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[Bigmac77]

Hi, this is my first post here please be gentle with me. I'm having ongoing problems with my broadband, I won't go into a huge amount of detail or this will be a huge post but some detail is necessary so here goes.

I started with download speed problems (speed went down to 0.13Mbps) a few months ago, since then I have used the BT forum to contact the moderators and have had three engineers visit. The first fixed a HR fault, (things temporarily improved) the second replaced the line from the local distribution point to my house (again things temporarily improved) and the third put me onto a different pair all the way from the distribution point to the exchange. The last engineer has improved my broadband but it's still not 100%. My problem now is that my router will not hold sync for more than a day and everytime it re-syncs it keeps my profile lower than it should be. I've tried 2 BT Homehub 2's these performed the worst, dropping the connection many times a day. I've tried a 2Wire 2701, it performed quite well but the sync speed was the lowest and eventually it started loosing sync like the Homehub's. I am now trying a Netgear DG834G v3, it syncs well at nearly 4800 Kbps (my line has an attenuation of 52 dB) but looses sync around midnight. I also have a DG834G v4 but have not tried it yet.

Around 10pm everyday the noise margin drops to around zero.

Here is a graph from router stats, do I have a fault or is it something else?
I also have a shilded RJ45 cable running from a NTE-2005 faceplate from ADSL nation. Any ideas?

[Bigmac77]

Here is a graph up to 2230 hrs, the router resyncs after 2220.

[burakkucat]

Hello BigM and welcome to the Kitz forum. 

Ideally we would like to see at least a full 24 hours Routerstats graph to be able to see how your line's performance varies. The fact that the modem renegotiates sync when the SNRM has dropped to zero comes as no surprise.

What would be useful, if you could arrange to do it, would be to initiate a modem re-sync between 1000 - 1400 hours (i.e. in daylight) and as soon as the connection is established, take note of both of the DS & US SNRM, Sync speed and Attenuation values. Please do this as soon as the modem has resynchronised with the DSLAM/MSAN as that will be the only way we can deduce your current target SNRM.

As you probably appreciate, the SNRM can vary over the 24 hour period. During the hours of darkness, there can be significant RFI induced into the xDSL pair and, thus, the SNRM is depressed.

Finally, a few simple questions. To which exchange is your line connected?  To what broadband service are you subscribed?

[kitz]

Are those graphs more or less the same every day? - the following assumptions are made on the fact that they are:-


4800 is a good sync for 52db
Theres a lot of SNRM fluctuation but its still within what would be classed as normal variation by BT on a 52db line. 

It looks like it could be EMI and therefore needs a higher SNRM that 6dB to keep the line stable.
..  or you could try some investigative work to see if you can spot any sign of EMI/REIN.

Asking your ISP to increase your target SNRM will keep the line stable but you will loose a bit of sync speed.

.. or you could keep it sync'd as is it now..  and hopefully the SNR will increase tomorrow but if you ever sync that line before 9pm then it will likely drop again come later in the evenings..  at some point the DLM should kick in and auto increase the target SNRM anyhow.

>>> Around 10pm everyday the noise margin drops to around zero.... but looses sync around midnight.

What happened @ around 9.15? 
Does your street lights come on?

>>> Warning - while you were typing a new reply has been posted. You may wish to review your post.
B*cat beat me to it..  but still posting this anyhow.

[Bigmac77]

Thanks for the replies. Yes the graphs are pretty much the same every day. Everyday now for the last three weeks with all the routers I've tried the same pattern occurs. Between 8am and 11am the router will resync with the exchange at 4500 Kbps +/- 300 Kbps then it will hold stable until around 9:30 - 11:30 the router will resync again at lower speed and hold this over night until the process starts over again. I'm surprised I've not had my SNR increased to 9 dB but I'm sure my current target remains at 6 dB.

I live in a very rural area there are no street lights within a mile but there are some lights nearer to the exchange as its in the middle of the Amlwch which is a small town.

My exchange is Amlwch code WNAML and I'm on BT option 2.

[kitz]

>> Between 8am and 11am the router will resync with the exchange at 4500 Kbps

Can we see the graph at that time please...   
Is this resync automatic or manual..  if auto I find that a bit strange, normally with REIN, the additional noise will cease and the line will hold just showing an increase in SNRM.

>> no street lights within a mile

Streetlights was the first thing that came into my head because of the time.. but it could be anything in your home (or neighbours) that comes on at around that time each day.

>> I'm surprised I've not had my SNR increased to 9 dB but I'm sure my current target remains at 6 dB.

According from the info in the graph at around 22.25, it certainly looks like your Target SNR is 6dB atm, although how long that will last for Im not sure:(

[Bigmac77]

Once the routers are plugged in I don't touch them any resync is automatic, nothing in my house comes on around 9-10pm to make sure I turned everything off in my home at the switchboard (except the sockets that the router is plugged into) and it makes no difference. Where I live there are five other houses the nearest is currently being renovated/rebuilt and they've not got any power into the property yet, the others are a distance away form the phone line over 50 metres could they be emitting some set of REIN from that distance?

[kitz]

>> resync is automatic,

Thank you - would like to see what is happening to the SNRM at these times from the graph.


>> others are a distance away form the phone line over 50 metres could they be emitting some set of REIN from that distance
Its not impossible, we have seen cases where faulty tvs/sterios have knocked out a whole street.

Really do need to see a whole days graph now please to get a bigger picture.
(b*cat has already asked for those, so perhaps I shouldnt have jumped in too quick  )

[Bigmac77]

I'm currently gathering data will post back soon.

[burakkucat]

I'm currently gathering data will post back soon.

Thank you. We look forward to examining any graphs. 

[Bigmac77]

I switched over to the DG834g v4 that I had on Saturday just too see how it performed. I am amazed by the performance now, over a 24 hr period it has produced the graph below far more stable than anything I had seen before.

[Bigmac77]

Here is another graph from router stats. Any opinions on the condition of my line greatfully received.

[burakkucat]

I switched over to the DG834g v4 that I had on Saturday just too see how it performed. I am amazed by the performance now, over a 24 hr period it has produced the graph below far more stable than anything I had seen before.

Looking at that graph in isolation, I can see nothing to be concerned about. When using the DG834Gv4, it appears to be a very well behaved line. With regards to "hours of darkness" RFI and its effect on your SNRM, a swing of 2 dB is really quite good! 

[burakkucat]

Here is another graph from router stats. Any opinions on the condition of my line greatfully received.

Graphs of that type get me well confused, so I shall refrain from commenting. I have every confidence that A.N.Other will shortly be passing by and will offer up an analysis for our edification. 

[Bigmac77]

Thanks, I think it looks ok but as you say it is in isolation. What other graphs from routerstats are helpful in checking the quality of a line?