Forum Discussion

decipher's avatar
decipher
Contributor
9 years ago

Have an Arris SB6183 or SB6190? Check this out!

Cox is failing to diagnose this problem.  
Cox claims that my signal strength is good.  
Everything checks out ok, even after a home visit by a Cox tech.
I've been spending lots of time and $$$ on this problem.
It seems highly unfair for me to be paying a premium for this service. 
I've had this new modem for over 5 months. 
Why does it take me so long to diagnose a problem?
Why am I the one who must diagnose this type of problem? 

My connection problems continue...


Let's get to the guts of the problem: 

According to ARRIS, without being in range, these two modems (SB6183,SB6190) lack sufficient power to operate, providing end users with intermittent performance.


Here is current info showing my range (SB6183):

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 2 5120 Ksym/sec 23300000 Hz 40.9 dBmV
2 Locked TDMA and ATDMA 1 2560 Ksym/sec 18400000 Hz 39.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 29800000 Hz 41.0 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36300000 Hz 42.5 dBmV

Current System Time: Mon Mar 14 14:01:22 2016

  • SB6190
  • SB6183

These are both approved by Cox.

Arris says that users of these new modems need Upstream Bonded Channel Power ranges within: 51 dBmV - 45 dBmV.

You can check your modems configuration by entering: http://192.168.100.1/ in a browser.
Go to the status page, then scroll down to find the upstream bonded channel power. 

Arris suggested solutions for Cox:

  • Use attenuator: to adjust setting
  • Add new / change current splitter configuration
  • Adjust amplifier / service amplifier at house / service port at street
  • Tecknowhelp's avatar
    Tecknowhelp
    Valued Contributor II
    9 years ago

    I don't understand what you are trying to say here. I think maybe you may only be seeing skin deep of the issue. Upstream power level is determined through a process called DOCSIS between the modem and Cox's Cable Modem Termination System(CMTS). See here for more info on how a CMTS works.Different upstream channels are negotiated through channel bonding to pick the channels with the highest upstream(US) signal to noise ratio(SNR). This process is controlled through MAC messages and interaction on the PHY layer. See here for more info on DOCSIS. 

    The way SNR works is it's a ratio between signal and not signal. If US SNR is high and power level is low, then noise level must be low by the equation. If the CMTS detects problem with noise on a US channel it will tell the modem to increase power level to try a different channel until it finds one with a sufficient SNR. Where problems can occur are systems that have intermittent noise spikes. These otherwise benign tremors in the system can cause issues with people with lower US power levels(Tx). That is because with a lower power level, smaller noise issues can cause stronger effects. 

    The difference between the the SB6183/SB6190 and say the SB6141 is how it uses the tuner's channel width to connect on the upstream. Perhaps since they use the single channel sweep method, they might be more prone to the SNR issue mentioned above. Is that what you are summarizing? They need higher Tx?

  • Mike_Harris's avatar
    Mike_Harris
    New Contributor
    9 years ago

    My SB6190 is running all 24 down channels and 4 up channels at around 36-40dBmV without any issues.  

     

  • decipher's avatar
    decipher
    Contributor
    9 years ago

    A Cox tech just installed an attenuator on my modem.  

    Now the upstream levels are more ideal for this modem.

    Upstream Bonded Channels
    Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
    1 Locked ATDMA 2 5120 Ksym/sec 23300000 Hz 46.0 dBmV
    2 Locked TDMA and ATDMA 1 2560 Ksym/sec 18400000 Hz 46.0 dBmV
    3 Locked ATDMA 3 5120 Ksym/sec 29800000 Hz 47.5 dBmV
    4 Locked ATDMA 4 5120 Ksym/sec 36300000 Hz 48.0 dBmV
  • Tecknowhelp's avatar
    Tecknowhelp
    Valued Contributor II
    9 years ago

    The amount of upstreams channels isn't just a matter of signal quality. Those US channels have to be opened on the CMTS. Some areas have more then others. Have you ever been able to get more then 4? What state do you live?