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Standard User Rex_Luscus
(newbie) Sat 03-Mar-18 17:21:23
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Aluminium cable and speed limits


[link to this post]
 
TLDR
Has anyone else experienced limited bandwidth due to aluminium phone cable? (I've read the thread re G.Fast and aluminium from 08/17, but I'm no wiser re the extent of this issue)

Is there a solution which doesn't involve paying BT to recable between my house and the cab?

If I move to a product with lower rated speed (55 or 35 Mbps instead of current 76Mbps), will I still get my current 33Mbps, or will I only get approx half the service speed I subscribe to?

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Just over 2 years ago, we were the first household in this village to have FTTC broadband installed, having taken out a subscription to SSE's 76Mbps service. When the OpenReach engineer had finished doing his thing and announced a successful connection, I noticed his tester was reporting 33Mbps, and I queried why I wasn't receiving the full fat service I was expecting. He couldn't answer, but went off to take another look at the cab (IIRC about 100m away), returning after a little while having changed the connection, but still no better speed. He suggsted I contact my ISP, which I did.

There then followed a series of phone calls, email exchanges, interspersed with BT speedtests, which culminated in a further visist from OpenReach. The latest engineer, after some to-ing, fro-ing and headscratching eventually advised that I 'probably' had aluminium phone cable between the cab and the house, and that this was limiting my bandwidth.

SSE offered to downgrade my service, but this would have meant that my upload rate would also have been reduced (at the time I had also signed up for online backup service which required a fairly quick upload rate), and the slower service wasn't much cheaper than my intro discount rate, so I remained on the 76 Mbps service.

As my intro offer with SSE has now expired, I'm once again looking at fibre broadband products, and am prompted to wonder if anything can be done to get a full 76Mbps service, or if I settle for a slower service if I'll still achieve 33 down/6 up? (I'm considering Vodafone, but I'm anticipating that I won't get the advertised discount for slower than advertised service because the speed they guarantee is measured between the exchange and the cab, correct?)

Thanks in anticipation
Standard User MHC
(sensei) Sat 03-Mar-18 17:36:44
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Re: Aluminium cable and speed limits


[re: Rex_Luscus] [link to this post]
 
If you move to a 55 or 38 down and 10 up service then you should continue to get 33Mbps down and 6 up. So, you will not lose out. If you move to a supplier that still offers 38/2 (if any do) then down will remain at 33 but up will be cut.

What are you current line stats? Attenuation, SNRMargin, Max achievable and Sync in both direction?


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User Zarjaz
(eat-sleep-adslguide) Sat 03-Mar-18 17:51:51
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Re: Aluminium cable and speed limits


[re: MHC] [link to this post]
 
I find it impossible to imagine that only ‘approx 100m’ of aluminium would provide only 33 meg ?

Summat amiss there don’t you reckon ?


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Administrator MrSaffron
(staff) Sat 03-Mar-18 17:53:40
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Re: Aluminium cable and speed limits


[re: Zarjaz] [link to this post]
 
100m but may be wiring distance is further

Or the cabinet is not that cabinet

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Zarjaz
(eat-sleep-adslguide) Sat 03-Mar-18 18:33:15
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Re: Aluminium cable and speed limits


[re: MrSaffron] [link to this post]
 
All bets off until some stats seen I reckon.

Standard User nemeth782
(committed) Sat 03-Mar-18 18:34:39
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Re: Aluminium cable and speed limits


[re: Zarjaz] [link to this post]
 
Alu really can screw over a connection, I used to live somewhere with an aluminium segment on the line and where I would have expected 80meg from the distance I only got about 45.
Standard User nemeth782
(committed) Sat 03-Mar-18 18:44:55
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Re: Aluminium cable and speed limits


[re: Rex_Luscus] [link to this post]
 
There are 4 VDSL products sold to ISPs by BT Openreach. All use the same 17Mhz of bandwidth, and the maximum sync speed does not change between them, however, there is a cap on your sync speed of the maximum product speed.

80meg down 20meg up, commonly sold as "up to 76 mbit".

55meg down 10meg up, commonly sold as "up to 52 mbit"

40meg down 10meg up, commonly sold as "up to 38 mbit"

40meg down 2meg up, also sold as "up to 38mbit".

Your actual speed will be the lower of the maximum speed your line supports, or the product speed listed above.

As you say you are getting 33meg down, you will get exactly the same downstream on any of the 4 VDSL options.

As you say you are getting 6 meg up, you will get exactly the same downstream on the first 3 options, but this will be capped to 2meg up if you go to someone using the "40/2" service. Examples are Talktalk and I think Plusnet used to? But that might be out of date.

The VDSL/FTTC segment of your line will perform exactly the same whichever provider you go with assuming you are on the 40/10 or higher services, barring some small differences in performance of ISP supplied modem, although this is eliminated if you use your own. The difference comes in the ISP's network and level of congestion. Different ISPs might offer different estimates, but this is just a difference in their level of optimism, and not a reflection of which ISP can offer you better speeds (they are all the same).

The new Vodafone offer will not help you, in that the payment will be based on your line syncing slower than the prediction they give you, not it being slower than the maximum rate for your selected product. However, if your line is inconsistent in sync speed, this might still be good.

You mention speed tests etc, the problem with speedtests is that there are too many factors, the issue could be the client device, wireless if used, ISP congestion, or any number of hundreds of other issues. This is why it is best to work on the basis of the "line stats" or "sync speed" which should be available from your router.

As for replacement of the Aluminium, you have basically no hope, short of throwing money at BT, and even then it will be difficult for you to get them to take your offer of £thousands seriously. In all honesty you are probably better off looking at FTTPoD or waiting for G.Fast, it will probably be a similar cost. (dig up road, replace aluminium with fibre, is a similar cost to replace with copper).
Standard User monkeyman86
(newbie) Sat 03-Mar-18 19:45:56
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Re: Aluminium cable and speed limits


[re: Rex_Luscus] [link to this post]
 
Do you have any extension wiring in the house or can you confirm that the line runs directly into your main socket only? Extension wiring can have a significant impact on speeds.
Also without further details it is difficult to know whether the cabinet you mentioned is a main one with a corresponding DSLAM or a secondary one (SCP) between you and the main cabinet.
Administrator MrSaffron
(staff) Sat 03-Mar-18 21:02:32
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Re: Aluminium cable and speed limits


[re: nemeth782] [link to this post]
 
G.fast is not likely to be deployed to areas with Al, since the higher frequencies suffer even more

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Rex_Luscus
(newbie) Sun 04-Mar-18 01:11:31
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Re: Aluminium cable and speed limits


[re: Rex_Luscus] [link to this post]
 
Thanks very much for your timely responses and advice.

I checked on my cab, and although it's about 200m as the crow flies, it's actually over 400m following road/footpath.
Don't think I can post images here, so the stats from my router give me:

Downstream
Link Rate 35000kbps
Line attenuation D0(17.2) D1(47.2) D2 (72.5) dB
Noise Margin D0 (8.5) D1 (8.6) D2 (N/A) dB

Upstream
Link Rate 5827 kbps
Line Attenuation U0(8.6) U1(41.9) U2(58.1) dB
Noise Margin U0(6.4) U1(6.2) U2 (6.2)

VDSL2 Profile 17a

Here's a recent TBB speedtest:
My Broadband Speed Test

I'm aware of the issues re extension wiring, and previous tests using BTw speed tester with modem direct to BT's socket and all other devices disconnected only added about 2Mbps to the 31.5 Mbps downstream speed experienced with normal network and wired extension.

From nemeth's helpful post (for which, many thanks) it seems I'd be better off downgrading to 40/10 or 55/10 - just hope there's capacity left if/when I switch.
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