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Author Topic: REIN REIN, go to Spain...  (Read 19771 times)

Weaver

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Re: REIN REIN, go to Spain...
« Reply #15 on: May 27, 2018, 10:25:50 PM »

He loses the mains? Would it be worth getting your own mains supply checked? To see if there is voltage drop, ripple, noise spikes up the mains? Try putting in a UPS then mains filters after it?
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boozy

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Re: REIN REIN, go to Spain...
« Reply #16 on: May 28, 2018, 01:44:09 AM »

He was away tonight, but there are weird noises on 657kHz on the radio - pulsing alien noises, need to check when it seems clear of FECs.  I might convince him to get an UPS (cheaper option than me doing it;)).  Someone was trying to convince me about a device that gives a building a clean 220V and saves about 10% on electricity costs, I may want to have a talk about that (he was Facilities Manager in a shopping centre, so it may not be a consumer device... and I wasn't really paying attention at the time)

Pretty curious to see if he's banded or what his sync rate is, given he is about equidistant to me from the pole.  I was banded down to 32.4Mb with a bridge tap until recently.  Interestingly the BTW speed test reports the profile you are about to go to the day before it happens, although got it wrong on the day the DLM relented (reported 30Mb and it resynced to 40Mb).  The bridge tap only showed up when it was damp, looking like a wet joint (long, painful story - this is just the tail end and more obvious now that there only seems to be one pattern left).

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roseway

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Re: REIN REIN, go to Spain...
« Reply #17 on: May 28, 2018, 07:01:11 AM »

Quote
Someone was trying to convince me about a device that gives a building a clean 220V and saves about 10% on electricity costs,

I remember those devices being introduced with a great fanfare a couple of years ago. The company which developed them was grossly over-egging the pudding with claims for savings which simply couldn't be verified. It was all based on the assumption that a drop in voltage directly equated with a drop in power consumption. This ignored the effect of switch-mode power supplies on most electronic equipment, and thermostats on things like fridges and freezers. It also ignored human nature, whereby the lower brightness of electric lights would tend to be compensated by using bigger or more lamps.

Sorry, that's off-topic.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #18 on: May 28, 2018, 10:55:46 PM »

I'll avoid the power saver ;)

I'm not sure I'm getting anywhere.  Of the houses in the row (all 5) 4 have nothing on a timer, one has and it's controlled remotely (ecomony 7 heating or some such - but that won't be kicking in at 7).  One has frequent disconnections and has been considering phoning about it, one has no internet, one didn't know much about it (only streams) and another has just had a repair to get up to 40Mb/s from 19 on a 40Mb/s service.  They were still having problems but it seems better now... the line is now interleaved (20ms ping) and it seems slower to them than before (It might also be banded to 37.5 from the speed test at 34.5Mbs).  If his line is similar to mine, then a large SNR Margin didn't help.

Of the 4 business 2 have nothing on a timer - and the other two had the day off.

The problem is likely further from me - or down at the exchange (the cabinet is across the road from the exchange, although my line takes a 300m detour rather than cross the road (a friendly OR engineer was surprised by the line length and had a look).  There's nothing between the businesses and the exchange but fields, so it leaves quite a narrow area, if my timer theory is correct i.e. whatever is causing it is on a timer, given the regularity of it starting.

I think the only things I have found, using the radio, are a French radio station on 621kHz, a Czech? on 639kHz and more strange noises on 657kHz - I recorded a few seconds for posterity :)

I'll maybe see if any of the networks guys in work know anything about QLN, given the earlier thoughts it was dodgy.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #19 on: May 29, 2018, 10:17:42 AM »

Taking a step back.

The thing that annoys me is that VOIP is awful. According to the TBB quality ping a reasonable amount of packets are lost. According to the HG612 there’s not much loss.  Running pings from my end I’m not seeing much loss (certainly nowhere near TBB), but lots of variance .

So the one thing I can try is a different phone.  If it doesn’t work (I’ll try an iThing as at least they’re supported by all providers) then...  not sure.

The REIN and interleaving are irritating, but as @ejs said - it shouldn’t matter and likely doesn’t explain the problem with VOIP.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #20 on: May 30, 2018, 04:28:53 PM »

Much improved today after accidently pulling out the power lead and getting a few Mb slower sync (and less interleaving).  Only one noticeable glitch in 2 hours of calls.

Not sure what to make of the ping from TBB   :o



Edit: I've run speed tests and checked the stats - those numbers aren't right (the speed test gives close to max I could get given the profile).  Either the problem isn't my end or the Fritzbox has decided it's under a ddos (I can only see 1 setting and it's not to reply to ICMP at all).  I'll turn off the monitoring as it wasn't too bad before last night's resync, and turn it back on tomorrow.
« Last Edit: May 30, 2018, 10:36:33 PM by boozy »
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j0hn

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Re: REIN REIN, go to Spain...
« Reply #21 on: May 30, 2018, 04:36:03 PM »

Just wow. That's a shocking amount of packet loss.

That would need thousands of constant ES for the DSL link to be causing anywhere near that amount of packet loss. FEC's are errors that have been corrected so you can ignore them.
ATM I'm getting 100,000+ FEC/min and I'm not worried about it at all.

What router are you using and have you tried another 1?
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boozy

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Re: REIN REIN, go to Spain...
« Reply #22 on: May 30, 2018, 04:54:47 PM »

I'm not seeing that - there have been just over 100 Error Seconds today and 10 CRCs per hour according to DSLStats.  I'm seeing a fair bit of improvement  :lol:

If I ping TBB:

Ping statistics for 80.249.99.164:
    Packets: Sent = 100, Received = 100, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 21ms, Maximum = 57ms, Average = 24ms


Confused seems to be the correct description.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #23 on: June 01, 2018, 06:41:53 PM »

The Quality stats are now working (the ISP had a trace on too which was causing the modem to not respond) and it's showing clean.  I've checked all but one businesses, and nobody has anything on a timer - guess I surrender if there is nothing there.

A lightning shower has just been and gone and it's left me with a question.  Why was only downstream affected?  That seems wrong to me, but that's what the graphs show!  I caught the SNR margin per tone during a bolt, again - only the downstream seems affected.  Really curious about the reason.

Although from what my daughter said OR we're working in the cabinet (or possibly the All in One beside it), when the lightning started.
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burakkucat

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Re: REIN REIN, go to Spain...
« Reply #24 on: June 01, 2018, 08:32:08 PM »

I can't give you a definitive answer to your question but I will offer a comment . . .

Looking at the full 4096 sub-carriers of a profile 17a G.993.2 service we see, left to right, the frequency increasing in 4.3125 kHz increments. The bands, left to right, are US0, DS1, US1, DS2, US2, DS3.

In your "SNRMperbandDownstream-2018-06-01-15.54.34" plot we see a upward stepwise change at approximately 1455 hours which was preceded by a downward perturbation. Of the three DS bands, the one most significantly affected is DS3. The DS3 band relates to the highest frequencies of a profile 17a G.993.2 service.  :hmm:

In your "snr thunder" image we see that you captured what appears to be some "ringing" in the DS bands and that the xDSL link had dropped.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #25 on: June 01, 2018, 11:04:37 PM »

Thanks for that @burakkucat, although I have a particular reason for the question...  I've previously had weather related problems on the line where chunks of the SNR graph vanish suddenly.  I had thought it was fixed, slightly worried now.  If you look at the two following the thunder on reconnect and then the screenshot from Feb (the slightly darker lines are the minimum and maximum) - the jump seems similar.  Unsurprisingly in Feb I had multiple line drops per day and error seconds in the thousands.  I'm a bit concerned I'm going to have another winter talking to support watching the intermittent problem vanish as I get put through  ;D.  Sub Zero temperatures were a real problem, which aren't happening now.

You also commented on the QLN graph - when translated into the SNR graph I've seen the SNR per tone move (the sinuous part) by about a quarter of the wave in D3 (and smaller in D2 and 1), if that helps jog your memory.  I suspect that may have something to do with it, but no idea what it could be.
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burakkucat

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Re: REIN REIN, go to Spain...
« Reply #26 on: June 02, 2018, 12:02:54 AM »

Ah, yes. It was your circuit that was clearly showing an underlying sinusoid, towards the higher frequencies, in the Hlog QLN plot. Unfortunately I am unable to think of anything that would cause such an effect.

Hmm . . . I just typed that last sentence when I had a sudden thought. A number of years ago I performed a series of experiments which consisted of harvesting the data and creating the four snapshot plots (Bit Loading, SNR, QLN & Hlog v sub-carrier) from a circuit whose length (between VTU-C and VTU_R) was increased in 100 metre lengths, up to a maximum of 600 metres. I was using two reels of three pair, CW1308 specification, cable of length 100 metres. To achieve any length greater than 200 metres I was using more than one pair in any one cable. For the full 600 metres, all three pairs were in use . . . VTU-C, reel one blue pair, reel two blue pair, reel two orange pair, reel one orange pair, reel one green pair, reel two green pair, VTU-R. As the total circuit length was increased, so was the coupling between the pairs in the cables. A new term, SIXT (self-induced cross-talk), was proposed for the effect seen.

And now that I have typed that paragraph, I realise that the effect was similar to that seen with a bridged-tap and not an underlying sinusoid, as seen with your circuit.

[Edited to correct the punctuation and an incorrect statement.]
« Last Edit: June 02, 2018, 05:20:21 PM by burakkucat »
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Weaver

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Re: REIN REIN, go to Spain...
« Reply #27 on: June 02, 2018, 06:33:55 AM »

My maths is shaky after forty years, sounds a bit like a reflection, time-delayed. Is that possible?

See time shift at http://nptel.ac.in/courses/IIT-MADRAS/Principles_Of_Communication/pdf/Lecture05_FTProperties.pdf

It is possible to determine the length of the delay by looking at the period of the sinusoid in the frequency-domain, the spacing in frequency terms between peaks.

Is a bridged tap a source of reflections?
« Last Edit: June 02, 2018, 06:38:08 AM by Weaver »
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Weaver

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Re: REIN REIN, go to Spain...
« Reply #28 on: June 02, 2018, 06:53:55 AM »

Are there any phone line extensions in the property? I’m thinking about any ones that may not have filters on them, in case they might be a source of reflections.

I see what Burakkucat is referring to now, I think. What is the level of quantisation noise / rounding error, is it less than the 1dB level? I appreciate that it is not visible elsewhere. It is quite ‘blocky’ and not so easy to see absolutely clear periodicity, but I can definitely understand what Burakkucat is seeing.
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boozy

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Re: REIN REIN, go to Spain...
« Reply #29 on: June 02, 2018, 01:19:44 PM »

There is just one line in with a single filter, one phone and one modem...  Extension wiring was removed a long time ago.  A bridged tap was removed recently (orange wire, I think - I'll find out if someone thinks it's important) about 80m away, 80m long - an old second line to the house.  I suspect my line was Exchange Only at one point but now turns back on itself 3 times before reaching the cabinet - it goes through a number of caverns before it reaches it's destination, so there are more joints than you would normally expect, I think.  I'll have a look through the captured graphs, after the bridge tap was removed, and see if any show the sinusoid more clearly.

My Maths degree was 30 years ago and I didn't like Fourier Series then (and up to now I've never found a use for it), willing to have a look but I am totally unfamiliar with the domain i.e. I can do equations, but have no idea about the meaning (or I might have cleared that memory and need a few weeks to redo that module :)).
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