Cabling for TVs

[highleigh]

I am just getting to the stage of putting the wires in for some of the upstairs rooms. Electrician is doing the electrical stuff but I want to but in the best I can to each room for the TV's. i will ultimately put in provisioning for TV's in 6 rooms.

I am quite IT literate so will put in cat5 or 6 to each TV point but am a little unsure as to what to put in for for the audio/visual. For the wall mounted TV's I will put in a fixed HDMI cable to somewhere where a PC/DVD etc. could go but I am unsure what else to put in other that I will need something to send a transmitted picture. I have done a bit of googling and see that the consensus seems to be a couple of RG6 and 2 cat 5e is enough, however I then see ct-100 is better?

I just want to be able to send TV transmissions from an aerial and from a sat dish to each TV from a central location. Would RG6 or ct-100 be best for this and what would I need in terms of a distribution box for these?

Anyone have any other ideas of what to put in while I have the chance?

 

[ChrisFrost]

CT100 is perfect for TV distribution. Those of us in the trade use it for TV and satellite work.

As for whatever else to add, the options are legion. It very much depends on what you want to hang off the ends of the cable and the size of your budget.

If you haven't a lot of cash to throw at this then just do the basics and then provision for future expansion. An aerial distribution system gives you the ability to provide Freeview and to pipe the RF2* feed from a Sky box round the house. The Sky feed is simply a window on whatever the main room is watching. Adding magic eyes to the TVs gives everyone control of the box, but it doesn't change the fact that only one channel can be viewed on all TVs from a single box. All of this can be done with a single coax of CT100.

Distributing the raw satellite dish signal is trickier. If you plan to add Freesat recorders or Sky boxes to each room then you would be better off with 2xCT100 per room dedicated to satellite use along with the single CT100 for the TV. Put the two feeds to a position in each room where a box would live. Those cables will wire back to either a pair of dishes fitted octo-LNBs (8 outputs - 2x per room), or more commonly they'll go to something called a Multiswitch which in turn is fed with all four cables from a special LNB called a Quatro LNB.

A quatro LNB provides all four satellite signal states simultaneously. The multiswitch takes those (and RF fron the aerial if required) and serves each on demand to the various satellite receivers round the home. The size of the multiswitch is governed by the number of outputs you need. In this way a single dish can feed several rooms without the conflicts inevitable if you tried to share one LNB feed among several receivers. Local Sky/Freesat boxes then removes the need for a control system and priority switching that can get really messy with centrally located boxes in a rack system.

CAT6 is what I'm spec'ing in all my pre-wire jobs. For networking then CAT5 will do fine unless you live in Windsor castle. But having it all standardised on a single cable spec is simpler.

If money is no object then you can run everything as IP. That makes sense if you have digitised your media library and have steaming boxes at the TV ends. Look at Western Digital, Boxee, Roku as starting points. You can also convert video and HDMI to an IP signal and distribute it that way. You could distribute the HD signal from one or more Sky boxes that way. The same caveats apply as watching Sky via RF though. You also need to consider control. With Sky you can still use the magic eye via the RF network even though you are viewing via the network. Distributing a DVD or Blu-ray player is possible... But you'd have to ask why. Apart from the immediacy of playing a disc it does add a whole layer of complexity for what will be a rarely used facility.

The cabling for all this could be done via CAT6. Put at least one behind the TV (Smart TV features), a couple to a box location perhaps below the TV, and then a couple of HDMI feeds up to the TV for the local sources and streaming boxes. Also consider some network points for connecting ancillaries (PC, games console etc).

While you are spec'ing cables, have a think about sound. TV speakers are fairly poor now on flat screen TVs. Some form of sound reinforcement makes sense.




* someone is bound to chime in that the latest Sky HD box no longer has an RF output for control. This is true. Your solutions are either some secondhand boxes or a 3rd party RF out & control box.

 

[Sam Gangee]

Only the little Amstrad DRX595 "multiroom" Digibox has no RF outputs. The rest have. There is no simple workaround for this so, if you have this model and need RF output and/or "magic eye" remote control, swap it for a different model.

CT100 cable hasn't been manufactured since 2005 when the manufacturer, Raydex, went out of business. If you come across "CT100 equivalent" which seems cheaper than the rest, there's a reason for that.

If you are simply trailing it across the floor as a "fly lead" then it doesn't matter what you use because it's easily replaced when you discover how much it affects your signal. However, if you are plastering it into a wall or installing it outside, use a recognised type such as WF100 or TX100. If you want cheap & cheerful, RG6 is usually a safe bet but it tends to degrade quickly outdoors.

The main criteria to look for in good quality cable are:
Copper wire core
Copper wire braided shield
Copper foil shield
White dielectric (foam)

 

[highleigh]

Thanks for the replies, looks like I am on the right tracks for now.

 

[SimonH2]

The best advice I can give is not to plaster cables in, but to use conduit - electrical wholesalers sell "white oval" conduit in several sizes, the largest of which will take four coaxes side by side. When installing, use a deep double backbox (metal "flush box") - they go to 47mm and that's what I'd suggest to give yourself plenty of room.

It needs a bit of work, but don't do the usual electricians trick of stopping the conduit short of the box and putting a dogleg in the cable to go through the pre-punched round knockouts in the box. Spend a bit of time making a larger hole that the conduit will fit through and make sure the end of the conduit "just" enters the box. Otherwise changing cables is "unnecessarily hard" because the conduit isn't lined up with the hole in the box.

Done that way, if/when technology moves on and/or you change your mind - you can lift a few floorboards or go in the loft as appropriate and pull in different cables.

OK, not so easy if you have concrete floors etc.

EDIT:
Just to add, at my mates bungalow we installed rectangular trunking down the walls so we can get HDMI cables through with connectors fitted - they won't fit in white oval. However, you can get HDMI over Cat5 sets quite cheap these days which allows the use of fairly cheap Cat 5 cables.

 

[oldcardriver]

I googled CT100 and this article says that WF100 foam dielectric is better than CT100 airspaced dielectric, see:-

http://www.megalithia.com/elect/cable/index.html

More types of cable are mentioned here:-

http://www.aerialsat.com/prod/25m-wf100-pvc-webro-coax-cable.html

BTW Maplin do some coax connectors with a retaining grub screw for the centre conductor, see:-

http://www.maplin.co.uk/high-quality-coax-plug-1606

 

[Sam Gangee]

Also see http://www.glodark.com/cable.htm
and http://www.satcure.co.uk/tech/cable.htm

As I stated, above, CT100 is no longer available. Read the articles carefully.

 

[Monkeh]

BTW Maplin do some coax connectors with a retaining grub screw for the centre conductor, see:-

http://www.maplin.co.uk/high-quality-coax-plug-1606[/QUOTE]

They're crap in numerous ways, the fact that they use a screw being just one of them.

 

[oldcardriver]

BTW Maplin do some coax connectors with a retaining grub screw for the centre conductor, see:-

http://www.maplin.co.uk/high-quality-coax-plug-1606[/QUOTE]

They're crap in numerous ways, the fact that they use a screw being just one of them.

What other "numerous ways" and doesn't the grub screw give better continuity? What do you use?

 

[Monkeh]

BTW Maplin do some coax connectors with a retaining grub screw for the centre conductor, see:-

http://www.maplin.co.uk/high-quality-coax-plug-1606[/QUOTE]

They're crap in numerous ways, the fact that they use a screw being just one of them.

What other "numerous ways" and doesn't the grub screw give better continuity? What do you use?

They're poorly fitting, fiddly to fit in the firstplace, and totally unsuited anyway (not that you get a choice in that..).

No, a grub screw doesn't give better continuity. Solder or go home.

Personally, I fit F connectors and use adapters.

 

[ChrisFrost]

The problem with grubs screws is how it affects the solid core centre conductor.

I have some Belling-Lee female coax connectors. These use a grub screw to secure the centre conductor. What I found is that it is surprisingly easy to over tighten the screw which then dents the centre core causing a weak spot. The result is that the centre core breaks if the plug is twisted slightly.

So yes, I share Monkeh's mistrust of this type of fixing when used with solid core cables. They are okay with cables that have a stranded centre conductor.

 

[Sam Gangee]

The result is that the centre core breaks if the plug is twisted slightly.

I had that happen with a wall plate where no movement was involved at all. To make matters worse, it created an intermittent "no satellite signal" fault and it was a pig to trace. Since the wall plate was the last thing I'd installed, it was the last thing I thought to check, but I got there through the usual process of elimination.

In short: "I agree".

 

[oldcardriver]

The problem with grubs screws is how it affects the solid core centre conductor.

I have some Belling-Lee female coax connectors. These use a grub screw to secure the centre conductor. What I found is that it is surprisingly easy to over tighten the screw which then dents the centre core causing a weak spot. The result is that the centre core breaks if the plug is twisted slightly.

So yes, I share Monkeh's mistrust of this type of fixing when used with solid core cables. They are okay with cables that have a stranded centre conductor.

Thanks for the explanation Chris.

Does anyone recommend a particular make of connectors?

 

[1028741]

It's a good idea to run a couple of coaxial cables to each tv point. With satellite TV (e.g. sky) you can install a "loftbox" and remote "magic eyes" so that you can watch sky from one box on any of the tv's. If you run all your coaxial cables to one point, in future it is extremely easy to install sky boxes in different rooms e.t.c. Also a good idea to run all speaker cables and cat5 from the rooms to the same location, so you could install a whole-house speaker system, with volume controllers in the rooms