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Wednesday, August 26th, 2026 5:48 AM

Recurring Signal Collapse / Massive Uncorrectable Errors (Outside Plant Issue)

Hello,

I need help addressing a recurring signal collapse on the outside plant in my neighborhood. This issue began after two consecutive service outages last week.

I have already verified all internal coaxial connections and completely bypassed all splitters. The issue is happening before the drop enters the home.

The connection appears to recover during the heat of the day, but consistently collapses every evening as temperatures drop.

Here is the data comparing today's daytime stability to the nighttime collapse:

Daytime Operation (Logged approx. 3:30 PM):

  • Status: Stable, all 32 channels locked.

  • Downstream Power: Sitting healthy between +6.1 dBmV and +8.8 dBmV.

  • Downstream SNR: Locked at 43.7 dB to 45.4 dB.

  • Event Log: Clean, no timeouts.

Nighttime Collapse (Logged approx. 11:30 PM):

  • Status: Modem falls into Partial Service mode. 5 downstream channels completely drop (Not Locked, 0 SNR/0 Power).

  • Downstream Power Collapse: Plummets by 21 dBmV down to -13.0 dBmV (well out of spec).

  • Downstream SNR Collapse: Drops to a failing 26.5 dB to 27.2 dB in the 525–580 MHz band.

  • Massive Uncorrectable Errors: Channel 25 alone generated nearly 100 million new uncorrectable errors in an 8-hour window. My OFDM carriers are also showing millions of uncorrectables.

  • Event Log: Flooded with RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW, MDD message timeouts, and Event Type Code: 4 errors starting reliably around 10:00 PM.

I have full modem logs available detailing the specific frequency bands and the exact timestamps of the DRW violations and T3/T4 timeouts.

Could an employee please pull the CMTS telemetry for my node? You should see my modem (and likely my neighbors') throwing massive uncorrectables and DRW violations every night. Would it be possible to have someone investigate the tap and neighborhood amp?

Thank you!

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Official Employee

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3.3K Messages

3 hours ago

 

aoortiz5 Hi there! Thank you for reaching out to us here on our Community Forum. We appreciate the breakdown you provided, and we are sorry to hear that you're having connection issues. We would also encourage you to check our Xfinity Status Center, if there is something going on in the area that has been flagged by our Maintenance Team as an interruption or maintenance might be taking place, that is the first place it will be posted. Outside of that, let's take a closer look and see what is going on. Please send a DM with your full name and address.

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