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Topic # 115371 23-Mar-2013 19:32
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Just moved into a new rental, Naked DSL syncing at 6-7Mbps ADSL2+ when attenuation indicates 16-18Mbps is possible. 
(At my last place there was a loose pair down the street which was fun)

Chorus map shows me just outside VDSL range (by 30m or so ha ha) so can't be that far from the exchange.

Tested different modems with different cables around the house (4 jacks), same results.

Problem is this is a townhouse and the phone lines come in to the roof of the other unit, then into my roof. I can't see a master splitter up there but i'll go climbing when i can borrow a ladder and check.

Could be internal wiring, and i'm especially suspicious with the lines coming in to the other unit.

Line Mode     ADSL2+      Line State     Show Time  
Line Power State     L0      Line Up Time     11:02:10:31
Line Coding     Trellis On      Line Up Count     1

Statistics     Downstream     Upstream
Line Rate     6659 Kbps     989 Kbps
Attainable Line Rate     8740 Kbps     969 Kbps
Noise Margin     12.4 dB     12.4 dB
Line Attenuation     26.0 dB     7.4 dB
Output Power     18.6 dBm     12.4 dBm

Quick questions:
- The theoretical attenuation : speed thing seems to indicate a big problem: is this correct?
- What are my options? Particularly if the splitter is in next door roof (joined to our roof)?

Cheers!

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  Reply # 786019 23-Mar-2013 19:32
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Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

 



 

If you are posting regarding DSL speeds please check that

 



 

- you have reset your modem and router

 


 

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

 

- you are not being throttled by your ISP due to going over the monthly cap

 


 

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

 


 

- you read this topic and follow the instructions there.

 



 

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

 



 

- Your ISP and plan

 


 

- Type of connection (ADSL, ADSL2, VDSL)

 


 

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

 


 

- Your general location (or street)

 


 

- If you are rural or urban

 


 

- If you know your connection is to an exchange, cabinet or conklin

 


 

- If your connection is to a ULL or wholesale service

 


 

- If you have done an isolation test as per the link above

 



 

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

 



 

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

 



 

I recommend you read these two blog posts:

 



 

- Is your premises phone wiring impacting your broadband performance? (very technical)

 


 

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?




I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.



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  Reply # 786027 23-Mar-2013 19:37
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You're right about the speed being low for 26 dB. I'm at 27 dB and get 14.8 Mb/s ... and like the robot I suspect that it's your wiring.

Edit: That's interesting about VDSL range though; I'm about 375 m past the green area on the map and have about the same attenuation as you do.

 
 
 
 




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  Reply # 786037 23-Mar-2013 19:41
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Thanks for comparison. I'm 30m out from VDSL as the bird flies but that's another street - could be 200m+ down the cable depending on how they've wired it!

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  Reply # 786053 23-Mar-2013 20:15
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Ahh, that would explain it :)

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  Reply # 786066 23-Mar-2013 21:11
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Just a quick question What town are you.

Cyril



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  Reply # 786195 24-Mar-2013 09:40
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lower hutt.

don't think the ULL is a problem here, especially not with 12db on the line.

Anyways went up and crawled around in the loft space this morning - there are 2 black wires intertwined coming from the other roof and going down to the jack at the other end of the house. 

Someone has simply cut these in two halfway down and twisted on 3 other lines (that go off to the other jacks), taped it all up and hey presto. I'd imagine that's the source of the problem but then again not sure if the two black wires are hooked up to another splitter (?) where the cable comes in off the street (in the other townhouse roof).

If i undid this "DIY splitter" and tied the main black lines into the one jack line i need to use (naked dsl), would this be likely to diminish interference?


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  Reply # 786196 24-Mar-2013 09:45
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giollarnat: lower hutt.

don't think the ULL is a problem here, especially not with 12db on the line.

Anyways went up and crawled around in the loft space this morning - there are 2 black wires intertwined coming from the other roof and going down to the jack at the other end of the house. 

Someone has simply cut these in two halfway down and twisted on 3 other lines (that go off to the other jacks), taped it all up and hey presto. I'd imagine that's the source of the problem but then again not sure if the two black wires are hooked up to another splitter (?) where the cable comes in off the street (in the other townhouse roof).

If i undid this "DIY splitter" and tied the main black lines into the one jack line i need to use (naked dsl), would this be likely to diminish interference?



Yes.. You should have a single wire going from the black wires only to the jackpoint you need.

Not so sure about just twisting them together as really they make joiners for those sorts of things rather than a twist and a bit of tape over the top.  If you had a soldering iron and put a blob of solder on it to properly seal it up.  Otherwise get Cyril7 out to do a proper job as he is in Wellington.

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  Reply # 786202 24-Mar-2013 10:01
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Hi, sounds like you just need to do as you intend, take the first pair from the black cable coming in, will be white/blue pair or yellow/black, assuming who ever wired it kept to convention, maybe a photo of the mess.

Remove all the unwanted cables and connect it to a pair of the cable going to the jack you want to lite up. I would doubt a split in the cable occurs elsewhere but if there is a black cable in the roof and depending on the age of the wiring its likely that the black cable goes all the way back to the street pedastal with no ETP.

Again a photo will help. As for making the joint, scotch locs are best, jaycar have them or electrical wholesalers, if you work in the city near featherston st contact me via PM and I can give you a few.

Cyril



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  Reply # 788236 27-Mar-2013 20:55
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Thanks for the advice. I went and got a few scotch locs on my way past jaycars.

If i connect one pair from the two mains black lines to my jack line, should i disconnect the other one to avoid interference, or does it not matter?

I'll try to get a photo when i'm up there.

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  Reply # 788249 27-Mar-2013 21:18
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giollarnat: Thanks for the advice. I went and got a few scotch locs on my way past jaycars.

If i connect one pair from the two mains black lines to my jack line, should i disconnect the other one to avoid interference, or does it not matter?

I'll try to get a photo when i'm up there.


That is the whole point. You need to disconnect all other extensions and only have a single jackpoint working to where the dsl is delivered. All the other jackpoints even if they aren't connected is causing your issue.



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  Reply # 790278 1-Apr-2013 19:51
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Slightly disheartening - i discarded all internal wiring and connected my one jack to street pair with scotch locs. Same stats...

Line Mode ADSL2+ Line State Show Time
Line Power State L0 Line Up Time 00:00:03:10
Line Coding Trellis On Line Up Count 1

Statistics Downstream Upstream
Line Rate 7027 Kbps 997 Kbps
Attainable Line Rate 8472 Kbps 993 Kbps
Noise Margin 12.3 dB 12.7 dB
Line Attenuation 25.5 dB 10.8 dB
Output Power 18.9 dBm 12.4 dBm

Considering that all the jacks were twisted together on to the street pair and held by nothing but some empty wire shells, at two different locations along the street pair, i am a bit disappointed!

I imagine that it is not the huge gauge difference between the wires in the scotch locs - took a few tries to get them to grab both (street cable core is copper at least as thick as outdoor tv coax wire and had to cut insulation to fit it in) - as stats are back to starting point.

So is the problem further upstream? Or could it be downstream - how the jack is wired? [Ed. most unlikely as the isolation tests were poor for all jacks previously] 

If the black cable does go back to street with no ETP ... any suggestions what to check next?

Many thanks!

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  Reply # 790327 1-Apr-2013 21:43
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Worth getting Cyril7 out to check the situation, or ring up your ISP and get them to send out Chorus to check it out.

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  Reply # 790331 1-Apr-2013 21:53
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If the outdoor black cable is that thick then its probably not actual telephone cable. Get some pics to be sure.




Richard rich.ms



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Master Geek
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  Reply # 790392 2-Apr-2013 00:04
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the black cable (well actually two cables - the pair is twisted but completely separate) runs through the roof from the other attached townhouse (which shares the same roof) but the solid core conductor is definitely the same as coax - copper and thick. No copper shielding (it's not rg-59 or something!) just a layer of thin soft red plastic insulation and the black outer layer. i'd estimate that it's max 12-13m long from the connection point with the street overhead line on the side of the house (in the neighbours section of the roof).

is this type of wire likely to be a problem - should it have extra shielding or something?

i've managed to scotchloc it to the tiny (in comparison) standard blue and white phone wires from the jack. works fine but same speed problem.

my camera ain't working but pics won't show you anything except for these 2 intertwined black cables coming from neighbours roof into mine.



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  Reply # 792565 3-Apr-2013 17:51
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Ok here are some pics:
Street pair attached to neighbours house - same type of "tru rip" cable as the one in the roof it would seem.



Here's the twisted cables come into my roof and what they look like up close.



Would this type of cable cut my DSL speed in half?
Should/can i get my ISP to phone Chorus and get it replaced?


Other thing is I rang Slingshot and the guy thought it was a normal speed and that the max recorded speed at the local exchange was 13Mbps (seems ridiculously low). I told him that my 7Mbps didn't fit my 25db attenuation but he didn't know what to say to that. I asked him about the exchange and he told me it was a BUBA. Is this just a clueless techie or is the local exchange just really slow?


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