Always One Channel High SNR

[Greenpalmer]

I always seem to have one downstream channel with high noise - it's always either channel 4 or channel 12 with a bit of overspill into adjacent channels.

Every time I reboot the router within a very short time channel 4 or 12 goes down to 33.

Also I often get only 16 or 32 qam on upsteam channels instead of the regular 64.

Router stats and log follow:

Downstream bonded channels

Channel	Frequency (Hz)	Power (dBmV)	SNR (dB)	Modulation	Channel ID
1	203000000	4.3	37	256 qam	9
2	139000000	6.8	37	256 qam	1
3	147000000	6	37	256 qam	2
4	155000000	6	37	256 qam	3
5	163000000	5.5	37	256 qam	4
6	171000000	5.5	37	256 qam	5
7	179000000	5	37	256 qam	6
8	187000000	5	37	256 qam	7
9	195000000	4.6	37	256 qam	8
10	211000000	4.1	37	256 qam	10
11	219000000	3.7	34	256 qam	11
12	227000000	3.7	33	256 qam	12
13	235000000	3.2	37	256 qam	13
14	243000000	3.2	37	256 qam	14
15	251000000	2.9	37	256 qam	15
16	259000000	3	37	256 qam	16
17	267000000	2.7	37	256 qam	17
18	275000000	2.4	37	256 qam	18
19	283000000	1.9	37	256 qam	19
20	291000000	1.2	37	256 qam	20
21	299000000	1.2	36	256 qam	21
22	307000000	1.9	37	256 qam	22
23	315000000	2.5	37	256 qam	23
24	323000000	2.9	37	256 qam	24

Downstream bonded channels

Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	37.3	1449	648
2	Locked	37.3	2452	542
3	Locked	37.3	1108	572
4	Locked	37.6	1346	12888
5	Locked	37.6	997	1002
6	Locked	37.6	1249	963
7	Locked	37.3	1103	1049
8	Locked	37.3	917	823
9	Locked	37.3	773	833
10	Locked	37.6	818	699
11	Locked	34.3	1145020	563
12	Locked	33.9	4226461	848
13	Locked	37.3	1209	490
14	Locked	37.3	700	421
15	Locked	37.3	744	515
16	Locked	37.3	1357	503
17	Locked	37.6	918	533
18	Locked	37.6	937	480
19	Locked	37.6	1059	608
20	Locked	37.3	1782	550
21	Locked	36.6	1968	560
22	Locked	37.3	1079	764
23	Locked	37.6	1409	710
24	Locked	37.6	712	742

Upstream bonded channels

Channel	Frequency (Hz)	Power (dBmV)	Symbol Rate (ksps)	Modulation	Channel ID
1	39400053	48	5120	64 qam	4
2	53700200	49	5120	32 qam	2
3	46199912	48.5	5120	16 qam	3
4	60300010	49.3	5120	64 qam	1

Upstream bonded channels

Channel	Channel Type	T1 Timeouts	T2 Timeouts	T3 Timeouts	T4 Timeouts
1	ATDMA	0	0	4	0
2	ATDMA	0	0	3	0
3	ATDMA	0	0	5	0
4	ATDMA	0	0	1	0

Network Log

Time	Priority	Description
21/08/2021 07:43:22	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
21/08/2021 02:01:4	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/08/2021 15:24:48	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/08/2021 09:40:48	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/08/2021 14:59:32	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/08/2021 14:01:4	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/08/2021 17:06:21	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/08/2021 07:10:48	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/08/2021 21:04:55	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/08/2021 02:01:4	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
12/08/2021 00:11:28	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
11/08/2021 17:48:2	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
11/08/2021 13:16:11	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
11/08/2021 11:51:52	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/08/2021 16:50:40	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/08/2021 14:01:3	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/08/2021 05:07:48	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
08/08/2021 00:53:34	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/08/2021 02:01:3	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
06/08/2021 16:13:24	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[Andrew-G]

Looks like you've got some upstream noise issues, and downstream is particularly affected by noise ingress of signals in the 220-230 MHz range.  The downstream issues are probably due to DAB radio broadcasts.  Assuming you haven't got any DIY coax modifications, then it's possibly a damaged cable or poor joint, or it could be a poorly fastened coax connector on the lead between the hub and the wall box.  

Have you checked that the coax cable is undamaged (and unkinked) and the connections are secure with the securing nuts done up finger tight?

If that's been done, then you'll need a technician visit, and in that case wait for the helpful forum staff to advise as the telephone agents won't have clue what you're talking about.

[Greenpalmer]

@Andrew-G, thanks for the reply.

I have checked the coax cable and connections and they all seem fine so I guess, as you say, that I need a technician visit.

Forum staff - please can you arrange.

[David_Bn]

Good Afternoon @Greenpalmer and I'm sorry to hear of the issues you've been experiencing with our services.

I've been able to locate your account and it appears that you're currently subjected to an area outage that is due to run until 09:15 on 31/08

We apologise for the inconvenience this may cause and our team will do all that's possible to have this resolved as soon as possible 

Kindest regards,

David_Bn

[Greenpalmer]

Hi David, thanks for the response.

I've looked on the Service Status page on My Virgin Media and there are no issues listed, and everything seems to be working reasonably normally so it doesn't seem that we do have an area outage.

[newapollo]

Hi Greenpalmer,

The issue may be listed on the  Service Status number  0800 561 0061.  This often gives details of more local issues down to postcode level.

[Greenpalmer]

Hi newapollo,

Thanks for that information.

I phoned the number you gave and the recorded message told me that there is indeed a very complex problem in my area that Virgin engineers are working very hard to fix and it may take longer than normal.

[Gareth_L]

Hello Greenpalmer

Sorry for the issues in your area

I have had a look into this and were are expecting this to be fixed around the 31/08/21

If it's still the same dater that date pop back on hare and ask for an update on the below reference number F009235929  

Gareth_L

[Greenpalmer]

Hi Gareth,

It's September 2nd now - can I have an update please

[John_GS]

Hi Greenpalmer

Thanks for coming back to us. Unfortunately from checking this, the SNR (signal to noise ratio) issue has been extended to the 9th September.

Kind regards,