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[shmertmoans]

Hi,

First off, thanks to kitz for a great site ive used it quite a fait bit over the last few months.

Anyway heres my story.

I have been having problems with my sync droppin then reconnecting straight away(30secs or so)..no good for gaming

It was intermitting and could be stable for a day or so or disconnect as much as 4 times in an hr.

I was using a ZyXel P-660HW-T1 and it was syning at 2600kbps -3000kbps with theses line stats-

Downstream stats-

noise margin downstream: 6 db
output power upstream: 18 db
attenuation downstream: 61 db

upstream stats-

noise margin upstream: 19 db
output power downstream: 12 db
attenuation upstream: 31 db

From what i read i did think it was snycing too fast but as i have no control over this, i couldnt experiment.



Anyway, i spoke with my service provider and they asked bt to do some snr profile changes....things have been better but it still was dropping every day/second day....I was fairly pleased with this improvment but tbh i want it stable for longer than this..

So after reading this site and some others i found that people were recommending the netgear DG834G router as one that would maitain a stable connection on crappy lines.

Ive just set it up and i am now on the net but after checking the stats on my line now it has synced a great deal slower..heres my new stats-

ADSL Link                 Downstream              Upstream
Connection Speed      1024 kbps          448 kbps
Line Attenuation      61.0 db                 31.5 db
Noise Margin              16.8 db                  18.0 db

As you can see it has synced alot slower than the zyxel router (which should help my line stay stable i recon) but why is this??

Is this router making a "better connection for my poor line" or is ther a setting on the netgear i may dont know about.

[roseway]

Hi and welcome.

What seems to have happened is that the automatic DLM process in the exchange has determined that your line is unstable, and has increased the target noise margin to stabilise it. This results in a more stable, but lower speed, connection. With a line as long as yours (61 dB downstream attenuation) that may be the best option. I imagine that if you were to put the Zyxel back its stats would now be similar.

Just to confirm that this is the case, you could check the router stats immediately after a re-sync. If the downstream noise margin is in the region of 15 dB at that time, then this would confirm the point.

With a long line like yours, you're always going to be a bit on the edge, so the most useful thing you can do is make sure that your own internal telephone wiring is as perfect as you can make it. There are some tips here.

[shmertmoans]

Thanks,

I've had this problem for a while though so why wouldnt the dlm process have dropped the speed before??. Every time it re-sync's it has been @ 2600-2700kbps (for a good few months) lol

Just before i changed router to netgear one the zyxel had been up for 45hrs(longest in months) @ 2700kbps. Then i swap it and straight away netgear is 1024kpbs.

 I changed 1 setting on netgear(DSL MODE) to ADSL(G.DMT), it had been AUTO (Muliti-mode before)  and i now get 1312 kbps.

I will check zyxel one again later ...im going to leave this one in and see how long it works at this speed.

Thanks again

btw- thanks for the tips/link but ive already did this...

[soms]

By the looks of your post the change in margin could be a change by the Dynamic Line Management taking drastic action or BT manually changing the SNR margin at the request of your ISP.

In theory the target noise margin will be dropped and the sync rate improve if the line remains stable for a period of time. As roseway suggested, look at the advice on the website for improving your lines performance.

If you have already optimised your internal configuration, think about any potential sources of interference which might be causing your problems. In the majority of cases a line will not want to resync 4 times in an hour with a 6dB noise margin without some obvious cause of interference.

As for the routers, the DG834 is one of the most stable available and will hold sync well as the noise margin varies throughout the day. The line performance with the Netgear is governed by the exchange and if you reconnect the Zyxel, you might find the stats even worse depending on how well they perform in DSL terms.

[shmertmoans]

thanks alot.

Yes i think bt (at request from service provider) have changed my SNR margin on downstream just at weekend. This must be it taking effect now.

Ill leave new router on and hopefully ill stay up forever(ish). Ive also put routerstats on to monitor the situation.

When you say it will "drop the target SNR and sync rate should improve if the line remains stable for a period of time"..what sort of time frame? Ive read elsewhere 3days.

[roseway]

No, the three days refers to something else - the period which it takes for an IP profile to be raised after getting a higher connection speed. In fact this period is now anything between 4 hours and 5 days, depending on how big the change is (big changes happen more quickly).

The progressive reduction in target noise margin takes longer, and the process doesn't seem to be well documented. As far as I know, the target should be reduced by 3 dB after 14 days of stability, then another 14 days for the next 3 dB, and so on.

[shmertmoans]

Thanks alot.

I'll leave my router connected for at least the next 2 weeks(provided it dont disconnect itself). Hopefully the speed will increase after this.

Should the target noise margin change whilst connected or will it need a re-boot/reconnect to show this reduction in the routers stats? why i want to know is so that i could check the stats to see if they change without having to dissconnet. I could wait till it shows a 3db reduction then try a reboot if this was the case.

[Ezzer]

As youv'e changed routers, one point worth loking at, are you using the same lead from the microfilter to the router ? If your using the new one for the new router is it still coiled up or sitting predominately around other transformers/mains cables.

This usualy dosn't make any difference but some times you may be picking up some noise via this lead because in a typical set up this may be clumped togeter with other transformers mear the mains supply.

Also a lot of people will coil any spare cable up to keep things tidy. Avoid doing this with the dsl lead from the filter to your router/modem (also the same with any data cables such as the ethernet cable). Best practice lay this cable out as long as you can, maby back & forth a couple of times, away frombeing directly by any transformers and not running parallel within 50mm of any mains/power cable if you can.

 Also some times it may be wrth trying to move the cable/router modem away from any plumbing/ pipe work in case this makes a difference. sometimes if something electrical is dumping current back doem the earth, then this can be retransmitted via metal plumbing.

As I said this isn't very typical but might be worth trying, it's a nice easy fix when trying the above youy suddenly find, Hello my stats/sync have improved.

[shmertmoans]

As youv'e changed routers, one point worth loking at, are you using the same lead from the microfilter to the router ? If your using the new one for the new router is it still coiled up or sitting predominately around other transformers/mains cables.

This usualy dosn't make any difference but some times you may be picking up some noise via this lead because in a typical set up this may be clumped togeter with other transformers mear the mains supply.

Also a lot of people will coil any spare cable up to keep things tidy. Avoid doing this with the dsl lead from the filter to your router/modem (also the same with any data cables such as the ethernet cable). Best practice lay this cable out as long as you can, maby back & forth a couple of times, away frombeing directly by any transformers and not running parallel within 50mm of any mains/power cable if you can.

 Also some times it may be wrth trying to move the cable/router modem away from any plumbing/ pipe work in case this makes a difference. sometimes if something electrical is dumping current back doem the earth, then this can be retransmitted via metal plumbing.

As I said this isn't very typical but might be worth trying, it's a nice easy fix when trying the above youy suddenly find, Hello my stats/sync have improved.

thanks for reply..


yes im now using the new cable and filter but they are totally uncoiled and are running the same way to socket as before-(well away from mains cables, plumbing etc and oly 1m long or so)..ive ordered a new screened rj11 anyway so will swap it asap.


think its more likely that is due to bt changing my SNR margin from 6db up to 16.8db....

hopefully this will retrain and ill get a little more speed but still maintain a stable line.......maybe i need a bit more than 6db but i doubt i need as much as 16.8db(neva know tho)


saw that i could get firmware(not official netgear tho) that you can frig this value to get more...may try this after a few months or "retraining"

[shmertmoans]

after day 1 of new netgear with router stats i got these results from 4 am to 7am it was like this..... at all the other times of the day it was reasonably flat at around 16db and no drop in speed.

the router has not disconnected at all(good) but on the graph it shows a drop in speed(see pic)

Any help appreciated

Also- what is the most likely place this noise is getting picked up on - the rj11 cable from router to wall or the bt line comin into my house picking up streetlights etc. I will be trying a screened rj11 cable shorlty so that should eliminate the rj11 from the problem surely.

All i can think that switches on around this time is my white meter heaters and hot water tank(12-7am) but the closest heater is about 6 meters away from router and cable and water tank is other side of house.

[attachment deleted by admin]

[roseway]

You've got several fairly devastating noise spikes over a short period, and switching of heaters and similar things are the most likely suspects. This sort of interference can be conducted over the mains wiring, which seems quite likely in view of the physical distances you mention. If it weren't the middle of winter I would suggest that you switch off the heating for 24 hours and see what happens, but I don't expect you want to do that.

Unless anyone has got any better ideas, I think you may have to think about using mains suppressors, or even running your router from a UPS, to keep the noise spikes out.

[kitz]

As eric says - looks like some serious noise spikes thats taking your connection out.

Whats the SNRM like during the rest of the day? ...  or is it just 4am ish?

[shmertmoans]

You've got several fairly devastating noise spikes over a short period, and switching of heaters and similar things are the most likely suspects. This sort of interference can be conducted over the mains wiring, which seems quite likely in view of the physical distances you mention. If it weren't the middle of winter I would suggest that you switch off the heating for 24 hours and see what happens, but I don't expect you want to do that.

Unless anyone has got any better ideas, I think you may have to think about using mains suppressors, or even running your router from a UPS, to keep the noise spikes out.

thanks for reply.

Say it is caused by spikes on my mains wiring, is this coimg through the power adaptor for router and onto adsl line?

I will try leaving the heating(white meter) off tonight. I can use an electric fire later i to heat the place..

If it is this i will try a mains suppressor as well as the screened rj11 ive ordered.

[shmertmoans]

As eric says - looks like some serious noise spikes thats taking your connection out.

Whats the SNRM like during the rest of the day? ...  or is it just 4am ish?

the graphs for the rest of the day are a failry straight line @ about 16dB. this was just earlier and were like this apart from a few hrs i metioned (4am-7am)

[attachment deleted by admin]

[kitz]

>>> Say it is caused by spikes on my mains wiring, is this coimg through the power adaptor for router and onto adsl line?

The problem with REIN faults is that it can come from various sources..  it may not even be something in your own home.  Theres a list on that page of typical culprits (kindly provided by Ezzer)... but that list is by no means exhaustive :/