Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: bossian on August 24, 2013, 08:44:17 PM
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Well Virgin have decided to put up my cost of 120/12 another £2.50! >:( That's a second rise this year >:( >:( >:( >:(
So enough's enough......I've decided that for the near on £40 they want for just broadband, I might as well go with BT infinity 2....well for an extra £1.50 I get another phone line and BT sports for free ;)
So having 2 VDSL2's down the same drop wire........is it ok? I have 2 BT business BB at work, one vdsl and one adsl and they work ok.
I know it may sound OTT, but I want the redundancy 2 separate WAN's provide :blush:
So one 80/20 from Plusnet and one 80/20 from BT....both on the same CAB......now that should give me plenty of stats and readings to use against each of them ;D
I have 2 HG612's too ;)
Thoughts on this guys?
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Some people are never satisfied! ::)
In all honesty, I can't see any great reason why it would 'Not Be A Good Idea'. Obviously you may observe cross-talk between the two services . . . but on the whole, I'll say just 'suck it and see'. :)
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So having 2 VDSL2's down the same drop wire........is it ok?
Well, it will certainly be interesting to see your results. :) It would be interesting if you had the stats to see the extent of the FEXT effect on the first line, when the second line is connected. :hmm:
I assume that you have a least two pairs in your current drop cable.
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Yep, there's a second pair in my drop cable
And the new pair will follow the exact same route as my existing pair
And I'm never satisfied....... ;)
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@ BossIan,
Glutton for punishment comes to mind !
You'd better swat up on your Indilish too !
I wonder how long the "Free" sports will last ?
Kind regards,
Walter
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you will almost certianly see crosstalk. Pairs sharing a dropwire are very prone to crosstalk on vdsl.
Whether or not it has a big enough impact for you to care remains unknown tho.
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you will almost certianly see crosstalk. Pairs sharing a dropwire are very prone to crosstalk on vdsl.
Whether or not it has a big enough impact for you to care remains unknown tho.
Mmmmmmmm this should be interesting then. I haven't experienced cross-talk yet.
At my work we have a 20 pair coming onto site to a DP on the front of the building, in that 20 pair there is my new VDSL and an ADSL, which travel across the building roof in a drop wire to the same area. Also in that 20 pair is the companies ADSL, 2 leased lines and 6 phone lines. The VDSL connection is great, clean and so far, faultless. I'm still getting 72/20 as I did on the day it was installed....and it's showing as up for 325 hours now!
What do I need to look for in cross-talk? What are the clues?
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@ BossIan,
Perhaps I should have been more explicit instead of joking about gluttony !
Given that you have the luxury of both major providers, maintaining a full dual-diverse routed configuration has perhaps some significant value ?
Kind regards,
Walter
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you will almost certianly see crosstalk. Pairs sharing a dropwire are very prone to crosstalk on vdsl.
Whether or not it has a big enough impact for you to care remains unknown tho.
Mmmmmmmm this should be interesting then. I haven't experienced cross-talk yet.
At my work we have a 20 pair coming onto site to a DP on the front of the building, in that 20 pair there is my new VDSL and an ADSL, which travel across the building roof in a drop wire to the same area. Also in that 20 pair is the companies ADSL, 2 leased lines and 6 phone lines. The VDSL connection is great, clean and so far, faultless. I'm still getting 72/20 as I did on the day it was installed....and it's showing as up for 325 hours now!
What do I need to look for in cross-talk? What are the clues?
well I am talking of 2/4 pair dropwires not 20 pairs, in your case its different. But you said also is only one vdsl in all those pairs?
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Sorry if Im being thick because its a genuine question.. why does a 2 pair make xtalk more likely than over 20/30/50 pair cable.
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As I understand it, 4 wire drop wire is NOT made up from twisted pairs, so I would think cross talk would be highly likely.
I also have two SEPARATELY ROUTED broadband lines to my home. One ADSL O2/Sky broadband provided via a drop wire through a tree outside, and Virgin broadband routed under ground. I also have two Sipgate V.O.I.P. phone lines that share the same number. In this way hopefully I will never be without the phone, even if a broadband fails before I spot it. Think carefully if you need the broadband never to fail you.....................
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BT standard black dropwire 2 pair is twisted pair
The twists are nowhere near as tight as cat 5 twists are.
The specs are
orange/white pair 1 twist every 89mm
green/black pair 1 twist every 95mm
These specs (from BT spec CW1411 external 2 pair dropwire datasheet) came from B3 cables who have since gone into administration.
I grant you totally that the pairs not tightly twisted nor is the cable or the pairs in them shielded in anyway.
I don't have any specs for BT main supply cable either D side or E side as to what the twist specification is for them.
(The breaking load in the spec is quoted as being between 1350 and 1550 Newtons for the above dropwire)
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>> BT standard black dropwire 2 pair is twisted pair
I thought it was too... the BToR who replaced my internal cable via an outside wall run used black external cable with 2x twisted pair.
.. which is why I wondered what difference it made.
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Looks like the BT man I spoke to last year gave me wrong information. I am not an expert on drop wire as my training in the early 1960's involved my climbing up 10 foot poles ( fortunately ) and tensioning copper wires....... I don't think now I would even manage the 10 foot poles.....
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The attached images show the specifications for both CW1411 and CW1417 aerial cables . . .
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If anyone is interested, I have copies of two PDF format documents that I can share . . .
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Thank you B*cat.. so if I understand correctly, then they are basically the same other than the 2pair has slightly more of an insulated diameter. Everything else seems about the same... except the capacitance unbalance... anyone know what difference that makes?
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Getting a little bit OT for this thread but here follows four images with the specifications for CW1308 cable . . .
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Sorry if Im being thick because its a genuine question.. why does a 2 pair make xtalk more likely than over 20/30/50 pair cable.
because the pairs are defenitly next to each other, whilst in a 50 pair the odds are much more in favour.
also twisting doesnt kill crosstalk it just reduces it. twists in dropwires tend to be of less tightness than whats in the ground, and even in the ground its of variable amounts.
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Gentlefolk,
If you have a nice kind engineer who takes the trouble (s)he will sometimes install a dropwire 12 which only has a single pair of thicker conductors.
Kind regards,
Walter
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I forgot to add I share a 4 pair dropwire with my neighbour, when a engineer temporarily gave me a new dropwire I had over 30mbit added to my attainable sync speed but it was only temporary, BT forced me back to the shared dropwire.
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Well after all that, Virgin came back to me and offered me the 120/12 service I'm on at £26.00 a month for 12 months on a new 12 month contract! Result ;)
Thanks for all the input on here guys......and after a bit of research, maybe it's better than going down the road of crosstalk and dodgy BT call centres!
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Well done BossIan,
I hope you find VM is more reliable too - ergo fewer call centre investigations, but hope contention doesn't interfere too much.
Many don't realise that their co-axial cable with joint pods means there is far less disturbance (and fewer cable joints) with the main cable and they don't have anything like the birds-nests we see elsewhere. Some of their cabinets do get bashed about a bit so they're not very pretty.
Kind regards,
Walter
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Fair call about the fewer joints, but 'Birds nest' wiring, (although unsightly), is a) Not as common as some may think, b) Very rarely on view to the EU, and c) Has no detrimental effect whatsoever on service.
Hope you are happy with VM's service ....... god knows, they need the business. ;) ;D :lol:
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I am retracting my previous comments about risk of crosstalk, in the past couple of weeks I have seen a few posts from people who have 2 lines in the same DP enabled and they insist they either have no or minimal crosstalk, so this changes the %'s a bit. Previously I had known 4 accounts of multiple lines in a DP which all had severe crosstalk now I know of 9 with the other 5 not having severe crosstalk.
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I am retracting my previous comments about risk of crosstalk, in the past couple of weeks I have seen a few posts from people who have 2 lines in the same DP enabled and they insist they either have no or minimal crosstalk, so this changes the %'s a bit. Previously I had known 4 accounts of multiple lines in a DP which all had severe crosstalk now I know of 9 with the other 5 not having severe crosstalk.
Interesting comment Chrysalis. I'm sorted here at home now with a blend of Virgin and Plusnet FTTC.
Now work is a different thing.....
At my work we have a 20 pair coming onto site to a DP on the front of the building, in that 20 pair there is my new VDSL and an ADSL, which travel across the building roof in a drop wire to the same area. Also in that 20 pair is the companies head office (intranet) ADSL, 2 leased lines and 6 phone lines. The VDSL connection is great, clean and so far, faultless.
So I'm toying with the idea of converting the second ADSL to VDSL too. The 20 pair is around 80 metres from CPC10 to the outside of the building's DP, all the lines and the companies kit is within 5 meters of this DP. The VDSL and ADSL I'm on about is an additional 30 meter away down it's own drop wire across the roof.
I'm pulling 70/20 on the VDSL and 5/.8 on the ADSL....so changing the ADSL to VDSL would be a benefit, even if there is crosstalk. I'm back next week, will give BT business a call and see how much this extra change will cost me.
If nothing else, it may be an excellent opportunity for me to gather some info for us guys on the effects of 2 VDSL's on the same drop wire ;)
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Go for it, Bossian.
I have to say, the comment about gaining 30Meg just by being moved to a different DW, has never been heard of before ?? Assuming the DW goes 'Pole to premises', the longest span we can erect is 68mtrs. So, are we to believe that crosstalk in 68mtrs of DW causes 30Meg of speed-loss ?? As I say, with plenty of experience in this arena, I have never heard of that, ever.
By having another VDSL line in your 'bundle', will have very little effect, Bossian.
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I forgot to mention the 20 pair from the CPC to the DP on the building is underground in it's own duct.
The extra 30 meters of drop wire is just laid loosely across the roof. I did this as it was a shorter way than trying to go around the inside of the building....that would have added another 50 meters to the run!
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Go for it, Bossian.
I have to say, the comment about gaining 30Meg just by being moved to a different DW, has never been heard of before ?? Assuming the DW goes 'Pole to premises', the longest span we can erect is 68mtrs. So, are we to believe that crosstalk in 68mtrs of DW causes 30Meg of speed-loss ?? As I say, with plenty of experience in this arena, I have never heard of that, ever.
By having another VDSL line in your 'bundle', will have very little effect, Bossian.
adsl24 reported they lost 30meg or so when they enabled a 2nd line in a bundle. aaisp have also reported on their blog of users occasionally seeing sudden large drops of sync speed when a neighbour gets enabled, not frequently but occasionally.
I do wonder what would have happened if you was my engineer investigating my issue earlier in the year, because some of your comments go against the BT trend, eg. I have been told by the CEO office staff and 3 engineers that 30+ mbit of lost attainable sync speed is normal part of the service and expected. I then temporarily had a new DW fitted and my speed comes back (but then I couldnt keep it) and then last week I gain this 30mbit attainable speed again (temporarily) simply from an engineer swapping my pair between the 2 cabinets, that is what? maybe 20metres to the cabinet and back.
I can only guess based on your comments the condition of the cables in my area must be in a sorry state compared to the area you work in. Although if you know another possible cause for the problems I am seeing it would be appreciated as so far you havent commented on any of my posts.
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My mistake. I mis-read the quote ....... I thought you meant actual speed, not attainable.
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My mistake. I mis-read the quote ....... I thought you meant actual speed, not attainable.
I think with adsl24 it was actual speed.
in my case not, so the question is if you turned up at a job where a ton of attainable speed was lost, but only 'some' of that was actual speed (about 10% actual speed loss) would you still investigate it and try and fix it or just say its how it goes lines slow down. Thats all I am curious about and basically your best guess of what the problem may be, because what got my attention is you feel based on your experience its unusual for crosstalk to cause sudden large drops of speed in one go. Lost attainable speed is still something that eats away at the noise margin so the line stability is impacted as a result. I basically went from a 80mbit sync with over 10db margin down to 71-73mbit range with a 6db margin. The neighbours I have spoken to have suffered similiar issues. I dont know anyone who now has a 80mbit sync near me, but they all have had it at one point (the ones I have spoken to) but lost it like me. One guy got his sync speed back with a pair swap but it only lasted a few weeks until he lost it again. My install engineer told me its crosstalk as he checked the 2 date/time's and matched them to new installs.
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Chrysallis ..... I generally stay away from 'remote faulting' on a forum, especially speed-dips/increases as it could be absolutely anything causing them ?? If it's fluctuating attenuation, or something of that nature, then it's something that can be whittled down via a forum, but I wouldn't want know what to say regarding your issue without being on-site with my JDSU.
PS ..... regarding 'attainable speed' losses. Our systems (or the systems that I have access to) don't keep a log of 'attainable speeds'. Ergo, when I go about my faulting techniques, I work to synch speed only. It does sound feasible that it is crosstalk causing the problem, and if the other engineer proved this from dates and times, then I'd have to accept that.
I can't offer any other input i'm afraid, as I don't view 'attainable speeds' as part of my job.
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no problem, I have had a call not long ago of the guy I met last week, I been informed I will have outages tommorow as they going to try and diagnose where the problem is.