Noise Margin reset query

If I use the Telnet facility on my Netgear DG834Gv4 to reset my target noise margin will this register as a fault at the exchange and result in my default noise margin being raised?
My sync was 4768 and my margin 6.9 (this had been stable following a target reset 15 days earlier). Resetting my margin to 6dB (66%) resulted in sync 4896 at 7.2 margin. My internet connection then became disconnected (red light on router). Then reset margin again got 4608 at 7.6 margin. Can someone offer any explanation?

Strange figures, but without doing a logarithmic calculation I suspect your untweaked sync-time (target) margin is 9dB, and you are tweaking to 66% of that. Remember, 50% of 9dB is 6dB.

As long as you don't do several re-sync's in a short time I wouldn't expect the MSAN/DSLAM to react by raising the target margin.

That you should then have had a disconnection sounds more like coincidence to me. Some other event causing it.

In reply to a post by RobertoS:

Strange figures, but without doing a logarithmic calculation I suspect your untweaked sync-time (target) margin is 9dB

Confirmed by 66% of 9 dB = 7.2 dB {10 x log (0.66 x 10^0.9) }.

You need to read off the NM immediately after a re-sync to get the Target NM and make sense of these figures. Did you do that in all cases?

In reply to a post by XRaySpeX:

You need to read off the NM immediately after a re-sync to get the Target NM and make sense of these figures. Did you do that in all cases?

I have checked back over my RouterStats log which is set to log every 5 sec. and observe that whenever I resync the initial margin is similar to the figures I quoted in my original post. Is this the way to do it ? If not please advise. I am however reluctant to resync now as I have now been steady at at 4928 and 6.8dB for 16 hours. Highest sync I have ever achieved.

Thanks for the post on log calculations, dusted off my book of log tables but could not remember how to use them. (same problem with slide rule)

In reply to a post by RobertoS:

That you should then have had a disconnection sounds more like coincidence to me. Some other event causing it.

Reasssured by your post-thanks. As my BT download speed (checked on two other speed testers) became higher than my ISP imposed profile and changes were due by ISP on the 12th they may have been responsible. Things have been stable now