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Unexplained change in attenuation

maranello
Aspiring Pro
Posts: 939
Thanks: 75
Fixes: 1
Registered: 11-01-2008

Unexplained change in attenuation

According to my router stats, at around 13:40 on the 13th Feb, my connection appears to have reset.
The stats report a d/s attenuation of 60.5dB. I have up to this point never had a value of less than 63db.
I still live at the same address, the exchange still appears to be in the same place. Somehow the line length has reduced and the potential speed for my connection has increased  - Whoopee!
A recent BT speedtest reports a speed of 1.62Mbps, but a profile of 2.57. The Plusnet profile has not increased and is still at 1.75Mbps.
Three questions
1. What could cause the reduced attenuation?
2. Why has the PN profile not increased automatically to match the BT profile?
3. As I believe I am still on ADSL1, why would the BT profile be 2.57 and not 2.5Mbps.
My other car isn't a Ferrari
6 REPLIES
Superuser
Superuser
Posts: 9,128
Thanks: 535
Fixes: 46
Registered: 06-04-2007

Re: Unexplained change in attenuation

Is your exchange 21CN enabled? Just wondering if you've been moved from 20CN to 21CN though still using ADSL1, which is appropriate for the speeds you mentioned.
David
maranello
Aspiring Pro
Posts: 939
Thanks: 75
Fixes: 1
Registered: 11-01-2008

Re: Unexplained change in attenuation

Exchange is 21CN enabled, but I have in the past been advised that speeds were unlikely to improve with ADSL2 over 21CN, and would more likely result in increased attenuation. Plusnet policy was at one time not to migrate customers on long lines. If I have been migrated I would like to know if it was instigated by Plusnet or BTOR (due to BTOR removing the 20CN equipment from the exchange, perhaps?).
On the other hand, I believe I was told that I was on ADSL1 over 21CN some time ago. Possibly someone at Plusnet could confirm?
Quick update - just checked old posts, which confirm I was on ADSL1 20CN. It is possible I have been migrated to 21CN, though keeping with ADSL1, which would explain the BT profile of 2.57Mbps, for a sync of around 2.9 (if I remember correctly).
If only the PN profile could catch up
  Roll eyes
My other car isn't a Ferrari
Community Veteran
Posts: 3,186
Thanks: 20
Fixes: 2
Registered: 31-07-2007

Re: Unexplained change in attenuation

Could be BT did some work on your cabinet and or moved you to a new line from the cabinet to exchange.  I had a change in attenuation/speed etc when that happened last year.
Unvalued customer since 2001 funding cheap internet for others / DSL/Fibre house move 24 month regrade from 8th May 2017
Community Veteran
Posts: 1,829
Thanks: 93
Fixes: 5
Registered: 21-01-2013

Re: Unexplained change in attenuation

Could it be you previously connected at G992.5 (ADSL2+)
And the present connection is G992.3 (ADSL2) or G992.1 (ADSL1).
ADSL2+ gives an attenuation about 3 dB higher than the others.
Note:
On a long line such as yours, ADSL2 or ADSL1 often gives slightly better results than ADSL2+
Plusnet Help Team
Plusnet Help Team
Posts: 12,776
Thanks: 108
Fixes: 32
Registered: 27-04-2007

Re: Unexplained change in attenuation

Quote
If only the PN profile could catch up

Hint received and profile manually updated Smiley
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
maranello
Aspiring Pro
Posts: 939
Thanks: 75
Fixes: 1
Registered: 11-01-2008

Re: Unexplained change in attenuation

Sometimes a hint is more effective than a rant  Wink
Thank you Adam, much appreciated
My other car isn't a Ferrari