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Standard User Nitro93
(regular) Tue 25-Sep-18 18:45:47
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FTTC after powercut


[link to this post]
 
Hey all,

So after a port change about 5 months ago my BT FTTC connection was cruising along happily at a solid 76mbps and an attainable of 77mbps and never left this region at all during this time.

Until the last few days where we've had a string of power cuts which looks like it has now activated DLM (fun). When i turned the juice back on at the trip switch it synced to an even higher 77mbps which was lovely, although I knew this wouldn't last. I've come home from work and it's now dropped down to 65mbps - not a major loss, but if another powercut happens I fear the speeds are going to suffer significantly.

What bothers me is that the attainable has now dropped to 66mbps on a 2.9 noise margin.
Has this done permanent damage? What time lengths if at all can I expect this to return back to how it was?

Cheers!
Standard User iwish
(committed) Wed 26-Sep-18 01:06:06
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Re: FTTC after powercut


[re: Nitro93] [link to this post]
 
wait a few days then do a restart just before 12pm. a would give it as long as your willing to wait
Standard User WilliamGrimsley
(experienced) Fri 28-Sep-18 14:20:14
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Re: FTTC after powercut


[re: Nitro93] [link to this post]
 
Can you post detailed line stats? If the attainable is lower than the actual, then it's likely that the lower noise margin is due to crosstalk.

William Grimsley.


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Standard User Nitro93
(regular) Sat 29-Sep-18 12:09:32
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Re: FTTC after powercut


[re: WilliamGrimsley] [link to this post]
 
Yeah sure - screenshot below
https://ibb.co/bZbdUK

We had another powercut last night, so I've hooked the hub up to a UPS now to prevent any further damage to sync.

Before these series of about 5 powercuts over the course of this week, the max attainable was circa 77500 - 78000

Before it dropped to this, it spiked to 78Mbps and then reset itself Tuesday afternoon to what it is now

The sync data rate was between 75Mbps and 76Mbps so we've lost about 10 Mbps in sync speed.
The noise margin at the time was 2.9 - 3 on the downlink and line attenuation has always remained constant.

DLM potentially?

Edited by Nitro93 (Sat 29-Sep-18 12:23:50)

Standard User WilliamGrimsley
(experienced) Sat 29-Sep-18 12:46:20
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Re: FTTC after powercut


[re: Nitro93] [link to this post]
 
It looks like DLM has dropped the DS target SNRm to 3dB, as the DS attainable rate is higher than the actual rate. Have you got a third party router lying around that can provide more detailed stats?

William Grimsley.

Edited by WilliamGrimsley (Sat 29-Sep-18 13:04:02)

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