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Best configuration chain for additional TVs

Discussion in 'Audio Visual' started by pmc64, 28 Jul 2018.

  1. pmc64

    pmc64

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    Hi All

    As you can see I have 2 fixed digital aerials (both the same models) supplying rooms 1 & 2 (Both supporting freeview TVs) In a domestic Victorian style house. Merseyside.

    I would like to know the best or correct way to extend their feeds to at least one extra TV each (FreeView) or Just one to multiple TVs, as I'm not sure how digital signals should be dealt with rather than the old UHF.
    (Years ago, I would've simply put a 4-Way booster from the loft aerial to supply other rooms)

    I don't want to get on the roof to add a booster close to the aerial so let's rule that out please (my signal percentages are ok too)
    I was imagining I would have to add 2 X plug-in digital signal boosters (or are they just boosters?). One in the loft and one in room 2. Or could/should I simply just use splitter blocks; OR option in Room 3 below; or non of the above?

    Anyhow any info for the correct configuration and parts would be of great help.

    Room 1 Scenario is approx 11M total run (5 & 6M runs from booster)
    Room 2 Scenario is approx 15M total run (5M from booster to additional set)
    Room 3 Scenario fed from room 2 booster because it's from a roof aerial, which
    I suppose receives a stronger better signal and saves time and money ?

    Run in coax 2 years ago Webro.com black outer sheaf followed by silver strands and silver foil before copper tip, and will use the same for additional runs.

    Thanks Aerial Extensions.jpg
     
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  3. Lucid

    Lucid

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    With amplified splitters the best way is to have the unit as close to the aerial as possible. That will provide the cleanest signal to the amp, and from there to the TV. It doesn't have to be on the mast. The amp.can be in the loft.

    If you're going to split at the set back (and provided that the signal is strong enough and of high enough quality) then use a passive splitter on each.

    Passive splitters introduce no noise. However, they don't amplify the signal either, so an excessively long cable run from the split point to the next TV won't be compensated for if that's required.
     
    Last edited: 29 Jul 2018
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  4. big-all

    big-all

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    ok my thoughts
    often tvs in a different room will get different levels off signal or channels or at least that was the case pre 2012 round here before digital went full strength
    my suggestion is to chose the feed that gives the best choice off signal/strength/number off channels you like iff different and boost/split from that assuming a clean signal
     
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  5. winston1

    winston1

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    No such thing as a digital aerial. You have 2 aerials. Why? One would do with a splitter.

    Anyway almost certainly passive splitters are all you need. Certainly worth trying them first.
     
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  6. pmc64

    pmc64

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    Thank you all for taking the time to reply.

    I attached the roof aerial when I had some scaffolding up for new roof tiles, it was originally going to supply ground room 4.
    Then it was easier and safer for myself to just install another aerial in the loft Winston, when I later added another TV point in Room 1.

    Am I right in thinking it would be best to use a 3 or 4 way passive splitter behind set back supplied by (Roof aerial going to room 2) to supply 3 signals to 3 TVs.
    If I get weak signal or loss of channels at any of the other TVs, then replace 3 or 4 way splitter with a 3 or 4 way booster?

    I Just wasn't sure how digital signals share output when split, and thinking of it like water in a pipe.
    Best to have 2 open taps on 2 separate mains feeds, than three open on one main, if you get my thinking?

    Regards
    Paul
     
  7. Lucid

    Lucid

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    The best positions for powered versus unpowered splitters are different because of the way they work. That means if you go to all the trouble of running the cables for 2 or 3 additional TVs to the back of one TV as you might for a passive splitter layout, but then find that there's too much loss, you're going to be in a poor position when you switch to a powered splitter. The reason for this is signal noise.

    Signal noise is what's measured by the Q (Quality) reading on a TV. For digital signals it is the single most important facet of the signal. It's way more important than signal strength. Signal strength can always be boosted with an amplifier. But once the signal's Quality has degraded there's no practical way to get that back.

    The Quality of your signal is the best it will ever be at the take-off point on the back of the aerial. Once the signal travels down some cable then it's picking up noise along the way. That's okay though because as long as there's enough Quality at the aerial then there's a decent safety margin to cope with some increase in noise along the way.

    The beauty of passive splitters is that they don't increase the noise in the signal, so the relative proportion of signal to noise doesn't change comparing the output to the input. For example, if it was 99 parts signal to 1 part noise going in to the splitter, it would still be 99:1 on the output. What would change though is the amount of signal in total. In very rough terms, a 4 way passive splitter would see each output at 1/4 of its original value. It's still a very high quality signal, but there's just a lot less of it.

    Bringing this back to the position of passive splitters versus amplified splitters, with a passive splitter you want the incoming signal to be as low noise as possible and the output runs from the splitter to the TVs to be as short as possible. That happens when the splitter is as close to the extra TVs as possible. The reason for keeping the output runs short is that the divided and reduced signal is far more susceptible to noise picked up in the cable.

    With an amplified splitter, the device adds some noise to the signal, but the amplification makes the output signal far more tolerant of noise picked up in the cable run. For this reason the amplifier should be as close as possible to the aerial. That means an amplifier positioned behind a TV is working at a distinct disadvantage compared to one in the loft.

    All of this is subject to the condition of the source signal. If you have tonnes of signal coming off the aerial, and it's really very high quality, then you could get away with a 4-way passive splitter without a blinking an eye. You'd wonder what all the fuss is about. On the other hand, if you're using a wideband high-gain aerial and trying to pick up stations that are out of its optimum reception frequencies, or the aerial is misaligned or perhaps having to point through some trees, then you could find that splitting even just two ways is a step too far. You see, with digital TV, the signal works and works and works until a point where it suddenly stops. We call this the Digital Cliff. It's exactly as it sounds. The signal drops off dramatically past a certain point just like someone walking off the edge of a cliff. One step too far and it's adiós amigo.

    Personally I'd go with a powered splitter in the loft, but not because it's better than a passive splitter. There is no "better" in absolute terms, only "more suitable".

    The reason I prefer splitting in the loft is it's then easier to make the cable runs neater to each room rather than having four coax cables coming in to a bedroom or living room that's acting as the split point.

    If you want to try the passive route first though, there is a way to test it without going to the hassle of running all the cables. screwfix has the Labgear 4 way splitters for a little over £6. You'll need some screw-on type F connectors and some coax to make up connection leads. Connect it to the incoming RF cable behind one of the TVs. Hook up a single fly lead to that TV. You'll be getting the same signal reduction as running all four TVs. If the signal goes pixelated or breaks up then you know that passive splitting isn't an option for you.
     
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  8. pmc64

    pmc64

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    I think I will heed your excellent, informative and extensive advice Lucid and go with boosting the loft aerial to 3xsets. Yes the signal quality should no doubt be better from the roof aerial, but for safety, neatness and cost effectiveness it makes sense to go with the loft aerial option.

    One point I'm a bit stuck on is what 3 or 4 way booster/amplifier? should I be looking at, as I've googled a few that look very different and I don't want to make a mistake of purchasing a wrong type (if there is such a thing).

    Could you post a handy link for one or more recommended boosters/amplifiers to reassure me please?

    Also I have the coax and f-type connectors already

    Best Regards
    Paul


    TV set ups from loft.png
     
  9. winston1

    winston1

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    Try a passive splitter in the loft first. Better still put a passive splitter in room 2 from the roof aerial and feed the other TVs from there.

    No point in wasting money on a booster that I doubt you need, and have problems getting power to it in the loft.
     
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  11. pmc64

    pmc64

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    Yes as you have both stated a £6 splitter could be sufficient, so I suppose it's the sensible thing to do first. Worst scenario, £6 loss. Thanks Winston.

    Roof aerial - Kept in Room 2 - Passive splitter - Single fly lead to room 2 set - No pixelation or break-ups - Good for other 2xRooms supply.

    Regards
    Paul
     
  12. pmc64

    pmc64

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    I bought the splitter today and decided to get a TV outlet Although both feeds are NOT from cable TV or a satellite dish: can I still use a satellite outlet to link to my freeview TV?
    The guy in B&Q told me it wouldn't work as I needed a decoder? But I have installed an outlet for another set with the female F-Type screw on fitting from the loft aerial and it works!
    Not sure if I got lucky first time and it's some sort of TV outlet but with an F-type fitting, but I ended up getting the normal TV outlet on the assistants advice.

    Can you advise or paste a link if there is a female F-type TV outlet for the job (can't remember where I got the last one) But they are better as a connection, especially as the tv will be
    hung on a canter levered extending bracket. If so I'll exchange the one I got...Thanks.
     
  13. winston1

    winston1

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    Typical ignorance from a shop floor person. It is only a socket so why would it not work or need a decoder? The only instance when it would not work was if it was a combined outlet with a filter.
     
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  14. ericmark

    ericmark

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    TV outlet plates often have filters in them so radio, terrestrial TV, and satellite TV, can be combined, sent down one cable the separated again. Others are far simpler, the filter is just to stop you getting a shock from static around the aerial, and some have nothing in them, Sky boxes and mast head amplifiers send DC through the cables, so filters block the DC, so some times you simply don't want a filter. Other times there are people like me who transmit at up to 400 watt so you need the filter to stop interference.

    Listen to Lucid she is local to us and very clever, she told me to buy good coax, and it has made such a difference and so simple. I should have know I did study and pass my radio amateurs exam so should have known.

    Although I installed a system to have a TV in every room, that was years ago and things have changed. The aerial went to main TV in living room, plus the Sky box and Blueray player, from there it want to loft, and a 4 way booster splitter, and then to each room.

    With 14" TV's this was fine, but with 32" TV's you can see the picture is not too good, I have two dishes one front of house and one back, each has 4 outlets, over the years I have gained satellite boxes, so have one in each room, however again tried SCART and HDMI and with a 32" TV you can really see the difference, beauty of satellite the dish does not need to be too high, so one at front of house only needs a set of steps. Because I can get both Winter Hill and Moel-y-parc for freeview the TV is forever asking to be retuned.

    The HD free to air satellite box is very good, I watch ITV3 a lot, also ITV3+1 and when in the middle of a program it says ITV3+1 in freeveiw will close down at 12:04 which would be middle of the program I am watching I am glad I am not watching on freeview. The dishes were put up for Sky, but although we have one paid for sky box, in the main just watch free to air, intend to cancel sky subscription soon.

    I will admit having set bottom boxes to watch satellite is a pain, means in most cases two remote controls, although the Flipper remote will work both together, the aerial used for freeview is hit and miss at times and no way am I climbing a ladder to find out what is wrong. Mothers old house also satellite dish only needs a set of steps.

    There are more ways than coax to get TV signals, we use some wifi, Utube has most the old films no cost and no adverts, there are devices that send TV signals through the LAN, and also wifi. Not used them, but Lucid in really good, listen to what she says and you won't go far wrong.
     
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  15. Lucid

    Lucid

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    Yep. This is what happens when companies selling wallpaper, drills and paint start dabbling in areas where they have no real expertise. They might have part of the answer but very little depth of knowledge to explain why it won't work and to help the customer buy the right thing.
     
    Last edited: 4 Aug 2018
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  16. Lucid

    Lucid

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    It does depend on what it looks like on the back. If it's something like this Tristar twin output socket then the answer is no.

    coax socket.jpg

    The big silver lump is a frequency filter. To make proper use of this type of socket there would be an aerial distribution amp that includes an input for a satellite signal. The amplifier combines the two and sends both signals down single coax runs to each TV point.

    The wall plate such as the one above then de-combines the two signals. What you then have is the aerial signal only on the TV socket, and the satellite signal only on the Sat socket. As a result, there's no TV signal to be had from the Sat socket. In this respect, the person from B&Q was correct that for this type of wall plate you'd normally be connecting the Sat output to something with a satellite signal tuner. In most cases that "something " would be a satellite receiver or a TV that has both a Freeview tuner and a Freesat tuner.

    ... That's because the screw-type connector can be used with TV aerial signals. It has nothing to do with changing the signal running through the cable.

    Go back to the analogue TV days and any bit of domestic indoor signal distribution gear you could buy retail would probably have come with aerial coax sockets; the same kind of socket that you have for the aerial input on the back of a telly or VCR. These are fine and do the job except for one flaw: They're a push-to-fit connection and so in some circumstances they work loose. That's a bit of a pain if it's behind the telly or video in the lounge, but it's not such a big deal to fix. It's more of a problem though for gear in lofts or somewhere out of sight or not so accessible.

    With the switch to digital TV broadcast, and the need for better screening in coax cables as a result, the industry has been migrating towards using F-type connectors on domestic aerial distribution gear. It's a more fool-proof connection for screening, and it provides better contact without the need for special tools during fitting in cases where an aerial system might also be carrying power for a remote distribution amp/masthead amplifier or Sky magic eyes.

    You can now buy aerial distribution amps that have nothing to do with satellite signals, but the sockets are all the F-type commonly seen on the back of satellite receivers.



    Are you hoping to have the cables concealed in-wall with a wall plate hidden behind the TV? If so, there might be a better and more flexible solution.
     
    Last edited: 4 Aug 2018
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  17. pmc64

    pmc64

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    Sorry for the late reply, and thanks for all your very kind input. In answer to Lucid's questions about face plate design/configuration...The outlet I was querying at B&Q was just a single F-type skt with "SAT" written above it. It was in a box and there was no view of the back of the unit, I also didn't have my reading glasses to see any small print. It made me question it before purchase as my other TV outlet (F-type) that I had previously installed didn't have any wording on it., ergo the need to ask a staff member. Typically I have mislaid the original receipt for the push fit plate, so will have to bite the bullet with that purchase, as I do want something better than the push fit type especially as the TV will be movable.

    I would like to hear your more flexible solution though Lucid?

    Coax to a single skt box for TV Outlet plus D/skt..

    TV on chimney breast.JPG
     
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