Post RS Errors
 

I've noticed for a couple of weeks now that I've been getting some post rs errors showing in the downstream stats. If I've understood correctly, these are packets of data that can't be corrected? Current values are below:

DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 267000000 275000000 283000000 291000000 307000000 315000000 323000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 5 1 2 3 4 6 7 8
Modulation 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) -1.37 -1.73 -1.63 -1.39 -1.33 -1.05 -1.05 -1.08
RxMER (dB) 34.63 34.63 34.35 34.63 34.77 34.77 34.77 34.63
Pre RS Errors 100113 94327 120390 106905 61287 80476 82631 121075
Post RS Errors 14220 4505 1530 11368 19479 20452 20391 20630

The SH2 was reset 4 days ago and I cleared the counters after it had finished booting up. Are they anything to be concerned about? Speed and ping seems fine.

Re: Post RS Errors
 

The MER Levels are borderline hence the Pre/Post Errors. So could need investigating

Re: Post RS Errors
 

those levels are fine

Re: Post RS Errors
 

Nobody will investigate an SNR over 34db

Re: Post RS Errors
 

Haven't had any more post rs errors overnight, pre rs have gone up but I don't think they are anything to be concerned about? Any ideas why the post rs errors are occuring? Doesn't seem to be affecting anything as far as I can tell.

Is it possible to adjust the SNR from my side? Or is it something that is done in the cabinet? I know I can adjust the power levels through different value attenuators.

Re: Post RS Errors
 

Do you actually have problems with your internet access? If so, what?

Re: Post RS Errors
 

Not that I've noticed, was just more out of curiosity than anything.

Re: Post RS Errors
 

Sometimes a loose coax connection going into your router causes this.

Re: Post RS Errors
 

Both ends are tight from the internal wall box to the modem. Not checked outside in the external wall box.

Re: Post RS Errors
 

Sometimes thats just the snr of the area

Re: Post RS Errors
 

Over 34dB no, but under 34dB then that will cause problems as was experienced

Re: Post RS Errors
 

Was going to post back and say that everything was fine after reseating the coax cable and resetting the SH on Wednesday. Post RS errors stayed at 0 until Thursday morning. Gone back up into the thousands again now. Did have a brief loss of sync Thursday morning. Can't see anything obviously wrong other than 3 of the channels are a smidge below 34dB.

DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 267000000 275000000 283000000 291000000 307000000 315000000 323000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 5 1 2 3 4 6 7 8
Modulation 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) -0.99 -1.52 -1.36 -1.11 -1.06 -0.83 -0.84 -0.78
RxMER (dB) 33.96 34.48 33.60 33.83 34.21 34.21 34.21 34.08
Pre RS Errors 325679 111039 783248 500481 134774 161912 171494 252541
Post RS Errors 16306 11872 16601 16775 16798 16723 16672 16579

Re: Post RS Errors
 

There should be no post-RD errors. They are lost packets and if your downloads are UDP without software checking, the packets are irrecoverable.

It will be down to the SNR (RxMER). I suggest you post on the VM forum so that the VM bods there can check what's happening on your circuit.

Re: Post RS Errors
 

Thanks for the reply Sephiroth. Have posted on the VM forum (as you've already seen). Will have to wait and see what they say.

Re: Post RS Errors
 

Technician came out a bit earlier and couldn't really find anything wrong. Took the 6dB attenuator off as said it wasn't needed. Checked everything was ok with a signal meter.

DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 267000000 275000000 283000000 291000000 307000000 315000000 323000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 5 1 2 3 4 6 7 8
Modulation 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) 4.50 4.33 4.22 4.47 4.55 4.91 4.82 5.01
RxMER (dB) 34.63 34.63 34.48 34.48 34.63 34.77 34.77 34.63
Pre RS Errors 480 454 625 495 218 114 111 273
Post RS Errors 0 0 0 0 0 0 0 0

SNR has gone up a smidge with the attenuator off. He did suggest it could of just been down to an intermittent issue with SNR dropping briefly? Will keep an eye on it but pretty sure it'll be fine.

Just as an aside and it's something that has been mentioned on here, he did mention that the tiers are likely to be going 100, 200, 300Mb this year.