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Forum Discussion
2.4ghz not connecting
I have a CAX80. I recently just changed the SSID password and I noticed the cable connection was poor. We also just has a a small snow storm.. I have power cycled the router multiple times and same thing. How do I fix and what is going on? Thanks.
9 Replies
they already provisioned my modem why would they do it again?
Because "something has changed" There could be damage to your cable line/components that affects only your service. Or, other houses may have similar problems but since service continues, they have no reason to call. You are somewhat unique in having the ability to observe information about the cable connection.
Downstream OFDM Channels
Channel LockedStatus ProfileID ChannelID Frequency Power SNR/MER ActiveSubcarrier Unerror Correctable Uncorrectable
1 Locked 0 ,1 ,2 ,3 159 300000000 Hz 13.68 dBmV 42.3 dB 296 ~ 7895 44219236 2418682 0
2 Not Locked 0 0 0 Hz 0 dBmV 0 dB 0 ~ 4095 0 0 0
Upstream OFDMA Channels
Channel LockedStatus ProfileID ChannelID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
Event Log
Time Priority Description
Mon Feb 23 04:35:40 2026 Critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Mon Feb 23 04:34:00 2026 Warning Dynamic Range Window violation
Mon Feb 23 04:34:00 2026 Warning RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Mon Feb 23 04:34:00 2026 Warning Dynamic Range Window violation
Mon Feb 23 04:34:00 2026 Warning RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Mon Feb 23 04:33:56 2026 Notice DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Mon Feb 23 04:33:55 2026 Notice TLV-11 - unrecognized OID;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Mon Feb 23 04:33:54 2026 Warning DHCP WARNING - Non-critical field invalid in response ;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Thu Jan 1 00:00:38 1970 Notice Honoring MDD; IP provisioning mode = IPv4
Thu Jan 1 00:00:25 1970 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:35:02 2026 Critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:32:13 2026 Critical No Ranging Response received - T3 time-out;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:31:53 2026 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:31:28 2026 Critical No Ranging Response received - T3 time-out;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:31:14 2026 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:29:57 2026 Critical No Ranging Response received - T3 time-out;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Wed Feb 18 10:29:48 2026 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=f8:b7:e2:05:18:eb;CM-QOS=1.1;CM-VER=3.1;
Thu Jan 1 00:02:44 1970 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Thu Jan 1 00:02:32 1970 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Thu Jan 1 00:01:00 1970 Critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=34:98:b5:cd:ef:91;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Firmware Version 5.1.1.8
Internet Access: Good
Downstream Status: Poor
Downstream Power Level: Poor
Downstream power is poor (10.1dBmV). The recommended level is between -10dBmV to 10dBmV.
Downstream SNR: Good
Upstream Status: Good
Upstream Power Level: Good
Current time: Mon Feb 23 04:41:58 2026
Startup Procedure
Acquire Downstream Channel: 237 MHz Locked
Connectivity State: OK Operational
Boot State: OK Operational
Security: Enabled BPI+
Downstream Bonded Channels
Channel LockedStatus Modulation ChannelID Frequency Power SNR Correctables Uncorrectables
1 Locked 256 QAM 45 237000000 Hz 9.5 dBmV 40.3 dB 0 0
2 Locked 256 QAM 1 723000000 Hz 2.8 dBmV 37.8 dB 0 0
3 Locked 256 QAM 2 729000000 Hz 3.1 dBmV 38 dB 0 0
4 Locked 256 QAM 3 735000000 Hz 2.2 dBmV 37.7 dB 0 0
5 Locked 256 QAM 4 741000000 Hz 2.1 dBmV 37.6 dB 0 0
6 Locked 256 QAM 5 747000000 Hz 2.1 dBmV 37.6 dB 0 0
7 Locked 256 QAM 6 753000000 Hz 1.5 dBmV 37.3 dB 0 0
8 Locked 256 QAM 7 759000000 Hz 1.1 dBmV 37 dB 0 0
9 Locked 256 QAM 8 765000000 Hz 0.8 dBmV 36.8 dB 0 0
10 Locked 256 QAM 25 117000000 Hz 6.6 dBmV 38.5 dB 0 0
11 Locked 256 QAM 26 123000000 Hz 6.6 dBmV 38.4 dB 0 0
12 Locked 256 QAM 27 129000000 Hz 6.6 dBmV 38.5 dB 0 0
13 Locked 256 QAM 28 135000000 Hz 6.4 dBmV 38.9 dB 0 0
14 Locked 256 QAM 29 141000000 Hz 6.2 dBmV 39 dB 0 0
15 Locked 256 QAM 30 147000000 Hz 6.2 dBmV 38.8 dB 0 0
16 Locked 256 QAM 31 153000000 Hz 6 dBmV 38.5 dB 0 0
17 Locked 256 QAM 32 159000000 Hz 6.4 dBmV 38.7 dB 0 0
18 Locked 256 QAM 33 165000000 Hz 6.6 dBmV 38.8 dB 0 0
19 Locked 256 QAM 34 171000000 Hz 6.7 dBmV 39 dB 0 0
20 Locked 256 QAM 35 177000000 Hz 7.3 dBmV 39.3 dB 0 0
21 Locked 256 QAM 36 183000000 Hz 7.5 dBmV 39.5 dB 0 0
22 Locked 256 QAM 37 189000000 Hz 7.7 dBmV 39.4 dB 0 0
23 Locked 256 QAM 38 195000000 Hz 8.1 dBmV 39.5 dB 0 0
24 Locked 256 QAM 39 201000000 Hz 8.6 dBmV 39.4 dB 0 0
25 Locked 256 QAM 41 213000000 Hz 9.3 dBmV 39.4 dB 0 0
26 Locked 256 QAM 42 219000000 Hz 9.5 dBmV 39.6 dB 0 0
27 Locked 256 QAM 43 225000000 Hz 9.5 dBmV 40.2 dB 0 0
28 Locked 256 QAM 44 231000000 Hz 9.5 dBmV 40.3 dB 0 0
29 Locked 256 QAM 40 207000000 Hz 9 dBmV 39.3 dB 0 0
30 Locked 256 QAM 46 243000000 Hz 9.8 dBmV 40.5 dB 0 0
31 Locked 256 QAM 47 249000000 Hz 9.9 dBmV 40.4 dB 0 0
32 Locked 256 QAM 48 255000000 Hz 10.1 dBmV 40.3 dB 0 0
Ok, looks like you have some channels that are getting too much power. Any over +7dbm is too much:
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
Might ask the ISP to get a -3 or -6dbm coax cable attenuator installed.
Power is all over the place. Should be more constant in between the channels.
Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.
Have the ISP check the signal and line quality UP to the modem.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
Be sure to power OFF the modem for 1 minute then back ON.
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/
Thank you for the insights. Is this why my cable connection has a status of "poor". All has been fine. What can lead up to the spikes in the power as you say. And when they already provisioned my modem why would they do it again?
attached
I checked with COX and they do not do much. Form what they know the signal coming in is good. Unless multiple homes on my street report the same issue they are probably not coming out. But you know it was working. I only spotted it because I was logged into the router settings. The average person would not do that in general. I downloaded the updated firmware and reinstalled it in case the existing firmware was corrupted. I have verstion 5.1.1.8.
LOG FILEPossible due to snow storms and such, could be effecting the ISP cable lines and interconnecting service boxes up the line. Something the ISP will need to check into as the storms pass...
What Firmware version is currently loaded?
Please post a copy and paste of the modems connection status and event log page.
