Line Stats Analysis Results

Expert

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 (5.29.135.47).

 

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 (8,750 Views)
ACE - Expert

Re: Line Stats Analysis Results

Think pair bonding will help alot in your case as you are living right on the edge w/no headroom for comfort. :smileywink:


Chris

____________________________________________________________________

Please NO SD stretch-o-vision or 480 SD HD Channels
Your Results May Vary, In My Humble Opinion
I Call It Like I See It, Simply a U-verse user, nothing more

*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
Message 226 of 283 (1,225 Views)
Expert

Re: Line Stats Analysis Results

You have a bridge tap in that line also.  Removing that alone will probably improve your max rate by at least 5 Mbps.

 

Message 227 of 283 (1,225 Views)
Expert

Re: Line Stats Analysis Results

Joe, I downloaded the latest update of the Uverse Realtime app, and I noticed I could see 3 of my stbs and what channels they were on with the wireless laptop.  However, I didn't see the dvr stb in the list.  I also noticed that the dvr info was not listed.  I am just pointing this out, I figured you already know.  Just making mention of it.  I do see it when I use the computer that is connected wired to the RG.

Message 228 of 283 (1,225 Views)
Expert

Re: Line Stats Analysis Results

I can't guarantee that everything will work properly on UVRT with wireless because different wireless cards handle the multicast traffic very differently.

 

I know that most of the Intel wireless chipsets built into many laptops will work pretty good.  I have reports of other wireless chipsets working OK also.  But I also have seen ones that don't work at all and ones that only work partially.  It completely depends on the manufacturer's drivers and how they handle multicast over wireless.

 

Message 229 of 283 (1,225 Views)
Contributor

Re: Line Stats Analysis Results

Thanks Chris and thanks Joe!

I appreciate the input.and time.

Message 230 of 283 (1,225 Views)
Teacher

Re: Line Stats Analysis Results

Hey SomeJoe... could you give me your opinion of my bitloading also? Here is a screenshot...

1859i83EB2A6EC4928E0B

Message 231 of 283 (1,408 Views)
Expert

Re: Line Stats Analysis Results

Distance-wise it looks fine, and there appears to be no bridge taps.

 

However, there is some interference at the 1.0 MHz point.  This could be a close AM radio station or some other type of electronic device that's interfering.  Doesn't look like it's really affecting your service, though.

 

Message 232 of 283 (1,408 Views)
Highlighted
ACE - Expert

Re: Line Stats Analysis Results

Zeonis, put your cursor right in the very middle of that point about 1000khz  to find the frequency, then go to radio locator to find the station.


http://www.radio-locator.com/

I have 760 WJR and 800 CKLW hit my bitloading chart here in metro Detroit, but no problems from them. :smileywink:


Chris

___________________________________________________________________

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

*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
Message 233 of 283 (1,408 Views)
Teacher

Re: Line Stats Analysis Results

I checked my bitloading again and found the interference is now less. Based on radio-locator.com it would appear I am getting interference from 1050 AM KTCT which is 3.9 miles away and 1100 AM KFAX which is 4.9 miles away. I would think that I would get interference also from 860 AM KTRB which is 4.8 miles away but I don't see that it is showing up in the bitloading. Here is another screenshot...1861i4E26005C19809AA7

Message 234 of 283 (1,411 Views)
ACE - Expert

Re: Line Stats Analysis Results

W/o seeing the chart yet, might be night time antenna orientation away from you.  KTCT has a smaller night time footprint, KFAX doesn't have a coverage map, but is 50,000 watts 24 hours.  It may hit you w/lower signal strength though at night time. :smileywink:


Edit: Looking at your original bitloading chart I clearly see a spike at 860 kHz for KTRB, it has a night time change too.

 

Chris

______________________________________________________________________

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

 

*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
Message 235 of 283 (1,411 Views)
Professor

Re: Line Stats Analysis Results

Just for shoots and giggles here are my stats.2198i46B336D6706AE3BF2200iDA7694CA20A2FAB02202i15427A15E5F37E25

Message 236 of 283 (1,411 Views)
ACE - Expert

Re: Line Stats Analysis Results

Looks good NorthLine Tony, you're getting hit by WJR (760), just down the street from you, but shouldn't affect any service.  I see it a bit less over here in Grosse Pointe Park, but also see CKLW (800) in mine, but no problems. :smileywink:


Chris

___________________________________________________________________________

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

*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
Message 237 of 283 (1,411 Views)
Explorer

Re: Line Stats Analysis Results

I'm wondering if I'm able to get a 3HD profile, based my stats i dont think so.  could someone please take a look at my stats and offer any suggestions for improvement?  thanks in advance.

 

2220i7F5639286B5CBFB1

 

2218iB9F3AC5C18935AA1

Message 238 of 283 (1,411 Views)
Expert

Re: Line Stats Analysis Results

No, you will not be able to get the 3HD profile (currently).

 

Technically, you shouldn't really even be on the 2HD profile, but if it's working OK you might want to leave it.

 

There are rumors circulating that everyone will get one additional HD channel added soon, and if you currently have 2HD, you may end up with 3.  But I'm not sure how well your system is going to work if you attempt to eatch 3HD channels simultaneously.  Your line issues may cause problems at that point.

 

Message 239 of 283 (1,411 Views)
Explorer

Re: Line Stats Analysis Results

thats what I thought.  so in terms of improving my stats/performance,  any suggestions?

Message 240 of 283 (1,411 Views)
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