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I purchased a Arris SB8200 cable modem. It worked for several months until one of your contractors removed an old phone line box after a new phone modem was installed. The internet modem status page showed it all of the channels locked, but no upstream data being transmitted. The Cox repairman that came out said Cox has been having problems with the SB8200 modems randomly failing for no reason.
I put back in an older SB6182 and the internet works now. I am able to see that the internet still slows down and occasionally drops.
I contacted Arris tech support and they said that the problem is with the signal strength. I am only getting around 35 dbmv to 38 dbmv upstream. "I reviewed the screenshots you sent and it seems that your SB8200 is currently able to receive signal from your internet provider, downstream channels are at the specified range, unfortunately upstream channels are not how we expected, according to channel type and frequency upstream power levels must be at a range from 45 dbmv (min) to 51 dbmv (max) to let your modem deliver its potential. This is a common issue our customers have when the ISP do not provide the signal that modem requires, that can be the cause of intermittent connection and slow speed issues."
I have had several issues with service over the years, signal strength related, cable and internet. All of the coax and splitters in my house house have been replaced, other than the run from the pole to the house. Each repairman that has come out, refuses to replace it. How can you resolve this? Is it a problem with cable between the house and the pole, or is it a problem with your infrastructure further up the line?
I am having a very similar issue. A few months ago something happened in my area. After a lot of tech support, I decided to upgrade my model from an SB6182 to an SB8200, hoping the additional available channels would help. I also hoped to get gigablast. At first, it stayed up for several weeks. The past few months, it's been sporadic at best. During troubleshooting, we rolled back to my SB6182 and that worked for a few weeks. Support said my SB8200 was bad, but they keep issuing outage notification for my area. Additionally, a month ago, I had a rep come out and check my house. The ONLY line in it is less than 2 years old. The rep said the signal at my tap was bad, and measured the same (bad) signal at my house. I found out later than an upstream amp had been messed up.
I'm taking screenshots of the signal meter every so often. it's really getting frustrating; I've burned several hours on the phone with support that can't seem to help. They ether don't know what is going on or don't have the tools to help :(
I'm back on the SB6182 for the moment. Going to review the snapshots I took of signal and compare to the notes posted below.