Edit: Issue was taken to ComcastCares on twitter. They were helpful in scheduling a tech visit for me and verified that the appointment is in the system. I will be adding another update on connection quality sometime later next week.
Edit: For improved visibility I'll be placing the link for the most recently recorded modem signals here
1/19 2:10 pm
When we first got our Internet service 3 years ago the signal levels were great 40 db all around on the downstream, the only issue the line installer mentioned was that the signal came in too hot and installed a splitter in front of the cable modem to tone it down. Recently, the signal levels have continued to weaken to where we were experiencing intermittent connectivity issues so I decided to replace that with a forward path attenuator to clean the signal up since we only have one coax run in the house connecting to the modem. I also inspected and tightened any loose connections from the modem to our home tap next to the power meter, but there are still times throughout the week where the internet gets flaky which isn't always consistent, but appears to happen more during the mornings and evenings, it also happens sometimes in the afternoon. This is most readily observed during video conferencing and online gaming.
The only place I cannot do a line check myself is the aerial drop next to the powerline since it's real high up. The downstream power levels tend to be pretty erratic, one night it was reaching 11 dbvm on most of the channels so I had to install another pad to bring those levels down. Currently there is only a forward path attenuator on the line and below are some of the screenshots. In the last screenshot some channels are getting really close to the 35 db floor with one going under at 33 db. I forgot to take a screenshot of the event log before resetting the modem, but there were plenty of T3 timeouts listed in it.
If a line tech can come check for the source of the issues on the line and bring the signal quality back to what it was before that would be great, especially since a majority of the classes are being offered only online now.
The SNR levels are roughly the same without any attenuators/splitters, but that leaves the line with downstream power levels fluctuating 8dbvm to 11dbvm and these levels tend to spike hard at nighttime. This setup also accumulates T3 timeouts regularly and causes problems with time sensitive traffic. The stats from the first image was from an 8db pad and the second was from a 6db forward path attenuator. I've also used the forward path attenuator in addition to a 3 db pad when the downstream power levels get too hot, but anything beyond that will cause the upstream power to go out of spec. I have also tried installing these attenuators at different locations from the wall plate to the tap next to the power meter, but nothing really changed.
The downstream power levels tend to drop in the negative values in the mornings and increase over the afternoon into the evenings. This going back and forth to try to tame the line for the course of a day is getting exhausting though, and I'm hoping a line tech can come up with a more permanent solution.
I'll try checking the levels coming directly from the aerial drop line with the modem later.
Hello, I'm back with another update. So I went and hooked up 1 ft of coax to the ground block and connected it to the modem. These screenshots were taken between 1:00-1:30 pm. The modem was turned off before taking each reading.
The signal levels here are nearly identical to the ones taken in home, so if there is ingress on the line then it is probably coming from the aerial drop.
I'm worried that the internet will get flaky during online exams. My sister also works remotely through a vpn which kept reconnecting constantly today. She needs a reliable connection as well. If someone can forward this to the proper channels so a tech can come check the lines I would greatly appreciate it.
The splitter is out of the picture, in my first post I mentioned that I had it replaced with an attenuator due to a loss of signal. (The downstream power was still too hot then, this was from a few months ago). Our line had a solid 40 db downstream from when it was installed and it stayed that way for nearly 3 years until recently where suddenly started dropping. Nothing was ever changed in our network topology, and now there are some channels that are going under spec (See channels 2, 3, and 8 in my last post). I am aware that the connectors used in these networks can degrade over time due to weather. I am also aware that these networks are subject to fluctuations in power due to temperature, but there shouldn't be such drastic spikes (11dbvm) like I'm seeing on some nights.
The internet still gets flaky at times during the day without an attenuator. My sister, who used to have no problems, now has trouble maintaining a connection through her vpn tunnel for work. Online gaming freezes at times now, and there is a delay in streaming content that wasn't there before.
From this morning, there are no splitters/attenuators on the line.
It's really frustrating especially since we have online classes going now.
Edit: Here with another update
12 channels are going below the mininum specs for SNR with the lowest being 29.9 on channel 9 which is also accumulating lots of errors. Nothing has been changed since checking the readings at the ground block yesterday, and all connections have already been checked. If someone can take a look into this I would greatly appreciate it.