Here we go again, more upstream problems caused by interference

This has been an ongoing problem for over 2 years since I moved into this house.  Download speeds remain constant while upload speeds crash multiple times per day, down from 30 Mbps to less than 1 Mbps.  I've had multiple techs in the home with no resolution, it gets elevated to plant/line technicians who clean up interference in the upstream and the problem goes away for a few weeks/months and then it comes back as always.

I've eliminated just about every variable I can think of in my home.  It was built in Oct 2014, so barely 2 years old.  Never had TV installed, only internet, so no splitters and the drop line from the street to the home is relatively new.  PC is wired through the router, but wiring directly into the modem doesn't change anything.  Using cat6 ethernet cables, a Netgear CM600 modem and R7000 router.  Problem was identical when I used a SB6190 modem as well.

With me being home more the last week around holidays I've been able to monitor my connection very closely.  I can be gaming online and notice the second the issue happens that causes my upload speeds to crash.  I can predict within a few minutes when some error messages will appear in the modem logs.  I've been getting an increasing amount of T3 and T4 errors, and considering my previous history in combination with the errors, the only logical explanation is interference/noise in the upstream channels.

When visiting family I can check their modem logs and only see a handful of errors for months at a time.... I've been getting 10-15 a day.  Today has been a bad one with nearly my entire log page filled with errors only from today.  Here's a snapshot of what my modem levels and logs look like:

Notice how the correctable/uncorrectable errors build up to a certain frequency and then just stop altogether?  I'd bet money that whatever interference is causing the upstream problems is also causing those problems.  Whenever I notice the problems starting to occur, I can go do a speed test at Cox, testmy.net, dslreports, speedtest.net... it doesn't matter.  I will get 300 Mbps down and less than 1 Mbps up.  My most recent test at Cox is 317 down and .79 up.  This will happen only a few times a week and then accelerate, right now it probably happens 3-4 times a day and lasts 30 minutes to an hour each time.


I'm tired of calling support on the phone, them telling me the modem levels look appropriate, resetting the modem remotely and then saying it should be fixed.  I'm not an idiot, I know when it's working and when it's not.  I also know that power cycling the modem doesn't work, it won't fix the cause of the problem when is interference somewhere on the line before it gets to my house.  

I know this has been resolved at least 3 times in the past by a plant technician, George.  He usually emails me when he's done to let me know what he did and to ask me if the problem has subsided.  I don't know if he creates a work number each time he works on it or not if an employee here is looking up my account.  I'm getting to the end of my patience though with how this keeps getting a band aid and never permanently resolved.  I'm also tired of having go through the whole song and dance of calling phone support, having a tech in the home tell me exactly what I already know and having to take a day off work before it is finally referred to someone who can actually address the problem.  Then it's a whole other issue if they actually resolve the problem.... clearly they haven't found a fix yet but instead keep employing temporary measures.

The reason I post all this is I'm hoping someone at Cox can help me skip the procedure of checking levels in home that I have to take off work for them to say they can't find anything wrong.  The last 3 guys haven't found anything wrong and only one of them even had the decency to refer it to a line technician, the other 2 just said it looked good and that they fixed it (they did nothing).  The errors in the modem log and all the pattern of correctable/uncorrectable errors in the downstream make it pretty obvious what's going on and that nothing can be done in the house to fix it.  I'm spent a lot of time and money on my end to find a resolution to this, I just wish Cox would make the same effort.  Otherwise, what's the point of paying for the Ultimate tier connection when i'm getting the connectivity of the most basic tier.