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Terrible SNR after Docsis 3.1 Upgrade

Straight6Petrol
Dialled in

Hello all,

Following the install of my services mid 2021 I have been seeing high (but somewhat fluctating) SNR and power levels on my Super Hub 4. They used to sit around 5/6db and around 39/40 on SNR.

A couple of months ago we had a total outage and when the services went back online the power dropped to around 0/1db and the SNR around 34. However, it was now showing a 3.1 channel as being online. 

Ever since the SNR has been dropping and recently it's showing 30 on a couple channels with loads of pre-rs errors and a couple "uncorrectables" on the 3.1 channel.

I'm assuming this will need an engineer visit? I've reset the router, rebooted about a hundred times and all connections from the drive to router are tight and clean.

Thanks in advance for any assistance, I'll try post stats on the following posts.

1 ACCEPTED SOLUTION

Accepted Solutions

Hub just restarted on its own and the SNR is now 40 on all channels. 

I assume VM did something so massive thanks to anyone involved!

See where this Helpful Answer was posted

5 REPLIES 5

Straight6Petrol
Dialled in
Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
25 330750000 2.1 34 QAM256 25
1 138750000 2.6 30.4 QAM256 1
2 146750000 2.8 30.6 QAM256 2
3 154750000 3.2 31.1 QAM256 3
4 162750000 3.1 31.3 QAM256 4
5 170750000 3.1 31.7 QAM256 5
6 178750000 3.1 32 QAM256 6
7 186750000 3.4 32.2 QAM256 7
8 194750000 3.6 32.6 QAM256 8
9 202750000 3.7 32.7 QAM256 9
10 210750000 3.5 33 QAM256 10
11 218750000 3.6 33 QAM256 11
12 226750000 3.3 33.1 QAM256 12
13 234750000 2.9 33.1 QAM256 13
14 242750000 2.7 33 QAM256 14
15 250750000 2.7 32 QAM256 15
16 258750000 2.3 33.1 QAM256 16
17 266750000 2.4 33.4 QAM256 17
18 274750000 2.7 33.5 QAM256 18
19 282750000 2.8 33.8 QAM256 19
20 290750000 2.7 34 QAM256 20
21 298750000 2.6 34 QAM256 21
22 306750000 2.4 34.5 QAM256 22
23 314750000 2.5 34.3 QAM256 23
24 322750000 2.5 34.5 QAM256 24
26 338750000 1.7 33.8 QAM256 26
27 346750000 1.4 33.8 QAM256 27
28 354750000 1.5 34 QAM256 28
29 362750000 1.3 34 QAM256 29
30 370750000 1.2 33.8 QAM256 30
31 378750000 1.4 33.8 QAM256 31

Channel Lock Status RxMER (dB) Pre RS Errors Post RS Errors
25 Locked 33.956509 3263 0
1 Locked 30.366289 115609 0
2 Locked 30.646576 66174 0
3 Locked 31.136440 38806 0
4 Locked 31.335388 19405 0
5 Locked 31.688669 11135 0
6 Locked 31.993563 6504 0
7 Locked 32.237156 4733 0
8 Locked 32.584778 2214 0
9 Locked 32.676208 1208 0
10 Locked 32.962662 757 0
11 Locked 32.962662 488 0
12 Locked 33.062504 536 0
13 Locked 33.062504 674 0
14 Locked 32.962662 642 0
15 Locked 31.993563 5923 0
16 Locked 33.062504 550 0
17 Locked 33.376591 285 0
18 Locked 33.486542 120 0
19 Locked 33.834164 47 0
20 Locked 33.956509 43 0
21 Locked 33.956509 30 0
22 Locked 34.483570 16 0
23 Locked 34.345688 16 0
24 Locked 34.483570 12 0
26 Locked 33.834164 37 0
27 Locked 33.834164 86 0
28 Locked 33.956509 51 0
29 Locked 33.956509 38 0
30 Locked 33.834164 93 0
31 Locked 33.834164 88 0

3.1 Downstream channels
Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)
33 94 4K 1840 QAM4096 424


3.1 Downstream channels
Channel ID Lock Status RxMER Data (dB) PLC Power (dBmV) Correcteds (Active Profile) Uncorrectables (Active Profile)
33 Locked 36 0.4 19227025 1

3.0 Upstream channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 46200000 42 5120 KSym/sec 64QAM 7
2 60300000 42.3 5120 KSym/sec 64QAM 5
3 39400000 42 5120 KSym/sec 64QAM 8
4 53700000 42.3 5120 KSym/sec 64QAM 6

Hub just restarted on its own and the SNR is now 40 on all channels. 

I assume VM did something so massive thanks to anyone involved!