Same thing happened to me,
But the noise was intermittent 2 minutes every 10 or so. It was upstream channels, so tech suspected it was someones modem failing.

No way to find out who’s modem without shutting them down in groups in process of elimnation.

Took about 2 days and my upload was eventually returned from 100k back to 10mb

Had this happen and it was a loose connection to my modem. Was also during a solar flare.

I work at an ISP and we have guys doing this constantly. It’s not always at a customers house but yeah. A fault on the cable going to your house causes your modem to increase the power it uses to talk to the node in your neighborhood that connects back to the ISP. If your modem uses too much power and drowns out the signals from your neighbors going to the same node, then everyone else’s service can suffer and yours is just fine. It’s weird but that’s how it is.

A connector might have gotten rusted or a landscaper might have nicked a cable with a weed Wacker or something.

I had cable internet for about 9 years, no issues at all, one day the isp truck came by and disconnected my connection at the street pole end without any warning. ISP said my connection the cause of the signal interference to my neighborhood cable internet issue. The tech tested the cable from the street pole to my house demarc. The connector at the street pole end is rusted and there were sign of water get into the cable and turned the cable into an antenna. They ran a new cable replaced that segment. Everything was okay since. I switched over to fiber now.

maybe powerline adapters

I’ve previously reported an issue to my ISP and it turned out to be loose cables and unterminated cables. Once that was taken care of all was well again. So now every once in a while I check the tightness. I find it amazing they can even loosen up, but they do just from minor jostling of boxes.

I had this same thing happen to me for the first time a few months ago. It was my fault because I had done some changing and it was just a not fully right cable connection in my basement. They had been going up the line to each house to isolate to noise my connection was feeding back in.

If you have any MoCA adapters and you don’t have a filter on your house… you might be sending that info out over the wire. I had that happen once… using MoCA adapters. Cable guy calls me and says I am putting out “stuff” into the system. I happened to be on vacation at the time… told him I would be back next week… I added an adapter inside my attic before the coax went out to the neighborhood and asked them to check again… they never responded and never came back.

Then years later (maybe 1 year ago) when a guy came over to re-run my line out to the box (I think neighbors lawn people cut it)… he slapped a MoCA filter into the connection box and said they were standard/required now. So I was able to remove the one in the attic.

This is 90% of my job every day. Something in your house is acting like an antenna and interfering with the return path. Most of the time it’s a loose connector behind the modem but any bad connection can cause it. I usually track the noise to a house and use a filter at the tap that blocks the noise and leaves the sub online, then create a job to get an tech in the house

I had this happen a few months ago. They weren’t nice enough to call, they just trapped my line and shut off my internet for up to 2 days while I had to wait for a tech to come.

First time they needed to replace the line from the box to the house. After that they couldn’t find what was wrong but they shut it off like 2 more times :(