Noise margin on line suddenly dropped from 14 dB to 11 dB...

[mtsindy]

I use UVRT to check my line stats, error totals, and bitloading a few times a week.  This morning, I logged in and saw red -- literally.  The noise margin on my line had been 14 dB since we got U-verse in Nov 2009, but this morning it is reporting as 11 dB.  I did a power-cycle on the RG, but the noise margin didn't improve.  

The utilization on the line is now over 90%, whereas it used to hover in the mid-80s.  Likewise, UVRT is now recommending the 25/2 profile, since I'm technically overdriving my current line with the 32/5 profile I have had since it rolled out.  The estimated distance from the VRAD hasn't changed though.  I did notice on the bitloading graph that things look good with the exception of about half as many upload bits in the 5.3-5.7GHz range.

I can post screen shots from UVRT this evening, but I am curious what may have caused the drop (since about last Thursday) in the noise margin.  I am assuming this drop is what's driving or related to the other anomalies I am seeing in my statistics in UVRT.  We haven't made any changes whatsoever (wiring, new devices, profile changes, etc.).

Also, what should I be concerned about in terms of potential issues?  We haven't noticed anything odd in our services (voice, internet, TV), but it sounds like an 11 dB margin is at or below the service threshold.

[JefferMC ACE - Wizard]

Something has changed in your environment.  I could be that a new U-verse subscriber has hooked up and now there is crosstalk in your bundle causing issues.  It could be that rain has penetrated a pedestal case and one of your connection points has been compromised.  It could be that an AT&T voice customer in your bundle has disconnected and there is an open pair acting as an antenna and placing crosstalk on your pair.

Unfortunately, the best way to figure out which of these things it really is (or something else entirely) is to get a competent engineer to look at what's happening on your line.  You may have to wait until it affects your service before you can log that service call though.

[mtsindy]

Thanks, JefferMC.  That is good information to have available, should it be needed.  I came home this afternoon, fully prepared to take screenshots and scan my services for signs of trouble, but what did I see?  Everything back to its normal, pristine state.  (I checked my baseline screen shots from a few months ago, and it turns out my noise margin was -- and is now -- 16dB, not 14dB as I stated in my initial post.)

Perhaps as you suggested, there was some work going on at the RT or VRAD, and it was left overnight before being resolved sometime today.  Either that, or maybe I watered my hydrangeas a little too vigorously.