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Internet slowing waydown, intermittent

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Frequent Visitor

Internet slowing waydown, intermittent

Hello. New DOCSIS 3.1 (SB8200) modem didn't fix the issue. Speed continues to vary from over 300MBps (which is my top speed as per my plan), all the way down to 25Mbps sometimes. ALl measured connected straight to modem via ethernet cable to rule out router issues. 

 

Example.   

 

Sunday - tests troughout the day varied in results from 25Mbps to 180Mbps. 

Monday - tests throughout the day all netted 300+Mbps even during peak times 6-10pm.  

Tuesday - tests throughout the day netted results from 60Mbps-140Mbps. 

 

I did a speed test just now. Initially went to 307Mbps, and then started falling down all the way to 70Mbps once all set and done. This seems to be the case usually. Starts up at 150 to 300Mbos for  a second, then falls on its face down to 25 to 100Mbps. 

 

 

What could this be? What should I be telling Comcast when I call them to come out?

 

Levels below. Taken a few minutes after reboot first screenshot) as well as a couple hour after reboot (2nd screenshot). 

 

 

 

 

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Expert

Re: Internet slowing waydown, intermittent

There are some borked downstream channels that have out of spec SNR's. Seems like there is some extraneous noise ingressing into the line(s) somewhere. You can try this stuff but you may need a tech out;

 

In a self troubleshooting effort to try to obtain better connectivity, 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.



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Frequent Visitor

Re: Internet slowing waydown, intermittent

Thank you. Yeah there are no splitters anywhere. One line from pole coming to NID. Then one cable from there straight into modem inside house. The below however is interesting. Unplugged coaxes on the pole.

Maybe @ComcastMichael can chime in...
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New Poster

Re: Internet slowing waydown, intermittent

I have the same issues.

Disconnected wires at the pole shouldn’t be a worry. Only 1 goes to your house (maybe 2). If they were the culprits, you wouldn’t have anything.
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Frequent Visitor

Re: Internet slowing waydown, intermittent

Yup. I see. Issue however is definitely somewhere on the lines. As this happens usually only after it rains.
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Expert

Re: Internet slowing waydown, intermittent

Then get a tech out as stated earlier to investigate / correct the problem.

 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

Good luck with it !



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Official Employee

Re: Internet slowing waydown, intermittent

Hello jnowakphoto, thank you for reaching out to us here with this concern. I wanted to circle back to see if this issue has been resolved, if not please send me a private message by clicking on my name then click "Send a message". 


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Frequent Visitor

Re: Internet slowing waydown, intermittent

Hello . I continue having intermittent speed issues. Modem logs show a large amount of HEC and CRC errors as well as weak SNR on 6 channels (sometimes gets as low as 25...).
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New Poster

Re: Internet slowing waydown, intermittent

After a ton of internal troubleshooting, I called support. Fortunately, I was connected with someone who actually seemed to know what he was talking about.

He had me do a hard reset & he then reprovisioned my cable modem (something no one else from support had tried)... and to my surprise, that did the trick! I haven’t had to reset my cable modem since.
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Expert

Re: Internet slowing waydown, intermittent

Glad you got it sorted. Wonder how the original poster is making out ?



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Frequent Visitor

Re: Internet slowing waydown, intermittent

Still waiting to hear from @ComcastAmir
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Expert

Re: Internet slowing waydown, intermittent

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards.  You should get a reply here in your topic. Good luck !



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Official Employee

Re: Internet slowing waydown, intermittent

Hello and thank you for replying here, I apologize for my delay in response. For further assistance please send me a private message with your full name and account number. We can take a look at your signal levels to see if a provisioning is needed to resolve your issue. 


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