Intermittent issue causing slow download speeds

[Zoomeh]

Hey VM community.
There's a long running issue in my area that is progressively getting worse with it now occurring multiple times a day for extended periods. It looks to be a noise issue with SNR on some channels occasionally dropping to 0.
Weirdly enough it only affects download speeds and latency.
I'm IT inclined and have tried the usual troubleshooting but this looks to be something a VM engineer will have to resolve.

Gig1.
Hub5.
Modem Mode.

Here's a speedtest showing the issue.

My BQM for today.

Modem Stats:
Modem was restarted 30 mins before these readings.

Cable Modem StatusItem Status TypeChannel Overview Downstream Upstream

Cable Modem Status	Online	DOCSIS 3.0
Primary downstream channel	Locked	SC-QAM
DOCSIS 3.0 channels	30	5
DOCSIS 3.1 channels	1	1

3.0 Downstream channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	611000000	-7.8	34	QAM 256	32
2	387000000	-8.3	27	QAM 256	4
3	419000000	-8	31	QAM 256	8
4	427000000	-7.8	28	QAM 256	9
5	451000000	-8.3	34	QAM 256	12
6	459000000	-8.5	33	QAM 256	13
7	483000000	-8.6	33	QAM 256	16
8	491000000	-8.7	32	QAM 256	17
9	515000000	-8.7	32	QAM 256	20
10	523000000	-8.4	32	QAM 256	21
11	547000000	-7.6	31	QAM 256	24
12	555000000	-7.2	32	QAM 256	25
13	579000000	-7.1	33	QAM 256	28
14	587000000	-7.2	34	QAM 256	29
15	603000000	-7.7	35	QAM 256	31
16	619000000	-7.8	33	QAM 256	33
17	627000000	-7.9	35	QAM 256	34
18	635000000	-8.3	35	QAM 256	35
19	643000000	-8.4	34	QAM 256	36
20	651000000	-8.5	34	QAM 256	37
21	659000000	-8.4	34	QAM 256	38
22	667000000	-8.5	34	QAM 256	39
23	675000000	-8.5	34	QAM 256	40
24	683000000	-8.1	35	QAM 256	41
25	691000000	-8.7	34	QAM 256	42
26	699000000	-8.9	34	QAM 256	43
27	707000000	-8.8	35	QAM 256	44
28	715000000	-8.9	34	QAM 256	45
29	723000000	-9.2	35	QAM 256	46
30	731000000	-9.6	34	QAM 256	47

3.0 Downstream channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1	Locked	34	34950	0
2	Locked	27	61932464	6231823
3	Locked	31	3899618	0
4	Locked	28	66176698	676589
5	Locked	34	5001343	64
6	Locked	33	14276929	508
7	Locked	33	100962	0
8	Locked	32	541764	0
9	Locked	32	434429	0
10	Locked	32	2930016	4
11	Locked	31	3918411	51
12	Locked	32	316758	16
13	Locked	33	89525	0
14	Locked	34	9992	0
15	Locked	35	5235	0
16	Locked	33	79490	0
17	Locked	35	2140	0
18	Locked	35	1828	0
19	Locked	34	3610	0
20	Locked	34	3235	0
21	Locked	34	4499	0
22	Locked	34	18789	0
23	Locked	34	11354	0
24	Locked	35	2622	0
25	Locked	34	7266	0
26	Locked	34	7286	0
27	Locked	35	4218	0
28	Locked	34	8111	433
29	Locked	35	4441	1887
30	Locked	34	5141	0

3.1 Downstream channels

Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)

159

190

4K

3736

QAM 4096

148

3.1 Downstream channels

Channel ID Locked Status RxMER Data (dB) PLC Power (dBmV) Corrected errors (Active Profile) Uncorrectable errors (Active Profile)

159

Locked

34

-11.1

61465322

27634850

3.0 Upstream channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

0	49600000	55.3	5120	QAM 64	1
1	43100000	54.8	5120	QAM 64	2
2	36600000	54.5	5120	QAM 64	3
3	30100000	54.3	5120	QAM 64	4
4	23600000	53.3	5120	QAM 64	5

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

0	ATDMA	0	0	0	0
1	ATDMA	0	0	0	0
2	ATDMA	0	0	4	0
3	ATDMA	0	0	0	0
4	ATDMA	0	0	0	0

3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation

6

10

49.0

2K

QAM 256

3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts

6

OFDMA

200

74000000

0

0

[Zoomeh]

Network Log

Time Priority Description

01-08-2024 15:51:02	notice	CM-STATUS message sent. Event Type Code: 4; Chan ID: 4; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:50:52	warning	MDD message timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:41:41	notice	CM-STATUS message sent. Event Type Code: 4; Chan ID: 4; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:41:22	warning	MDD message timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:34:53	notice	CM-STATUS message sent. Event Type Code: 4; Chan ID: 4; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:34:42	warning	MDD message timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:42	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:23	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:23	warning	DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:19	notice	REGISTRATION COMPLETE - Waiting for Operational status
01-08-2024 15:28:14	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:14	warning	Dynamic Range Window violation
01-08-2024 15:28:14	warning	REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:14	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:14	warning	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:14	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:14	warning	Dynamic Range Window violation
01-08-2024 15:28:14	warning	Dynamic Range Window violation
01-08-2024 15:28:14	warning	Dynamic Range Window violation
01-08-2024 15:28:14	warning	RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:08	notice	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:04	notice	TLV-11 - unrecognized OID;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:02	warning	DHCP WARNING - Non-critical field invalid in response ;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:28:00	notice	Honoring MDD; IP provisioning mode = IPv4
01-08-2024 15:27:26	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:27:20	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2024 15:27:19	critical	Cable Modem Reboot because of - HW or Power-On Reset
23-07-2024 09:51:54	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
23-07-2024 09:51:48	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
23-07-2024 09:51:47	critical	Cable Modem Reboot because of - HW or Power-On Reset
22-07-2024 14:47:09	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
22-07-2024 14:47:01	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

[Client62]

The Downstream power levels should be between -7 to +7 with a max of +10 dBmV
most channels are too low resulting in many errors that can not be corrected.

3.0 Downstream channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	611000000	-7.8	34	QAM 256	32
2	387000000	-8.3	27	QAM 256	4
3	419000000	-8	31	QAM 256	8
4	427000000	-7.8	28	QAM 256	9
5	451000000	-8.3	34	QAM 256	12
6	459000000	-8.5	33	QAM 256	13
7	483000000	-8.6	33	QAM 256	16
8	491000000	-8.7	32	QAM 256	17
9	515000000	-8.7	32	QAM 256	20
10	523000000	-8.4	32	QAM 256	21

3.1 Downstream channels

Channel ID Locked Status RxMER Data (dB) PLC Power (dBmV) Corrected errors (Active Profile) Uncorrectable errors (Active Profile)

159

Locked

34

-11.1

61465322

27634850

[Beth_G]

Hi Zoomeh

Thanks for your post, welcome to the Community Forums.

Sorry to see you're having trouble with your connection and speeds. You're quite right, your downstream channels are too low and so we'll need to get an engineer out to take a look. There's no known outages in your area that could be causing this by the looks of it.

I've dropped you a PM 😊

[Anonymous]

Have you thought about moving home, it'll be quicker, easier and less stressful than getting a reliable service from this crowd.

[Zoomeh]

Happy to report that I had a competent engineer who replaced everything except the main coax run to my property and sorted out the mess in the cab which has brought the power levels back in to spec and solved the dropouts and speed issues.
Cheers.