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Standard User FarmerGilesUK
(regular) Wed 13-Apr-11 23:21:37
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Poor SNR Margin even with better router.


[link to this post]
 
We'll I swapped out my neighbour's BT HomeHub v1.5 for a 2wire Business Hub this evening and it was rather disappointing tbh. Router synced at 894kbps (to be expected given the unstable state of the DSL recently) but the 2wire's stats showed the SNR Margin as 5/6db. We monitored the stats for a couple of hours and saw about 3000 FEC errors and 250 CRCs. I'm no expert at interpreting these results but it seemed to me that with a sync of 894kbps the SNR margin should be higher if the line were good. Line attenuation was 63dB. By the way, the BT Homehub was retraining every 30 mins or so.

I checked all their internal wiring and it all looked OK but they have two extensions other than the BT master socket, with the router plugged in one of the extensions (not ideal) as there is no power near the master socket. They've used a star topology for their extension wiring with a link from the faceplate of the master to a junction box and then going out to the two extensions. The good news is that both extensions are fairly close to the master.

I removed the ring wire and replaced all the filters with new ADSL Nation devices. Only two devices plugged in - Router and a DECT phone (nothing in the master socket).

They are going to monitor the stats for a few days to see how it looks in terms of resyncs, FEC/CRCs etc.

Maybe time for a visit from a BT Broadband Boost engineer?

Regards all
Standard User iwish
(committed) Thu 14-Apr-11 00:19:51
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Re: Poor SNR Margin even with better router.


[re: FarmerGilesUK] [link to this post]
 
Run a power extension up to the master socket and test from behind the face plate
Standard User MHC
(legend) Thu 14-Apr-11 09:08:15
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Re: Poor SNR Margin even with better router.


[re: FarmerGilesUK] [link to this post]
 
63 dB - or maybe a lot more. Most modems will only report downstream attenuation to a maximum of 63 or 63.5 dB and upstream attenuation to 31 or 31.5 dB.

The 2wire gives a graphical display of the bin loading - can you get a snapshot of that? And the FULL stats from the 2wire?





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M H C


taurus excreta cerebrum vincit


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Standard User E7er
(knowledge is power) Thu 14-Apr-11 09:44:00
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Re: Poor SNR Margin even with better router.


[re: FarmerGilesUK] [link to this post]
 
In reply to a post by FarmerGilesUK:
We'll I swapped out my neighbour's BT HomeHub v1.5 for a 2wire Business Hub this evening and it was rather disappointing tbh. Router synced at 894kbps (to be expected given the unstable state of the DSL recently) but the 2wire's stats showed the SNR Margin as 5/6db. We monitored the stats for a couple of hours and saw about 3000 FEC errors and 250 CRCs. I'm no expert at interpreting these results but it seemed to me that with a sync of 894kbps the SNR margin should be higher if the line were good. Line attenuation was 63dB. By the way, the BT Homehub was retraining every 30 mins or so.

They are going to monitor the stats for a few days to see how it looks in terms of resyncs, FEC/CRCs etc.

Maybe time for a visit from a BT Broadband Boost engineer?

Regards all
Hi, with the 2Wire 2700HGV router, a mass of connection information at http://192.168.1.254/mdc

Orange (SMPF) LLU 20 Meg. Sync 11864 Kbps Downstream, 1157 Kbps Upstream.
3Com 3CRWDR101A-75 ADSL2/2+ wireless router
Netgear DGN1000 ADSL2+ wireless N 150 Router supplied by Orange
BT Business Hub 2Wire 2700HGV v2 ADSL2+ Dual SSID wireless Router
Standard User MHC
(legend) Thu 14-Apr-11 11:41:49
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Re: Poor SNR Margin even with better router.


[re: E7er] [link to this post]
 
In reply to a post by E7er:
Hi, with the 2Wire 2700HGV router, a mass of connection information at http://192.168.1.254/mdc



Only works on the V4 but not V6 though.





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M H C


taurus excreta cerebrum vincit
Standard User FarmerGilesUK
(regular) Thu 14-Apr-11 18:12:45
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Re: Poor SNR Margin even with better router.


[re: MHC] [link to this post]
 
Its a version 5.x and /mdc does work.

I am due for a progress report from the user tonight.

Regards
Standard User MHC
(legend) Thu 14-Apr-11 19:26:23
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Re: Poor SNR Margin even with better router.


[re: FarmerGilesUK] [link to this post]
 
The V5 uses a very similar UI to the V4 so I'm not surprised.


Don't forget to try and get full stats and if MDC gives anymore information - the real attenuation level.





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


M H C


taurus excreta cerebrum vincit
Standard User FarmerGilesUK
(regular) Thu 14-Apr-11 20:17:17
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Re: Poor SNR Margin even with better router.


[re: MHC] [link to this post]
 
No link drops and only a few more CRCs in 24 hours apparently. I am trying to get a screen dump of the full (mdc) statistics for you all to have a look at.

Thanks and regards
Standard User FarmerGilesUK
(regular) Fri 15-Apr-11 09:44:26
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Re: Poor SNR Margin even with better router.


[re: FarmerGilesUK] [link to this post]
 
Link retrained 12 times last night, even at 800kbps, so defo something up with the line. No apparent noise on BT quiet line test. User is going to report fault to BT.
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