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Standard User Brib
(newbie) Wed 25-Oct-17 22:47:47
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Speed decrease


[link to this post]
 
Hi All,

I've had BT's increased profile and reduced SNR Margin from 6db to 3db, but have less sync currently than I had before October 1st. Has this happened to others?

Having been banded to 48998, margin 9.6 for about 9 months my sync increased to 54999, margin 6.8 at the end of July. I've seen max attainable speeds from 56000 to 60000 at different times.
So I had hopes of syncing higher, but this has not been the case.

Currently synced
1. Product Name: HomeHub5
2. Serial number:
3. Firmware version: v0.07.06.01239-BT (Type B) Last updated 3/3/2017
4. Board version: 01
5. VDSL uptime: 13 days, 14:30:07
6. Data Rate: 8120 / 53138
7. Maximum Data Rate: 8120 / 54608
8. Noise Margin: 6.1 / 3.5
9. Line Attenuation: 25.6 / 24.8

So have used 3db margin and I'm a little worse off.

Any suggestions as to why this might be please. Could it be the effects of crosstalk? Would the sync increasing on other nearby lines make it deteriorate more suddenly?

on the 1/10/17 I had this on my hub,

1.Product Name:HomeHub5
2.Serial number:
3.Firmware version:v0.07.06.01239-BT (Type B) Last updated 3/3/2017
4.Board version:01
5.VDSL uptime:
16 days, 19:01:05
6.Data Rate:8608 / 54999
7.Maximum Data Rate:8067 / 51112
8.Noise Margin:3.7 / 3.4.
Line Attenuation:25.7 / 24.9

Which was something I hadn't seen before and thought a bit odd Did others see this?.

Thanks Brian

Info :-
Line: Length 875m metres to cabinet
Modem router: HomeHub 5 B
IP Profile = Down 49.19 Mbps Up 20 Mbps
Now: BT infinity 1 FTTC SyncDown: 53138kbps SyncUp: 8120
2017: BT infinity 1 FTTC SyncDown: 54999SyncUp: 8608
2015: BT infinity 1 FTTC SyncDown: 40000kbps SyncUp: 9278
2013: BT Broadband ADSLMax 8Mbp Down: 6.79 Mbps Up: 0.36Mbps
2007: Newnet ADSLMax 8Mbp Down: 5986 kbps Up: 376 kbps
2005: Freedom2Surf ADSL Down: 5143 kbps Up: 374 kbps
Standard User Clive_
(regular) Thu 26-Oct-17 01:39:56
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Re: Speed decrease


[re: Brib] [link to this post]
 
I have noticed a drop in mine but haven't looked into it too much yet. I haven't noticed any noise on quiet line tests and my line doesn't have anything fancy to it. I would like to get back to that full sync at some point though. smile I am on the CMERD exchange if that helps at all.

21:10:42, 19 Sep. DSL Link Up: Down Rate=79987Kbps, Up Rate=20000Kbps; SNR Margin Down=10.9dB, Up=9.9dB
09:22:55, 08 Oct. DSL Link Up: Down Rate=68360Kbps, Up Rate=20000Kbps; SNR Margin Down=6.4dB, Up=9.5dB
14:32:32, 08 Oct. DSL Link Up: Down Rate=67983Kbps, Up Rate=20000Kbps; SNR Margin Down=6.4dB, Up=9.5dB

I don't have any old helpdesk info unfortunately, but here's my current:
1. Product Name: HomeHub5
2. Serial number:
3. Firmware version: v0.07.06.01239-BT (Type B) Last updated 6/3/2017
4. Board version: 01
5. VDSL uptime: 17 days, 11:04:25
6. Data Rate: 20000 / 67983
7. Maximum Data Rate: 25281 / 68691
8. Noise Margin: 9.6 / 6.3
9. Line Attenuation: 15.9 / 15.4
Standard User MCM
(knowledge is power) Thu 26-Oct-17 12:59:11
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Re: Speed decrease


[re: Clive_] [link to this post]
 
I would like to get back to that full sync at some point though.
I suspect that you drop off in sync rates is due to crosstalk and that this has increased as more people of your cab and more specifically those in the same D side bundle as yourself have taken up FTTC.

I've seen my max attainable drop 25% in the year since I was first connected, the second on our AIO cab, but having been over 100Mbps when first connected am fortunate that it is still in the 70s.


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Standard User Brib
(newbie) Thu 26-Oct-17 14:36:22
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Re: Speed decrease


[re: Clive_] [link to this post]
 
Hi Clive and MCM

Thanks for the posts.

I did a quiet line test too, but all seems okay. I've had a few faults due to trees on the overhead section of line. So I'm not surprised if I see an issue from time to time.

It's quite a distance to the cabinet too, so consider myself lucky to get what I have.

I think MCM's suggestion of crosstalk most likely abswer.

Does anyone know if crosstalk increases as existing customers speed increases or is it just extra connections on the cabinet?
Because I'm on a cabinet with only about 122 properties passed and unless a large proportion switched to FTTC in September it must be due to the speed boost.

Info :-
Line: Length 875m metres to cabinet
Modem router: HomeHub 5 B
IP Profile = Down 49.19 Mbps Up 20 Mbps
Now: BT infinity 1 FTTC SyncDown: 53138kbps SyncUp: 8120
2017: BT infinity 1 FTTC SyncDown: 54999SyncUp: 8608
2015: BT infinity 1 FTTC SyncDown: 40000kbps SyncUp: 9278
2013: BT Broadband ADSLMax 8Mbp Down: 6.79 Mbps Up: 0.36Mbps
2007: Newnet ADSLMax 8Mbp Down: 5986 kbps Up: 376 kbps
2005: Freedom2Surf ADSL Down: 5143 kbps Up: 374 kbps
Standard User MCM
(knowledge is power) Thu 26-Oct-17 15:27:22
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Re: Speed decrease


[re: Brib] [link to this post]
 
Brib,
Sadly just one customer can on occasion cause significant crosstalk especially if they happen to be in the same cable bundle as your line for part of the way. The relative location of the two cables in the bundle can also be a factor.

In my case, having seen the cab installed and the new wiring the network rearrangement required, I know that all of us are in the same cable bundle for the first 150m or so. Ours is an All In One (AIO) cab installed to feed the 75 EO lines on our development. With each new user I'm seeing some drop in maximum achievable synch rate. With 30-35 connected so far I'm just hoping that as the cab fills my rate doesn't drop too much further.
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