Issue began 4 days ago, internet connectivity on the modem is intermittent and gets worse later in the day (9PM - 1AM). Modem logs show T3 time-outs ("No Ranging Response received - T3 time-out") and Dynamic Range Violation Errors.
Basic troubleshooting completed. Checked the physical line and connection to my house, no damage.
Frequency Tables from modem (Netgear CM1200):
Startup Procedure
Procedure
Status
Comment
Acquire Downstream Channel
615000000 Hz
Locked
Connectivity State
OK
Operational
Boot State
OK
Operational
Security
Enabled
BPI+
IP Provisioning Mode
Honor MDD
honorMdd(4)
Downstream Bonded Channels (Partial Service)
Channel
Lock Status
Modulation
Channel ID
Frequency
Power
SNR
Correctables
Uncorrectables
1
Locked
QAM256
25
615000000 Hz
4.1 dBmV
40 dB
0
0
2
Locked
QAM256
1
459000000 Hz
3.3 dBmV
40 dB
275
854
3
Locked
QAM256
2
465000000 Hz
4 dBmV
40 dB
343
863
4
Locked
QAM256
3
471000000 Hz
4 dBmV
40.2 dB
350
831
5
Locked
QAM256
4
477000000 Hz
3.5 dBmV
40.2 dB
367
813
6
Locked
QAM256
5
483000000 Hz
2.8 dBmV
39.5 dB
458
796
7
Locked
QAM256
6
489000000 Hz
2.6 dBmV
39.7 dB
722
827
8
Locked
QAM256
7
495000000 Hz
2.3 dBmV
39.5 dB
956
842
9
Locked
QAM256
8
507000000 Hz
3.9 dBmV
40.2 dB
547
842
10
Locked
QAM256
9
513000000 Hz
4.6 dBmV
40.1 dB
312
799
11
Locked
QAM256
10
519000000 Hz
4.1 dBmV
40.1 dB
263
740
12
Locked
QAM256
11
525000000 Hz
2.8 dBmV
39.2 dB
266
730
13
Locked
QAM256
12
531000000 Hz
2.3 dBmV
38.5 dB
5918
4231
14
Locked
QAM256
13
543000000 Hz
2.7 dBmV
39.8 dB
179
699
15
Locked
QAM256
14
549000000 Hz
3.6 dBmV
40 dB
225
665
16
Locked
QAM256
15
555000000 Hz
4.1 dBmV
40 dB
204
684
17
Locked
QAM256
16
561000000 Hz
3.9 dBmV
40 dB
208
680
18
Locked
QAM256
17
567000000 Hz
3.4 dBmV
38.9 dB
202
732
19
Locked
QAM256
18
573000000 Hz
2.6 dBmV
39.5 dB
199
721
20
Locked
QAM256
19
579000000 Hz
2.2 dBmV
39.8 dB
188
752
21
Locked
QAM256
20
585000000 Hz
2.4 dBmV
31.2 dB
2934491
43643
22
Locked
QAM256
21
591000000 Hz
3.1 dBmV
33.7 dB
7705
0
23
Locked
QAM256
22
597000000 Hz
4 dBmV
38.6 dB
207
727
24
Locked
QAM256
23
603000000 Hz
4.7 dBmV
38.4 dB
201
724
25
Locked
QAM256
24
609000000 Hz
4.4 dBmV
39.1 dB
222
715
26
Locked
QAM256
26
621000000 Hz
3.5 dBmV
39.8 dB
183
732
27
Locked
QAM256
27
627000000 Hz
3 dBmV
39.7 dB
198
687
28
Locked
QAM256
28
633000000 Hz
3.1 dBmV
39.7 dB
209
690
29
Locked
QAM256
29
639000000 Hz
3.4 dBmV
39.7 dB
216
706
30
Locked
QAM256
30
645000000 Hz
3.6 dBmV
39.7 dB
221
671
31
Locked
QAM256
31
651000000 Hz
4.2 dBmV
39.8 dB
188
688
32
Locked
QAM256
32
657000000 Hz
4.6 dBmV
39.9 dB
202
646
Upstream Bonded Channels (Partial Service)
Channel
Lock Status
US Channel Type
Channel ID
Symbol Rate
Frequency
Power
1
Not Locked
Unknown
1
0 Ksym/sec
23700000 Hz
0.0 dBmV
2
Not Locked
Unknown
2
0 Ksym/sec
17300000 Hz
0.0 dBmV
3
Not Locked
Unknown
3
0 Ksym/sec
30100000 Hz
0.0 dBmV
4
Not Locked
Unknown
4
0 Ksym/sec
36500000 Hz
0.0 dBmV
5
Locked
ATDMA
5
1280 Ksym/sec
41200000 Hz
51.5 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
Downstream OFDM Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
SNR / MER
Active Subcarrier Number Range
Unerrored Codewords
Correctable Codewords
Uncorrectable Codewords
1
Not Locked
0
0
0 Hz
0 dBmV
0.0 dB
0 ~ 4095
0
0
0
2
Not Locked
0
0
0 Hz
0 dBmV
0.0 dB
0 ~ 4095
0
0
0
Upstream OFDMA Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
1
Not Locked
0
0
0 Hz
0 dBmV
2
Not Locked
0
0
0 Hz
0 dBmV
Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power
Current System Time:Mon May 25 12:55:04 2020
System Up Time:00:56:25
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The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of the multiple upstream channels (there should be 3-5. You only have 1).
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
EG
Expert
•
111.4K Messages
5 years ago
The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of the multiple upstream channels (there should be 3-5. You only have 1).
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
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