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Sync speed variations.... WHAT CAN I DO?!?!?!?

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Sync speed variations.... WHAT CAN I DO?!?!?!?

Hi,

This problem has been going on for months and months and I really don't know what to do!

I have reduced my home telephone service to a single master socket in the loft (lucky we have a cordless phone with a spare charger unit) where the wires come in from BT, this master socket has the faceplate replaced with an ADSL filter.

During the day (When PlusNet and BT are at work) I get a sync speed and noise of an acceptable >3200 and >12db.... In the evening this drops to <2200 and <negative-3db.... Thus my ADSL max never gets above 2megs.

Given that the wire comes into the loft and immediately gets converted at my NetGear Router. I know it is NOT my phone wiring - cos there is none!

At an earlier complaint BT found the wire from the pole to my house was dodgy (worn through to wire) so replaced this giving moderate improvement.

So what can I do? What is causing the noise in the evening? Is this normal? Short of vandalising all the wires between my house and the exchange, how do I get BT/PlusNet to troubleshoot?

I know this sort of question bounces around frequently (a number of times from me) but I've yet to understand what is a 'normal' variation in quality. If a variation of 1.5 megs sync and 15 db snr is 'normal' for my distance from the exchange, I'll just keep quiet and not mention the problem again!

Do BT have any plans to improve the lines to people who don't live next door to the exchange? Will I ever see speeds >2megs?

Thanks

Andy
29 REPLIES
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

Are you using a Netgear DG834?
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Sync speed variations.... WHAT CAN I DO?!?!?!?

Yes - DG834G

At my old house (closer to the SAME exchange) with PlusNet I was getting 4megs plus using this same router
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

There's a known bug with fluctuating SNR on those routers. Netgear have just released a new version of firmware which may help your issue.
N/A

Sync speed variations.... WHAT CAN I DO?!?!?!?

I recently upgraded the firmware - hoping it would fix the issue - its currently running V3.01.31....

This seems to be the latest version according to the Netgear web site... Do you know if there is a more recent upgrade?

http://kbserver.netgear.com/products/DG834Gv2.asp

This upgrade seemed to make no difference apart from the version number :-) on the start screen.

Andy
Community Veteran
Posts: 3,364
Thanks: 15
Registered: 06-04-2007

Re: Sync speed variations.... WHAT CAN I DO?!?!?!?

Quote

So what can I do? What is causing the noise in the evening? Is this normal? Short of vandalising all the wires between my house and the exchange, how do I get BT/PlusNet to troubleshoot?


The bad news is it is possible you can do very little about this. This is the downisde of trying to get 'the most' from your phone line.

The sources of noise are electrical interference in the 1 to 4MHz range.

You could try walking the whole length of your phone line from house to exchange and carry with your an old AM radio tuned midrange ... it may well inidcate when you are close to the noise source.

What are your line statistics (attenuation and noise margin values) like if you compare your old home with the new home?

SW.
--
3Mb FTTC
https://portal.plus.net/my.html?action=data_transfer_speed
N/A

Sync speed variations.... WHAT CAN I DO?!?!?!?

Hi,

I never really looked at the stats on my old line because I was happy with the speed I was getting.

My current stats (as of 30 seconds ago) are:

ADSL Link Downstream Upstream
Connection Speed 3200 kbps 448 kbps
Line Attenuation 45 db 13 db
Noise Margin 15 db 24 db

I would be quite happy if these were the 'normal' stats....

The line that BT replaced was not a detectable source of noise as such, just when it rained and got the bare wire wet and I guess the wet on the pole acted as an aerial for normal background noise. How many more bare wires are there between my home and the exchange?

Cheers

Andy
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

I have a simular problem, that I have been monitoring from the last 6 days.

My s/n margin falls from to 6dB at about 23:30 and returns to 12dB at 06:00

I am just waiting for a full week, and I will publish the MRTG graphs that I have been creating.

If you have linux and know what MRTG is then I can let you have the scripts that I am using the graph my s/n margin.
(For Netgear DG834)


Chilly
holdtight
Grafter
Posts: 1,634
Registered: 15-06-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

Quote
My s/n margin falls from to 6dB at about 23:30 and returns to 12dB at 06:00

Very interesting chilly as ive been seeing similar fluctuations and have also been monitoring since my stable rate dropped from 8000 to 7000 overnight

It will be interesting to see your results after a week


Bill.
Snarf
Grafter
Posts: 340
Thanks: 4
Registered: 04-08-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

How recently was the Netgear update released? I have one on order and I'm collecting it on Wednesday - seems like the first thing I'll have to do is update the firmware!
holdtight
Grafter
Posts: 1,634
Registered: 15-06-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

The latest firmware upgrade for the netgear DG834 can be found Here and is version 3.01.31 up from version 3.01.25


Bill.
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

OK, here is a preview;

Daily Graph


Weekly Graph


Note that the dB scale is x10 so 120.0 = 12dB

Chilly
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

Quote

The line that BT replaced was not a detectable source of noise as such, just when it rained and got the bare wire wet and I guess the wet on the pole acted as an aerial for normal background noise. How many more bare wires are there between my home and the exchange?


Could be a number, just needs one to be exposed and getting waterlogged or a loop creating with the other copper wire or another line to cause problems.

Then again it could just be something that happens in an evening, atmospherics and street lights and things like that will mean that most people will see a lower SNR in the evening than the day. If the line also goes past an electricity sub station or flood lights or something else that can cause interference this can easily cause problems.
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Sync speed variations.... WHAT CAN I DO?!?!?!?

A certain amount of mains hum is audible on the hi-fi from TV link if you listen carefully at full volume, this is accepted noise, if it gets loud you fiddle with the connections, check the earthing etc....

With ADSL I don't know what is 'acceptable' noise... I don't know if this noise in the evening is a 'normal' drop for an evening given my distance from the exchange, the number of substations/floodlights it passes etc. Or is this noise an indication of a line fault?

My SNR drops from as high as 16 during the day to as low as negative in the evening.... My sync speed drops from as high as 3.5 megs to as low as 1.5megs on a bad evening.... Is this considered acceptable/normal for an ADSL line that's a few miles long or should BT to do the ADSL equivalent of fiddling with the scart connector?

Andy
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Sync speed variations.... WHAT CAN I DO?!?!?!?

That kind of drop is unusual but not unknown for a Max line, there's clearly something causing interference on the line. The longer the line the more chances of something causing a problem.

The two main things that BT can do are increase the target SNR and apply interleaving, although it looks like this has already been done. There may be a line fault and I see no reason why it can't be looked into. So long as you've checked everything your side raise it via the Fault Checker under Connection Settings on the left and we can look into it and run some remote tests.