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1 Message
0.0dB SNR on OFDM channel problem
I just wrote out a whole post but when it had me sign in it erased everything so ill be a little shorter for the second go.
I am having an issue with my connection. There are no splitters in-between, and I will attach logs and connection levels below. As far as I can tell, everything else looks to be good but the modem constantly goes back and forth attempting to bond channels (blinking blue down arrow) nonstop and I am not getting the expected speeds. When it is flashing a blue down-arrow, I see the OFDM channel appear but shows 0.0 SNR. Would someone please help me take a look into this?
|
Startup Step |
Status |
Comment |
|
Acquire Downstream Channel |
543000000 Hz |
Locked |
|
Upstream Connection |
OK |
Operational |
|
Boot State |
OK |
Operational |
|
Configuration File |
OK |
|
|
Security |
Enabled |
BPI+ |
|
Channel |
Lock Status |
Modulation |
Channel ID |
Freq. (MHz) |
Pwr (dBmV) |
SNR (dB) |
Corrected |
Uncorrected |
|
1 |
Locked |
QAM256 |
20 |
543.0 |
0.3 |
44.1 |
0 |
0 |
|
2 |
Locked |
QAM256 |
1 |
429.0 |
1.8 |
45.2 |
0 |
0 |
|
3 |
Locked |
QAM256 |
2 |
435.0 |
1.5 |
44.9 |
0 |
0 |
|
4 |
Locked |
QAM256 |
3 |
441.0 |
1.6 |
45.1 |
0 |
0 |
|
5 |
Locked |
QAM256 |
4 |
447.0 |
1.7 |
45.1 |
0 |
0 |
|
6 |
Locked |
QAM256 |
5 |
453.0 |
1.4 |
44.9 |
0 |
0 |
|
7 |
Locked |
QAM256 |
6 |
459.0 |
1.5 |
45.0 |
0 |
0 |
|
8 |
Locked |
QAM256 |
7 |
465.0 |
1.5 |
44.9 |
0 |
0 |
|
9 |
Locked |
QAM256 |
8 |
471.0 |
1.4 |
44.9 |
0 |
0 |
|
10 |
Locked |
QAM256 |
9 |
477.0 |
1.4 |
44.8 |
0 |
0 |
|
11 |
Locked |
QAM256 |
10 |
483.0 |
1.2 |
44.7 |
0 |
0 |
|
12 |
Locked |
QAM256 |
11 |
489.0 |
1.2 |
44.7 |
0 |
0 |
|
13 |
Locked |
QAM256 |
12 |
495.0 |
1.5 |
44.9 |
0 |
0 |
|
14 |
Locked |
QAM256 |
13 |
501.0 |
0.9 |
44.5 |
0 |
0 |
|
15 |
Locked |
QAM256 |
14 |
507.0 |
1.0 |
44.5 |
0 |
0 |
|
16 |
Locked |
QAM256 |
15 |
513.0 |
1.0 |
44.6 |
0 |
0 |
|
17 |
Locked |
QAM256 |
16 |
519.0 |
0.3 |
44.1 |
0 |
0 |
|
18 |
Locked |
QAM256 |
17 |
525.0 |
1.0 |
44.6 |
0 |
0 |
|
19 |
Locked |
QAM256 |
18 |
531.0 |
0.4 |
44.2 |
0 |
0 |
|
20 |
Locked |
QAM256 |
19 |
537.0 |
0.3 |
44.1 |
0 |
0 |
|
21 |
Locked |
QAM256 |
21 |
549.0 |
0.1 |
43.8 |
0 |
0 |
|
22 |
Locked |
QAM256 |
22 |
555.0 |
0.1 |
43.8 |
0 |
0 |
|
23 |
Locked |
QAM256 |
23 |
561.0 |
0.0 |
43.7 |
0 |
0 |
|
24 |
Locked |
QAM256 |
24 |
567.0 |
-0.6 |
43.3 |
0 |
0 |
|
25 |
Locked |
QAM256 |
25 |
573.0 |
-0.1 |
43.7 |
0 |
0 |
|
26 |
Locked |
QAM256 |
26 |
579.0 |
-0.4 |
43.3 |
0 |
0 |
|
27 |
Locked |
QAM256 |
27 |
585.0 |
-0.5 |
43.2 |
0 |
0 |
|
28 |
Locked |
QAM256 |
28 |
591.0 |
-0.3 |
43.5 |
0 |
0 |
|
29 |
Locked |
QAM256 |
29 |
597.0 |
-0.7 |
43.1 |
0 |
0 |
|
30 |
Locked |
QAM256 |
30 |
603.0 |
-0.6 |
42.9 |
0 |
0 |
|
31 |
Locked |
QAM256 |
31 |
609.0 |
-0.3 |
43.4 |
0 |
0 |
|
32 |
Locked |
QAM256 |
32 |
615.0 |
-0.9 |
42.8 |
0 |
0 |
|
33 |
Locked |
OFDM PLC |
193 |
957.0 |
3.6 |
0.0 |
0 |
0 |
|
Channel |
Lock Status |
Channel Type |
Channel ID |
Symb. Rate (Ksym/sec) |
Freq. (MHz) |
Pwr (dBmV) |
|
1 |
Locked |
SC-QAM |
17 |
5120 |
16.4 |
40.5 |
|
2 |
Locked |
SC-QAM |
18 |
5120 |
22.8 |
40.5 |
|
3 |
Locked |
SC-QAM |
19 |
5120 |
29.2 |
40.5 |
|
4 |
Locked |
SC-QAM |
20 |
5120 |
35.6 |
40.5 |
|
Time |
Priority |
Description |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
10:29:05 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
11:49:06 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
13:29:07 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
15:09:08 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
15:19:08 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
16:49:09 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
16:59:09 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
17:44:01 Sun Jul 2 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
12:43:56 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
14:06:45 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
14:28:41 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
15:08:42 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
15:12:15 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
Time Not Established |
Notice (6) |
Honoring MDD; IP provisioning mode = IPv6 |
|||
|
15:42:39 Mon Jul 3 2023 |
Notice (6) |
DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
|
15:42:45 Mon Jul 3 2023 |
Critical (3) |
UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
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15:42:54 Mon Jul 3 2023 |
Notice (6) |
CM-STATUS message sent. Event Type Code: 21; Chan ID: 32; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:90:f0:4c:03:00;CM-QOS=1.1;CM-VER=3.1; |
|||
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15:42:56 Mon Jul 3 2023 |
Warning (5) |
MDD message timeout;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
|||
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15:43:25 Mon Jul 3 2023 |
Notice (6) |
CM-STATUS message sent. Event Type Code: 1; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1; |
jweaver0312
Expert
•
2.1K Messages
2 years ago
The 0.0dB could possibly be a glitch causing it to not be read correctly, a reboot might clear that by unplugging it and plugging it back in. Other than that one showing 0.0 dB (possibly a glitch), these stats look ok. It could be possible the OFDM channel is being lost intermittently too.
Internet Troubleshooting Tips has some other things you can try while also inspecting the cable.
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XfinityDemitrius
Official Employee
•
2K Messages
2 years ago
Hey @J0E,
Thank you for visiting our Xfinity Community Forums support page. We would be more than happy to assist with the intermittent Internet connection you are experiencing. I see that you have already tried a few things and do not have a cable splitter.
Would you be able to check the coax cable connection and ensure all connections are tight. Could you also check that the cable is in good condition such as no hard bends, kinks, bite marks, or cuts that could cause issues with the signal reaching the modem?
Please give these a quick check and let us know if you are still experiencing issues.
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