My signal levels are here: https://imgur.com/a/38i9QOc
- Modem: Netgear CM600 24x8 / DOCSIS 3.0
- Router: Archer C3150 v2
- Plan: Northeast Blast! 300/10
- I use ethernet for all of my stationary devices, and all others use 5ghz if possible.
- I only have internet. There is no TV provider or other service provider with lines to my house.
- There are no splitters. The modem gets a direct feed. The coax run is around 15ft and goes directly from wall-to-modem. The connections are finger-tight. The coax seems to be properly terminated as well. The coax itself is not around tons of electricity either (since apparently electrical interference with coax is a thing).
I believe there is noise coming into the line due to the low SNR on 733mhz. In the daytime it will be around 34dB-39dB, and in the night time, it's 40.1dB or greater. The problem is that sometimes the SNR will fall below 31dB, and cause uncorrectable errors on all channels and slow speeds over the entire network. The speeds will be around 5-20mbps whenever the SNR drops too low.
Once, the modem has dropped 733mhz completely and it didn't lock that channel back in until a reboot. Logs reported SYNC errors. During that time there were also 10,000 or so uncorrectables for that channel, 5,000 for 727mhz, and 1000 or so for all other channels which had a normal SNR.
Whenever I do notice things getting slow I reboot the modem, and speeds go back to normal. It'll lock in a different set of channels which do not have a low SNR, or it will lock back into that same range, with 733mhz being the problem channel. It'll relock 733mhz with a lower SNR than the others, but it won't impose speed issues. A tech (with their remote tools) has told me that they detected "moderate noise" on the line.
The thing I am confused about the most is
- During the night time (1am-6am), the SNR for that channel is always 40dB or higher, consistently. And during normal hours it will always fall below 40dB. This occurs every day. I feel like LTE (700mhz) or others' modems are causing the line ingress.
- This issue is very intermittent. The modem seems to drop out when the noise is too much or SNR is too low, but most of the time speeds will be 360/12.
- Whenever the modem locks into the lower half of the channels starting at 505mhz, two out of the 24 channels seemed to have a consistent SNR of 38db, and the rest were always 41.5dB or greater. I don't think that points towards an issue for those channels however.
I don't believe there's any issues with my equipment or wiring inside my house. I've checked everything I possibly can, and it's a very simple setup to boot. Outside of my house doesn't have a demarc because I only have and had internet. I'm assuming there's a moca filter and the right weather proof fittings for the coax, grounded, etc. for that line which is on my sloped roof.
I've also had another issue with slow speeds a year or two ago, which was due to a faulty splitter which was on the pole. The issue persisted with an XB3, XB6, MB7621, and the CM600 that I have now(and the issue was fixed while having.) I'm beginning to wonder if the line and drop in general are becoming faulty or if it's due to other equipment outside of my premises.
I would like for a technician to check or probe the outside wiring to see if the noise issue is due to the drop that I have or because of some other problem on the node. I also believe a 6db attenuator should be placed on the line to push the downstream power towards 0db. During the winter it will climb up to 9dB-ish or higher. It'll work but I don't want it to be that high.
Does anyone have any input? Anything I may be missing? I want this to be checked before I consider paying $160 for another modem or renting. )=
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