Pre & Post RS Errors - Is this Healthy?

[AndyB69]

Can anyone advise whether the below are good/bad/to be expected.  I am on M350 (in Modem Mode) and over the past 6 months have noticed a decline from our usual 75Mbps D/L speeds to regularly only getting 25Mbps (I would LOVE to think we ever got close to the advertised speeds).

I check using the Service Checker in case there are any known issues in our area.  In the olden times (we had this installed in 2000 when it was ntl - I was working for them back then) I would just call up and request a Service Engineer to come check (and would be happy to pay) but now I can't seem to get anywhere other than in a perpetual loop of check it myself, reboot the router, check it again.

If anyone can point me as to whether the below should be cause for both concern and insisting on a physical visit it would be much appreciated.

Downstream bonded channels

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

1	267000000	0	40	256 qam	17
2	275000000	0	40	256 qam	18
3	283000000	-0.2	40	256 qam	19
4	291000000	0	40	256 qam	20
5	299000000	0	40	256 qam	21
6	307000000	0	40	256 qam	22
7	315000000	0.2	40	256 qam	23
8	323000000	0.2	40	256 qam	24
9	331000000	0.2	40	256 qam	25
10	339000000	0.4	40	256 qam	26
11	347000000	0.4	40	256 qam	27
12	355000000	0.2	40	256 qam	28
13	363000000	0	40	256 qam	29
14	371000000	0	40	256 qam	30
15	379000000	0	40	256 qam	31
16	387000000	0	40	256 qam	32
17	395000000	-0.2	40	256 qam	33
18	403000000	0.2	40	256 qam	34
19	411000000	0.5	40	256 qam	35
20	419000000	0.7	40	256 qam	36
21	523000000	0	40	256 qam	38
22	531000000	-0.2	40	256 qam	39
23	539000000	-0.4	40	256 qam	40
24	547000000	-0.2	40	256 qam	41

Downstream bonded channels

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

1	Locked	40.3	720	8605
2	Locked	40.3	783	8509
3	Locked	40.9	747	8552
4	Locked	40.3	852	8507
5	Locked	40.3	368	1758
6	Locked	40.3	402	1767
7	Locked	40.3	394	1954
8	Locked	40.9	481	1848
9	Locked	40.3	534	1919
10	Locked	40.3	570	1931
11	Locked	40.3	617	1881
12	Locked	40.9	682	1803
13	Locked	40.3	694	1990
14	Locked	40.9	865	1813
15	Locked	40.3	863	1861
16	Locked	40.3	1114	1839
17	Locked	40.9	927	1892
18	Locked	40.9	932	2736
19	Locked	40.9	986	2336
20	Locked	40.3	854	3060
21	Locked	40.3	2696	986
22	Locked	40.3	3174	11444
23	Locked	40.3	3622	3227
24	Locked	40.3	4243	2931

[jbrennand · Accepted solution]

Do this...

Switch the Hub off and unplug it from the mains supply for five minutes. Whilst it's off, do a quick check that all of your coax and ethernet cable connections are in nice and "finger" tight - at the Hub and wall box and also at any connectors etc. Ensure there are no “unterminated cable loose ends. Disconnect all the connections and reconnect to be sure. Also check that the internal wiring is ok with no kinking or chaffing. When its light, check that all looks good with the outside cabling and wall box (no “staples, etc.,) piercing the cables. Then switch the Hub back on and leave ~5 minutes When all done, check back in the settings and ensure that the RS error counts and upstream T errors have all reset to 0. Then check every hour or so to see if they start reappearing - they shouldn't. If they do (particularly the postRS and T3 ones) you have a problem (noise) that only a Tech visit will sort.
Also check the Upstream QAM’s are all at 64

[AndyB69]

Many thanks John, I will do this tomorrow when it's light

Much appreciated

A

[AndyB69]

I have followed Johns advice (below) and following a reboot and the checking of all connections my readings are below.  I think it is now time for an engineers visit - can anyone advise how I can do this without going through the call centre and having them insist that I do all the resets myself again ?

Many thanks

Upstream bonded channels

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

1	36600000	40.3	5120	64 qam	3
2	23600000	40	5120	32 qam	5
3	30100000	40.3	5120	64 qam	4
4	43100000	40.8	5120	64 qam	2
5	49600000	41.5	5120	64 qam	1

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

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

Downstream bonded channels

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

1	267000000	0	40	256 qam	17
2	275000000	0	40	256 qam	18
3	283000000	0	40	256 qam	19
4	291000000	0	40	256 qam	20
5	299000000	0	40	256 qam	21
6	307000000	0	40	256 qam	22
7	315000000	0.2	40	256 qam	23
8	323000000	0.5	40	256 qam	24
9	331000000	0.5	40	256 qam	25
10	339000000	0.5	40	256 qam	26
11	347000000	0.4	40	256 qam	27
12	355000000	0.2	40	256 qam	28
13	363000000	0.2	40	256 qam	29
14	371000000	0	40	256 qam	30
15	379000000	0	40	256 qam	31
16	387000000	0	40	256 qam	32
17	395000000	0	40	256 qam	33
18	403000000	0.4	40	256 qam	34
19	411000000	0.5	40	256 qam	35
20	419000000	1	40	256 qam	36
21	523000000	0	40	256 qam	38
22	531000000	0	40	256 qam	39
23	539000000	0	40	256 qam	40
24	547000000	0	40	256 qam	41

Downstream bonded channels

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

1	Locked	40.9	1108	3473
2	Locked	40.3	1207	3541
3	Locked	40.9	1210	3512
4	Locked	40.3	1182	3212
5	Locked	40.3	1236	3440
6	Locked	40.9	1170	3490
7	Locked	40.9	1145	3072
8	Locked	40.3	1195	3295
9	Locked	40.9	1235	3011
10	Locked	40.3	1224	2845
11	Locked	40.9	1175	2936
12	Locked	40.3	1176	2910
13	Locked	40.3	1144	2826
14	Locked	40.9	1098	2624
15	Locked	40.9	1204	2728
16	Locked	40.9	1139	2502
17	Locked	40.3	1080	2413
18	Locked	40.3	1161	2685
19	Locked	40.9	1100	2234
20	Locked	40.9	1101	2594
21	Locked	40.9	1175	1897
22	Locked	40.3	1153	1631
23	Locked	40.3	1152	1879
24	Locked	40.3	1136	1686

[Kath_P]

Hi AndyB69, 

Thanks for taking the time to contact us via the Community. It's lovely having you on board with us in the Forums. ⭐

We're sorry to hear you're having issues with your connection. Checking things this end, all is looking good in terms of the power and signal levels. There is nothing ongoing in the area either however those Post RS errors are not great. 

We won't be able to fix this remotely so I would like to arrange for an engineer to come to take a look at this for you. 

I just need to confirm the address to ensure we are booking the visit on the correct account. I have sent you a direct message to allow us to do this with you in a private space. If you are using a PC/Laptop then you can just click on the little ✉ at the top right-hand side of the page to access your inbox. If you are on a mobile/tablet device then instead click on the little circle icon in the top right then select 'Messages'. 😊

Thanks,

[ALF28]

Pre & Post RS Errors

I also had the same issue with thousands of errors showing in the downstream bonded channels, these went to normal after I powered down the hub 3  for a few minutes and then back on.

I use hub 3 modem mode and have my own router, and have never before had so many downstream errors

I am not sure what caused the hub3 errors but there was also a lot of critical warnings in the network log.

The reboot solution did work for me so thanks for that.

Since I have a phone plugged in, the hub 3 is never switched  off. I noted that it updated with the green lights on for a while during power up, so that may have helped.

In spite of the errors the speed was normal and my laptop was connecting, but I was getting browser crashes, and I recently remove google chrome as it was changing my IP address during preloading and I thought that was odd (fetch tunnel), and also noticed some redirecting when doing edge searches, so have I have reset my  brave browsers but the edge browser has a microsoft fault at the moment preventing reset. My antivirus checks were all clear.