Disconnects/Noise margin problems after dark

[#1]

Quote from: Anotherone

Anyway it's not a Target Noise Margin change that's required as ReedRichards has incorrectly implied...

I beg your pardon?

Quote from: Anotherone

In time it will drop the Target SNRM as well as long as things look stable enough and the error rate is low enough.

Agreed

[#2]

The main problem at the time Reed was the banded speed, as you clearly didn't read carefully  

[#3]

will you two stop arguing in public - please continue by PM

[#4]

@Anotherone
No real joy in seeing what the jumps on the SNRM graph are. It looks as though PN have updated the IP profile this morning though:
Estimated line speed:
    8Mb (This may vary between 6.5Mb and 9.5Mb) - Checked on 2012-11-30 13:57:55
Current line speed:
    9.4 Mb

[#5]

Good news with the Profile. Did you try that double filtering I suggested?

[#6]

It had honestly slipped my mind, however I have just done that so I'll leave it monitoring during the day to see if that has made any difference.
Unfortunately though I have to report having another resync last night, noise margin was ~8.6 at the time and it dropped the speed to 10331 on reconnect. Again this morning it resynced back up to 11148, I'm beginning to think I have a duff router that is incapable of dealing with any kind of noise on the line at all.

[#7]

I'd have expected something to show up on the SNRM graphs. Go to the Setup >Graphs tab in RSL and change the sample time to 8 seconds and 900 points per page. This will give 2hrs per graph and show much more detail. Don't forget you've got these two lengths on untwisted pair cable which maybe picking up stuff. A more detailed look at the SNRM plots may help come to some better conclusions.

[#8]

Well nothing much to show from double filtering the Sky boxes. There was a dip at about 9.30am and a recovery at about 10.45pm, between those two points it showed the usual pattern of steady during the daylight and a slow drop of ~1db as it got dark. However last night was stable with no resyncs.
As an aside looking at my router this morning it has a very large value for "CRC" (currently 21,000) which I noticed was only ~150 when I went to bed last night after actually using the internet quite heavily all evening without the slightest hitch. Could these be CRC errors and the router resyncs when it reaches a certain threshold? As I've been sitting here for about 30 minutes that value has gone up by about 5000, just as dawn is breaking. The only other thing happening in the house is the washing machine was finishing up a spin cycle at around the same time.
What the router is reporting:
Downstream        Upstream
SNR Margin : 10.2 6.0 db
Line Attenuation: 37.0 20.1 db
Data Rate : 11118 1079 kbps
Max Rate : 11816 1080 kbps
POWER        : 0.0        12.3 dbm
CRC        : 21054 0
EDIT: to add there was nothing going on downloading wise or whatever overnight, my useage 12pm - 8am was 11.69MB, most of which was forum reading this morning.

[#9]

The modem/router won't be resyncing when you get to a certain "total" threshold of errors per se, but if you get a sudden burst of noise that saturated the BB signal then you'd see a huge number of CRC errors as well. But if the SNRM goes to zero for long enough, then you'd get a resync.
I would try and monitor what's happening to noise levels and errors when your washing machine is in use in future, electric motors can generate loads of interference if the brushes are on the way out, or a dirty commutator, or lack of/failing suppression, or even the switching if contacts aren't making and breaking cleanly.
The dip at 0930 and off at 1045 pm, something obviously switched on for the day, possibly not in your house, but check for things like the sky box, TV, fluorescent lights (all types), low voltage halogen, even mains LED bulbs I've even heard can chuck out some noise - that's bad design if they do! * anything else you can think of that might be switched on for that sort of timescale, including computers and monitors.
Edit: don't forget to adjust the plotting to see if we can spot any noise spikes!

[#10]

Do the problems coincide with the street lights?

[#11]

@AlaricAdair no, not that, it happens well after dark.
@Anotherone the SNRM didn't ever approach zero that I could see, the connection just dropped out from ~8.6db. It's easy to tell when it is about to happen as everything just slows down to dial up speeds for a minute or so beforehand so when that happens I tend to switch over to RSL to watch it go.
I've got the plots adjusted as you suggested but I'm not really seeing anything different. Obviously I haven't had another event since then though, although it has been slowing up a bit tonight with the CRC count going crazy again so we might get "lucky". 8.5db now appears to be the new zero for me

[#12]

Update on tonight's observations - because I was getting a slowdown and apparently lots of CRC errors and actually wanted to use the internet I forced the issue and did disconnect/reconnect and since then in about 3 hours of solid online gaming it has been rock steady with the router reporting only 6 further errors and the SNRM is at 11.5. Before the resync I was getting a ton of CRC errors and everything was lagging badly. Is there a sensible explanation for that? The sync speed is down somewhat from the previous 11118 to 10117 if that helps.

[#13]

I assume the attenuation has remained constant and there's been no change in any of the upstream stats?
What was the DS SNRM exactly immediately before you did the resync? Seeing the graphs for all that may help.

[#14]

Upstream speed fluctuates slightly but remains reasonably constant. Attenuation downstream has been 37 since I did the rewiring.
Current stats:
Downstream     Upstream
SNR Margin : 11.4 6.0 db
Line Attenuation : 37.0 20.1 db
Data Rate : 10117 1072 kbps
Max Rate : 12548 1076 kbps
POWER : 0.0 12.3 dbm
CRC : 248 0
I've attached 2 graphs, one for when I did the manual resync which shows the SNRM pretty constant at about 8.5 as things were slowing down on Wednesday and a second which looks like it shows a dropout which happened during the day yesterday, although the connection speed looks to have remained the same after the event with that one. I wasn't using the internet at the time so I can't say whether or not there was any slowdown before this happened or not.

[#15]

What's bugging me a bit at the moment is how this SNRM got as low as ~8.5dB. The previous information seemed to indicate the Target was probably 12dB and after DLM unbanded the sync speed it's not so clear, it may have been 9dB briefly, but as you mentioned 11dB I didn't think much more about it. Without both SNRM and Sync speed graphs for that time it's difficult to come to a firm conclusion but from the SNRM graph when you did the manual resync it would appear to be (or have gone back to) 12dB. But the way the SNRM fairly quickly declined over the next 20/25 minutes suiggests something very odd going on especially in light of your comments about performance and errors just before this manual resync.
The sooner that you can positively eliminate any equipment as potential noise sources by doing some methodical checking, the better.
If you are able to try/borrow another modem/router just to check whether the symptoms are the same and eliminate that from the equation, that would be a good idea.