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JHalverson's avatar
JHalverson
New Contributor II
4 years ago

Arris SBG8300 Upstream QAM Speeds.

I bought an Arris SBG8300 modem/router in one last June and upgraded to Gigablast. We've had several Cox techs to the house to narrow down the root cause of slow speed and intermittent connectivity issues we have. We have a new large gauge wire (11?) from the post in our yard to our house. From there it is a direct line (no splitters) to our Arris. So .

I ran a speed test hard wired to the modem/router. Here are the result (23 DL, 33 UL...on gigablast 😞
https://www.speedtest.net/result/11076560076

When contacting Arris about the issue they seemed adamant that the Upstream power levels were the issue (all five approximately 34dbmv) as they are well below the minimum recommended of 45dbmv. They way I understand it, Cox should be telling the modem what upstream power it expects, so the issue could be that this specific model was spec'd out incorrectly in Cox's system. I say this after having had the issue with two of these same Arris's since last June coupled with the fact that the tech who saw this modem tonight acted like I had exposed electrical wires (anecdotal, but techs see a lot of different hardware, so I think there's possibly some good reason for his reaction).

What're the forum's thoughts? I don't want to just buy more hardware as I have a hefty sum invested in this one and Arris is not exactly making it easy to get a refund.

Thanks,

Jamie

arris sbg8300
ArrisSURFboard
Cox
modemrouter
slow speeds
speed
upstream power

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  • Superbigwaff's avatar
    Superbigwaff
    Contributor
    4 years ago

    I've found wide variability in results using Okla Speedtest. It is heavily dependent on the server you are connecting to. For example, I'm in the Cleveland area and have the 500Mbps plan. Hard-wired into the modem I routinely get between 320-375 Mbps testing speeds against servers only "10 miles" away. However, I always get between 450-480Mbps testing against "Comcast" 88 miles away. Using Cox's speedtest available on Cox's web site when logged into my account, there is variability in results depending on which "Cox server" is selected as well, although the results across servers are consistently really good. Long story short ... which server you are testing against matters.

    I'm not discounting you may have legitimate issues with your service. I count myself very lucky to have had consistent and high quality internet service from Cox over the years, especially after following the forum messages for the past several months. If you plan to collect "speed test" data, I recommend you also include results from the speed test on Cox's web site. More than likely these results will only bolster your claims and make it harder for Cox to question the results.

    I hope your issue gets resolved soon.

  • Dave9's avatar
    Dave9
    Contributor III
    4 years ago

    Your upload is 36 MBps which is above your specified upload speed of 35 MBps for Gigablast. Therefore your upstream signals and power are fine. Arris gives out a lot of bad advice about upstream power levels being "too low". Ignore that advice. There's definitely something wrong with your downstream however. Reset your modem, let it run for at least 4 hours, then post your signals and logs.

    • JHalverson's avatar
      JHalverson
      New Contributor II
      4 years ago

      Will do Dave. I'll reset now and then speed test via Cox's speed test (incorporating the advice from both comments).

      • Dave9's avatar
        Dave9
        Contributor III
        4 years ago

        Speed test only shows you that a problem exists. Signals and logs are the only way to start to identify possible cause of the problem.