Mystery Problem...

At least it has BT Openreach and Sky beaten.....

I am barely1km from my local exchange on Sky LLU.
This is the actual distance by cable length.

4 weeks ago my Broadband stopped, with no synch.

After many weeks and much line checking and some new splices we now have Broadband, but despite the line being "clean" ( B.T comment) my stats are as follows:-

ADSL Link Downstream Upstream
Connection Speed 16027 kbps 765 kbps
Line Attenuation 21 db 8 db
Noise Margin 7 db 15 db

THe line attenuation on ADSL2 is only 21db, but the noise margin is only 7db at best.

Even on ADSL 1 I can only achieve 6440 download connect...
The line attenuation drops to 16db but I cannot achieve the full 8128 connect.

I have a filtered faceplate on my master socket.

BT Openreach have been out 3 times to my home, and can find no problems with the wiring inside or out to the pole. The drop cable was also replaced.

Any ideas why the maximum attainable synch is lower than I should be achieving?

The BT engineer has confirmed I am not on anything other than copper as far as he can tell.

One BT engineer did achieve just over 17mb with his router though.

5 netgear DG 934s have been tested to rule out a router problem.

Everyone is baffled.

Any thoughts anyone?

Edited by tempus (Thu 01-Apr-10 22:18:04)

Maybe you're too close to the exchange

I said 1 km not 1 meter!

In reply to a post by tempus:

At least it has BT Openreach and Sky beaten.....

I am barely1km from my local exchange on Sky LLU.
This is the actual distance by cable length.

4 weeks ago my Broadband stopped, with no synch.

After many weeks and much line checking and some new splices we now have Broadband, but despite the line being "clean" ( B.T comment) my stats are as follows:-

ADSL Link Downstream Upstream
Connection Speed 16027 kbps 765 kbps
Line Attenuation 21 db 8 db
Noise Margin 7 db 15 db

THe line attenuation on ADSL2 is only 21db, but the noise margin is only 7db at best.

16Mb. What's the problem?

Err...try re-reading it, maybe?

I didn't want fatuous replies, but maybe some intelligent reasoning as to why a line of this quality can't achieve what it should?

Otherwise, buying a car that is capable of 100mph which can only achieve 65mph would merit the same throw away response as yours....

THe line attenuation on ADSL2 is only 21db, but the noise margin is only 7db at best

What do you expect the noise margin to be and why?

In reply to a post by Apprentice:

THe line attenuation on ADSL2 is only 21db, but the noise margin is only 7db at best

What do you expect the noise margin to be and why?

It's more a case of what SKY and BT expect.

Obviously the line attenuation suggests the line is capable of more.
It is in reasonable condition, and is copper without any large chunks of aluminium, if any, en route.

The line should easily manage either 20mb on ADSL2, or very close anyway.
On g.dmt it should easily achieve 8mb.

It does neither.

The router is a netgear 934, and it is looking likely from some other forum postings that Sky may have compatibility problems with their own eqipment (lucent) and some netgears.

I have not yet been able to hear other people's experiences , particularly those on Sky Voice and Broadband, maybe those using the Sagem or even other makes?

So I am hoping for lucid, cogent experiences or possible explanations of what may be happening.

What was your sync rate and noise margin prior to your problems a few weeks back?

Downstream Upstream

16909 1139

Line Attenuation 20db 7db

Noise Margin 10db 8db

I suggest you beg, borrow, or steal some other makes and models of modems and see how they fare.

In reply to a post by john2007:

I suggest you beg, borrow, or steal some other makes and models of modems and see how they fare.

Thanks, I think that may be the next option!



Sky have so far sent me 4...yes 4 netgears, but no sagem.........

They feel it is the modem.

As they try and get their equipment working well, it seems that some new problems are appearing.

I know many would love the speeds I am getting, but having seen better, it is difficult to accept second best!

As BatBoy says, what is the problem? Who says it is not achieving what it should? If the SNR margin is 7 dB then there is nothing much there to change.

Why not tell us what you think is wrong or what the problem is.

You claim the line is in good condition - how do you know? Have you crawled through the ducts to inspect you pair all the way back to the exchange?

In reply to a post by MHC:

You claim the line is in good condition - how do you know? Have you crawled through the ducts to inspect you pair all the way back to the exchange?

I shall ignore your sarcasm for the moment.

I'd suggest you re-read what I had written.

I was expecting possibly some informed comment, as it is obvious both Sky and BT thought there were problems.

It is not purely my expectations!

Since I started this thread over the last two weeks BT Openreach have pinned down an intermittent line fault causing the target SNR, set at 7db,to drop due to intermittent bursts of noise causing the line to drop and re-sync lower than it should.

Work is in hand to check for the faulty splice (or whatever) and I will let anyone interested know the outcome.

So, turn off sarcasm mode next time and you may learn something

You have just proved yourself wrong - you stated there line is in good condition and then say there is a "splice fault" which means totally the opposite.

And it was not sarcasm, it was a legitimate question. You failed to explain why you thought there is a problem.

I can point to very short lines with a lot less than 20dB of attenuation and SNRs of 6dB and nothing that can be done.

No, I said BT said the line was clean.

Try reading my original post if you can...

"After many weeks and much line checking and some new splices we now have Broadband, but despite the line being "clean" ( B.T comment) my stats are as follows:-"

BT have now said this is not the case.

Anyway, I can't waste any more time playing semantics.

I suggest you read the dictionary definition of sarcasm.

I won't rise to the bait, but I will let anyone genuinely interested know the outcome, because it may help them with a similar problem, which is the whole point of this excellent forum!

Or do you think it's all about jibes and irony??