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mikew650
Contributor
369 Views
Message 1 of 12

Target Signal Noise Ratio

Hello again

 

Regarding john46 reply to my post in thread "Incredibly Slow Broadband for 10 days"

 

I would like to reduce my TSNR. Can I say the reason it increased last year from 9 to 12 db was because I had the router on 24/7 during some thunderstorms. I had over 31 disconnections in 9 hours along with other ones previously and looking at the router stats showing lots of errors, CRCs etc.

 

I have found with my line and exchange, because of the unstable line, it pays me to only switch the router on when I need to be online, avoiding late evenings and heavy rain storms. I am a light user, about 1 hour a day.


When I have left the router on 24/7 I get the odd disconnection, usually after 10 PM and before 8 am resulting in a reconnect at a lower speed and IP profile. It can take up to 3 days to get my IP profile back and because I may experience more disconnections in that time I find switching the router on for about 1 hour each day mid morning when the connection speed is best and then switching off again I can always get my profile to match the best speed.

Catch 22 otherwise, the disconnects occur because of the unstable line and  so cannot stay connected for up to 3 days.

 

So I regret leaving my router on 24/7 because of the TSNR increase. Previous to last year I did what I do now and always had a 9db margin for 3 years. I would like it back to 9.

 

At present I have these stats and my IP profile is 2.5mb. BT speedtest no longer works for me apart from the beta version.

 

ADSL line status

Connection information
Line stateConnected
Connection time0 days, 1:22:28
Downstream3,008 Kbps
Upstream448 Kbps

ADSL settings

VPI/VCI0/38
TypePPPoA
ModulationITU-T G.992.1
Latency typeInterleaved
Noise margin (Down/Up)12.8 dB / 19.0 dB
Line attenuation (Down/Up)55.0 dB / 25.0 dB
Output power (Down/Up)18.4 dBm / 11.9 dBm
Loss of Framing (Local)0
Loss of Signal (Local)0
Loss of Power (Local)0
FEC Errors (Down/Up)531 / 0
CRC Errors (Down/Up)17 / 2147480000
HEC Errors (Down/Up)nil / 0
Error Seconds (Local)13


 


Just for this I will leave the router switched on. It is connected to a SSFP with a 2 meter asdl cable.

 

Thanks

 

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11 REPLIES 11
Distinguished Sage
Distinguished Sage
360 Views
Message 2 of 12

Re: Target Signal Noise Ratio

a profile of 2.5mb is correct for your current connection speed.  if you could get the noise margin down to normal noise margin of 6db that would give you a speed increase to about 3.5mb maybe slightly more.

 

if you are connected to a filtered faceplate that should be as good as you get.



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mikew650
Contributor
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Message 3 of 12

Re: Target Signal Noise Ratio

Yes imjolly I used to get 3 to 3.5 mb last year by careful management of my line use, ie never leaving it switched on 24/7 and avoiding those time when line noise might increase.

 

I have been at 1mb speeds leaving it switched on. I can manage at 2.5 mbs, don't do TV online, but I've noticed with the warmer weather my line attn. has gone up to 55 db from 53 db in winter and I coulld drop another band to a 2 mb IP Proflie if the speed drops into the low 2800.

 

So I would like a lower TSRN, 9 would do and 6 would be interesting, may be to lean for my line. If I can stay connected for 3 days maybe you can help with this?

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Distinguished Sage
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Message 4 of 12

Re: Target Signal Noise Ratio

the up crc errors are a known firmware glitch the errors are very low the fec's are just showing that interleaving is working and nothingto worry about
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Distinguished Sage
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Message 5 of 12

Re: Target Signal Noise Ratio

the forum moderators can reset your noise margin but they will need to see a stable 3 days connection first before they can carry out a reset this is a link to them 

http://bt.custhelp.com/app/contact_email/c/4951
they normally reply by email or phone directly to you within 3 working days

They are a UK based BT specialist team who have a good record at getting problems solved

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mikew650
Contributor
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Message 6 of 12

Re: Target Signal Noise Ratio

Ok thanks, I will leave it on and see if it will survive 3 days.

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Distinguished Sage
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Message 7 of 12

Re: Target Signal Noise Ratio

please keep us posted on progress
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mikew650
Contributor
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Message 8 of 12

Re: Target Signal Noise Ratio

Hello

 

I checked the router this morning and sad to say it disconnected early morning. Stats and logs below.

 

ADSL line status
Connection information
Line state    Connected
Connection time    0 days, 6:46:45
Downstream    2,528 Kbps
Upstream    448 Kbps

ADSL settings
VPI/VCI    0/38
Type    PPPoA
Modulation    ITU-T G.992.1
Latency type    Interleaved
Noise margin (Down/Up)    14.3 dB / 18.0 dB
Line attenuation (Down/Up)    54.0 dB / 24.5 dB
Output power (Down/Up)    17.4 dBm / 11.9 dBm
Loss of Framing (Local)    0
Loss of Signal (Local)    0
Loss of Power (Local)    0
FEC Errors (Down/Up)    8540 / 0
CRC Errors (Down/Up)    130 / 2147480000
HEC Errors (Down/Up)    nil / 0
Error Seconds (Local)    365

 

00:59:43   5 Jun     FIREWALL event (1 of 7): deleted rules
00:59:43   5 Jun     xDSL linestate up (ITU-T G.992.1; downstream: 2528 kbit/s, upstream: 448 kbit/s; output Power Down: 17.4 dBm, Up: 11.9 dBm; line Attenuation Down: 54.0 dB, Up: 24.5 dB; snr Margin Down: 18.0 dB, Up: 12.1 dB)
00:59:26   5 Jun     FIREWALL event (1 of 29): created rules
00:59:25   5 Jun     xDSL linestate down

 

I cannot get to 3 days without a disconnection. I have tried before and and been lucky to get beyond 3 days very rarely.

 

So I am now back to 2mb profile as seen on the beta speed test. Like some others the normal speedtest fails to work now, though it used to do in yhe past.

 

To get my 2.5 mb profile back I have restarted and have the following stats.

 

ADSL line status
Connection information
Line state    Connected
Connection time    0 days, 0:15:00
Downstream    3,040 Kbps
Upstream    448 Kbps

ADSL settings
VPI/VCI    0/38
Type    PPPoA
Modulation    ITU-T G.992.1
Latency type    Interleaved
Noise margin (Down/Up)    12.5 dB / 18.0 dB
Line attenuation (Down/Up)    54.0 dB / 24.5 dB
Output power (Down/Up)    18.5 dBm / 11.9 dBm
Loss of Framing (Local)    0
Loss of Signal (Local)    0
Loss of Power (Local)    0
FEC Errors (Down/Up)    149 / 0
CRC Errors (Down/Up)    4 / 2147480000
HEC Errors (Down/Up)    nil / 0
Error Seconds (Local)    3

 

One of those faults that not seen as such by BT. I can manage this line to get the most out of it and I would like it back to 9db margin. Can you do anything.?

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Distinguished Sage
Distinguished Sage
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Message 9 of 12

Re: Target Signal Noise Ratio

Your estimated maximum speed is only 3904Kbs for your line length, so you are not going to see any real improvement until you are upgraded to ADSL2+. Then you should get about 4096Kbs.

 

You are now connected at 3040Kbs, which is probably the closest you are going to get, as you probably have occasional noise bursts, hence the error seconds count.

 

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mikew650
Contributor
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Message 10 of 12

Re: Target Signal Noise Ratio

I know I'm not badly off as i'm about 6 kms from the exchange. I just wanted to say leaving my router on all the time would result in a lower profile sometimes less than 1 mb. At least I can get my profile back to max using it as I do.

I shall switch off now while I'm at 3040 kbs and in 2 to 3 days time my profile will be back to 2.5 mb.

Thanks
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