Help diagnose line quality issues since switching to Arris CM8200?

bordenhausbordenhaus Posts: 1
edited October 24 in Connectivity Oct 24, 2020

Looking at the modem status it seems like I definitely need to do something. My connection is pretty stable and I am getting close to my plan speeds. At my box I am connected straight from the incoming line to a line in my living room to the modem.

Attached is a snapshot of my downstream and upstream channels as well as the event log.

Just look at channel 33, wow!


  • misterjmisterj Posts: 119 ✭✭✭✭
    Oct 24, 2020

    bordenhaus, I see nothing really wrong with the numbers. Channel 33 is an OFDM (other) channel. I have an Arris SB8200 that reports two connections as yours does. I strongly recommend you provide a screenshot to Arris and ask what it means - do you have a DOCSIS 3.0 or 3.1 connection or both? I cannot get them to answer me. The SNR looks a little low and possibly accounts for the large number of errors. What is your paid speed and measured speed? For testing, I recommend:

    My SNRs are about the same as yours but but my errors are far less. I measure 235 Mbps on a paid 200 Mbps account. You may have some ingress noise problems. A technician call will identify this for you.

    Thanks and enjoy, John.

  • Lake802Lake802 Posts: 49 ✭✭✭✭
    Oct 24, 2020

    Hello Bordenhaus - sorry to hear you are having internet service issues. There are a couple of signal gremlins on the screen shots you provided but in most cases they are resolvable by a onsite technician visit from Spectrum. Signals can appear "in spec" on RX TX and SNR but you can still have service problems. In your case the modem is registering multiple T3 and T4 timeouts. When Spectrum technician arrives , ask them to correct the source of the T3 and T4 timeouts. The number of uncorrectable errors on the example you provided are also too high.

    The modem logs are somewhat limited and unfortunately do not tell you when the uncorrectable occurred - they could have happened six months ago, the modem log just tallies that the uncorrectable errors are occurring.

    You will know things are "fixed" when you see no more T3/T4 errors in the modem log and the uncorrectables are not incrementing significantly from the current levels you documented..

    Please let us know how it goes after the technician visit.

  • LGTLGT Posts: 107 ✭✭✭✭
    Oct 24, 2020

    While Arris will tell you -15 to +15 dBmV is in spec for downstream levels most people prefer -10 to +10 dBmV. Plus the number of uncorrectables is completely unacceptable, should be close to zero in a properly wired system. As is the standard advice for this forum check all the coax connections, make sure the wire is in good shape and there are no open splitters or outlets and all connections are tight. If your wiring is OK time to call Spectrum and have them check their end of it.

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