Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: SNRM tweaking  (Read 1870 times)

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6971
  • Retd sw dev; A&A; 4 7km ADSL2; IPv6; Firebrick
SNRM tweaking
« on: December 22, 2015, 04:16:05 PM »

Could anyone tell me if they have any experience of SNRM tweaking and on what device? What level has been successful for you?
Logged

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 25889
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: SNRM tweaking
« Reply #1 on: December 22, 2015, 04:36:39 PM »

I have done so on Broadcom based devices (Huawei HG610, HG612 & HG622).

The rule I have followed is to monitor the daily swing in DS SNRM for a week (or even a month) and then tweak by the value that will allow there to still be a 3 dB SNRM at the lowest point of the 24hour cycle.
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6971
  • Retd sw dev; A&A; 4 7km ADSL2; IPv6; Firebrick
Re: SNRM tweaking
« Reply #2 on: December 22, 2015, 05:08:56 PM »

In that case then starting with a target SNRM of 6 or 7 dB and then at least trying 3 dB should be reasonable?

One thing that attracted me to Billion modems is the possibility of SNRM tweaking. This would only be relevant if the 21CN standard 3 dB profile were not usable but something in between 3 and 6 turned out to be of some value. (I don't know if an intermediate value is even sensible. Half a bit?)
« Last Edit: December 22, 2015, 05:18:32 PM by Weaver »
Logged

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 25889
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: SNRM tweaking
« Reply #3 on: December 22, 2015, 05:26:43 PM »

In that case then starting with a target SNRM of 6 or 7 dB and then at least trying 3 dB should be reasonable?

It would, indeed, be a reasonable experiment.

When I was using an HG612 on my ADSL2 line, I actually saw the SNRM go negative and the device held on all the way down to -1.9 dB. It was only at -2.0 dB DS SNRM that it finally let go and re-synchronised back at a 6 dB DS SNRM level.
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

Black Sheep

  • Helpful
  • Kitizen
  • *
  • Posts: 4941
Re: SNRM tweaking
« Reply #4 on: December 22, 2015, 05:31:54 PM »

Didn't Konrado have some kind of similar success, Mr Cat ??
Logged

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 25889
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: SNRM tweaking
« Reply #5 on: December 22, 2015, 05:44:52 PM »

Didn't Konrado have some kind of similar success, Mr Cat ??

Yes, he did. I believe he set his target SNRM to a fraction of 1 dB, on one occasion. Being an xDSL service in Poland, we were really uncertain what would have happened but, if I remember correctly, his circuit was very well behaved and remained stable with an essentially non-existent SNRM.
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

Black Sheep

  • Helpful
  • Kitizen
  • *
  • Posts: 4941
Re: SNRM tweaking
« Reply #6 on: December 22, 2015, 05:51:58 PM »

Thanks, BC ...... can you remember his DS attenuation for comparison purposes ??
Logged

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 25889
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: SNRM tweaking
« Reply #7 on: December 22, 2015, 06:13:06 PM »

Thanks, BC ...... can you remember his DS attenuation for comparison purposes ??

Unfortunately not. But I have a vague feeling that it did not "indicate" a line of short length . . .  :-\
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: SNRM tweaking
« Reply #8 on: December 22, 2015, 06:49:00 PM »

My attenuation at this moment on Netgear DGND3700v2 is 23.5/15.5 dB. At this moment I have SNR margin ~4 dB and the same synchronization since 4 months. But upstream SNR margin is consistently deteriorating. On the first month I have ~6 dB, now I have ~2.5 dB. On the first month almost 0 CRC errors on weeks, now I have about 60 000 CRC errors per 12 hours.

Best regards
konrado5
Logged

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: SNRM tweaking
« Reply #9 on: December 22, 2015, 06:54:11 PM »

Logged

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6971
  • Retd sw dev; A&A; 4 7km ADSL2; IPv6; Firebrick
Re: SNRM tweaking
« Reply #10 on: December 22, 2015, 06:56:09 PM »

Indeed I remember Netgear modem routers showing negative SNRM (as some huge wrapped-round number).
Logged