Drop in performance from Hub 3 to Hub 5 - low SNR and high errors on two channels?

[redbull-89]

Hello everyone,

A couple of weeks back I upgraded to the Hub 5 from the Hub 3 which had been working seamlessly in modem mode for about one year, and consistently given me download speeds of 600-660mbs even in peak hours / upload more variable but up to 42ish mbs (am on VM600).

While upon initial installation the Hub 5 looked to match that performance (I ran quick speed test when all was up and running and hit well above 600mbs download in the evening), it's been about a week now that I have noticed a drop in performance and a peak download speed that's typically 100-200mbs lower than what it used to be (so down to 350-550mbs) and a lot more unstable (at times sub 100mbs). Upload is still as good as it used to be,

After reading a few posts on this forum, I checked signal stats and noticed that there's 2 to 3 channels with low SNR and high post RS errors, see below. Have tried to reboot the router a few times but no real joy. If anything channel 12 twice showed 0 SNR post rebooting, while channel 4 is the one exhibiting the least stable SNR as it flips between 40ish and 32ish at almost every check.

Could SNR / post RS errors be the source of the issue? How would I be able to fix it?

FWIW the white coaxial cable going into the hub is the only one that I have touched when switching Hub and it's tight. All other coaxials appear to be tight too.

Downstream bonded channels

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

1	330000000	1.7	41	QAM 256	25
2	138000000	-1.1	39	QAM 256	1
3	146000000	0.7	39	QAM 256	2
4	154000000	0.7	32	QAM 256	3
5	162000000	0.7	40	QAM 256	4
6	170000000	0.6	41	QAM 256	5
7	178000000	0.4	41	QAM 256	6
8	186000000	0.2	41	QAM 256	7
9	194000000	0	41	QAM 256	8
10	202000000	0.1	41	QAM 256	9
11	210000000	0.4	38	QAM 256	10
12	218000000	0.2	27	QAM 256	11
13	226000000	0.5	27	QAM 256	12
14	234000000	0.6	41	QAM 256	13
15	242000000	0.5	41	QAM 256	14
16	250000000	0.6	41	QAM 256	15
17	258000000	0.8	41	QAM 256	16
18	266000000	1.1	41	QAM 256	17
19	274000000	1.3	41	QAM 256	18
20	282000000	1.6	41	QAM 256	19
21	290000000	1.8	41	QAM 256	20
22	298000000	1.7	42	QAM 256	21
23	306000000	1.9	42	QAM 256	22
24	314000000	1.9	42	QAM 256	23
25	322000000	1.8	42	QAM 256	24
26	338000000	1.8	41	QAM 256	26
27	346000000	1.8	42	QAM 256	27
28	354000000	1.8	42	QAM 256	28
29	362000000	2	42	QAM 256	29
30	370000000	2	42	QAM 256	30
31	378000000	2	42	QAM 256	31

Downstream bonded channels

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

1	Locked	41	0	0
2	Locked	39	13213	2182
3	Locked	39	0	0
4	Locked	32	23	0
5	Locked	40	0	0
6	Locked	41	0	0
7	Locked	41	0	0
8	Locked	41	0	0
9	Locked	41	0	0
10	Locked	41	0	0
11	Locked	38	0	0
12	Locked	27	29064215	3906521
13	Locked	27	31645097	1431861
14	Locked	41	0	0
15	Locked	41	0	0
16	Locked	41	0	0
17	Locked	41	0	0
18	Locked	41	0	0
19	Locked	41	0	0
20	Locked	41	0	0
21	Locked	41	0	0
22	Locked	42	0	0
23	Locked	42	0	0
24	Locked	42	0	0
25	Locked	42	0	0
26	Locked	41	0	0
27	Locked	42	0	0
28	Locked	42	0	0
29	Locked	42	0	0
30	Locked	42	0	0
31	Locked	42	0	0

Upstream bonded channels

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

0	49600000	50.3	5120	QAM 64	1
1	43100000	50	5120	QAM 64	2
2	36600000	49.8	5120	QAM 64	3
3	30100000	49.8	5120	QAM 64	4
4	23600000	49.5	5120	QAM 64	5

Upstream bonded 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	0	0
3	ATDMA	0	0	0	0
4	ATDMA	0	0	0	0

[redbull-89]

By way of update, I see my hub channel list has shifted to higher frequencies but am still using one channel with low SNR running into post errors and its adjacent channel is being skipped.

I understand from a quick research that those two might be the DAB frequencies.

Tried to call Virgin support but they've not been of much use other than mentioning it might be due to an issue in my area which I however can't seem to find reference of online.

Speed is acceptable but stability hasn't been great.

Any suggestions? 

1	330000000	2	41	QAM 256	25
2	178000000	0.3	41	QAM 256	6
3	186000000	0.1	41	QAM 256	7
4	194000000	0.2	41	QAM 256	8
5	202000000	0.3	41	QAM 256	9
6	210000000	0.6	40	QAM 256	10
7	218000000	0.5	30	QAM 256	11
8	226000000	0.8	0		12
9	234000000	0.8	41	QAM 256	13
10	242000000	0.8	41	QAM 256	14
11	250000000	0.9	41	QAM 256	15
12	258000000	1	41	QAM 256	16
13	266000000	1.4	41	QAM 256	17
14	274000000	1.6	41	QAM 256	18
15	282000000	1.9	41	QAM 256	19
16	290000000	2.1	41	QAM 256	20
17	298000000	2	41	QAM 256	21
18	306000000	2.2	41	QAM 256	22
19	314000000	2.2	41	QAM 256	23
20	322000000	2.1	41	QAM 256	24
21	338000000	2.1	42	QAM 256	26
22	346000000	2.1	42	QAM 256	27
23	354000000	2.1	42	QAM 256	28
24	362000000	2.2	42	QAM 256	29
25	370000000	2.3	42	QAM 256	30
26	378000000	2.3	42	QAM 256	31
27	386000000	1.8	41	QAM 256	32
28	394000000	1.5	41	QAM 256	34
29	402000000	1.3	41	QAM 256	35
30	410000000	1.3	42	QAM 256	36
31	418000000	1.4	41	QAM 256	37

[Reece_MH · Accepted solution]

Hi @redbull-89,

Thanks for your post, and a warm welcome to our Community Forums.

I'm sorry to hear you're having some problems with your service. After running some checks on my side, it does appear that there is currently a known problem in your area, the details are:

Fault Type: SNR (Signal-To-Noise)
Impact: You may find your Broadband, TV and Phone services are intermittent
Fault Ref: F010200206
Estimated Fix: 02 DEC 2022 15:30

I'm very sorry for any inconvenience this is causing in the meantime.

Thanks,

[Tudor]

From what I can see of your stats there is a noise ingress problem on the frequencies that are also used for DAB radio.

[redbull-89]

Thank you. Will keep an eye on it and see if it does indeed get fixed tomorrow.

[redbull-89]

Looks to be the case indeed. I can see from the other post that it could be an area issue.

Suppose there's no smart way for me to see if it's my setup causing it (to me and my neighbours)? What could cause the noise on those frequencies? 

[redbull-89]

@Reece_MH, the expected date has passed but I can confirm the issue is still there. It's possible Virgin engineers have made changes (power has gone up, the range of frequencies the modern is using has shifted up) but the DAB frequencies are still noisy and full of errors.

Can you provide an update on the issue please? Do I need an engineer visit?

Downstream bonded channels

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

1 330000000 4.4 42 QAM 256 25

2 178000000 2.2 41 QAM 256 6

3 186000000 2.5 42 QAM 256 7

4 194000000 2.7 42 QAM 256 8

5 202000000 2.8 42 QAM 256 9

6 210000000 2.9 41 QAM 256 10

7 218000000 3 30 QAM 256 11

8 226000000 3.1 27 QAM 256 12

9 234000000 3.2 42 QAM 256 13

10 242000000 3.2 42 QAM 256 14

11 250000000 3.3 42 QAM 256 15

12 258000000 3.3 42 QAM 256 16

13 266000000 3.7 42 QAM 256 17

14 274000000 3.9 42 QAM 256 18

15 282000000 4.2 42 QAM 256 19

16 290000000 4.4 42 QAM 256 20

17 298000000 4.3 42 QAM 256 21

18 306000000 4.5 42 QAM 256 22

19 314000000 4.5 42 QAM 256 23

20 322000000 4.5 42 QAM 256 24

21 338000000 4.5 42 QAM 256 26

22 346000000 4.4 42 QAM 256 27

23 354000000 4.5 42 QAM 256 28

24 362000000 4.6 42 QAM 256 29

25 370000000 4.7 42 QAM 256 30

26 378000000 4.7 42 QAM 256 31

27 386000000 4.2 42 QAM 256 32

28 394000000 3.9 42 QAM 256 34

29 402000000 3.7 42 QAM 256 35

30 410000000 3.6 42 QAM 256 3 6

31 418000000 3.8 42 QAM 256 37

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

1 Locked 42 36 0

2 Locked 41 354 0

3 Locked 42 231 0

4 Locked 42 229 0

5 Locked 42 148 0

6 Locked 41 177 0

7 Locked 30 20283823 3414

8 Locked 27 68886137 12411183

9 Locked 42 383 0

10 Locked 42 264 0

11 Locked 42 60 0

12 Locked 42 143 0

13 Locked 42 48 0

14 Locked 42 32 0

15 Locked 42 65 0

16 Locked 42 13 0

17 Locked 42 19 0

18 Locked 42 15 0

19 Locked 42 14 0

20 Locked 42 35 0

21 Locked 42 20 0

22 Locked 42 25 0

23 Locked 42 30 0

24 Locked 42 3 0

25 Locked 42 7 0

26 Locked 42 4 0

27 Locked 42 9 0

28 Locked 42 6 0

29 Locked 42 1 0

30 Locked 42 27 0

31 Locked 42 3 0

[David_Bn]

Thanks for coming back to the thread @redbull-89.

I'm sorry to say that having looked into the local area, the estimated fix date and time has been extended to 08/12/22 15:30.

We apologise for any inconvenience this may cause you, and will ensure that all is done to have this resolved as soon as possible.

Kindest regards,

David_Bn

[redbull-89]

Thank you @David_Bn for getting back. I got in touch with customer support and scheduled for an engineer to come and see our property as well (after the deadline you report below).

What if it's actually my property causing noise ingress though? I have noticed I do have a fiddly wall socket connector for one of the two TV boxes I have with Virgin and putting it somewhat more firmly in place has boosted SNR to a more acceptable 31-33 range for the two DAB channels.

Note I only have one virgin cable coming into my property, then split three way to the router / modem and the two TV boxes.

---

@David_Bn wrote:

Thanks for coming back to the thread @redbull-89.

I'm sorry to say that having looked into the local area, the estimated fix date and time has been extended to 08/12/22 15:30.

We apologise for any inconvenience this may cause you, and will ensure that all is done to have this resolved as soon as possible.

Kindest regards,

David_Bn

---

[Robert_P]

Thanks for the update redbull-89, we're sure the technician will be able to get this looked into and resolved for you. Please keep us up to date with how the visit goes and the outcome 🙂

Rob