My real attenuation vs what Telecom think my attenuation is

Forums › Spark New Zealand (including Skinny and BigPipe) › My real attenuation vs what Telecom think my attenuation is

BlueToothKiwi

282 posts

Ultimate Geek
+1 received by user: 3

Trusted

#129452 16-Sep-2013 17:53

I just ordered VDSL via Telecom. During the conversation, the lady told me that my attenuation is 4 well under the 10 threshold that Chorus have for going ahead with VDSL.

Yet my old ADSL modem stats page says my attenuation is 14dB. Does that mean Telecom measure the attenuation using some other way other than reading the data off my modem?

Should I discard the old wiring between the demarcation point and my ADSL socket, so that when they install the new splitter it will work great?

Tim M, Auckland
Blog: http://paddler.co.nz

michaelmurfy

meow
13579 posts

Uber Geek
+1 received by user: 10910

Moderator

ID Verified

Trusted

Lifetime subscriber

#896451 16-Sep-2013 17:55

It's based on the street, so sounds like your internal wiring is pretty bad.

Michael Murphy | https://murfy.nz
Referral Links: Quic Broadband (use R122101E7CV7Q for free setup)

Are you happy with what you get from Geekzone? Please consider supporting us by subscribing.
Opinions are my own and not the views of my employer.

cbrpilot

964 posts

Ultimate Geek
+1 received by user: 555

Trusted

Spark NZ

#896456 16-Sep-2013 18:07

Hold on here. Attenuation is not just stand-alone variable for a phone line.

Attenuation is associated with a particular frequency range, and can not be talked about in isolation of that frequency range. So when comparing two attenuation values here, you may not be comparing apples to apples unless they are being measured at the same frequency.

My views are my own, and may not necessarily represent those of my employer.

johnr

19282 posts

Uber Geek
+1 received by user: 2526
Inactive user

#896458 16-Sep-2013 18:12

Maybe your house wiring is Kaka causing a higher attenuation

plambrechtsen

1948 posts

Uber Geek
+1 received by user: 459
Inactive user

#896471 16-Sep-2013 18:24

johnr: Maybe your house wiring is Kaka causing a higher attenuation

Or the copper back to the dslam is causing it too. The attenuation they quoted would normally be a dsl pre qualification so one can assume since it is so different that your internal wiring is causing it and post master filter it would be much better.

BlueToothKiwi

282 posts

Ultimate Geek
+1 received by user: 3

Trusted

#896501 16-Sep-2013 19:20

cbrpilot: Attenuation is associated with a particular frequency range, and can not be talked about in isolation of that frequency range. So when comparing two attenuation values here, you may not be comparing apples to apples unless they are being measured at the same frequency.

Lets assume the TG582n router comes up with the attenuation stats by checking how much the signal is attenuated as an average against all the frequencies that it uses. If that is the case, (and given my modem is only an ADSL router), one would hope the frequency range used by my modem to get the data would be lower than whatever the VDSL pre qualification test (which need higher speed (and hence higher frequency)). So if the discrepency is caused by the frequency range difference used in the two measurements, one would expect the attenuation figure for the VDSLpre qualification test to be higher than the ADSL modem stats. Not 10 dB lower? Right?

plambrechtsen: ... since it is so different that your internal wiring is causing it and post master filter it would be much better.

The house currently have a electrician installed master splitter inside the wall behind the ADSL socket. Hence my original question - should I replace the old phone cable inside the wall with a shielded Cat 6 cable before the Chorus tech comes next week? I am scared they will install it and say I got too crappier wiring and roll back my connection to ADSL....

Tim M, Auckland
Blog: http://paddler.co.nz

Yyrael

222 posts

Master Geek
+1 received by user: 45

Trusted

#896526 16-Sep-2013 19:44

BlueToothKiwi:
cbrpilot: Attenuation is associated with a particular frequency range, and can not be talked about in isolation of that frequency range. So when comparing two attenuation values here, you may not be comparing apples to apples unless they are being measured at the same frequency.

Lets assume the TG582n router comes up with the attenuation stats by checking how much the signal is attenuated as an average against all the frequencies that it uses. If that is the case, (and given my modem is only an ADSL router), one would hope the frequency range used by my modem to get the data would be lower than whatever the VDSL pre qualification test (which need higher speed (and hence higher frequency)). So if the discrepency is caused by the frequency range difference used in the two measurements, one would expect the attenuation figure for the VDSLpre qualification test to be higher than the ADSL modem stats. Not 10 dB lower? Right?

plambrechtsen: ... since it is so different that your internal wiring is causing it and post master filter it would be much better.

The house currently have a electrician installed master splitter inside the wall behind the ADSL socket. Hence my original question - should I replace the old phone cable inside the wall with a shielded Cat 6 cable before the Chorus tech comes next week? I am scared they will install it and say I got too crappier wiring and roll back my connection to ADSL....

The chorus technician should be installing Cat 5 cable from the ETP to the JP and will probably install a newer splitter.

Mighty Ape

Shop now at Mighty Ape (affiliate link).

insane

3324 posts

Uber Geek
+1 received by user: 1006

ID Verified

Trusted

2degrees

Subscriber

#896547 16-Sep-2013 20:26

cbrpilot: Hold on here. Attenuation is not just stand-alone variable for a phone line.

Attenuation is associated with a particular frequency range, and can not be talked about in isolation of that frequency range. So when comparing two attenuation values here, you may not be comparing apples to apples unless they are being measured at the same frequency.

I believe you are right Sir as when I switched from ADSL2+ to VDSL my attenuation dropped quite a bit, not quite from 14 to 4, but from around ~15 to ~8 I believe.

Stu

Hammered
8737 posts

Uber Geek
+1 received by user: 2390

Moderator

ID Verified

Trusted

Lifetime subscriber

#896636 16-Sep-2013 22:58

Yyrael: The chorus technician should be installing Cat 5 cable from the ETP to the JP and will probably install a newer splitter.

Not what was done here. There was an existing master installed for ADSL, feeding an old BT jack via old "six way" cable. All the Chorus tech did was replace the master splitter with a new xDSL splitter.

Quick and easy for him. I'm going to have to upgrade the cabling etc myself if I want it done.

People often mistake me for an adult because of my age.

Keep calm, and carry on posting.

Referral Links: Sharesies -

Are you happy with what you get from Geekzone? If so, please consider supporting us by subscribing.

No matter where you go, there you are.

BlueToothKiwi

282 posts

Ultimate Geek
+1 received by user: 3

Trusted

#899005 20-Sep-2013 13:55

OK - Got a new VDSL2 modem by courier - plugged it in - and the speed / bandwidth stays the same - but Ping ties takes a dive from 30+ to 10ms.

How do I know when the VDSL2 kicks in - or does it not happen till he Chrorus guy replaces the ADSL splitter with a VDSL2 splitter?

Tim M, Auckland
Blog: http://paddler.co.nz

cbrpilot

964 posts

Ultimate Geek
+1 received by user: 555

Trusted

Spark NZ

#899047 20-Sep-2013 15:00

The switchover doesn't happen until the Chorus tech comes.

Depending on what modem you've been sent, you may have to factory reset it if it doesn't immediately link up and grant you internet access with VDSL as you've plugged it in early.

Your sync rate in your modem will give you the new speeds at the connect time, but it can take a little longer for the Telecom systems to update your profile. I.e. it may be a few hours after the Chorus tech leaves the site that you'll get the full speeds on any speedtest site.

My views are my own, and may not necessarily represent those of my employer.

chevrolux

4962 posts

Uber Geek
+1 received by user: 2638
Inactive user

#899123 20-Sep-2013 16:49

Not what was done here. There was an existing master installed for ADSL, feeding an old BT jack via old "six way" cable. All the Chorus tech did was replace the master splitter with a new xDSL splitter.

Quick and easy for him. I'm going to have to upgrade the cabling etc myself if I want it done.

Is it possible to replace that six way? Chorus REQUIRE installers to run a new cable to the ETP of it isn't up to scratch. An old six way is better than an old tru-rip but if it was me I would want a proper twisted pair cable.
If it was me I would demand Chorus back.