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SNR/Connection speed wobble.

jab1
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Registered: ‎24-02-2012

Re: SNR/Connection speed wobble.

For information, here are the graphs (Rx) since late evening yesterday to the last capture. As you observe, the longer trasients seem to have decreased markedly in number recently - coincidence or a result of NP's actions? - and the night-time levels seem to hold up well.

It would be good if I could get an SNRM reset, so long as it was fixed at 6dB minimum - anything less causes havoc - and see if the stability is maintained. 12 days with no significant actions is good!Rx_Noise_margin_(dB)-2019Sep07-2147.jpgRx_Noise_margin_(dB)-2019Sep08-0042.jpgRx_Noise_margin_(dB)-2019Sep08-0242.jpgRx_Noise_margin_(dB)-2019Sep08-0441.jpgRx_Noise_margin_(dB)-2019Sep08-0640.jpgRx_Noise_margin_(dB)-2019Sep08-0935.jpgRx_Noise_margin_(dB)-2019Sep08-1135.jpg

John
jab1
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Re: SNR/Connection speed wobble.

Tx GraphsTx_Noise_margin_(dB)-2019Sep07-2147.jpgTx_Noise_margin_(dB)-2019Sep08-0042.jpgTx_Noise_margin_(dB)-2019Sep08-0242.jpgRx_Noise_margin_(dB)-2019Sep08-0441.jpgTx_Noise_margin_(dB)-2019Sep08-0640.jpgRx_Noise_margin_(dB)-2019Sep08-0935.jpgRx_Noise_margin_(dB)-2019Sep08-1135.jpg

John
Superuser
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Re: SNR/Connection speed wobble.

Do one drop of each form, but a massive reduction in occurrence. It could be worth contacting the power co again and advise that things are much improved but there are still issues. Could they take another look at the installation?
jab1
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Re: SNR/Connection speed wobble.

I will ask, they can only say yes or no, and they do sound fairly willing.

John
jab1
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Re: SNR/Connection speed wobble.

@Townman The sub-station is due a major overhaul at the end of October, so they say no more sticking plaster at the moment - just hope we see some more improvement after that. :smiley:

@Gandalf I'm not aware of any drops since the last Plusnet intervention, but can you confirm please? I'd rather you didn't run any tests that may destabilise things at the moment, but is it possible to have a look at what is causing the 15dB level?

John
Plusnet Alumni (retired) Optimatts
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Re: SNR/Connection speed wobble.

Hi @jab1, your connections been solid for the last 27 days without interruption.

Unfortunately there isn't a way to determine the cause of your SNR being high as it's based on the DLM detecting a condition that then adjusts the margin.

I haven't ran any tests on the line and in theory it won't pick anything up other than the numbers we already know.

Realistically the only way we can get an understanding of what the cause is, would be to get an engineer to take a look.

 

I hope this helps.

If this post resolved your issue please click the 'This fixed my problem' button
 Matt L
 Plusnet Help Team
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Re: SNR/Connection speed wobble.

I think is fairly clear what and why...

Something is giving rise to a -12dB noise spike. At at SNRM of 15dB the line remains in sync through the spike.

The something is not identified, is probably not identifiable given the randomness of its occurrence. Given the marked change since the power co undertook remedial work and their intention to refurbish the site, I would suspect that the residual interference is coming from the sub station. I see little point in sending in BT engineers as I doubt they have the means of locating the issue even if its occurrence could be forecast.

Personally if I were in your shoes I’d watch out for work activity at the substation and monitor performance during and after the works.
jab1
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Re: SNR/Connection speed wobble.

@Optimatts Thanks - that is exactly the response I needed to confirm what I understood.

As @Townman says, there is no point in involving BT/OR until we see the effects (if any) of the sub-station work, but I will most likely be back after they have finished to see if we can reduce the SNRM safely and get back that little extra speed.

FYI, @Townman I am not monitoring between ~2200-~0700 as there seems little point at the moment.

John
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Re: SNR/Connection speed wobble.

I suggest that you need to continue to monitor 24x7 as you need to know what happens when … to be sure its gone when you look afterwards!!!

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jab1
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Re: SNR/Connection speed wobble.

OK, but there will be a 15 day gap from the middle of next week as I'm away and my second machine sadly broke earlier in the year.

John