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Unstable Internet

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Official Employee

Re: Unstable Internet

Hello Cellindre, I can look into the signals outside of your home to get your issue resolved. To get started, could you please send me a private message with your full name and account number? 

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Frequent Visitor

Re: Unstable Internet

Most definitely still borderline but at that point the issue would have to be outside of my house as I'm connected to the closest point possible.

Diamond Problem Solver

Re: Unstable Internet

O/k the stats are still borderline. Could use more improvement.

Frequent Visitor

Re: Unstable Internet

Check my message just before your last post. I'm pretty sure this was spot on.

Diamond Problem Solver

Re: Unstable Internet

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


Frequent Visitor

Re: Unstable Internet

I think I figured out my problem. The initial coax cable in my house was connected to a splitter with one of the splits completely open. I decided to test my modem on the open split and manage to bring my downstream powers between -9.7 dBmV and -12.8 dBmV. My upstream went from 54 dBmV across the board to  51.5 dBmV and 51.8 dBmV. Gonna run more tests but so far things are looking bright.

Diamond Problem Solver

Re: Unstable Internet


@Cellindre wrote:

The first picture simply shows the Xfinity Status Center recognizing an issue with the modem. The second picture shows the power levels of all my channels are between -15.2 dBmV and -19 dBmV with SNR levels between 31.9 dB and 35.9 dB.


The downstream power is low / out of spec. The SNR is low. What does the upstream power look like ?

Frequent Visitor

Re: Unstable Internet

The first picture simply shows the Xfinity Status Center recognizing an issue with the modem. The second picture shows the power levels of all my channels are between -15.2 dBmV and -19 dBmV with SNR levels between 31.9 dB and 35.9 dB.

Diamond Problem Solver

Re: Unstable Internet

We can't see your pics because they need to be approved by a Forum Admin. I'm going to try referring this to the resident "Experts" here who can then escalate your issue to an Admin / Comcast  employee. 

Frequent Visitor

Unstable Internet

I bought a new SB6183 because my previous modem (SB6121) is now considered End of Life and I was getting disconnects and speed drops from time to time. Now I am getting even worse connection issues and much more frequently, making playing any sort of game online impossible. At first I thought it was a bad modem so I went back to best buy and exchanged it for a different one of the same model but the issue was still there. The Xfinity Status Center detects an issue (shown below) with the modem but running the troubleshoot doesn't fix the issue. Issue detected.png

I decided to check the power levels for my modem and it appears that every channel is way out of spec: Power levels.pngRunning speedtests I get bursts of speeds upto 175Mbps and then 0Mbps for the remainder or it timesout before even starting. I've tested both through a router and straight to the modem through an ethernet cable and the problem persists.