Orbi WiFi 7 RBE973
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High Uncorrectables lower channel

Drez_19
Aspirant

High Uncorrectables lower channel

Two xfinity calls and 4 new coaxial cables later I'm still having issues with downstream power ramping up and lowest channel uncorrectables. My DS varies from +5 - +9 and the lowest channel is always lower SNR and within hours has 2-4x more uncorrectables than corrected. Is this normal behavior?

Comcast says everything is within specs but earlier my higher channels hit +10 and higher DS power. I ordered some -3 and -6 attenuators but not sure if they will help.

To wrap up is this something that can be fixed by:

1. Adding an attenuator to lower power
2. Changing starting frequency to next channel that seems to be fine
3. Give up and pay for tech visit

Any suggestions welcome
Model: CM600|CM600 High Speed Cable Modem
Message 1 of 7
Drez_19
Aspirant

Re: High Uncorrectables lower channel

Also forgot to note all the cables I've used are not connected to a splitter and are simple RG6 1.5ft cables from the line to the modem direct.
Message 2 of 7
DarrenM
Sr. NETGEAR Moderator

Re: High Uncorrectables lower channel

Are you getting T3 and T4 timeouts in the logs of the modem?

 

DarrenM

Message 3 of 7
Drez_19
Aspirant

Re: High Uncorrectables lower channel

Thank you for replying. I accidently cleared the logs but since yesterday I did have another one. Previously I've had one every other day.
Message 4 of 7
Drez_19
Aspirant

Re: High Uncorrectables lower channel

Wanted to post another update in case you're still monitoring, had another T3 error today and my two lowest DS channels continue to have a 4:1 ratio of Uncorrectables to Correctables:

 

2019-03-08, 18:37:56 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:5e:cb:a8;CMTS-MAC=00:01:5c:6b:56:67;CM-QOS=1.1;CM-VER=3.0;
2019-03-06, 23:47:43 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:5e:cb:a8;CMTS-MAC=00:01:5c:6b:56:67;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6

 

 

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 1 507000000 Hz 6.1 dBmV 37.1 dB 577 2799
2 Locked QAM256 2 513000000 Hz 5.8 dBmV 40.3 dB 443 2060

 

 

 

Model: CM600|CM600 High Speed Cable Modem
Message 5 of 7
DarrenM
Sr. NETGEAR Moderator

Re: High Uncorrectables lower channel

Here is a good article on what those errors mean

 

https://pickmymodem.com/cable-modem-t3-and-t4-timeouts-error-messages-and-how-to-fix-them/

 

DarrenM

Message 6 of 7
Drez_19
Aspirant

Re: High Uncorrectables lower channel

Posting back with a post-Comcast tech visit. They removed an unnecessary splitter from the main switch/box on the home, power values on each channel are now lower/better but I cannot get rid of the two lowest frequencies that have ever-growing Uncorrectables. Is this still a Comcast/Xfinity signal issue or do I need to dump my CM600 and get a different model? This is causing dropouts/ping spikes during gaming and even streaming video.


Standard setup is CM600 > Orbi RBR40 + 1 RBS20, results are the same with or without Orbi in the mix. 

 

Things tested/fixed:

  1. Running a Ping test directly from Outside Line>Modem>Mac without the router invovled I get random ping spikes as well as Timeouts.
  2. Ran 4K video stream on Youtube while running Ping and saw Timeouts/Dropped frames in the video (With Settings for Nerds turned on)
  3. Doing anything extra like Dropbox syncing etc causes ping to jump from 10ms to 500ms or higher, same with Speedtests which actually hit 1200ms and them Timeout. 
  4. Done soft resets, factory resets, and reset through my Xfinity app and the two lowest channels remain with uncorrectables. 

 

 

After 45min of uptime. Note that these continue to have a 4:1 ratio of higher uncorrectables.

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 1 507000000 Hz 3.0 dBmV 37.1 dB 27 164
2 Locked QAM256 2 513000000 Hz 2.6 dBmV 40.3 dB 18 97
3 Locked QAM256 3 519000000 Hz 3.0 dBmV 40.5 dB 0 0
4 Locked QAM256 4 525000000 Hz 2.9 dBmV 40.4 dB 0 0
5 Locked QAM256 5 531000000 Hz 2.8 dBmV 40.3 dB 0 0
6 Locked QAM256 6 537000000 Hz 3.2 dBmV 40.5 dB 0 0
7 Locked QAM256 7 543000000 Hz 2.8 dBmV 40.3 dB 0 0
8 Locked QAM256 8 549000000 Hz 3.0 dBmV 40.4 dB 0 0
9 Locked QAM256 9 555000000 Hz 3.4 dBmV 40.5 dB 0 0
10 Locked QAM256 10 561000000 Hz 3.1 dBmV 40.3 dB 0 0
11 Locked QAM256 11 567000000 Hz 3.4 dBmV 40.6 dB 0 0
12 Locked QAM256 12 573000000 Hz 3.6 dBmV 40.6 dB 0 0
13 Locked QAM256 13 579000000 Hz 3.4 dBmV 40.5 dB 0 0
14 Locked QAM256 14 585000000 Hz 3.8 dBmV 40.8 dB 0 0
15 Locked QAM256 15 591000000 Hz 3.7 dBmV 40.7 dB 0 0
16 Locked QAM256 16 597000000 Hz 3.9 dBmV 41.0 dB 0 0
17 Locked QAM256 17 603000000 Hz 4.3 dBmV 42.0 dB 0 0
18 Locked QAM256 18 609000000 Hz 4.2 dBmV 41.9 dB 0 0
19 Locked QAM256 19 615000000 Hz 4.4 dBmV 41.9 dB 0 0
20 Locked QAM256 26 657000000 Hz 4.6 dBmV 42.0 dB 0 0
21 Locked QAM256 28 669000000 Hz 4.5 dBmV 42.0 dB 0 0
22 Locked QAM256 30 681000000 Hz 4.8 dBmV 42.5 dB 0 0
23 Locked QAM256 31 687000000 Hz 4.5 dBmV 42.5 dB 0 0
24 Locked QAM256 32 693000000 Hz 4.8 dBmV 42.5 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 3 5120 Ksym/sec 23000000 Hz 46.3 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 35800000 Hz 45.5 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 29400000 Hz 46.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16600000 Hz 46.8 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Model: CM600|CM600 High Speed Cable Modem
Message 7 of 7
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