Extremely bad packet loss and service outages

The symptom began pre-COVID...about a year ago...and has progressively worsened to a barely operational connection.

First thing is to clean up the tangle of cable(s) outside your house.  Is this a single-family house with no other renters?

Except for a short segment of cable emerging from the ground and into the Network Interface Device (plastic box), you shouldn't see any coaxial cable outside the house.  Also, under an eave of a roof is no place for a splitter.

I'd first talk to your landlord about absorbing the cost of a tech because you shouldn't incur it.

The rat's nest may not even be the problem, but you should rule it out.

Looks like I spoke too soon. The issue has returned again, the packet loss and high latency again returning at hop 2 (10.5.0.1)

The modem signals page is not showing any uncorrectables this time though. Going to be calling another technician out to see if they'll just replace the entire line running to this particular cable jack.

Here are images of the outside cabling. Maybe "rat's nest" is not actually an accurate descriptor as I did not notice the bundle on the left was a drip loop below the ground. You can see the additional (and unnecessary?) splitter screwed in beneath the edge of the roof. I am unsure whether the landlord's contractor installed these cables or if they were run by cox.

I have not attempted to open the cable box.

My main question is now is if I have a technician replace any or all of this am I likely to expect a $75 service charge? I've heard their responsibility ends at the box on the side of the house. If so I'll just bite the bullet and subscribe to complete care for an extra $10/mo to lower the cost.

(Sorry for the filthy siding, we haven't bothered cleaning any of it during the winter months.)

Landlord informed me that the wiring for the cable was done by Cox before we moved in.

I also have a technician coming out to investigate and repair the lines today. I'll update later this evening as to whether or not it solves the issue.

Technician came early and I presented him with the information you guys pointed out to me. While testing the line he could not see any problem at that particular moment however he did acknowledge the antiquated NIU, the horrible wiring job, and the unnecessary splitters. He cut down a lot of the old wiring and replaced them, replaced the entire NIU and replaced the fittings on every cable. He mentioned that having the ground exposed is not really ideal but typically wouldn't be causing the issue I'm experiencing so he left that alone.

Whoever installed all of this wiring originally seems to have not cared about it "being up to code" and just installed it however they liked.

He also came inside and tested the line from the inside at my desk. He could not get a signal at all through my indoor coaxial cable so he replaced that as well. Before he did so though he also tested straight through the cable jack and that seemed to indicate things were fine. He did say that if the problem reoccurred to check the attic (where the cables pass through) to see if there were any more unnecessary splitters leading to my jack and he gave me a piece to replace said splitter with instead. If the problem reoccurs and there is no splitter or replacing the piece doesn't work, I was advised to call back and they would probably just run new lines.

Overall, he couldn't explain to me why the outside wiring was done the way it was outside of the person who originally did it being lazy or not caring, especially when it came to running the cables directly along the power lines from the junction box into the house, which he also fixed so they are no longer in contact with each other.

The SNR  for the OFDM PLC on the modem signals page is apparently a false reading. The current firmware I'm using is apparently notorious for showing the SNR on that channel as much lower than it actually is. I know there are newer firmware versions available but so far cox has not pushed an update to my modem which is presently on 8600-18.2.9.

In any case I left WinMTR run again for a good long while and took another snapshot of my signals pages. The odd (false?) reading on the OFDM channel aside, everything seems to be working perfectly now. If things go awry again later this evening, I will update this post again just for reference and in hopes of helping other people figure out what might be happening with their connections as well.

Tremendous thank yous to WiderMouthOpen and Bruce for helping me figure out what was happening here and how it should be addressed! Thank you to the Cox Technician Mel who went above and beyond to try to help remedy the problem in the field!

Here are my readings as of now, let's hope it stays this way:

"While testing the line he could not see any problem..."  I'll assume this test was at your outdated NIU to measure the signal from Cox before he did anything.  If he didn't detect any problems, this would be an in-spec signal from Cox.  This is good.  I guess the power line wasn't affecting your signal after all.

I imagine him clipping a hedge to replace your nest.  I also imagine your landlord install the nest.  (Just saying)

If his in-the-house test passed AFTER removing your nest, this is also good.

So your coaxial cable enters your house at the roof...into the attic...and down to the area of your desk?  Hopefully this rerun fixed your problem but if it does reoccur, a new, more direct connection to your desk-area would be nice.  Meaning, no routing through the attic.  If you do replace this portion, notify your landlord, again, because there'll be some drilling.

Overall, your new log looks good:  power on all downstream channels increased an average of 7.3 dBmV and SNR increased overall 0.5 dB, especially on the first 8 channels.  I'm happy to read 14.9 dB is an erroneous measurement.  Upstream specs look about the same.

Now let's rollback to bens1's attempt.  If you have a standalone modem, directly connect an Ethernet cable from the modem to a device and run a speed test.  If you have...for example...a 150 Mbps plan, your results should be close to 150 Mbps.  This will measure your bandwidth.  Now you're good at uploading images, post the results of your speed test.

Thanks, Mel!

I even got disconnected from this forum while I was attempting to post this.

Is the problem as bad as it was a week ago?

Was there a splitter in your attic?

The Cox router may be a choke point.

Another technician should be here in an hour or two.

Modem is currently showing a lot of T3 and T4 timeouts as of yesterday. I am also getting a few uncorrectables on Downstream channel 2 as well. I don't suppose 10.5.0.1 could refer to my own modem could it?

Technician came and went after an hour or so, could not see any issues on the line at all, their reader showed perfect speeds and no packet loss what so ever. He did go up to the pole and replace something just for good measure and called his supervisor to ask about having maintenance sit on this area and watch for anything happening very late at night (which is generally when I have these issues.)

He asked that I forward screenshots of any more T3 / T4 errors and packet loss issues to his Supervisor when they next occur but the only thing he can think of beyond what they've already done is replacing the line from the box to my coax jack.