier way of doing this? I.e can you get a splitter in the loft which distributes multiple signals from one LNB feed? I want two signals in each room ideally (for freesat boxes) so maybe just running the cable is the only way of achieving this?
     
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  3. Lucid

    Lucid

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    The head-end gear which is the LNB and a multiswitch as a way to distribute the four states of the LNB to multiple rooms still requires one cable per satellite tuner to work.

    You can't split satellite signals in the way you do with Freeview DVB-T/T2 from an aerial feed. The way satellite receivers work isn't the same Freeview tuners.

    The aerial feed for Freeview is simply a whole band signal that includes all the muxes for the channels. Satellite doesn't work that way. The sat tuner sends either a hi or lo voltage up the cable, and it's either a positive phase or a negative phase; so that gives four possible combinations to which the LNB responds by switching between four different reception bands. Once on a specific reception band then all the channels within that band are available. You could split that between two sat tuners - and so long as they both want channels out of the same band then it will look like the split worked. However, as soon as one tuner asks for a different band then you'll run in to trouble. There'll be a conflict either on voltage or polarity. One tuner will get a signal, but the other won't.

    A multiswitch gets around this problem with a special version of the LNB and its ability to manage the demand from any attached tuner. However, you still need one cable from the switch going to each and every sat tuner. So, a TV with a single sat connection = 1 cable. A recording PVR with two sat sockets requires two sat cables if you want the full functionality to work.

    Bottom line - Don't split sat cables. It'll fall over sooner or later.


    If this answer helped, click the THANKS button. Costs you nowt to do and is quicker than typing thanks in a post. (y)
     
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  4. danechip

    danechip

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    One cable to one tv or box unless you plan on recording multiple channels at the same time, then 2 required as you would end up with only the Vertical polarisation at 17VDC over riding the Horizonalat13VDC (this is how it's switched between the 2). There are these 2 states send from your LNB.

    Just run shotgun from LNB to your 2 new locations from the 4 remaining ports. Done forget to get 4 boots or self amalgamating tape when you order your cable, clips and F plugs.
     
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  5. winston1

    winston1

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    Correct theory wrong way round. Vertical uses 13v approx and horizontal uses 17v approx.
     
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  6. danechip

    danechip

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    My bad. Out of practice. 18 years since I last played.
     
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  7. *Dan*

    *Dan*

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    thanks for this detailed explanation I’ll just run individual shotgun cable to the downstairs rooms after reading this. It’s a messy job so I may as well send two cables to each room so I don’t regret it further down the line.

    One of the rooms is still using the sky issued cable and it’s awful compared to the webro stuff - I’m having issues terminating the sky issued cable at a wall point whereas the webro in the other room terminates with no issues. Just need to get another roll of it to continue - I’m sure it’s the Sky cable breaking when I clamp it down as it’s so thin..

    Also, is it possible to get extra flexible patch cables for the wall to Freesat box as I’m using the webro but it is not flexible at all due to its quality and is a pain to screw on to each end. I’m using lab gear blue compression fittings on my cables inside and outside.
    Thanks for the reminder with the tape (And advice) as I had nearly run out!
     
  8. Lucid

    Lucid

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    What's the back of the wall plate look like that you're terminating the Sky mini shotgun cable in to?



    You mean something like this? Deleycon flexible window feeded? I've never needed to use anything like this myself as I've either been able to route the cable so it's not an issue, or use a 90 degree adapter where I need the cable running flat against a wall with the minimal amount of space for the bend.

    90 degree F adapters LINK This should give you an idea of what to search for.


    Hit me up with a thanks if this was helpful :)
     
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  10. *Dan*

    *Dan*

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    The 90 degree adaptors will be needed in another room but the window feed is not what I’m after. I’m looking for simply a more flexible cable for the link between the wall plate and the Freesat box as the webro cable is very stiff and hard to screw onto the threaded connector.


    I tried the euro module f connector for sky with it not connected to the wall plate and it worked but then when I went to clip it back in the wall it stopped working. The cable seemed ok in the back box I.e, no scuffing or tears so I think it came loose inside the terminal when it was clipped back on. I put quite a bit of strain on the cable as I bent it back onto the euro module wall plate.
     
  11. Lucid

    Lucid

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    I'm a little surprised you seem to be having so much of an issue with this cable. I use WF100 for all my own work. Here's a bit of it I have lying around the office. This piece has one of my screw-on connectors attached, but I use the same compression plugs as you for my outdoor and loft work and it doesn't change the behaviour of the cable. It'll take a bend quite easily.

    Obviously it's going to be stiffer than the WF65-size twin shotgun that Sky use because it's thicker and includes a proper copper foil shield rather than Mylar which is aluminium-coated plastic, but I wouldn't call it especially stiff. It's not like WF125 for example.

    wf100 bend.jpg

    I know that the weight and leverage of some cables can be an issue for weaker grid modules. I've come across situations where Cat5e network cable has pulled out weaker modules in a Euro face plate, so I can imagine that the same might be true with RG6-sized coax, especially if equipment is pushed up against a wall which then leads to a bit of leverage pressure on the cable.

    If you're still struggling with the fly leads I can make up some single run WF65-sized coax with crimp connectors for you. That's going to be about the most flexible you'll get in a standard foil/braid shielded coax without going to flat ribbon or sacrificing the foil shield.

    The other alternative is some mad double braid shielded BBC coax I have, but it's a hell of a lot heavier for only a marginal increase in flexibility. The density of the double braid shielding won't completely compensate for the loss of the foil shield, but it's never come up as a problem in the OB rigs where this type of cable was used.

    double shield 600x600.jpg
     
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  12. *Dan*

    *Dan*

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    thanks once again for the help and also the offer of making up some fly leads. I actually realised that the issue I have with the fly leads is using compression joints on them makes it far harder for me to screw them onto a tv or box. I removed one of the compression joints the other day and replaced it with a screw on connector and the result was it was much easier at screwing onto a device. Moving forward will use the compression for outdoor and loft use as you say. It’s also cheaper that way as well!

    Is there an easy way of testing signal without connecting up using tv or Freesat box from the other room. It’s a real faff doing this as I just want to check I have a good feed when I wire up the room again with the sky cable and euro modules.
     
  13. Lucid

    Lucid

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    I tend to do meter checks as I'm running through an installation. Most of my RF distribution work is based around Freeview, so I can hook up my meter to check levels. That'll tell me quite quickly if there's a signal/no signal situation.

    [​IMG]


    TBH, fitting F plugs rarely results in a no signal situation unless the cable has been damaged in some way by builders, or I'm hooking up to older existing cable.

    F plugs use the centre pin of the cable as the signal conductor, so there's nothing to get in the way of that. The return path/shield connection is going to be made when you fold over the braid for a screw-on plug, or where the shield sleeve of a compression plug slides between the white dielectric insulation and the foil & braid shield.

    For compression plugs, so long as you've trimmed the WF100 so that it's cut straight with just the centre core sticking out a centimetre, and then you've pushed the compression plug home so the dielectric is flush or close to the top level inside the plug before compressing, then it's a pretty-much foolproof connection.

    If you have or can borrow a small portable TV with a Freeview tuner, that'll make it easier to check for DVB-T signals. Checking for satellite signals; other than having a sat meter or hooking up a sat receiver then all you can really do is check for electrical continuity, presuming of course that you have a multimeter to hand. But you're going to have to unhook the feeds at the LNB end, then short each to test the signal and return path. That seems like more work than carting the Sky/Freesat receiver around with a small portable TV.

    Where you don't mind splashing a little cash, then something such as the Fringe TV Sat Finder would do. LINK It seems a bit OTT though just for a few connections on a one-off job.
     
  14. *Dan*

    *Dan*

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    I’ll see how I get on with the second attempt of wiring this cable onto my euro f connector outlets. I have a Humax Freesat box in other room so will use that as my signal tester as you say it’s not worth spending the £25 or so on a tester.
     
  15. Sureitsoff?

    Sureitsoff?

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    if you are fitting to a plasterboard box in a stud wall cut the base of the box out and bring the sat cables in that way
     
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