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Forum Discussion
24 channel from 32? / day 8/ unstable xfinity internet / power 14.3 dBmV / SNR 36.5db
xfinity 400Mb service CM1000 V7.01.01 last 8 days internet drops for 10min to 1-2 hours 5-8 times a day. one coax line straight to my cm. Line levels checked at home show the bottom 3-4 cha...
I think you have a misunderstanding of your levels for upstream/downstream.
Your downstream (signal coming in) levels are high. That can cause errors. Thats the cmts sending the power to your device. This can by high if you're to close or the amplifier is turned up to high. It should be between -7.5dbmv to 7.5dbmv.
The upstream is the power that your own modem is sending to the cmts. It should be roughly 35-49dbmv. If its lower, it tends to indicate you're close to the hub and the modem doesn't need as much power to communicate with it. When you're further away, you need more power.
Them adding an attenuator can help based off your current numbers. It'd cut your downstream power down and your upstream would increase because of the attenuator
yes the upstreams are fine currently
It is a few downstreams that fall below 33db(SNR/MER) during the day and the internet becomes unstable and requires the cm to reboot.
lowering the power(dBmV) does not help with the SNR levels currently.
The tech says the LTE cell tower is interfering with channels on the modem for downstream and making the SNR values go down and thus the service fails eventually or part of it.
I do not know enough about 32 bonded channels, but it sure seems like a bad design if 2 or more channels cause the entire service to fail. If that is my symptom, measured so far, that it makes me want to avoid those channels some how. forcing to 24 channels and not using that with a 24 channel modem came to mind.
the tech says the cable plant is not to use 733.75MHz & 739.75MHz anymore but they turn it on occasionally. so much of this is out of our control. i would sacrifice speed for stability, that's a inclination to go to move to 16 or 24 channels and find a way to lock channels with good signal metrics. doesn't seem likely though with xfinity or the way cm's are designed.
perhaps some AI in the modem to select better channels over time?
I really do not want to spend my life monitoring xfinity....
jms23 wrote:yes the upstreams are fine currently
It is a few downstreams that fall below 33db(SNR/MER) during the day and the internet becomes unstable and requires the cm to reboot.---If your snr is dropping that much, the signal is getting intererence from somewhere. It should be fairly consistent and not change a whole lot.
lowering the power(dBmV) does not help with the SNR levels currently.----Its not about the SNR. Its about the errors you have in your line. You have a bunch of them. You can have the best SNR possible but if you have errors, then theres a problem with the line, the cmts, or the modem
The tech says the LTE cell tower is interfering with channels on the modem for downstream and making the SNR values go down and thus the service fails eventually or part of it.----this is a load of BS.
I do not know enough about 32 bonded channels, but it sure seems like a bad design if 2 or more channels cause the entire service to fail. ----its not the channels, its the interference thats causing it. If that is my symptom, measured so far, that it makes me want to avoid those channels some how. forcing to 24 channels and not using that with a 24 channel modem came to mind. ----doesn't work like that. You can feel free to try though.
the tech says the cable plant is not to use 733.75MHz & 739.75MHz anymore but they turn it on occasionally. so much of this is out of our control. i would sacrifice speed for stability, that's a inclination to go to move to 16 or 24 channels and find a way to lock channels with good signal metrics. doesn't seem likely though with xfinity or the way cm's are designed.
perhaps some AI in the modem to select better channels over time?----the cmts from your ISP is the one that sets the channels to use. Not netgear or the modem.
I really do not want to spend my life monitoring xfinity....