Extending TV coax to an extension

[monday]

Can anyone offer advice on the cleanest way to extend TV into an extension?

I have an external roof aerial feeding an aerial amplifier in the loft space. This has 4 output sockets feeding various rooms, only two are ever used at one time. I am building a new extension which is on the opposite side of an external wall to the lounge. The easiest coax feed would be from the existing TV socket on that external wall. Otherwise I have to run all the way from the loft.

Is there a neat way to connect a new cable to the back of the existing socket, preferably within the back box, to run into the extension? I can see I could get both centre cores into the same terminal but how best to join the screens. Or is there a front plate available to take two cables?

 

[Lucid]

Satellite cable F connectors and an F back-to-back

Look at 6 - 7 mm Cable repair joint kit on this page (scroll down)

 

[OwainDIYer]

you shouldn't just spur off the existing socket; if you extend the cable to the extension you won't be able to have the socket in the lounge (whether you use it or not).

Or you can use a splitter but that may be awkward to arrange neatly.

 

[ericmark]

Transmission cables should be correctly terminated and the theroy is quite complex. To stop losses the impedance of cables and connectors is important so when you want to divert signal to another room then something like this

will allow you to transfer will minimum loss of signal or to use an active (powered) device to amplify and split if that is what is required.

Non powered splitters have resistors in them to try and match the impedance but this means losses so much depends on how strong the signal is to start with.

However saying that one can get some odd results and some times a simple connector works even though theory says it shouldn't.

Even the length of cable can make a huge difference cutting an inch off the cable can both reduce and increase signal strength I am not really into UHF but something I seem to remember tells me 9 inches for the short lead to connect or multiples there of.

A simple double socket

will allow you to change at will what you want link when no TV in place at original location and amplified two way splitter if both are used.

If signal is good one of these may work

if you break it apart you will find two resistors which is an attempt to keep the impedance correct.

 

[Sam Gangee]

But don't use an UNSCREENED socket as depicted in that image!
http://www.satcure.co.uk/tech/wall_plates.htm

The white plastic UNSCREENED splitter can also cause problems.

 

[monday]

Thanks to all for some good ideas. I'll investigate further over the next few days.