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chinmaya's avatar
New Contributor

Upload power levels jumping and modem resets

This is the current power levels for upload channels 

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 36300000 Hz 42.7 dBmV
2 Locked TDMA and ATDMA 1 2560 Ksym/sec 18400000 Hz 44.2 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 23300000 Hz 40.7 dBmV
4 Locked ATDMA 3 5120 Ksym/sec 29800000 Hz 45.2 dBmV

Periodically it jumps to >54dMv and I get an error from the modem that's this 

Tue Nov 15 15:15:53 2016 Warning (5) Dynamic Range Window violation

This has been happening alot now and it's quite frustrating. Any help will be appreciated. We plug the modem directly to the line on the wall with a cable and don't have any splitters in between.

Update: Contacted support via chat and they said there were too many power adjustments being done by the modem and they think the fault is the modem. Also here's the info I have right now on the downstream channels:

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 62 975000000 Hz 2.7 dBmV 38.2 dB 32 0
2 Locked QAM256 57 945000000 Hz 2.7 dBmV 38.2 dB 0 0
3 Locked QAM256 58 951000000 Hz 2.5 dBmV 38.2 dB 0 0
4 Locked QAM256 59 957000000 Hz 3.2 dBmV 38.6 dB 1 0
5 Locked QAM256 60 963000000 Hz 2.8 dBmV 38.2 dB 4 0
6 Locked QAM256 61 969000000 Hz 3.0 dBmV 38.3 dB 23 0
7 Locked QAM256 63 981000000 Hz 2.0 dBmV 37.9 dB 30 0
8 Locked QAM256 64 987000000 Hz 1.9 dBmV 37.8 dB 86 400

4 Replies

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  • grymwulf's avatar
    Contributor II

    Dynamic Range Window violation really are indications that your transmit levels change in levels over 12dBmV between extremes.

    This usually is caused by several possibilities:

    1. Bad filter/too much noise.  (possible ingress?)
    2. Bad Amp
    3. Bad modem
    4. Issue at node (can easily tell by checking modem logs on Cox's end from nearby customers - see if anyone else is experiencing the same issue)
    5. Bad/loose connector (this will usually result in wild swings in Rx power levels/SNR levels as well)
  • chinmaya's avatar
    New Contributor

    So got a replacement modem and I'm still having T3 timeouts and high upload power levels. Internet resets atleast 3 times a day and I'm getting more frustrated with the service so much so that I'm considering finding another isp at this point.

  • grymwulf's avatar
    Contributor II

    At that point it does look like the other causes (not the modem) would be likely to be the issue.  Have you called phone support to get  a technician out?

  • cpljp's avatar

    Power adjustments and T3 timeouts, in my experience, is a result of either noise, micro reflections caused by an impedance in the line, or an impedance in general. The modem keeps having to adjust its power to overcome said impedance. I'd recommend scheduling a tech visit at this point