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Standard User nemeth782
(member) Wed 02-Sep-15 09:50:30
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Re: Alu FTTC line


[re: WWWombat] [link to this post]
 
Me to cab is ~331meters, in a straight line down the road.

Cab to exchange is 332meters, assuming the line follows the road it is a gentle S shape so more like 345meters.

[censored] MSpaint drawing:

http://i.imgur.com/fVrB14b.png

Blue arrow points to the Cabinet. Yellow box is a manhole cover I know my line is in, large red blob is the pole my line is on.

Smaller red blob is where my house is, black line is the line itself, for the known parts of it's route.

Green dots are houses forecast 74mbit down 20mbit up on the address checker, that don't seem to come via the pole (can see cable entry points on the front of their houses).

I almost think if I order a 3rd line they will bring it in via the front of the house (as my overhead line is draped over 3 peoples gardens, getting permission to get ladders in to replace it could be awkward).
Standard User MHC
(sensei) Wed 02-Sep-15 09:54:24
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
Have you done a reboot this morning?


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

M H C


taurus excreta cerebrum vincit
Standard User nemeth782
(member) Wed 02-Sep-15 09:57:27
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Re: Alu FTTC line


[re: MHC] [link to this post]
 
In reply to a post by MHC:
Have you done a reboot this morning?


No, was almost late for work so didn't get chance, will do it tonight/tomorrow morning.

It is a bit variable, when the BT engineer was there yesterday, he resynced the line a number of times. I was monitoring sync speeds and saw as high as 51m down, and as high as 7mbit up, although not at the same time.


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Standard User MHC
(sensei) Wed 02-Sep-15 10:07:20
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
I know I commented on te upstream being "missing" above tone 2350, what is also difficult to understand is that there is no data for anything including D3 which starts at 2793. Even if the bins were empty, I would still expect to see something on the SNR, QLN and HLog graphs.

Can you copy the pbParams page from DSLStats?


One reason I suggested a morning reboot was that it tends to be a low noise time - less electronics running and if there is a Radio Ham close by, he is more likely to be off at that time. Still try it when you get home though - a managed drop of connection should not have any adverse effects.


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

M H C


taurus excreta cerebrum vincit
Administrator MrSaffron
(staff) Wed 02-Sep-15 11:22:46
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
If a third line is difficult to provide BT may charge you full cost of delivering it, fixed price installs under USO only apply to the first line at a property.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User nemeth782
(member) Wed 02-Sep-15 13:25:24
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Re: Alu FTTC line


[re: MHC] [link to this post]
 
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 3
Last initialization procedure status: 0
Max: Upstream rate = 7312 Kbps, Downstream rate = 47992 Kbps
Bearer: 0, Upstream rate = 6866 Kbps, Downstream rate = 47993 Kbps

Discovery Phase (Initial) Band Plan
US: (6,31) (882,1193) (1984,2770)
DS: (33,857) (1218,1959) (2795,4083)
Medley Phase (Final) Band Plan
US: (6,31) (882,1193) (1984,2330)
DS: (41,857) (1218,1959)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 7312 kbps 47992 kbps
Actual Aggregate Tx Power: 3.2 dBm 12.9 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 4.1 31.9 49.9 N/A N/A 16.5 46.8 76.7
Signal Attenuation(dB): 4.1 31.8 49.7 N/A N/A 15.7 46.4 N/A
SNR Margin(dB): 6.3 6.1 6.3 N/A N/A 6.2 6.2 N/A
TX Power(dBm): -3.5 -9.6 1.8 N/A N/A 11.5 7.3 N/A
#


Wow, that attenuation really climbs on the higher bands!
Standard User MHC
(sensei) Wed 02-Sep-15 14:26:49
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
Could be the Al tail off ...

I notice that the Final Band Plan stops at 2330 so nothing would happen after that.

Do the reboot later and see if it changes much at the high end and also see if the QLN, Hlog and SNR lists have any data above 2330 - do not paste them here though


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

M H C


taurus excreta cerebrum vincit
Standard User WWWombat
(knowledge is power) Fri 04-Sep-15 19:03:32
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
In reply to a post by nemeth782:
Cab to exchange is 332meters, assuming the line follows the road it is a gentle S shape so more like 345meters.


Right - that is quite a short distance, so the cabinet doesn't have to reduce power much for FTTC connections. You can see a small dip in SNR and bit-loading on the tones just below 512; above 512, bit-loading jumps back to normal.

In reply to a post by nemeth782:
Me to cab is ~331meters, in a straight line down the road.


Eek. My previous line was around 370 metres, and I believe it was 0.5mm copper all the way. It achieved 80/20 speeds for a long time (crosstalk from neighbours eventually reduced it to 78/20, but that was 4 years after the cab was installed). That line had an attenuation of around 16dB.

It just goes to show the impact of a stretch of aluminium.

I agree with the others that the drop-off you see is because aluminium is just not as good for the higher frequencies - as you note later:

In reply to a post by nemeth782:
Text
1
23
45
67
====================================================================================
  VDSL Band Status      U0      U1      U2      U3      U4      D1      D2      D3  Line Attenuation(dB): 4.1     31.9    49.9    N/A     N/A     16.5    46.8    76.7
Signal Attenuation(dB): 4.1     31.8    49.7    N/A     N/A     15.7    46.4    N/A        SNR Margin(dB): 6.3     6.1     6.3     N/A     N/A     6.2     6.2     N/A
         TX Power(dBm): -3.5    -9.6    1.8     N/A     N/A     11.5    7.3     N/A#


Wow, that attenuation really climbs on the higher bands!


To give you a comparison of my previous, 370m copper, line:
Text
1
23
45
6
====================================================================================
  VDSL Band Status       U0      U1      U2      U3      U4      D1      D2      D3  Line Attenuation(dB):  4.4     22.2    33.4     N/A     N/A    11.6    28.0    42.6   
Signal Attenuation(dB):  4.4     21.2    32.3     N/A     N/A    16.2    27.7    42.6           SNR Margin(dB):  7.1     7.2     7.1      N/A     N/A    6.3     6.2     6.2    
         TX Power(dBm): -2.5    -21.0    6.5      N/A     N/A    9.7     7.8     6.9


In reply to a post by nemeth782:
I almost think if I order a 3rd line they will bring it in via the front of the house (as my overhead line is draped over 3 peoples gardens, getting permission to get ladders in to replace it could be awkward).


Good luck with that. If you could avoid that aluminium, it would be reasonably worthwhile.
Standard User Nightglow
(regular) Fri 04-Sep-15 21:01:11
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Re: Alu FTTC line


[re: nemeth782] [link to this post]
 
In reply to a post by nemeth782:
I almost think if I order a 3rd line they will bring it in via the front of the house (as my overhead line is draped over 3 peoples gardens, getting permission to get ladders in to replace it could be awkward).


If there is a spare pair on your exsisting cable, they will use them, rather than putting a new cable at the front.
Standard User nemeth782
(member) Fri 04-Sep-15 23:10:47
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Re: Alu FTTC line


[re: Nightglow] [link to this post]
 
In reply to a post by Nightglow:
In reply to a post by nemeth782:
I almost think if I order a 3rd line they will bring it in via the front of the house (as my overhead line is draped over 3 peoples gardens, getting permission to get ladders in to replace it could be awkward).


If there is a spare pair on your exsisting cable, they will use them, rather than putting a new cable at the front.


The drop wire from my roof to the two master sockets is 4 pair, it was fitted when I ordered the 2nd line (previously figure-8 cable). The overhead cable ( http://i.imgur.com/jPUiWkf.jpg ) is two pair according to the engineer that fitted the 2nd line.

It would be necessary to replace this cable for a 3rd line, it's copper, but from the estimates given to neighbouring houses that don't go via that pole, I think the Alu section is the bit that goes to said pole.

I feel like they would probably just refuse to install a 3rd line without massive excess construction costs though.
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