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Drop of SNR in working hours

w23
Pro
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Registered: ‎08-01-2008

Re: Drop of SNR in working hours

I can pick up a distinctive pulsing hum on the car radio (tuned to 612 AM) when on my driveway a few feet from the pavement, I'll check if this disappears when the margin returns to normal.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
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spraxyt
Resting Legend
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Registered: ‎06-04-2007

Re: Drop of SNR in working hours

The bitswap vs tone number plot shows significant activity across much of the upper half of the frequency range, no pointer to a specific frequency. I guess that suggests the cause is something electronically noisy that shouldn't be. For reference tone 142 is at 612kHz.
What does the bitswaps vs time plot look like? That's the one on the third tab. In my case that shows mainly 0 or 1 during daylight hours, rising to 10-15 after dark when lights and electrical things are on in our neighbourhood. Successive samples form a solid blue plot then.
Does your phone line run on poles or underground? Not sure if that makes any difference.
David
carrot63
Grafter
Posts: 599
Registered: ‎12-07-2007

Re: Drop of SNR in working hours

Quote from: spraxyt
I guess that suggests the cause is something electronically noisy that shouldn't be.

The engineer who made the best inroads on my issue said the major cause he encountered was either faulty earthing or (more likely these days) cheap asian made TVs etc that were not earthed at all when they should be. BTs Comtrend made Homeplug units are also notorious for interference, as are neon strips with starters that are reaching their sell by and Sky boxes.
If possible, you should try to run routerstats 24/7, and take a careful note of the start/finish times/days and any multiple occurrences in a day. It might help you to nail the source to domestic/industrial/retail premises nearby, depending on the makeup of the area you live in, and it might help convince BT there is an issue if it gets that far with the faults team.
If it perseveres, at some point you should try shutting down every electrical device in your own property and check if there's still a pulsing noise on the radio (assuming that does correlate to the times the SNR drops). It's surprising how many things around the home have internal cycles or timers, although in all probability, if the timing doesn't ring a bell, its nothing to do with you.
Edit: added Sky box
w23
Pro
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Re: Drop of SNR in working hours

Web very slow today but I managed to run the BT Speedtester.  NOT a very good result .
[EDIT] My Broadband Speed - History for this morning showing decline in performance added.
Call me 'w23'
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jojopillo
Plusnet Alumni (retired)
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Re: Drop of SNR in working hours

HI walker23,
I'm still waiting for the email response. I'll keep you posted.
Jojo Smiley
w23
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Re: Drop of SNR in working hours

Had no problems Thusrday (10 Mar) but back to the usual tricks on Friday.
Somehow lost my bitloading information on Routerstats so I can only report observations from when it was working OK - During the day when the line is 'clear' there are very few bitswaps (the odd 1 or 2 in some minutes, usually none) but when the line problem occurs this rises to an average of 50 per minute.
I did set Routerstats to monitor CRC errors as a User-Defined plot, this has proved very interesting as the rate of CRC errors is quite steady when the line is good and suddenly increases to a much higher (but still steady) rate when the line problem occurs (roughly 1,440,000 in just under 7 hours or about 340 per minute) the graph shows this very clearly.
The bitloading (when it was working) shows a distinctly different pattern between 'line good' and 'line bad' conditions, when the problem occurs there is a drop across tones 210 to 280 with a corresponding increase in lower (and higher) tones - even using the previously unused tones 339 to 343.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
amcclean
Rising Star
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Registered: ‎30-07-2007

Re: Drop of SNR in working hours

I have been having issue for the past two weeks which sound pretty similar. SNR is normally 3 and above, sync in the 7000 plus but SNR has suddenly gone down to 0.5 and access to the net has become impossible. My line has remained sync'd to the exchange throughout.
I have tried two routers and 3 filters, no ring wire all in the test socket. It can happen at anytime of day. both routers are adsl 2+ listed.
PN are sending me out a test router. Walker23  I have checked and we are not on the same exchange it's just that we have similar symptoms.
Not sure when I should receive any contact from PN.
w23
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Re: Drop of SNR in working hours

@ podman,
I have a BT engineer coming tomorrow morning to investigate, I just hope the problem manifests itsself at the time, at least mine is fairly predictable regarding time of day, just it doesn't happen every working day.
I'll let you know if there's any useful outcome.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
amcclean
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Re: Drop of SNR in working hours

@ walker
I keep updating pn via the ticket with screen captures and phone calls it turns out each update may be knocking my ticket to the back of the que so I don't know when I'll get a resolution. called tonight to find out faults stop at 9pm so another call wasted.
will keep an eye out for your resolution too.
w23
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Re: Drop of SNR in working hours

BT Engineer has been, he confessed he was not a broadband expert and was only there to test the line (the line passed his 'insertion loss' test, he fitted a new linebox (master socket) 'just in case') and  about 1/2 hour after he left my telephone and broadband were reconnected, as of 11:00, no problems so far today.
I await the inevitable drop in SNR margin when it next decides to happen.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
orbrey
Plusnet Alumni (retired)
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Posts: 10,540
Registered: ‎18-07-2007

Re: Drop of SNR in working hours

Glad to hear that it's working, I hope it stays up for you Smiley As ever please let us know if not and we'll refer it back for further investigation.
w23
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Re: Drop of SNR in working hours

Back to usual problems as of about 10:00 this morning  Sad
Ticket updated acordingly but unable to attach a routerstats capture on the ticket (on each of 3 attempts it said attached file was invalid), I assume this may be because of the terrible line performance.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
w23
Pro
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Re: Drop of SNR in working hours

Captures attached (hopefully)
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
orbrey
Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 10,540
Registered: ‎18-07-2007

Re: Drop of SNR in working hours

Hi walker23,
I can see the SNR drop in the graph, but your connection's been live for over 24 hours now at a profile of 6000 so it shouldn't be making a difference to your service. If it is please advise what you're seeing when it happens?
w23
Pro
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Registered: ‎08-01-2008

Re: Drop of SNR in working hours

Hi Matt,
the problem has never been anything to do with disconnections, I think this issue has only caused one or perhaps two disconnections over that past weeks, almost all disconnections have been me tryting to resolve the problem (the last ones were probably the BT Engineer).
The issue is, when the SNRM drope and CRCs fly up webpages (like this one just now) take ages to load and the internet becomes almost unusable (certainly if I'm trying to work from home).
I'm guessing that the high CRC rate means a lot of re-transmitted data to actually get things through causing a massive slow-down.
I hope the re-transmissions don't count as part of my useage  Grin
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.