Consumers - SB6141: Cable Signal Level
FAQs

Coronavirus (COVID-19) Disruption


Our Call Center is experiencing a high number of calls due to the COVID-19 situation. We are working to assist everyone who contacts us. In the meantime, please visit www.arris.com/selfhelp for most frequently asked questions about your device. We apologize for the inconvenience and will assist you soon.

ARRIS Consumer Care

Article

SB6141: Cable Signal Level

« Go Back

Information

 
Question
What are the acceptable cable signal levels for the SB6141?
Answer
Cable signal levels for all DOCSIS cable modems require to be within the acceptable level for the modem operate properly.  The three signal levels that need to be within the acceptable level are Downstream Power, SNR (Signal to Noise Ratio), and Upstream Power.  Downstream Power refers to the line signal sent from the cable provider to cable modem.  Downstream SNR (Signal to Noise Ratio) refers to the signal being sent in relation to the noise on the line.  Upstream Power refers to the line signal from the cable modem to transmit data back to the cable provider.  This document describes how to check the three signal levels to be within the acceptable level for the modem operate properly. 
 

Checking Cable Signal Levels

NOTE: If the SB6141 is connected to a router, it is recommended to disconnect the router and connect the SB6141 directly to a computer with an Ethernet cable.
  1. Launch a web browser, such as Internet Explorer, Firefox, or Safari.  Enter http://192.168.100.1 into the address box.  The Cable Modem Status page will appear.
     
  2. Click the Signal link on the top menu .  The Signal page will appear.
     
  3. In the Downstream section, verify Power levels are within the acceptable range of - 15 dBmV to + 15 dBmV for each downstream channel. 

    User-added image

     
  4. In the Downstream section, identify the Modulation and Power to find verify SNR levels are within the acceptable range for each downstream channel. 

    Acceptable SNR Levels (dB): 
    If QAM64SNR should be 23.5 dB or greater. 
    If QAM256 and DPL( -6 dBmV to +15 dBmV) SNR should be 30 dB or greater. 
    If QAM256 and DPL(-15 dBmV to -6 dBmV) SNR should be 33 dB or greater.   

    User-added image

     
  5. In the Upstream section, identify the Symbolic Rate to find verify Upstream Power levels are within the acceptable range. 

    User-added image

    Acceptable Upstream Power Levels (dBmV)

     
    Upstream Transmit Power Level
    ChannelUS Channel TypeSymbol RateAcceptable Upstream Power Levels
    SingleTDMA1280 Ksym/sec45 dBmv to 61 dBmV
    ATDMA2560 Ksym/sec45 dBmv to 58 dBmV
    5120 Ksym/sec45 dBmv to 57 dBmV
     TwoTDMA1280 Ksym/sec45 dBmv to 58 dBmV
    ATDMA2560 Ksym/sec45 dBmv to 55 dBmV
    5120 Ksym/sec45 dBmv to 54 dBmV
    Three or moreTDMA1280 Ksym/sec45 dBmv to 55 dBmV
    ATDMA 2560 Ksym/sec45 dBmv to 52 dBmV
     5120 Ksym/sec45 dBmv to 51 dBmV
  6. Refresh the page at least twice to identify variations in SNRDownstream Power, and Upstream Power.   

    NOTE: If the either of the signal levels are outside of the acceptable range, power cycle or factory reset the modem. 

     
  7. Contact the cable provider to adjust the signal level to the acceptable level range.

Acceptable Signal Levels
 
Acceptable Downstream Power Level
-15 dBmV to +15 dBmV
Downstream Signal to Noise Ratio (SNR)
ModulationDownstream PowerAcceptable Downstream SNR
64 QAMn/a23.5 dB or greater
256 QAM
 
-6 dBmV to +15 BmV30 dB or greater
-6 dBmV to -15 dBmV33 dB or greater
Upstream Transmit Power Level
ChannelUS Channel TypeSymbol RateAcceptable Upstream Power Levels
Single (1)TDMA1280 Ksym/sec45 dBmv to 61 dBmV
ATDMA2560 Ksym/sec45 dBmv to 58 dBmV
5120 Ksym/sec45 dBmv to 57 dBmV
 Two (2)TDMA1280 Ksym/sec45 dBmv to 58 dBmV
ATDMA2560 Ksym/sec45 dBmv to 55 dBmV
5120 Ksym/sec45 dBmv to 54 dBmV
Three or more (>=3)TDMA1280 Ksym/sec45 dBmv to 55 dBmV
ATDMA 2560 Ksym/sec45 dBmv to 52 dBmV
 5120 Ksym/sec45 dBmv to 51 dBmV

Feedback

 

Was this article helpful?


   

Your feedback is appreciated.

Characters Remaining: 255

 

Print
-->