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[mpooley]

My telephone connection has an external JB to a point in the middle of my rather large loft where it was cut and redirected by the previous owner using non paired cable.
WE are on the end of a very long line with a downstream attenuation of over 63.5 and when I moved in a few years back I could not get any line sync at all.
After lots of reading on this site and others I managed to improve this to roughly a 1mb download speed and then I bought a Billion 7800n and doubled that to 2mb !
Anyway to the point!
In the process of improving my line I replaced the above mentioned wire with some cat 5 cable about 25meters long.

As I am getting a FTTC modem fitted next week and as I had some spare very good quality cat6 cable I decided to change that cat5 with cat 6.
My download speeds did creep up a fraction so I though why not double up the wire?

I'm not sure if this is the cause but I did then lose about half a mb in speeds.
It's not always easy to tell exactly because my speeds seem to vary with the weather or the position of the  moon as far as I know!

So at last to my question did I do a sensible thing when I used two wires instead of 1?
I did use wires from separate pairs. should I have used them from a single pair?

thanks in advance for any advice.

Mike

[HPsauce]

I see no reason to use Cat6 over Cat5 it won't improve things and is less easy to route.
Yes, you must use one pair only and not cables that go across pairs.
If you can get a long length of shielded cable that might help a bit, I think Tandy sell STP ADSL cable.

[Black Sheep]

As above ........... it's imperative you only use ONE twisted pair to provide service, or you'll bugger up the AC Balance of the cable.

[guest]

You will have increased crosstalk between the pairs.

In terms of using STP rather than UTP - I wouldn't unless you know what you're doing as its all too easy to end up with a ground loop if the relevant screen connections to ground are on different ring mains. This is not a good thing and in some instances can be reasonably hazardous - if the circuits have ELCBs then they will probably trip every now & then due to current flowing in the earth wire. Edit - just noticed that HPSauce said "STP adsl cable", I was thinking more in terms of STP network cabling where you're going to need to supply a ground connection for the screen.

Decent CAT5 cable will be fine - make sure its solid core (ie use infrastructure cable rather than drop cables) & make sure you untwist the pair as little as humanly possible - that'll be fine for 17MHz VDSL2, and also for 30MHz VDSL2 (unlikely ever to see the light of day in the UK).

As an aside g.fast will be a whole different ballgame in terms of wiring issues inside the property & will likely require screened wiring in certain properties (terraced houses spring to mind immediately). I digress - again

[mpooley]

Thanks
So it looks like I have made a mistake then -Trouble is I  think I'll have to carry on using the cat 6 for now as I robbed out the cat 5 for another job and the routing of the cable is a nightmare!
So being a bit slow  what your'e all saying roughly is If I carry on using the cat 6   I should either use 1 single wire or 2 in the same pair?
I didn't understand about the earth shielding - are you saying that the silver screening should be earthed?  I never knew that!
what an idiot 

Taking into account that I have ballsed up and re-wiring will be a terrible PITA could you advise me what to do.
use 1pair yes?
earth the shielding ?  you mention different ring mains but It could only be earthed at one end anyway as the other end is in the loft.
I'm sorry I just don't understand that bit, is there a  terminal in the master socket for earth? I didn't notice one
Or have I totally misunderstood what you said.
Thanks for your help it looks like I need it 

Mike

[Black Sheep]

Just use ONE PAIR ...... the wires will be twisted around one another to identify that it is a pair. Use these two wires, and these two only.

Forget shielding for the time being, it isn't needed as yet.

[HPsauce]

If you're keeping the Cat6 use a single pair for the two wires you need to run ADSL.
Ignore the shielding for now.

@BS - snap!

How is the cable terminated/joined at each end? An incoming BT cable will normally only have 2 wires anyway (or unused spares).

[Black Sheep]

Wow ..... 40 second difference HP. What's that saying about senile minds thinking alike ?? 

[mpooley]

Ok I have been into the loft and am using only one pair now .
I just tested the speed  which is the same at 1.7mbs  but maybe it will take a while ?   

the incoming cable is 3 pair, quite good quality stuff  by the looks of it.
I joined it by soldering them together and screwing them down in to a terminal block for belt and braces.
I kept  the untwisted wire as short as possible.
obviously at the master socket it is those horrible push in connections which never seem all that good to me. I'd prefer an old fashioned screw terminal myself.

Mike

[guest]

The shielding/screening doesn't do much good (in fact it makes things slightly worse) if its not connected to ground somewhere. At current VDSL (FTTC) frequencies its exceptionally unlikely to be an issue for you.

The ring mains stuff :

For example lets say you connected a STP cable between the loft & a bedroom & earthed the screen/shield - that probably means you'd be using a lighting circuit in the loft for an earth which should be fine (technically this is verging on Part P electrical regs depending on your loft but meh).

However if someone later connects the screen/shield to earth on the bedroom circuit then you'd have bridged the earth on two different ring main circuits. This is a bad thing as if some electrical kit develops a fault on one ring main then the resulting current flow may not take the designed path to earth - ie it goes through the screen/shield on the STP cable which will cause some safety issues, even if they're not immediately apparent.