Another Crosstalk question

Since getting fibre just over a week ago my speeds which started at 22.5mbs quickly went down to 19.5mbs and then stayed steady for a week. As 1 or two more people in my village changed to fibre my speeds went down to 12mbs !

I read somewhere that crosstalk can reduce speeds by a third but I have lost nearly 50% in 1 week with only about 6 or seven people on the same cable connected to FTTC.
this seems ridiculous to me.
Do you think that this is a crosstalk problem or possibly something else.

My ISP is uno.net and I am 1.4km from the cabinet.

thanks

Mike

You're not the only one!
I quickly went from 30 > 20 on my FTTC connection (I've done all that's possible to optimise my wiring).

All my neighbours are roughly the same, way below BT's 'best' estimate.

Can you check TBB's figures to see what they say for you: http://labs.thinkbroadband.com/local/

I've mentioned to them via Twitter that none of my neighbours see the "...speeds will likely be above 30 Mbps" they quote.
Makes me wonder how real world all these 'super fast' stats are!

Don't recall the area - so tell us which cab/exchange and can double check the estimates.

Might be crosstalk, or might be the DLM making sure the line is stable or a mixture of the two.

At 1.4km-1.6km something in the 12 to 18 Mbps range would be considered normal

I might be being a bit thick but I'm not sure what I am looking for on those charts.
They seem to be historical averages, and I'm not sure where they are getting them from?
it is saying average for last 6 months was 6.2 down and 1.1 up but the village has only had FTTC for about 3 weeks

I was rock steady on 19.5 mbs for 6 days so I'm a bit gutted to go down so quickly from there.

I checked neighbor opposite and they are only getting 10mbs but they have a very bad crackly line that cuts them off broadband when the phone rings!!
needless to say open reach are mucking them about and say there is nothing wrong LOL
what a joke they are.

The exchange is stoke ferry in Norfolk and my village is west dereham.
I believe its cabinet 4 but there is another one which is much nearer us and the majority of houses but of course they only laid fibre to the easiest one for them !

In reply to a post by QuantumParticle:

I checked neighbor opposite and they are only getting 10mbs but they have a very bad crackly line that cuts them off broadband when the phone rings!!
needless to say open reach are mucking them about and say there is nothing wrong LOL
what a joke they are.

If they have a crackly line when using a corded phone (£5-£7 from many places) plugged into the test socket, report that as a line fault to their phone provider. Without mentioning broadband at all, in any way, shape or form".

That will get fixed, and 95%+ of the time sorts out the broadband.

Yep, I went from 75Mb down to 53Mb. Even though the BT checker states that on an impacted line, I should be getting at least 61Mb. For me has to be crosstalk as I'm probably only 170m away from the PCP.

In reply to a post by MrSaffron:

Don't recall the area - so tell us which cab/exchange and can double check the estimates.

It was part of this Twitter conversation with Rory from the BBC: https://twitter.com/HmmmUK/status/633304761735979008

I ended up DMing you my postcode.
You replied: Suggests a noise, cable quality issue, which is something difficult to predict for 1.7 million postcodes, will see if can be nuanced.

PS. Please don't mention my location on the forum I'm shy!

In reply to a post by QuantumParticle:

I might be being a bit thick but I'm not sure what I am looking for on those charts.
They seem to be historical averages, and I'm not sure where they are getting them from?

They take a bit of reading

After entering my post code I see this under the exchange name:

Notes On Connection Options
Fibre (FTTC) is possibly available and speeds will likely be above 30 Mbps.

Do you see something similar?

Lets see what moving the cabinet the 150m from our estimated position to the google maps lat/lng position makes.

There's something profoundly wrong. I sync at 58mbps and I'm 650 metres from the cabinet (albeit after optimising domestic wiring).

ah! I see it
FTTC Fibre based broadband may be available to you, but speeds are likely to be under 24 Mbps.

I have spent a lot of time and effort in getting everything top notch in my wiring.
When I moved here My netgear modem would'nt even sync with the line ! I gradually nursed it up to 2.5 mbs

40% is within vendor testing for crosstalk but is at the upper range of the lottery. Sadly it seems you have just been unlucky in that lottery.

With that said I think your line would fail a GEA test given how much you have lost in a short space of time. Which should merit at least an investigation.

Could you explain what a GEA test is please.

Oh BTW my upload has been a very nice 5.1mbs ever since Fibre was installed.
It dropped down to 3mbs today I don't know what the hell is going on!

GEA is Openreach "Generic Ethernet Access", which is its product available to Communications Providers wanting to use its FTTC/FTTP and related products. Example.

A GEA test will be an Openreach test, possibly available for CPs to use in the same way as other line checks they can do.

Thanks for that
I reckon I'll be back in about 6 months after I get a head transplant. and then read it LOL

It used to be a lot shorter and simpler. Keeping up with every three months of changes and additions takes more effort than learning the basics that it started as. And that is just one BT SIN. Google BT SIN INDEX and look at the list.

Thanks I'm trying to get my head round at least some of it.

My neighbour who was having her VDSL dropout when the phone rings has had Openreach here all day ! trying to find her a decent line in the copper from the cabinet.Apparently he said that the cable is in a bad way and there are split pairs being used including hers. She says her line is ok now though and getting speeds a little faster than mine.
I don't know if she is now on a proper pair or not I just hope he didn't swap it with mine lol

Split pairs at that level is terrible news. It's bad enough within the house.

The two wires of a pair are twisted round each other and that helps cancel out interference - I forget my school-day physics to explain why, but wires carrying a current create a magnetic field around themselves.

A split pair is when a circuit is made with a wire from one pair and the other from a different pair. Electrical chaos ensues. You may have seen blue or blue/white used with a white/blue, or orange/white with white/orange. If you see a blue/white with anything other than a white/blue it needs fixing. On home phone wiring this refers to terminals 2 and 5, that carry the signal. You may see a third wire on terminal 3, which should be irrelevant for this purpose but can cost broadband speed. See this easy page!

Yeah I did know what a split pair is and why its bad.
Cable must be bad if they have had to resort to split pairs
It just shows you how BT/Openreach will stitch you up rather than replace cable!


I wonder will happen when they just run out of any wires that work let alone pairs.

I suppose it would be better for us when they do as they would have to replace the cable surely?

I believe the OP is talking about split pairs in the Openreach network cable, not on the internal stuff Bob, so your description of the internal colour codes, whilst helpful, is not correct in this scenario. If punters are looking over an engineers shoulders whilst they dive into the world of UG cables, the colour codes are different, so don't be alarmed if what one sees bears no relevance to your description.

Yes, I agree. I know they are different. I described the colour codes he may have seen, or possibly easily can, in order to explain a split pair. That's why I specified that this was internal wiring.

That makes it also useful if anyone finds the post when looking for split pairs are in relation to their own property, or even fining burglar alarm wire there.

As for why a twisted pair is a good thing my understanding is that is has to do with the way interference is picked up on the two wires.

By twisting the wires the interference picked up on one is exactly mirrored by the interference on the other and they cancel each other out. At least that was the theory I was taught. If you use an untwisted pair you could be doubling the interference rather than cancelling it so it is not just a bad idea but a really bad idea.

This is the reason I avoid those flat extension cables.

In reply to a post by andyhurley:

By twisting the wires the interference picked up on one is exactly mirrored by the interference on the other and they cancel each other out. At least that was the theory I was taught. If you use an untwisted pair you could be doubling the interference rather than cancelling it so it is not just a bad idea but a really bad idea.

Not quicte exactly, but very very close in phase and amplitude!

Earlier this morning there was a Quinn's employee with a chamber open and a water proof junction open. It sounded as though he was not having a good time. In a short conversation he mentioned trying to find a suitable pair in fully loaded cables to get a customer back and working. He had a choice - Aluminium from there to cabinet which is around 500m or to use a split pair in full copper - although it may have needed to be one leg in one 50 pair and the second leg in another cable. He said there was absolutely nothing else available!

He had a choice - Aluminium from there to cabinet which is around 500m or to use a split pair in full copper - although it may have needed to be one leg in one 50 pair and the second leg in another cable. He said there was absolutely nothing else available!

What a doughnut ! And you wonder why us guys hate them ????

He would rather bodge to get the 'comp' on the task, when what he has done is create a bigger issue for others. Excessive management pressure is what I blame. [censored].

He did say he would be reporting what he had done and that at least the customer would have a basic service!

What other choice would he have?

well its not as if he could do the proper fix is it?

order some new working copper pairs

He did say he would be reporting what he had done and that at least the customer would have a basic service!

What other choice would he have?

I guess, but the chances are, now that the line tests OK due to his leg and leg bodge, nothing will get done.

He seemed to realise that it would give them severe FTTC issues but wanted to get them a basic phone service back. He did seem to be one of the "better" contractors and not one of the real cowboys.

He did seem to be one of the "better" contractors and not one of the real cowboys.

Oooh, they'll be shot of him shortly then.

It hasn't been said, but has been implied, that he chose the split copper pair option. For a basic phone service surely the choice should have been the aluminium?

Plus, how do we know which would give the poorer FTTC?

Edited by RobertoS (Wed 14-Oct-15 16:19:31)

I don't actually know which option he chose ... It was just one of those chance conversations.

my guess is the ali would be the far better choice, split pairs on dsl can cause utter chaos.

I think its harsh to blame the engineer, here, its the accountants that cause these situations, almost no investment goes into the local loop unless its for marketing (rollout of FTTC e.g.) or a last resort.

Edited by Chrysalis (Wed 14-Oct-15 15:08:26)