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10/26/2026 4:20 PM

Upstream OFDMA Channel 2 is failing to lock

A residential technician came out and verified that my inside wiring passes all static tests. However, my Netgear CM3000 is experiencing severe intermittent upload-only packet loss. My signal logs show my downstream is perfect, but my Upstream OFDMA Channel 2 is failing to lock (0 Hz / 0 dBmV), and Channel 1 is running on an exceptionally low transmit power of 37.8 dBmV. This is causing frequent Notice 6 Profile Flapping and T3 Timeouts. I need an escalation ticket submitted to the Outside Plant (OSP) / Line Engineers to balance the upstream carrier frequencies at the local node and check for upstream ingress noise.

Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Locked 11 ,13 43 36200000 Hz 37.8 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 4 393000000 Hz 2.7 dBmV 43.7 dB 0 0
2 Locked QAM256 1 375000000 Hz 3.0 dBmV 43.9 dB 0 0
3 Locked QAM256 2 381000000 Hz 2.9 dBmV 43.9 dB 0 0
4 Locked QAM256 3 387000000 Hz 2.8 dBmV 43.7 dB 0 0
5 Locked QAM256 5 399000000 Hz 2.6 dBmV 43.7 dB 0 0
6 Locked QAM256 6 405000000 Hz 2.5 dBmV 43.6 dB 0 0
7 Locked QAM256 7 411000000 Hz 2.4 dBmV 43.1 dB 0 0
8 Locked QAM256 8 417000000 Hz 2.2 dBmV 43.5 dB 0 0
9 Locked QAM256 9 423000000 Hz 2.1 dBmV 43.4 dB 0 0
10 Locked QAM256 10 429000000 Hz 2.1 dBmV 43.4 dB 0 0
11 Locked QAM256 11 435000000 Hz 2.1 dBmV 43.5 dB 0 0
12 Locked QAM256 12 441000000 Hz 2.1 dBmV 43.4 dB 0 0
13 Locked QAM256 13 447000000 Hz 2.1 dBmV 43.4 dB 0 0
14 Locked QAM256 14 453000000 Hz 2.2 dBmV 43.4 dB 0 0
15 Locked QAM256 15 459000000 Hz 2.2 dBmV 43.4 dB 0 0
16 Locked QAM256 16 465000000 Hz 2.2 dBmV 43.4 dB 0 0
17 Locked QAM256 17 471000000 Hz 2.2 dBmV 43.4 dB 0 0
18 Locked QAM256 18 477000000 Hz 2.2 dBmV 43.4 dB 0 0
19 Locked QAM256 19 483000000 Hz 2.1 dBmV 43.3 dB 0 0
20 Locked QAM256 20 489000000 Hz 2.1 dBmV 43.3 dB 0 0
21 Locked QAM256 21 495000000 Hz 2.1 dBmV 43.3 dB 0 0
22 Locked QAM256 22 501000000 Hz 1.9 dBmV 43.3 dB 0 0
23 Locked QAM256 23 507000000 Hz 1.9 dBmV 43.2 dB 0 0
24 Locked QAM256 24 513000000 Hz 1.8 dBmV 43.2 dB 0 0
25 Locked QAM256 25 519000000 Hz 1.9 dBmV 43.3 dB 0 0
26 Locked QAM256 26 525000000 Hz 2.0 dBmV 43.4 dB 0 0
27 Locked QAM256 27 531000000 Hz 2.1 dBmV 43.4 dB 0 0
28 Locked QAM256 28 537000000 Hz 2.0 dBmV 43.3 dB 0 0
29 Locked QAM256 29 543000000 Hz 2.0 dBmV 43.2 dB 0 0
30 Locked QAM256 30 549000000 Hz 2.0 dBmV 43.2 dB 0 0
31 Locked QAM256 31 555000000 Hz 2.1 dBmV 43.2 dB 0 0
32 Locked QAM256 32 561000000 Hz 2.2 dBmV 43.2 dB 0 0

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54 minutes ago

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XfinityPeterH

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54 minutes ago

 

ocp_qcd_pp
Thanks for laying all of that out and including the signal information. I can see why you're looking toward the upstream side, especially with the intermittent upload packet loss and the T3/profile-flapping events you've been seeing. Since you've already had a technician check the wiring at the home, I'd like to focus on what was documented during that visit and what our network diagnostics are showing so we can determine the appropriate next step rather than putting you through the same troubleshooting again. Please send us a DM with your full name and complete address. 

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