Noise Causing ADSL Sync Loss?

[bishop_dsl_user]

My Westell W327 modem/router combo started dropping sync (frequently loosing the DSL connection/DSL LED going off) about three weeks ago.  The drops appear to be time of day related.  Everything is UP and stable between about the hours of 8:30pm and 7:30am.  During the main part of the day, however, the Westell W327 goes down and then comes back up about every 5 minutes.  Prior to the current problem, my DSL had operated flawlessly for 1.5 years at an upstream rate of 447kb/s and downstream rate of 1,787kb/s.

Knowing how difficult it can be working through Verizon's foreign call center tech support process, I decided to wait a couple of weeks and see, if things would clear up on their own.  They didn't; therefore, I went through the mandated"Verizon support procedure" starting on 20 July.

Here is the specific data pertaining to my problem:

1.  Modem/Router - Westell W327 (D90-327W15-06 Rev. J)
2.  NID is connected to a Corning external POTS/DSL splitter (p/n 202-246), located about 4 inches from the NID (connecton posts labeled "network").
3.  Westell W327 is connected to the DSL splitter (connecton posts labeled "dsl") via a direct copper wire pair of about 4 feet in length.
4.  All voice telephone wires are connected to the DSL splitter (connecton posts labeled "voice").  NO DSL filters are employed whatsoever.
5.  Approximate number of "route feet" to the C.O. is 19,500 (ADSL-2, connection type is "routed bridge").
6.  All electronics, lights and even the airconditioning system within the house were turned off or unplugged to no avail.
7.  Sample of Westell W327 "system log" is listed below (please note that all log times are for the Eastern Time Zone, whereas, I live in the Pacific Time Zone -- therefore, subtract 3 from the hour to get local time):

FRI JUL 24 19:08:39 2009
      US Atten:     40.5 DS Atten:     58.5
FRI JUL 24 19:08:39 2009
      US Margin:     16.0 DS Margin:     10.0
FRI JUL 24 19:08:39 2009
      US Tx Power:     12.0 DS Tx Power:     16.3
FRI JUL 24 19:08:39 2009
      US DSL Rate:  447 kbits/sec DS DSL Rate: 1787 kbits/sec

FRI JUL 24 19:08:39 2009

      WanMgr reports DSL is UP

FRI JUL 24 19:07:53 2009

      WanMgr reports DSL is Down

FRI JUL 24 19:07:48 2009
      US Atten:     40.5 DS Atten:     58.5
FRI JUL 24 19:07:48 2009
      US Margin:     16.0 DS Margin:      2.5
FRI JUL 24 19:07:48 2009
      US Tx Power:     12.0 DS Tx Power:     16.2
FRI JUL 24 19:07:48 2009
      US DSL Rate:  447 kbits/sec DS DSL Rate: 1787 kbits/sec

FRI JUL 24 19:07:48 2009

      WanMgr reports DSL is UP

FRI JUL 24 19:07:48 2009
      WanMgr reports DSL is Down

FRI JUL 24 19:01:11 2009
      US Atten:     40.5 DS Atten:     58.5
FRI JUL 24 19:01:11 2009
      US Margin:     16.0 DS Margin:     10.0
FRI JUL 24 19:01:11 2009
      US Tx Power:     12.0 DS Tx Power:     16.2
FRI JUL 24 19:01:11 2009
      US DSL Rate:  447 kbits/sec DS DSL Rate: 1787 kbits/sec

FRI JUL 24 19:01:11 2009
      WanMgr reports DSL is UP

After spending several hours on the telephone, it was arranged for a lineman to pay a visit to my residence.  He arrived on the appointed day (22 July) and confirmed all of the particulars.  He only had test equipment that allowed him to check for continuity, line attenuation and distance from Central Office.

My wire path to the C.O. appears solid (although it is a LONG ways from the C.O.).  We could hear NO audible noise on the telephone lines.  But his and my opinion is that the Westell W327 is dropping sync because of intermittent line noise/interference.  If you look at the oldest (bottom) of the three groups of log entries above you will see that the DSL goes down about 5 minutes later.  The modem senses almost instantly that the line is up and restarts the line (or whatever you call that process).  Unfortunately, the downstream margin (which I take to be the margin of signal over noise in dB) at 2.5 dB is still too low to bring up the line.  It almost instantly, tries to resync the line again and is successful with a downstream margin of 10.0 dB.  It appears to me that the noise has temporarily gone away.  And the DSL will stay up for a few minutes until (presumably) another burst of noise is experienced.  I could have listed pages and pages of log entries, but they are substantially the same as the sample above.  Data rates NEVER change, upstream and downstream attenuation remain the same, as does the upstream margin.

The lineman agreed with the "noise" theory but didn't have any suggestions other than to try a different modem, which might be better able to deal with the noise situation.  Unfortunately, he had already loaned out all of the modems that he uses for testing.  So, I'm waiting for a modem.  Because everything works fine for 10 or 11 hours at night, I personally don't believe this is a modem problem, but "Oh Well."

Question No. 1
Is there anything else at this time that can be checked or done?  Apparently, the Bishop, California, Verizon office doesn't have any field test equipment capable of measuring signal/noise levels.

Question No. 2
The agravating thing about the Verizon tech support process is that every night I get a pre-recorded message saying that Verizon has automatically tested my line and everything has been fixed and that my trouble ticket has been closed.  This means that I have to go through the "call center" routine every day to keep my trouble ticket open.  (The lineman claims that he isn't closing the ticket.)  Dealing with people at Verizon is a GOOD experience.  Dealing with the Verizon support system, however, is NOT so good!!!  Is there any way to get Verizon to keep the trouble ticket open (at least until the problem has been fixed) so that my modem can be delivered and the lineman return?

[bishop_dsl_user · Accepted solution]

My problem was solved by the Verizon lineman.  There was nothing wrong with my modem, which is the first variable that testing eliminated.  The lineman did two things after which my problem was fixed.  I'm not sure, if both or only one of them was responsible for resolving the problem.  The first thing that he did was to cut out an old "bridge tap" up at the top of the telephone pole to which the wire pairs from my NID are connected.  The second thing that he did was to adjust some devices further down the line.  I can't remember exactly what he called them, but he explained that they were sort of like amplifiers.

Anyway, my modem came back up (when he was done) and displayed the BEST statistics that it ever has.  Please remember that I'm about 19,500 route feet from the Central Office.  The following data shows what my modem was experiencing before and after the fix:

BEFORE:
-------------
MON JUL 27 09:34:26 2009
      US Atten:     40.5 DS Atten:     58.5
MON JUL 27 09:34:26 2009
      US Margin:     16.0 DS Margin:      7.0
MON JUL 27 09:34:26 2009
      US Tx Power:     11.8 DS Tx Power:     15.9
MON JUL 27 09:34:26 2009
      US DSL Rate:  447 kbits/sec DS DSL Rate: 1787 kbits/sec

AFTER:
----------
MON JUL 27 18:14:40 2009
      US Atten:     36.5 DS Atten:     57.0
MON JUL 27 18:14:40 2009
      US Margin:     20.0 DS Margin:     17.0
MON JUL 27 18:14:40 2009
      US Tx Power:     11.9 DS Tx Power:     15.9
MON JUL 27 18:14:40 2009
      US DSL Rate:  447 kbits/sec DS DSL Rate: 1787 kbits/sec

As you can see, my line attenuaton (both directions) was improved.  More importantly, both my upstream and downstream signal to noise margins were improved.  upstream margin went from 16.0 to 20.0 dB.  More importantly, the downstream margin went from 7.0 (it previously varied between about 2.5 and 11.0 dB) to a wonderful 17.0 dB.  My DSL line has NOT gone down in almost 24 hours!

Regarding my other issue (somebody in the Verizon support system automatically closing my trouble ticket each night after seeing line continuity with my modem), the lineman explained that he doesn't pay any attention to such nonsense.  He closes his work ticket, when he verifies by actual telephone call with the customer that the problem is resolved (or informs them that he can't do any more for them).  I stand by my original statement that the Verizon field people are GREAT.  The Verizon system itself, however, leaves something to be desired.

To recap, both the lineman and I feel that there was some new source of noise on my line that was causing the original problem.  The lineman's two fixes worked to increase my signal to noise margin up to a level where it could overcome these periodic noise spikes.  I suspect that such problems are hard to resolve, but I got lucky and found a lineman who had enough practical knowledge and determination to help me out!!!  Thanks Ron!!!