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Line Stats Analysis Results


Line Stats Analysis Results

This thread will contain the results of the analysis of everyone's line stats that have been posted in the Data/Stats Collection Thread.


My initial analysis is not focused so much on distance from the VRAD.  The reason for this is that not too many people have distances that have been told to them by a tech using their specialized meters.  Furthermore, different line conditions can cause inaccuracy in their measured distances.


As it turns out, distance from the VRAD isn't the most important thing regarding the type and quality of service that you get anyway.  Instead, the wiring gauge, presence/absence of bridge taps, and the noise margin (signal-to-noise ratio) of the line are much more important.


To this end, the data that has been posted in the Data/Stats Collection Thread led to a rock-solid and extremely useful correlation that can be used to immediately judge the quality of your line and the service you can receive.  That correlation is the Downstream Noise Margin and the Max Line Rate.


Using only these two parameters, you can tell if A) Your line is working properly (i.e.. no bridge taps), B) What gauge wire is running from the VRAD to your NID, and C) What line profile you should be able to get.


Please note that I arrived at the wire gauge conclusions here because there are two distinct groupings of data points.  I am assuming the difference between them is due to wire gauge, because A) It is known that different neighborhoods around the country use two different wire gauges, 22 gauge, and 24 gauge, B) Thinner wire (24 gauge) would have higher attenuation in the high frequencies, which would reduce the max line rate for a given signal-to-noise ratio, which is exactly what the graph shows.  It is possible that the two groupings of data are due to a different cause, but until I either gather more data or have references to other possible conclusions, I'm going to assume the difference is due to wire gauge even though I cannot currently prove that with certainty.


There is a 3rd grouping of data that shows some people with a drastically reduced max line rate.  I'm fairly certain these people have a bridge tap on their line that is reducing the max line rate.  If their line was conditioned by I&R to remove the bridge tap, their max line rate would jump up into one of the other two groupings.  I have witnessed this first-hand, as my initial installation was on a line that had a bridge tap.  When the bridge tap was removed, the max line rate shot up by over 15000 Kbps.  I unfortunately cannot compare the numbers that I had at that point to the numbers I have now because those older numbers were using the VDSL1 protocol and at least 2 revisions earlier of the RG firmware.  Those values cannot be reliably compared to today's values obtained with the VDSL2 protocol and the current RG firmware revision (


Here's the first fully analyzed chart:






You can plainly see how well the data groups are formed here.  There are two distinct lines of people with properly working service, and a 3rd line of people with service that is probably not running right.  In addition, you can see the very rare people who are so close to the VRAD that they are currently being capped to a maximum line rate of 64000 Kbps.


For those of you who have some background in statistics, the linear correlation coefficients (R^2) for each of the 3 trend lines on the chart was > 0.98.  (This means that the computed lines fit the actual data very nicely).


The allowable line profile areas were computed by assuming that a line capacity of 80% is required for properly working service.  Line capacity = downstream profile rate / max line rate.  For example, for a properly working 32/5 profile, the downstream profile rate is 32200 Kbps.  FOr a line capacity of 80%, that means that Max Line Rate = Downstream Profile Rate / 80% = 32200 / .8 =  40250 Kbps, which I rounded to 40000.  The other rates separating the profiles were computed similarly.  The exception is the border for No Service, where I upped the allowed line capacity to 85% to allow just a little less max line rate.


The people whom I believe have a bridge tap on their line are very interesting.  The bridge tap reduces the max line rate that the line could theoretically carry by nearly 30%.  In the particular case of the person with an 18.5 dBm noise margin and 29000 Kbps max rate, having the line conditioned could conceivably get him a max line rate of 41000 Kbps, which would boost his allowable profile from 19/2 to 32/5 !  He could conceivable go from 1HD/3SD to 3HD/1SD just by having the bridge tap removed.


The person with the 10.0 dBm noise margin and a 19200 Kbps max rate is certainly experiencing poor service.  The line capacity in his case is at 100%, with no margin for errors.



In short, this chart can tell you at a glance whether your service is operating in agreement with everyone else's service.  It can immediately identify what profile you should be on or be able to get.  It can tell you if your line needs conditioning to have a bridge tap removed.  Based on my assumptions, it can also tell you your wire gauge, although that parameter is questionable.


When people post their line stats, this chart can be very useful in quickly determining if they are experiencing line problems or if their service is in agreement with normally working service.


Message 1 of 283

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Re: Line Stats Analysis Results

OK, here is a revised Noise Margin vs. Max Line Rate graph, now that it is known that the data shows a correlation between profiles rather than wire gauge.






This graph shows a bit more information than the previous one.


For properly working service that won't have a lot of errors, you need two things:


1) Sufficient max line rate so that the line capacity doesn't exceed approximately 80% when compared to your profile rate.  Line capacities exceeding approximately 80% causes the line to begin to take some errors.


Line Capacity = (Downstream Profile Rate / Max Line Rate) * 100


2) Sufficient noise margin such that the line does not take errors.  From people's stats, I am estimating the minimum required noise margin to be around 12.0 dB.


These two parameters gives rise to the two red areas on the graph, where the noise margin is too low for reliable service, or the max line rate is too low even for the 19/2 profile.  The minimum required max line rate for the 19/2 profile is given as 21800 kbps.  This is where the 19/2 profile line (derived from customer data) hits the 12 dB noise margin, for a line capacity of 88%.  This line capacity is a little high, but since the alternative is no service, it may turn out to be sufficient.


Similarly, the 25/2 profile line intersects the 12 dB noise margin limit at 30400 kbps, establishing that as the minimum required max line rate for the 25/2 profile, at a line capacity of 83%. 


Finally, the 32/5 profile line intersects the 12 dB noise margin limit at 39700 kbps, establishing that as the minimum required max line rate for the 32/5 profile, at a line capacity of 81%.



What is very interesting here is how we now know that the noise margin changes significantly with the selected profile rate.  We also know that the max line rate stays relatively constant when the profile rate is changed (see djrobx's data a few posts above).  Because of this nearly constant max line rate and the consistency of the customer data which has given us the profile lines, we can now predict where you will end up on the graph when your profile rate is changed.


For example, let's look at the customer who is currently on the 25/2 profile line (red) at an 18 dB noise margin and 41000 kbps max rate.  When this customer is upgraded to 32/5, the max line rate will stay nearly constant at 41000 kbps (it may go down slightly, no more than a few hundred kbps), but his service point will jump horizontally to the left (constant max line rate) to land on the blue 32/5 profile line at a much lower noise margin.  We can predict from the graph that his noise margin will be around 13.0 dB.


Since we know what the new noise margin will be due to the profile lines, we can now also identify by noise margin alone those people who should be able to move to a higher profile.  For example, people on the 19/2 profile who exceed a noise margin of 19.0 dB should be able to move to the 25/2 profile, since their new noise margin will be above 12.0 dB.  Similarly, people on the 25/2 profile whose noise margin exceeds 16.5 dB should be able to move to the 32/5 profile, again because their new noise margin will be above 12.0 dB.


And just for fun, we can also estimate that those people on the 32/5 profile with a noise margin exceeding some value would theoretically be able to move to an even higher profile.  Assuming the noise margin drops 6 dB for an increase in the profile rate of 8-10 Mbps, we could theoretically predict the existence of a new 40/5 profile that would be eligible for rollout to people on 32/5 who exceed 18 dB of noise margin and 50000 kbps of max line rate.



Now, since noise margin and max line rate are locked together on these profile lines, predicting whether a person has a noisy line or a bridge tap becomes more problematic.  The Dohrenburg DMT plot can be instrumental here.  Removing a bridge tap or removing a noise source can raise the max line rate (and noise margin with it), possible allowing someone to upgrade their profile.  However, this has to be done on a case-by-case basis, as there is no guarantee how much additional max line rate/noise margin you can achieve.


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Message 70 of 283

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Re: Line Stats Analysis Results

Not much you can do, you're simply too far away from the VRAD.


Message 241 of 283

Re: Line Stats Analysis Results

bummer!  thanks for the insight.

Message 242 of 283

Re: Line Stats Analysis Results

I downloaded the UVerse Realtime tool but it can't connect to my router.  I have a 3800 HGV-B.  Any ideas?

Message 243 of 283

Re: Line Stats Analysis Results

Oops.  Needed to change the IP of the router.  Duh!






Everything looks ok to me here but I have issues from time to time, usually on my SD sets.  Any recommendations on anything I need to change?

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Message 244 of 283

Re: Line Stats Analysis Results

Your line looks good.  You may want to verify your in-house wiring.  If it's coax, look on the Coax/HPNA tab to see if there's any yellow or red readings.


Message 245 of 283

Re: Line Stats Analysis Results



My profile was similar to yours. I'm 2650-2950ft to vrad depending on what test I ran. For 2 years I ran at 25/2 with a max of 32m. It then dropped to 26M last month. I had a prem tech basically to a new install with everything being replaced from the nid in. This got me back up to a max of 32M, though I didn't qualify for an upgrade.  Then I replaced my coax with CAT 5 from the NID/SNI to the RG. Now I have 43M at 2555ft. I now running at the 1/3 profile. My advice is to have your prem tech run cat5 or do it yourself. 

Message 246 of 283

Re: Line Stats Analysis Results



Actually that statement about Therat_1 isn't true. Standard feeds on the 25/2 profile should be 2SD/2HD for wan and ingress and 1SD/2HD egress. 

Message 247 of 283

Re: Line Stats Analysis Results


coolrda wrote:



Actually that statement about Therat_1 isn't true. Standard feeds on the 25/2 profile should be 2SD/2HD for wan and ingress and 1SD/2HD egress. 


What statement are you referring to?  He's currently on 25/2 with 2SD/2HD and his line can't handle it.  He should be on 19/2 with 3SD/1HD which is exactly what I told him.


Message 248 of 283

Re: Line Stats Analysis Results

He's only asked if he could get the third HD stream, which he will soon even with the 25/2. Already rolled out in California. I don't think he was complaining about his existing service.


Therat you should be able to get 32/5 with your footage. I see 3 major problems that a good prem tech and maintenance splicer could work out in 1-2 hours.


Does his service need work. Sure it does if he is concerned about getting the 32/5. We here make up about 1/100th of 1 percent of the Uverse subscribers. If all a person wants is SD streams and 6meg HSIA then so be it. They are fine with 19m service. Though I am an ATT MST, I'm also a sub and want and expect the best that my service can give me. My biggest problem has been recording conflicts and when I had enough I finally did something about it.



Message 249 of 283

Re: Line Stats Analysis Results

For the record, I'm not un happy with my serivce.  I'm quite happy.  I was simply curious if there was anything that could be done to my existing set-up that would enable me to "upgrade" my profile.  Sometimes I have a 3HD conflict , meaning I would like to record two and watch a third, having that 3rd HD stream would be nice.   I think I'll call ATT and ask to have someone come out and take a look at my set- up.  Worse case scenario things stay the same- i still currently get two HD feeds with no problems (knock on wood).  Thanks for your input.

Message 250 of 283

Re: Line Stats Analysis Results

I got a new one for ya.

System is working great on 32/5 profile. But check this out. I checked my stats from the TV and for the past 2 weeks it shows under the menu-options-system resources. The following


WAM profile        1SD / 3HD Max rate 66960400 (what profile is this)

Ingress profile   1SD / 3HD Max rate 66960400 (what profile is this)

Ingress                1SD/  2HD


On realtime it shows 32/5. As well as the 2 Wire Network page.


I was wondering if anyone else sees this and what it might mean? I read somewhere else that pair bonding is coming soon. Does this look like it??


Somejoe or mill  I think this one is for you two  to answers

Message 251 of 283

Re: Line Stats Analysis Results

No pair bonding is using 2 pr instead of 1pr to push uvers out to 6000ft  and beyond. It means you have been updated to 3 HD simultaneously. You can record 3HD feeds and watch a standard def or record 2HD and watch another HD feed. Watch for 0/4 in the near future (9/19?)

Message 252 of 283

Re: Line Stats Analysis Results

I'm not currently having problems, but I ran the Dohrenburg analysis on my line and came up with


By chance, why is 2.484MHz always 0 in a VDSL2 setup?

Message 253 of 283

Re: Line Stats Analysis Results

2.484MHz is reserved for the VDSL pilot tone.


Message 254 of 283

Re: Line Stats Analysis Results

It's a pilot signal on all users systems. :smileywink:



Please NO SD stretch-o-vision or 480 SD HD Channels
1-866-465-1496 for direct TS to avoid Mr. Voice recognition
Your Results May Vary, In My Humble Opinion
I Call It Like I See It, Simply a U-verse user, nothing more

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