Too much attenuation for VDSL - anything I can do about it?

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dinsdale123

6 posts

Wannabe Geek

#150613 28-Jul-2014 13:58

Hi experts,

I am on Telecom ADSL now and recently signed up for VDSL with them; things were proceeding (technician scheduled, modem shipped) until I got a call this morning that the install was off because a Chorus test showed too much attenuation on the line. Because of that, an installer won't be coming to my house anymore, and so I'm hoping to get some questions answered here...

All providers put my address within range of VDSL, and the Chorus map shows me as being in the middle of a VDSL pocket in my area (West Auckland). I know distance from the cabinet is not the issue, so I'm trying to understand what would be causing the attenuation and if there is anything I can do about it.

I have read some of the other posts on this topic (incl stickies), so I am aware that internal wiring issues can cause attenuation. I just wonder if the Chorus line test would include the impact of my internal wiring?

On my current ADSL, I (very consistently!) get 14.0-14.5 Mbps down and approx 1 Mbps up.
My modem (Technicolor) gives me the follow stats on my DSL connection:

Uptime: 3 days, 11:35:09

DSL Type: ITU-T G.992.5

Bandwidth (Up/Down) [kbps/kbps]: 1.080 / 16.604

Data Transferred (Sent/Received) [GB/GB]: 1,04 / 1,44

Output Power (Up/Down) [dBm]: 12,6 / 0,0

Line Attenuation (Up/Down) [dB]: 1,8 / 47,5

SN Margin (Up/Down) [dB]: 11,8 / 11,4

System Vendor ID (Local/Remote): TMMB / ----

Chipset Vendor ID (Local/Remote): BDCM / IKNS

Loss of Framing (Local/Remote): 0 / 0

Loss of Signal (Local/Remote): 0 / 0

Loss of Power (Local/Remote): 0 / 0

Loss of Link (Remote): -

Error Seconds (Local/Remote): 15 / 0

FEC Errors (Up/Down): 0 / 613

CRC Errors (Up/Down): 257 / 0
HEC Errors (Up/Down): 0 / 0

I must admit that most of these don't mean much to me, but the line attenuation of 1,8 dB up and 47,5 dB down seems weird. Other posts on this forum have these values much closer together...

Any words of wisdom? Anything I could/should do that would allow me to get VDSL?

Thx,

Erik

1 | 2

1647 posts

Uber Geek

#1097145 28-Jul-2014 14:46

Can you PM me your address, I'll do some checking for you.

DarkShadow

1647 posts

Uber Geek

#1097172 28-Jul-2014 15:23

Prequal comes back as 4-5dB and positive for WVS.

Coil

6614 posts

Uber Geek
Inactive user

#1097175 28-Jul-2014 15:25

Could be wiring fault inside of the house or on street.

This is interesting: Line Attenuation (Up/Down) [dB]: 1,8 / 47,5
Get a fault logged first.

dinsdale123

6 posts

Wannabe Geek

#1097181 28-Jul-2014 15:35

Thx for the responses so far.

I don't understand the various modem DSL stats, but the 1,8 up / 47,5 down seemed really weird to me.

Is that enough "basis" to log a fault?

SteveON

1916 posts

Uber Geek

#1097185 28-Jul-2014 15:38

Move closer?

Coil

6614 posts

Uber Geek
Inactive user

#1097186 28-Jul-2014 15:38

Yes, Log a fault. if the prequal is that far off. yes.
I can get distance if you PM me your address.

trig42

5816 posts

Uber Geek

ID Verified

#1097187 28-Jul-2014 15:40

I'm in pretty much the same boat as the OP, Chorus maps show me bang in the middle of the Dark Blue VDSL area, telecom sent me the modem but Chorus cancelled the install.
My downstream Attenuation (IIRC) is about 26.

I too was wondering if putting a master splitter on at the ETP on my house would fix it. I constantly get about 13-14mbps ADSL downloads.

I know the lines in my area are dodgy, since we've had this house I've called faults about 8 times in three years - which would easily be double the number of times I've called them for all my other houses put together over 20+ years. I think I'm just going to have to wait for Fibre, but will watch this post with interest.

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Athlonite

1828 posts

Uber Geek
Inactive user

#1097241 28-Jul-2014 17:07

That attenuation is real hookey if you ask me 47.5db shouldn't allow you 14~14.5Mbps something is not right at all as mentioned above log a fault last time I had that sort of att was before they put cabinets in my area and I had to go all the way to the exchange and only got around 2~2.2Mbps down stream sync

hio77

12999 posts

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Lizard Networks

#1097252 28-Jul-2014 17:19

Athlonite: That attenuation is real hookey if you ask me 47.5db shouldn't allow you 14~14.5Mbps something is not right at all as mentioned above log a fault last time I had that sort of att was before they put cabinets in my area and I had to go all the way to the exchange and only got around 2~2.2Mbps down stream sync

this.

do you have a second modem laying around you could toss in for a test? maybe even borrow one from a friend?

what part of west auckland is this?

seems plausible, that if the prequal is giving 4~5, likely its more like 4.75 and a miss reading...

ofcourse, prequals can be wrong sometimes - which is why sites automatically assume you can get it, when really you cant.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

dinsdale123

6 posts

Wannabe Geek

#1102032 4-Aug-2014 20:07

This story had an interesting conclusion, so I thought I'd post an update...

During various phone calls last week, Chorus and Telecom gave me a wide variety of reasons why VDSL was never going to work at my house...

too much attenuation on the line (18 supposedly)
too far from the exchange
too far from the cabinet
no available slots in the exchange/cabinet
might work, but not up to minimum VDSL service levels on Telecom's website (so they won't connect me)
might work, but would cause interference with my neighbors
(and I probably forgot a few)

So imagine my surprise on Fri when I got a txt message from Telecom, informing me that an installer would be at my house on Monday. I assumed this was just a leftover in their systems that they forgot to cancel. Even more surprise when I got a phone call on Sunday evening from the installer, letting me know he'd be there at 10:30.

And today: installer shows up (but only after I had pulled his van out of the mud a few 100 metres from my house, where he had stopped for breakfast), installs master filter, wires everything up, turns on the modem and lo and behold ... I get 38 Mbps down and close to 10 Mbps up. Not bad for something that couldn't work!

I'm not entirely sure whether I should be impressed or exasperated with the Telecom/Chorus combo...

Coil

6614 posts

Uber Geek
Inactive user

#1102037 4-Aug-2014 20:12

too much attenuation on the line (18 supposedly)
Too high
might work, but would cause interference with my neighbors
Yes
too far from the exchange
Yes
too far from the cabinet
yes
might work, but not up to minimum VDSL service levels on Telecom's website (so they won't connect me)
11.8 is maximum

No luck bud.

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1102038 4-Aug-2014 20:13

dinsdale123: This story had an interesting conclusion, so I thought I'd post an update...

During various phone calls last week, Chorus and Telecom gave me a wide variety of reasons why VDSL was never going to work at my house...

too much attenuation on the line (18 supposedly)
too far from the exchange
too far from the cabinet
no available slots in the exchange/cabinet
might work, but not up to minimum VDSL service levels on Telecom's website (so they won't connect me)
might work, but would cause interference with my neighbors
(and I probably forgot a few)
So imagine my surprise on Fri when I got a txt message from Telecom, informing me that an installer would be at my house on Monday. I assumed this was just a leftover in their systems that they forgot to cancel. Even more surprise when I got a phone call on Sunday evening from the installer, letting me know he'd be there at 10:30.

And today: installer shows up (but only after I had pulled his van out of the mud a few 100 metres from my house, where he had stopped for breakfast), installs master filter, wires everything up, turns on the modem and lo and behold ... I get 38 Mbps down and close to 10 Mbps up. Not bad for something that couldn't work!

I'm not entirely sure whether I should be impressed or exasperated with the Telecom/Chorus combo...

now that you have a new modem, wiring done and such, what is your reported attenuation?

almost all of the reasons you listed, are all directly attributable to the line attenuation being to high.

i suspect your speed will drop overtime if it is indeed 18dB.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

dinsdale123

6 posts

Wannabe Geek

#1102079 4-Aug-2014 20:55

> now that you have a new modem, wiring done and such, what is your reported attenuation?

I have gone through all the screen on the new modem (Huawei HG630b) but can't find any attenuation data anywhere...

hio77

12999 posts

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Lizard Networks

#1102098 4-Aug-2014 20:58

dinsdale123: > now that you have a new modem, wiring done and such, what is your reported attenuation?

I have gone through all the screen on the new modem (Huawei HG630b) but can't find any attenuation data anywhere...

bug in the HG630b firmware..makes it show as 0 ild say.

ild ask your isp what your current downsteam attenuation is since your modem does not show it.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

dinsdale123

6 posts

Wannabe Geek

#1102279 4-Aug-2014 23:59

OK, found it...

Line Status
Line standard: VDSL2
Downstream line rate (kbit/s): 39931
Upstream line rate (kbit/s): 10354
Downstream SNR (dB): 12.4
Upstream SNR (dB): 15.4
Downstream line attenuation (dB): 11
Upstream line attenuation (dB): 22.2
Downstream output power (dBmV): 13.5
Upstream output power (dBmV): -4.7
Downstream CRC: 53
Upstream CRC: 1
Downstream FEC: 121353
Upstream FEC: 161

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