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Understanding Line Attenuation, SNR and distance from Exchange

deejayburnout
Grafter
Posts: 150
Registered: ‎05-04-2014

Understanding Line Attenuation, SNR and distance from Exchange

Peeps
i have just moved home where i had a Sky Broadband.
I lived less that a mile from that exchange and my router was set up as 22811kbps upload and 797kbps download.
My Sky router setting were as follows
Broadband Link              Downstream    Upstream
Connection Speed          22811 kbps      797 kbps
Line Attenuation              18.5 dB              11.6 dB
Noise Margin                  6.1 dB                7.7 dB
My new house is probably the same distance from the new exchange if not a little further away but only by 10s of meters. My PN router is setup as 8096kbps download and 448kbps upload.
Now my PN router setting as as follows
Link Information

Uptime: 0 days, 3:57:40
DSL Type: ITU-T G.992.1
Bandwidth (Up/Down) [kbps/kbps]: 448 / 8,096
Data Transferred (Sent/Received) [MB/MB]: 694.73 / 848.88
Output Power (Up/Down) [dBm]: 12.1 / 19.9
Line Attenuation (Up/Down) [dB]: 10.5 / 18.5
SN Margin (Up/Down) [dB]: 28.0 / 10.1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN

now from what i have heard, generally speaking, the closer you are to the exchange, the better speeds you should be getting.
Is there a reason why my speed at my new house is not comparable to my old houseHuh
6 REPLIES
Community Veteran
Posts: 5,227
Thanks: 494
Fixes: 22
Registered: ‎10-06-2010

Re: Understanding Line Attenuation, SNR and distance from Exchange

The most significant difference in the PN router stats is "DSL Type:  ITU-T G.992.1"
That shows you are on ADSL1, which only goes up to 8M. Either 21CN ADSL2+ is not available from BTWholesale based providers like Plusnet at the exchange, or ADSL2+ is available but you have been put on ADSL1 for some unknown reason. You can check the availability here: https://www.btwholesale.com/includes/adsl/main.html
deejayburnout
Grafter
Posts: 150
Registered: ‎05-04-2014

Re: Understanding Line Attenuation, SNR and distance from Exchange

Thanks for that.
Looks like i am on ADSL then. the only bad thing about my new house is the broadband speeds.  Roll eyes
Oh well, need to wait for FTTC roll out in my area ( in about 6 months )


Superuser
Superuser
Posts: 13,048
Thanks: 4,341
Fixes: 26
Registered: ‎22-08-2007

Re: Understanding Line Attenuation, SNR and distance from Exchange

What did the website ejs pointed you to say about 21CN availability?
It is not quite so much an ADSL question rather a 20CN or 21CN issue.  20CN infrastructure does not support ADSL2.
I'd be guessing that you are on 20CN.  If 21CN is available on your exchange then the question to ask here is why am I on 20CN and can I be moved to 21CN?  If you are on 21CN then why are you configured as ADSL, rather than ADSL2+?
When you were with SKY it is likely that you were on their own LLU technology; sadly it is not unheard of that users moving from LLU providers to BT infrastructure in some areas find themselves on the inferior 20CN technology, especially in some semi rural areas.  I am a little surprised that a non 21CN exchange is going straight to FTTC.
Given the good ADSL1 performance of your line, you might see the top end of FTTC performance when it arrives.  FTTC is still delivered over your existing copper d-side - if that is rubbish (as they are in many places) then one is not going to get the best possible from FTTC.
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: Understanding Line Attenuation, SNR and distance from Exchange

21CN isn't available at this exchange I'm afraid which is why you've been placed on 20CN as this is the only technology supported at the moment.
Edit: Typo.
Chris Pettitt
Cloud Environments Engineer
Luzern
All Star
Posts: 3,518
Thanks: 381
Fixes: 3
Registered: ‎31-07-2007

Re: Understanding Line Attenuation, SNR and distance from Exchange

Chris! Does your post make good sense? Wink
No one has to agree with my opinion, but in the time I have left a miracle would be nice.
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: Understanding Line Attenuation, SNR and distance from Exchange

It didn't...but should do now Smiley
Chris Pettitt
Cloud Environments Engineer