Advice on improving my sync please (if at all)

[mouthrush]

I joined IDNet in Dec. No probs and love it. But I am concerned my sync speed could be better and wanted your experienced opinions!
Moved house, got BT phone connected. Called IDNet for broadband. Day 1 of connection going live I synced at approx 12Mb. Day 2 read approx 15Mb.  Next time I checked a few days later it was 6655kbps and has been that ever since. ROuter was turned off whilst at work on occasions. This is ADSL2+ enabled exchange.

Stats:-
Router : Netgear DG834v5 (firmware v1.6.01.34, ADSL firmware E.25.41.64 A)
Downstream connection 6655kbps
Upstream connection 1251kbps
Attenuation downstream 26db, upstream 10db
Noise Margin downstream 20db, upstream 6.5db

The router is currently plugged into the master socket (faceplate off, internal connection socket).
Swapped leads. Swapped filters. Turned off router for a day. Back on. Left it on for a few days. Moved it around the house. Turned wireless on/off on router (clutching at straws now).
Always at 6655kbps. Never changes.

I'm about 1km from exchange. I used to sync higher (7192) than that with same router when I lived further away on Max.
BT predicts 14mb connection for my location.  Speedtests show no probs on getting what I should get. I just would like to improve my sync. 
Is that bad SNR for ADSL2+ ?  Is that a typical sync in reality. Noisy BT line?
Hope you can help,
Andy

[DorsetBoy]

Your attenuation should mean a much better throughput, the 20db SNR is the issue, I would guess interleaving has switched on and limite your synch due to noise bursts.

[Gary]

Try to isolate what may be causing noise, make sure all your cables are shielded, not bell wire stuff, keep them away from Electrical power cables, make sure your bell wire is not connected as well, see the help section for how to do that. The v5 chipset is not great but trying another router may help, also avoid to many disconnections, it could be seen as an issue and increase your snr as well. Leave the router plugged in as much as possible.

[Steve]

You have placed on a banded profile by BT MSAN which is a tool used in adsl2+ to limit lines which have high error counts or show instability I.e resyncs. You need to see if you can source the noise your side of the master socket and then get yourself unbanded

Edit : manners sorry.

[Rik]

Hi and welcome to the forum, mouthrush.

You've done all the most obvious things already. Can you get your hands  on a MW, battery powered, radio? If so, de-tune it so you only have white noise, then use it to follow your phone wiring from where the cable enters the house to the router. If you hear an increase in volume of the white noise, that's interference that will be affecting the ADSL.

If that reveals nothing, can you borrow a spare router to try? As others have said, good screened cables are vital in a noisy environment.

[Simon]

[mouthrush]

Thankyou everyone for the prompt and detailed replies 

I should be able to borrow a router. *If* it was the router, would I see an immediate improvement in SNR? Or will it mean leaving it plugged in for a day, for example, before SNR drops back?  I ask so I know how long to request borrowing it for!

I havent replaced the small cable between router and socket yet - I shall source one of those.

Currently the faceplate is unscrewed from the master socket and the only thing plugged into the internal socket (via a filter) is the router. No phones attached. There is a mains plug socket within 15" of the master socket. I have a radio so I'll see what I can find. 

Thanks for taking the time to reply - I'll report back after tonight's tests,
Andy

[Ray]

 

[Steve]

I don't think you'll see any improvement in downstream sync until the banded profile has been removed, any increase in margin at the same sync is a sign that the interference has been reduced and conversely the opposite applies a decreased margin with the same sync means more interference.

[Rik]

As Steve says, in the first instance, you're looking for an increase in noise margin.

[mouthrush]

This evening I borrowed a router, modem cable and filter. Connected at master socket internal with nothing else connected, and configured - this router reported 22db. Left it for 20mins with no change.
Put my Netgear back - 20db.

Detuned portable MW radio. Most noise came when radio was held near NTE5 master socket and the BT junction box. Noisier than next to a mains socket. Noisiest cable was the modem cable from router to filter.
I took the cover off the small BT junction box next to the NTE5 box.  A mass of unused wires that were folded up sprung out (~12cm each). I carefully fanned them out to reveal the correct pair of wires connected at terminals. Their condition appeared fine. I glanced back at the router status to see the SNR was now 15.4db.  So pulling out the birdsnest gained 5db. I put them back and it went to 18db. I fanned them out - back to 15.5db. 
After much consideration I trimmed back the unused wires leaving ~3cm inside the little box and screwed on cover.
Its been fluctuating around 15.2 - 15.7db for the last hour.

I shall inspect the master socket tomorrow evening.  Is this getting nearer to a value that would allow a better sync?
Thanks again for taking the time to provide ideas,
Andy

[Steve]

Any of that nest of wires connected to terminals other than 2 and 5

[Lance]

If your snr went from to 20 to 15 at the same sync that is not a good thing. It means more noise is being picked up which reduces the margin.

[mouthrush]

No other connections to any other terminals in the small junction box. Spent a while staring at it, checking images online, double checking, photographed, etc.  Ran out of time last night to plug everything back into NTE5 as normal.
I checked the extension socket for the ringwire terminal - not connected. Will continue this evening.

Lance - are you saying my sync should dynamically change as/when the SNR changes?  Over the last month it has fluctuated between 15-20db. Sync has never changed from 6655. Is that a symptom of being "banded" (whatever that means)?

I remember at my last house on Max I had an SNR of about 8db.  I take it that SNR values are different for ADSL2+?

What number should I be aiming for?
Thanks,
Andy

[Lance]

Lance - are you saying my sync should dynamically change as/when the SNR changes?  Over the last month it has fluctuated between 15-20db. Sync has never changed from 6655. Is that a symptom of being "banded" (whatever that means)?

I remember at my last house on Max I had an SNR of about 8db.  I take it that SNR values are different for ADSL2+?

What number should I be aiming for?
Thanks,
Andy

The banding means that the BT line management has decided to prevent you from syncing any higher than the top of the band. Normally, your target snr is 6db (max and adsl2+) but if you acheive max sync then you will have margin to spare.

The target snr is what is aimed for when you first negotiate sync and will then fluctuate depending on noise. Sync does not dynamically change.

[Rik]

Hi Andy

A banded profile is a 'tool' BT introduced with ADSL2+ to, effectively, limit the maximum sync speed on an unstable line. While you are banded, you should see significantly higher noise margins than the default 6db. Note that the only figure of real use is that immediately after a resync, that establishes the baseline and it's the fluctuations from that which will give us a clue as to what is happening.

Noise margins haven't fundamentally changed with ADSL2+, though there is now an 'official' 3db target margin for good lines.

[mouthrush]

Lance and Rik - thankyou both for your explanantions and continued input. I appreciate your time in helping me understand the intricacies of broadband speed!
But I'm not there yet...
If I understand correctly, the Noise Margin number reported by the router (15.45db when last checked at bedtime) needs to become nearer 6db. However I'm not likely to see a value reported near 6db whilst I'm banded.  But if I make every effort to get that number towards 6db there is a likelihood that I trigger an automatic resync to a slightly higher sync speed (if I turn off router for 20min or more before starting it again).  Would a displayed noise margin of 12db trigger it? 13db?  I guess its more complex than that, but thats the only parameter I have a direct influence on.  Keen to understand though.
Then, if the new, slightly higher sync is not disconnected too much (your FAQs say 10 connections per hr)  then do BT automatically remove the banded profile after a few days of constant (router left on) stability?

Thanks,
Andy

[armadillo]

If I understand correctly, the Noise Margin number reported by the router (15.45db when last checked at bedtime) needs to become nearer 6db. However I'm not likely to see a value reported near 6db whilst I'm banded.  But if I make every effort to get that number towards 6db there is a likelihood that I trigger an automatic resync to a slightly higher sync speed (if I turn off router for 20min or more before starting it again).

No. You do not want to make every effort to reduce the reported noise margin from 15db to 6db. You want to make every effort to increase it to at least 18db. If you can hold it at 18db for a day or so and then resync, the resync will be at a higher speed with a noise margin close to, but slightly above, 15db. That is because your target noise margin (set by BT) is unaffected (stays at 15db).

Remember, increasing your noise margin without a resync means you have reduced your noise. You have to increase your noise margin at your existing sync speed if you ever want to resync at a higher speed.

The profile limits throughput but does not affect sync speed. Sync speed is determined by target noise margin and actual noise margin.

Sync speed then determines the profile in a fairly complex way. At a given stable sync speed, the profile will gradually increase in incremental steps but it will never be greater than the sync speed (subject to an occasional inexplicable anomaly in BT's mechanism).

[Steve]

A reminder of banded profiles used on adsl2+ , these limit the max sync obtainable and as far as I am aware there is no automatic removal, i.e find the fault if possible then ask for removal.

WBC banded line profile (rate kbps)
7168 - 14336
4864 - 9728
3328 - 6656
2272 - 4544
1472 - 3072
1152 - 2272
576 - 1152
288 - 576
160 - 288

[mouthrush]

Fantastic explanation Armadillo -  I will see if I can get the number to go up over the next few days and report back.
Thanks for the Profile list Steve. Here's hoping to increase my 6655.
Regards,
Andy

[Rik]

Support are going to re-start your training period, Andy. That will kill the banding, so try to keep the connection as permanent as possible, ie leave the router on 24/7. Running Routerstats would be useful.

http://www.vwlowen.co.uk/internet/files.htm
http://www.vwlowen.co.uk/moreinternet/files.htm

[mouthrush]

Thanks Rik - I'll ensure it stays on for the full 10 days.
Regards,
Andy

[Rik]

 

Let us know how it goes.

[mouthrush]

Fired up routerstats to keep an eye on things.
Had a quick look at graphs this morning before leaving the house. Syncing at steady 14383, noise fluctuating around 5.5 - 7db.
Total uptime 13hrs although looks like a reconnect 7hrs ago.

Another look tonight...
Andy

[Steve]

looking good if the margin is only fluctuating by 1.5dB