Menu
Reply
  • 971
  • 79
  • 244
vircom
Well-informed
508 Views
Message 1 of 6
Flag for a moderator

Downstreem Levels

I was getting a lot of T3 errors but appear to have fixed this by tightening up the connector on the incoming VM cable. I also improved my 2.4 wifi by manually changing the channel as my neighbours are using 1,3,4 and 5.

While checking the router (Shub 2) I noticed that the Downstreem power levels have a spread of about 5 to 8dB. Is this normal?

Downstream
DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 203000000 211000000 219000000 227000000 235000000 243000000 251000000 259000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 1 2 3 4 5 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) 8.10 7.47 6.60 6.66 7.11 6.53 5.52 5.14
RxMER (dB) 39.40 38.98 38.61 38.26 39.40 38.98 38.26 38.26
Pre RS Errors Reset Counter 5221 5021 611 3358 317 966 301 298
Post RS Errors Reset Counter 301 306 284 935 301 959 293 281

Apologies for the lack of formatting, but I think you can get the picture.

Thanks
0 Kudos
Reply

Helpful Answers
  • 20.52K
  • 541
  • 3.16K
Sephiroth
Alessandro Volta
1,007 Views
Message 2 of 6
Flag for a moderator
Helpful Answer

Re: Downstreem Levels

Whilst it's not normal for reasons I'll explain, in your case it's harmless.

The amplifier in the street cabinet should be "sloped" (google that) so that the higher frequencies and the lower frequencies have approximately the same power levels.   As you may know/learn, the higher frequencies attenuate signal over distance more than the lower frequencies and this is obvious from your downstream power levels.

VNM should really fix this because it is not in their standard specs.

 

 

Seph - ( DEFROCKED - My advice is at your risk)

  • 20.52K
  • 541
  • 3.16K
Sephiroth
Alessandro Volta
982 Views
Message 5 of 6
Flag for a moderator
Helpful Answer

Re: Downstreem Levels

They take about a week. There's a sticky post in Quickstart entitled POWER LEVELS & SNR which explains it all.

Seph - ( DEFROCKED - My advice is at your risk)


All Replies
  • 20.52K
  • 541
  • 3.16K
Sephiroth
Alessandro Volta
1,008 Views
Message 2 of 6
Flag for a moderator
Helpful Answer

Re: Downstreem Levels

Whilst it's not normal for reasons I'll explain, in your case it's harmless.

The amplifier in the street cabinet should be "sloped" (google that) so that the higher frequencies and the lower frequencies have approximately the same power levels.   As you may know/learn, the higher frequencies attenuate signal over distance more than the lower frequencies and this is obvious from your downstream power levels.

VNM should really fix this because it is not in their standard specs.

 

 

Seph - ( DEFROCKED - My advice is at your risk)

  • 20.52K
  • 541
  • 3.16K
Sephiroth
Alessandro Volta
498 Views
Message 3 of 6
Flag for a moderator

Re: Downstreem Levels

And, btw, power levels between 10 dBmv and -5 dBmv are usable though at those extremes they are potential victims of hot/cold weather as the cable metal expands/contracts.

Seph - ( DEFROCKED - My advice is at your risk)

0 Kudos
Reply
  • 971
  • 79
  • 244
vircom
Well-informed
497 Views
Message 4 of 6
Flag for a moderator

Re: Downstreem Levels

Thanks for the reply. I understand the tech point but did not know what limits VM specify. Hopefully one of their reps will pick this post up and comment.
0 Kudos
Reply
  • 20.52K
  • 541
  • 3.16K
Sephiroth
Alessandro Volta
983 Views
Message 5 of 6
Flag for a moderator
Helpful Answer

Re: Downstreem Levels

They take about a week. There's a sticky post in Quickstart entitled POWER LEVELS & SNR which explains it all.

Seph - ( DEFROCKED - My advice is at your risk)

  • 971
  • 79
  • 244
vircom
Well-informed
486 Views
Message 6 of 6
Flag for a moderator

Re: Downstreem Levels

Thanks for the link to your primer, looks like my levels are not `ideal` but should be okay. I have cleared the pre and post error logs and will see how things go with the tightened connection. Thanks again for your advice.
0 Kudos
Reply