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mbrijun's avatar
mbrijun
Joining in
31 days ago

Help needed with interpreting line stats

My new M125 connection uses Hub 3.0. The only thing on the line is a TRIS-102A 5-1000MHz (I assume this is a surge protector). I have not used the thin coax cable with a bulge in the middle (not sure what that is). The following are the line stats.

I have noticed that the upstream channel 5 fluctuates beteen 64 qam and 32 qam, which I believe indicates some noise on the line.

I would appreciate it if someone could explain if all these values are within their expected ranges.

Thank you in advance.

10 Replies

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  • carl_pearce's avatar
    carl_pearce
    Superstar
    31 days ago

    Your downstream power levels should really be between -6 and +10, 0 being optimal.

    QAM on upstream fluctuating does indicate noise.

    • mbrijun's avatar
      mbrijun
      Joining in
      31 days ago

      Thank you for commenting, @carl_pearce How can this be achieved? I am guessing that an attenuator will be required.

      • carl_pearce's avatar
        carl_pearce
        Superstar
        31 days ago

        For the upstream power levels yes, an attenuator is required.

        The QAM fluctuating needs the attention of an engineer visit, or possibly local fault, which you can check for:

        https://www.virginmedia.com/help/check/status

  • Tudor's avatar
    Tudor
    Very Insightful Person
    30 days ago

    You need a forward path attenuator fitted, only a VM technician can do this. 

    The primary place to report faults or for service requests is Customer Services on 0345 454 1111/150 if you have a VM landline or wait two or three days for a VM staff member to get to your post. This board is not a fault reporting system.

    • mbrijun's avatar
      mbrijun
      Joining in
      27 days ago

      I agree that this board is not meant to be used as an extension of the official support helpline. My recent experience with the phone helpline was quite hellish, with the robot going round in circles and me losing my patience and hanging up in the end. On a plus side, the web chat was very straightforward.

      An engineer arrived yesterday and installed a 10dB attenuator. He also gave me a 6dB one just in case the upstream signal gets too high, causing instability. With the 10dB attenuator, my DS signal is now at 2-4dBmV and the US signal is at 48.5dBmV. With the 6dB attenuator, the DS signal is around 6-7dBmV and the US is at 44.5dBmV. I am sticking with the 10dB attenuator.

      Everything is stable except for one of the US channels (channel 5 - 23.6MHz which is at 46.5dBmV and keeps switching between 32 and 64 qam). All other channels are stable. A quick scan on this community suggests that the 23.6MHz band is known to have some issues. I would appreciate further insights into whether this can be safely ignored or needs futher attention.

      Many thanks.

      • Robert_P's avatar
        Robert_P
        Icon for Forum Team rankForum Team
        25 days ago

        Thanks for the update, let us know how you get on or if you need further help with this.