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Standard User Livebox
(newbie) Mon 25-Jul-11 23:00:08
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Sudden drop in speeds, higher noise margin


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A while ago I posted on here and managed to increase my sync speed, resulting in our 1.5Mb broadband hitting 2-2.3Mb speeds. I am using an Orange Livebox. Recently, The speed has dropped to 1.1Mb, and I notice the noise margin has increased from 6dB to 14-15dB. BT line test reports no faults, and no audible noise on the landline phone. I did look inside the connection box outside, and lots of small creatures had moved in, I have swept them out, and all the wiring is pretty damp. Could this be the cause of the noise margin going up? Out of curiosity I got what I thought was a netgear DG384GT on ebay, but its actually a DG384G v3. The snyc speed was about the same as with the livebox. Would I possibly get a better snyc speed if I find a DG384GT? my livebox reports attenuation of 63.5dB, and the netgear reports 61dB. I had heard the DG834GT is very good on high attenuation lines.

Thanks if anyone can help!
Standard User burakkucat
(member) Tue 26-Jul-11 01:42:35
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
The speed has dropped to 1.1Mb, and I notice the noise margin has increased from 6dB to 14-15dB.
Strictly speaking, your signal to noise ratio margin (SNRM) has been increased, resulting in your sync speed dropping and thus you throughput dropping from its typical 2.0 - 2.3 Mbps to 1.1 Mbps.

BT line test reports no faults, and no audible noise on the landline phone.
That's good.

I did look inside the connection box outside, and lots of small creatures had moved in, I have swept them out, and all the wiring is pretty damp. Could this be the cause of the noise margin going up?
It's probably not very likely -- unless the insect infestation and dampness is a recent occurrence. Is there any sign of corrosion on the connectors? Could you take a picture for us, please?

A Netgear DG834Gv4 or DG834GT are considered to be good for long lines, as it the 2Wire 2700HGV (a.k.a. the BT Business Hub). The Netgear Gv4 because it is the best of the series for tweaking and the GT because of the availability of the alternate DGTeam firmware.

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100% Linux and, previously, Unix.
Standard User Livebox
(newbie) Wed 27-Jul-11 22:19:58
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Re: Sudden drop in speeds, higher noise margin


[re: burakkucat] [link to this post]
 
Image here: [img]http://postimage.org/image/1vhwfevk4/[/img]

Cant see any corrosion on the connectors. They look well sealed. I twisted the wires some time ago to try and improve speeds. I dont know how long the insects had been there for.

I plan to lookout for one of those routers, but as the noise margin is high with either of the two routers I have tried, I cant see I will get it much better really.


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Standard User XRaySpeX
(knowledge is power) Wed 27-Jul-11 23:22:41
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
In reply to a post by Livebox:
Out of curiosity I got what I thought was a netgear DG384GT on ebay, but its actually a DG384G v3.
Reject it as "Not as Described" and get your money back incl. your return postage. Buy a GT or G v4 instead.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 15.6 Meg LLU => 2011: Orange 16.8 Meg Untweaked WBC
Standard User burakkucat
(member) Wed 27-Jul-11 23:59:25
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
Image here: [img]http://postimage.org/image/1vhwfevk4/[/img]

Cant see any corrosion on the connectors. They look well sealed. I twisted the wires some time ago to try and improve speeds. I dont know how long the insects had been there for.
Thanks for posting the image. I now understand your situation. The actual connectors which have been used are gel crimps and are appropriate for that external location. When you are ready to refit the grey shroud you could, if you wish, give the cables & gel crimps a light spray of WD40 and then run a fillet of waterproof sealant between the shroud & the house's rough-cast. Certainly, from viewing the image, that amount of dampness with those connectors will not be a problem.

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100% Linux and, previously, Unix.
Standard User Livebox
(newbie) Thu 28-Jul-11 15:54:22
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Re: Sudden drop in speeds, higher noise margin


[re: burakkucat] [link to this post]
 
Ive run out of ideas in improving the line. Ive tried connecting with all the phones unplugged, with the phones plugged into filters (which I shouldnt need to as its a filtered faceplate) and the sync is no different. Few weeks ago synced at 2784. Now at only 1728.
Standard User burakkucat
(member) Thu 28-Jul-11 18:40:25
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
The only other advice I can offer is to:

(1) Take two clear photographs of each & every socket (an external view & of the wiring to the connectors) and make them available for us to view.

(2) Obtain either a Netgear DG834GT, a Netgear DG834Gv4, a 2Wire 2700HGV or a 2Wire 2701HG-C modem/router.

(3) Talk to your ISP.

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100% Linux and, previously, Unix.
Standard User alexrose1uk
(newbie) Fri 29-Jul-11 21:15:41
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
Like you suspect your issues are caused by your higher SNR profile.
This could have been caused by some line issues during some storms, an issue on the line, whatever, but for whatever that reason, the DSLAM has now decided for stability you're to be targetted at 15dB profile, rather than 6-9dB.

In your case; you've done what you can with your wiring, and as you don't have a modem which seems to have an obvious SNR tweak, you have two options - buy a router that'll allow you to tweak the target SNR down by say -6dB or get the ISP to persue a reset of your SNR profile.

Pipex-->UKFSN/Enta--->UKOnline--->ADSL24/Enta--->ADSL24/Murphx--->Vivaciti/Enta

Edited by alexrose1uk (Fri 29-Jul-11 21:16:58)

Standard User Livebox
(newbie) Fri 29-Jul-11 22:28:33
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Re: Sudden drop in speeds, higher noise margin


[re: alexrose1uk] [link to this post]
 
Yes I will seek out a better router. However the livebox has an additional landline number through voip, and we plug a usb printer into it aswell so I would have to do some readjusting.

I plan to try some of the custom firmware that is available online also. There are two extensions to the phone wiring that we never use, so I have disconnected those, to no effect. How long would I have to leave the router unplugged for the router/dslam to "forget" the 15db noise level? assuming the noise has gone as alexrose1uk suggested.
Administrator MrSaffron
(staff) Fri 29-Jul-11 22:44:21
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Re: Sudden drop in speeds, higher noise margin


[re: Livebox] [link to this post]
 
Assuming this is Orange via a BT Wholesale line (most likely if upstream is 448Kbps)

Then leaving modem unplugged means no data to base decision on, so margin will never come down, and you would wait for months with no broadband

What will happen is if the number of errors and resyncs is within a low figure then after two weeks the target margin is lowered by 3dB. If you are sure that work has stabilised a line, an ISP can bypass this wait, by reseting the target noise margin. Majority of support staff have no clue what this is

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
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