Kitz Forum
Broadband Related => Broadband Technology => Topic started by: Weaver on December 22, 2015, 04:16:05 PM
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Could anyone tell me if they have any experience of SNRM tweaking and on what device? What level has been successful for you?
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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.
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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?)
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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.
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Didn't Konrado have some kind of similar success, Mr Cat ??
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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.
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Thanks, BC ...... can you remember his DS attenuation for comparison purposes ??
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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 . . . :-\
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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
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Weaver:
Following there are my old posts about tweaking SNR margin.
http://forum.kitz.co.uk/index.php/topic,13884.0.html
http://forum.kitz.co.uk/index.php/topic,13750.0.html
http://forum.kitz.co.uk/index.php?topic=13775
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Indeed I remember Netgear modem routers showing negative SNRM (as some huge wrapped-round number).