justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
 ·AT&T Midwest
| reply to Old_Grouch
Re: Any 5100b technician page DMT/SNR data experts
I'm being patient because I'd rather have the problem completely fixed correctly, rather than quick fixed poorly, like they did when I was switch to a significantly poorer quality pair of wires on June 7th. (The change was from a pair capable of 5.4mb/1080 max attainable, to 3.2/600 max attainable.)
After reviewing yesterdays data and the day before, I think I might be seeing a larger trend across the entire day.
The lower download frequencies have significant SNRM degredation from 7am til just before 5pm. There's also typically a spurt of 100-300 CRC errors earlier in the morning too. Can't do it today or tonight, but sometime soon, I'm going to be reviewing the entire day's data for the last few weeks to see if I see the general trend during "business hours". I'd laugh if the hours match those of a local bank.
The "bit migration" problem occurs once or twice each morning. If it lasts for 45 minutes, it will usually only occur once. If it lasts for 35-40 minutes, it will usually occur twice. I need to reanalyze my data, but that's what I think I'm seeing.
I like your 3x5 crazy idea cards. Actually, a co-worker of mine who was having DSL problems proposed that some of the ASI telephone people have an 8-ball or a dart board that is weighted heavily on "inside wiring", "squirrels chewing on the wires", "high performance errors", and "bad modem". I would say "inside wiring" was the one that they hit me with the most.
--justbits |
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klevin
join:2004-07-26
Takoma Park, MD | how do you get those nice graphs (spectrum analysis?) |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
| I wrote some bash shell scripts.
I gather the technician data from the 5100b.
I parse out the SNRM & DMT data.
I put them into separate files.
I feed the data into gnuplot.
I gather and plot the data periodically (at least every 5 minutes) using a cron task.
I'm doing this on MacOS X, but I suppose it would be trivial to port to Linux or Cygwin.
--justbits |
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misskaz
@chcgil.ameritech
| reply to justbits
We're on the north side of Chicago - Lawrence and Ashland - but not as far west as you are. Our exchange is 773-275, so we're not in the same central office.
Apparently our internet connection has been worse than I previously thought - I'm on a laptop in the living room so I'm rarely looking at the modem, and I get much of my fill of the internet at work. According to my boyfriend, who is on the internet at home much more than I am, the connection was going out so often recently that we could barely keep the connection going for more than 1 hour.
I say "was" because today I woke up to find our internet not working and our voice line completely dead - no dial tone. I went out to the NID and couldn't get a dial tone there, at the one that had our apartment number on it. I called SBC and they must have detected trouble on the line, because they sent out a tech. (Although it turns out the jack at the NID with our apartment # and no dial tone wasn't actually the one for our apartment - isn't that helpful?)
After some testing on the jacks in the apartment, the tech found that a busted jack in our den that we never used had a broken connection, which somehow was screwing things up for the working jacks in the other rooms. Once he fixed that, our voice came back and our DSL has been working for an hour now with no problems. I'm optimistic, although I think my boyfriend has been so frustrated with all this lately that he still thinks our connection will drop.
Now we just have to wait to see if 1) the DSL keeps working and 2) we get charged for that tech visit despite subscribing to line-backer.
Good luck to you, justbits. I too admire your patience. |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
1 edit | Lucky me. A bunch of managers and techs were on site yesterday for a vendor meet. (SBC Ameritech-POTS + SBC ASI-DSL). Of course, they blamed the problems on my wiring AGAIN. I had a directly connected home run CAT 5 cable into the DSL modem and a regular microfilter in the NID that only provide POTS on a separate CAT 5 cable. They "replaced" those. They gave me an in-NID microfilter and a home run. The home run is a single, white outdoor CAT 5 cable into a simple plastic box marked "DSL" and "Phone". One pair of wires is DSL. One pair of wires is POTS. The in-house jack on the end of the home run has two CAT5 RJ45 8-pin connectors on it (it's not your the RJ11 6-pin jack that you'd normally expect.)
The in-NID microfilter seems to be signifcantly worse than the in-house ones that they provide! Isn't that great?
I used to get 3.2mbps max attainable. Now I'm down to 3.0 max attainable.
Best part is *drum roll please* the noisy signal still occured this morning.
I'm trying to see if I can get SBC to replace my F1 & F2 pairs with the previous ones that I had so I can get back to doing 3008/512. (The 5.4mbps+ capable wires.)
Here's a picture of the in-NID filter that I got. I'm probably going to see if I can figure out how to bypass it and run the pure POTS+DSL signal on one the DSL wire pair into my own in-door filter or even just run the customer side DSL+POTS wires directly into the modem.
Can anyone find who makes this device and what the internal wiring of it is? Is it an in-NID microfilter? It seems like it's gotta be.
SPS-SA1-SR1
104510-1A
E112187/4184
Communication Circuit Accessory
--Steve |
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Riss_Centaur
Mod'taur - - - - 4 On The Floor.
Premium,MVM,Ex-Mod 2005-07
join:2004-01-20
other
clubs:
1 edit | That splitter is a corning/siecor.
»www.corningcablesystems.com/web/···5-EN.pdf
Fairly standard in-NID pots splitter-filter.
-Riss
--
I have a plan so cunning you can pin a tail on it and call it a weasel! |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
2 edits | Riss: Thanks for digging up the information on the splitter!
I just finished running a brand new grounding wire to my TV antenna.
Menards copper grounding spire
Radio Shack 40 ft Aluminum Grounding Wire
I sanded off the wire terminals that connect to the antenna to the RG6 cable.
I also added a 25 foot run of cable to completely remove how taught the antenna cable used to be. I also used rubber outdoor tape to wrap the junction of the antenna to 25 foot cable run.
Today, I ran a new grounding wire to my TV antenna.
Menards 5 foot copper ground steak
Radio Shack 40 ft Aluminum Grounding Wire
I sanded off the wire terminals that connect to the antenna to the RG6 cable. I also added a 25 foot run of cable to remove how taught the antenna cable used to be.
It's amazing. I've always had static on Channel 2 & Channel 5. Even before today and at 12noon and 3pm. But, I'm not an avid TV watcher of those channels at all times of the day.
The change was made between 3pm and 4pm.
At 4:00 til 4:45, I had periodic spurts of extreme interference on Channels 2 OTA and Channel 5 OTA. (Over the air) It would be very noisy for a while, disappear for a few minutes or seconds and then reappear.
After 5:00pm or so, Channel 2 OTA and Channel 5 OTA show up with absolutely no interference!
At 8pm (now), the interference is back. (hrmm)
I'm going to start watching 2 & 5 to see if the high periods of interference coorlate with my DSL noise interference.
I just recalled that a few months ago (not sure when) my kitty-corner backyard neighbor installed a brand new roof top antenna. I don't believe he has his antenna grounded. It's also one I've never seen before. It's very very large. Even bigger than the biggest that Radio Shack sells.
Here's what my neighbor's antenna looks like.
Has anyone seen an antenna like this before?
See that telephone cable, where it runs down the pole into the ground. That's where my telephone wire goes about 300 feet underground to a cross connect box on a side street (that's a F2 pair). From the cross connect box, it goes directly to the CO (that's a F1 pair.) In the air from my house to the pole, I estimate that's between 130 and 150 feet. I'm pretty darn close to my neighborhood cross connect box.
I can see my neighbor's RG6 cable, but no grounding wire from this angle.
I'm probably going to stop by the neighbor and ask what model/brand it is. Then I'll ask if he's got it grounded and the RG6 cable surge protected. (It's best to have both, right? I do.)
--justbits
[edit: added note about f1 & f2 pairs] |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
| reply to justbits
I just found out that the reason why I'm down to 3.0 max attainable is because they switched my F1/F2 pairs on Thursday, in an attempt to solve the noise problem.
That's three pairs of wire that exhibit the same noise problem. Because the noise isn't causing a loss of sync anymore, I'm trying to get back the 5.4mpbs max attainable pair.
--justbits |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
1 edit | reply to justbits
My dad spotted the neighbor's antenna at Menards. $70
Phillips Magnavox
MANT901
51 elements
VHF 200 miles
UHF 80 miles
FM 150 miles
Digital & Satellite compatible
I've got a NTSC video capture device. I've got some samples of how great the signal looks at 7:49 am this morning, compared to 12:52am this afternoon. The differences are amazing.
10.5 SNRM on 5660 modem:
 200507080749···snap.zip 333905 bytes
(200507080749chimneysnap.mov)
8.5 SNRM on 5660 modem:
200507081244snap.zip 329365 bytes
(200507081244snap.mov)
--Steve |
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lev
Napoleon is always right
Premium,Ex-mod 2002-08
join:2001-05-30
Chicago, IL
clubs:  | Can you summarize, in two paragraphs or so, where we are now? This thing reads like an epic.  |
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justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
| Here's a one line summary:
SBC does not have the ability or expertise necessary to troubleshoot RF interference problems.
You're SOL if you have an RF interference problem on your DSL or telephone line!
Here's a summary of the epic:
SBC tried swapping telco lines three times. Each time the F1/F2 pair was swapped, they managed to find an increasingly worse line! Isn't that great! I went from a 5.4mbps max attainable line to 3.5mbps max attainable to the current 3.0 max attainable line. All three lines exhibited the same noise characteristics. Peridoically, during weekday mornings, the line suffers from noise that causes anywhere from a 3.0dB loss of SNRM (11.5 to 8.5) to a 7.5dB loss of SNRM (10.5 to 3.0.) For 40 days, when the problem first started occurring, this same recurring source of noise was strong enough to cause my DSL modem to lose sync every time the noise occurred.
I personally have gone many different routes attempting to troubleshoot the DSL problem. I have used 4 different modems now (two SpeedStream 5100b, SpeedStream 5660, SpeedStream 5360.) I have tried multiple CAT 5 cables. I have eliminated all inside wiring down to a CAT 5 cable running in a window to 1 telephone and 1 DSL modem for weeks now. I have a SBC provided Home Run (CAT 5) that connects directly to 1 telephone and 1 DSL modem. No other telephone wires are in use. No other telephones are connected.
I have tried telephone surge protectors. I have tried multiple DSL microfilters. Nothing changes the noise problem.
Sometimes, the noise problem manifests in thousands of CRC errors in a short amount of time. The noise occurs at different times on weekends and holidays, but is very consistently repeated during the week: 40-45 minutes where DMT bit bins are reallocated and SNRM drops significantly across the download portion of the lower frequency spectrum.
From SBC Direct, the last bunch of responses have all been related to getting me to attempt to find the source of RF interferece. Suggestions have ranged from using an radio frequency spectrum analyzer, an AM radio, to CB radios to attempting to coorrelate TV interference with the DSL problem... to even talking with my nearest neighbors in an attempt to find out if any of them are seeing any telephone, TV, DSL, Sattelite TV, Cable or radio interference at the same times of day that I am. All of these suggestions require an absurd amount of my time and money to troubleshoot and attempt to isolate... especially when the problem occurs during times of day that I am normally at work, not at home!
The whole Cable TV suggestion came in because I recently found a cable modem filter laying in my backyard. A "ARCOM WHP-5/13" coaxial signal filter was laying in the bushes behind my house. It's a "return path filter".
»www.arcomlabs.com/pdf/window.pdf
The telephone issue came into play because my directly West neighbor has been complaining to SBC for months about static, noise and crosstalk on her telephone line, but she's afraid to have them come out because they keep threatening her with "fees". She's not so happy with that idea because the problem is intermittent and she just knows that they'll come out and look at the line when the problem is not occuring. (But I haven't gotten data from her to coorelate her problems with mine yet.)
My latest troubleshooting attempts on my own behalf are in attempting to use a Formac Studio DV NTSC TV capture device to automate the collection of Channel 2 & Channel 5 TV interference that I am experiencing. At different times and durations during the day, Channel 2 and Channel 5 experience the same kind of interference: a poor TV signal with lots of interference. At other times of the day, I get dang near perfect Channel 2 and Channel 5 reception. It's frustrating. I even have two antennas available that I am sampling from: my outdoor chimney mounted antenna and an indoor RadioShack Digital HDTV amplified antenna. It's very hard for me to try to compare the data I'm capturing from the different antennas and come up with conclusions that may or may not be related to the DSL noise problem.
The Channel 2 & Channel 5 interference has become significantly worse ever since I changed the grounding on my outdoor chimney antenna. In the next few days, my father and I are going to attempt to see if his CB radio is able to cause interference on my TV. (I doubt it.) We're also going to disconnect the new grounding wire that we added to see if that changes the interference level. We're also going to reposition the outside antenna to see if that helps eliminate the Channel 2 & Channel 5 interference.
I have eliminated all electronic devices from my house as being the source of interference. I did this one day by turinging off absolutely every appliance and device in the house (except for a computer, and the DSL problem still occurred. I haven't tried this for the Channel 2/5 interference I'm seeing yet.
The funny thing is that periodically, during the day, Channel 2/5 will go from being very fuzzy to very clear, to fuzzy to clear, back to fuzzy for a long time in a 35 second sample that I just took. (118MB of raw video) Sometimes, a ghost appears... sometimes it's just a lot of static.
To do some DSL regression testing, I returned the 5100b that I borrowed from my brother and even set up his computer to start logging 5 minute snapshots during the day. He is connected to a different CO and is over 5 miles East-Northeast of my location. He experiences no sporradic RF interference on his DSL line. I obtained a new 5100b from SBC. This new modem captures the noise problem exactly the same way as the other 5100b modem I was borrowing.
So, in short, I'm attempting to correlate the Channel 2/5 interference with the DSL interference, but I'm pretty sure that's not going to prove anything at all. Coordinating with my neighbors to find out about their interference problems may be the only course of action I have in getting the FCC to come out and investigate the problem.  Has anyone dealt with the FCC regarding interference before?
--Steve |
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