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Co-ax connection conundrum |
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#1 |
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Join Date: Oct 2001
Location: London UK
Posts: 11,455
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Co-ax connection conundrum
I had the setup in my Before picture here: http://www.simlogical.com/exacc/Before.jpg which worked very well, apart from it wasn't wired to give me a satellite channel in the bedroom. I am in a good signal area for both satellite and terrestrial
I wanted to get the RF output from my Sky Digibox also going to my bedroom TV. I reconnected everything so that it looks like my After picture here: http://www.simlogical.com/exacc/After.jpg It all works except now I have poor terrestrial reception on my living room TV - snowstorms in analogue, blocky and jumpy in digital. Is the problem that I am trying to carry the signal from the roof aerial *sideways* across the splitters? I don't know how the insides of those work, I thought the signal just gets all squashed together in the middle of them and comes out all all three connections. Without actually running any new cables between the rooms, can I do anything to the connection flow to improve matters? |
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#2 |
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Join Date: May 2004
Location: Reading
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You've got it all wired up wrong!
![]() Plug the aerial direct into the back of the satellite receiver all by itself no splitters in the way. Plug the living room TV into RF 1 out of the satellite box. Plug the bedroom TV into RF 2 out of the satellite box Throw the splitters away! Job done. ![]() If the satellite box doesn''t have two RF outs (and most do) then... Plug the aerial into the Aerial IN of the satellite box directly Wire the RF1 out of the satellite box to a Spliter IN Wire the two Splitter OUTs to the two TVs. But the best option is not to use the splitters in the first place just use the two RF outs on the satellite box if you have them. Both sockets will carry the same mix of whatever is on the aerial IN and the modulator signal generated by the satellite box. Splitters, as the name implies, split one signal into two. The very nasty white plastic Y shaped types by and large do a p**s poor job of it anyway. They are also not very good when used in reverse to combine two signals into one. And if you DO try and use them as a combiner you need to plug the two signals into the OUT sockets and take the combined signal out of the IN (if that makes any sense). Last edited by chrisjr : 03-06-2008 at 13:58. Reason: By way of explanation |
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#3 |
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Join Date: May 2006
Location: Aberfeldy
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your just thinking too much into it
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#4 |
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Just had another look at the diagrams and perhaps the suggested solution is not that easy as first thought.
Would I be correct in say that there is in fact a wall between office and living room that you haven't shown? If there is then that might complicate things somewhat as you may not be able to wire the aerial lead direct to the satellite box as I first thought. Basically if you cannot get the aerial into the living room on it's own then I cannot see anyway to do what you want with only one lead between office and living room. The way you seem to have connected up the splitter in the office is correct to combine two signals into one. The way the one in the living room is wired is wrong. What you need to do is swap the TV and satellite box connectiions over. Trouble is the aerial feed wont cross over to the cable into the living room properly hence why you get lousy reception there. And the living room splitter is wired wrong to combine the feeds from office and satellite box to the living room TV as well. You need to swap the TV and satellite box connections over. However doing that will likely knacker the satellite feed to the bedroom TV and may make no differnce to teh aerial feed to teh living room TV. Basically a no win situation, esssentially the aerial lead is in the wrong place to make this easy. Or you need a second cable through the office/living room wall. The aerial really needs to be plugged direct into the satellite receiver and the two RF outs fed to each TV. As I see it without moving the aeriel downlead or putting in a second lead between office and living room there is no way to do what you want with the bits of wire you have. But all is not necessarily lost. You could hook up an AV sender to the satellite box and the bedroom TV to link the two that way. Then revert the aerial wiring back to how it was at the start. Obviously this needs both a spare SCART out on the satellite box and a SCART input on the bedroom TV. |
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#5 |
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Join Date: Oct 2001
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Quote:
Would I be correct in say that there is in fact a wall between office and living room that you haven't shown?
We're keen not to use wireless devices - and I hope no one will start a debate about that in this thread ![]() What if I were to introduce extra splitters/combiners into the equation? Like this: http://www.simlogical.com/exacc/Suggested.jpg |
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#6 |
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The more splitters combiners you introduce the greater the mess it will make
![]() What you have to do is combine both aerial feed and satellite output into one signal then split this comined signal out to the two TVs. There is NO other way to do it which will preserve quality of both aerial and satellite to both TVs. And that cannot be done with only a single cable between the office where the aerial and bedroom cables enter and the living room. Either the aerial or the bedroom cable needs to be re-routed into the living room (or both which would simplify things even more). The basic problem you have is that you are trying to make the one cable between office and living room do two jobs. Carry the aerial signal INTO the living room and carry the satellite signal OUT of the living room. Something it cannot really do. So I am afraid that without doing some re-wiring work you are stuffed basically. I cannot see any single combiantion of the cables that you have between the various devices and locations that will work. |
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#7 |
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Quote:
The basic problem you have is that you are trying to make the one cable between office and living room do two jobs. Carry the aerial signal INTO the living room and carry the satellite signal OUT of the living room. Something it cannot really do.
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#8 |
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RF is a black art.
Just because you poke signals down a bit of wire does not mean they behave in the way you think they do.I simply cannot see how what you want can be made to work with the cables you have in the locations they are. Basically you want to combine satellite and aerial then split out to both TVs. And that just cannot be done with the layout you have. I have no doubt if someone sat down with a bag of bits and a soldering iron and a very large pot of coffee they might come up with some kind of gizmo that would do the job. But it won't be anything you could buy off the shelf from Maplin or wherever. ![]() I think you are more or less going to have to bite the bullet and re-route or rewire the cables. or go back to the original installation and do without satellite in the bedroom. I cannot see any simpler solution to be honest. |
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#9 |
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Ok thanks. It's not really a big problem as such, since I can see all the channels I want to in the living room, just using the satellite connection. But I would have been interested in improving the terrestrial signal as an exercise in tweaking, if it had been possible.
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#10 |
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I supose before you rip it all up you could try a slight tweak of your Plan B set-up. Turn the splitters round at each end of the cable between office and living room so that the "input" connector of each is attached to this cable. As you have them in the third diagram but without all the other splitters involved.
Then in the office have the aerial plugged into one "output" and the bedroom TV into the other. In the living room have the satellite box plugged into one "output" and the TV into the other. Don't expect it will make very much difference, may make it worse but then again it might just work! Stranger things have been known to happen. |
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#11 |
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Ok, what that gives me is the living room has good terrestrial but poor satellite signal. The bedroom has good satellite and poor terrestrial.
This shows that the single cable can carry feed from both sources in two directions at once, but it is looking more like the problem is that signal is not transmitted well across the two arms on one side of the splitters. It is almost worth trying that scenario 3 I drew, as all signals can flow to both TV's *through* a splitter rather than across it. |
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#12 |
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Join Date: May 2006
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splitters can run one way suggesting your problems e.g. 1 in 2 out
roof aerial to sky box sky rf 1 to living room tv sky rf2 to bedroom no joins , no splitters |
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#13 |
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Quote:
splitters can run one way suggesting your problems e.g. 1 in 2 out
roof aerial to sky box sky rf 1 to living room tv sky rf2 to bedroom no joins , no splitters For now, I just wanted to find a way to make our existing cable runs deliver the best pictures they could.Is it possible to obtain multi-way splitters where the input of all three is valid output to all three - so that the signal can get across the arms as easily as it went in the arm and out the leg? |
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#14 |
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Quote:
Is it possible to obtain multi-way splitters where the input of all three is valid output to all three - so that the signal can get across the arms as easily as it went in the arm and out the leg?
Splitters as the name suggests take one signal and split it into several destinations. The opposite of that is a combiner which takes multiple sources and mixes them to one destination. What you want is some hybrid of these which to the best of my knowledge does not exist. The problem with that scenario is this... Say you have a three way device, legs 1, 2 and 3 and three sources A, B and C. You have source A connected to leg 1, B to 2 and C to 3. Now if all three sources A, B and C mix and appear on all three legs 1, 2 and 3, then on leg 1 you will get the direct feed of source A plus a mix of B and C form the other legs. But you will also get a contribution of source A back from legs 2 and 3. Which will cause interference with the direct feed. Which is likely to get back inro legs 2 and 3 and round and round the loop. And of course similar things will be happening on legs 2 and 3 with sources B and C Basically a bit of a mess. You mentioned trying your scenario 3 with a whole load of extra splitters. What you have to bear in mind with that is that each splitter will introduce loss into the signal path.. Now between the aerial and the TV in the living room you have no less than four splitters. Depending on the quality of the splitters that could be anything from 12 to 24dB of loss! Which would mean you would need a seriously good aerial signal to begin with to absorb that amount of loss. Anything vaguely marginal about the signal and you would be unlikely to get any digital reception at the living room. |
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#15 |
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Hehe I'll go back to my "After" arrangement then. It was good enough for now
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#16 |
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Forum Member
Join Date: May 2006
Location: Aberfeldy
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and if you use RF 2 and a magic eye you can watch and change channels in your bed with a magic eye
this works by 9 volts from sky box and has to be switched on and all distribution amps you may think of getting have to allow the 9 volts to work so you have your box in office and can change channels in office, living room and bedroom with one box |
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