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cobrien's avatar
cobrien
Tuning in
7 hours ago

High noise levels and service dropouts

I'm getting high levels of noise on my connection and periodic service dropouts requiring a manual router reboot.  I had a repull last year, and a recent visit from an engineer who checked everything internally but could find no fault but who said that a cable in the cabinet was damaged and looked like something heavy had been dropped on it. He said he would report it to to the network people but that was a few months ago and nothing has changed.  How can I get the network team to fix this fault?

Here are my noise levels after the router has been up for about 12 hours:

3.0 Downstream channels

 

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

1                          339000000        7.6                      40                            QAM 256           26

2                          147000000        7.2                      40                            QAM 256           2

3                          155000000        7.1                      40                            QAM 256           3

4                          163000000        6.9                      40                            QAM 256           4

5                          171000000        6.6                      40                            QAM 256           5

6                          179000000        6.3                      40                            QAM 256           6

7                          187000000        6.4                      40                            QAM 256           7

8                          195000000        6.8                      40                            QAM 256           8

9                          203000000        7.4                      40                            QAM 256           9

10                       211000000        7.7                      40                            QAM 256           10

11                       219000000        7.5                      41                            QAM 256           11

12                       227000000        7.4                      40                            QAM 256           12

13                       235000000        7.6                      40                            QAM 256           13

14                       243000000        7.6                      40                            QAM 256           14

15                       251000000        7.9                      41                            QAM 256           15

16                       259000000        7.4                      41                            QAM 256           16

17                       267000000        7.2                      41                            QAM 256           17

18                       275000000        7                          41                            QAM 256           18

19                       283000000        7                          41                            QAM 256           19

20                       291000000        7.2                      41                            QAM 256           20

21                       299000000        7.2                      41                            QAM 256           21

22                       307000000        7.4                      41                            QAM 256           22

23                       315000000        7.4                      41                            QAM 256           23

24                       323000000        7.2                      40                            QAM 256           24

25                       331000000        7.2                      40                            QAM 256           25

26                       347000000        8.5                      40                            QAM 256           27

27                       355000000        9.8                      40                            QAM 256           28

28                       363000000        10.8                    40                            QAM 256           29

29                       371000000        8.8                      39                            QAM 256           30

30                       379000000        4.2                      38                            QAM 256           31

31                       387000000        -1.9                     36                            QAM 256           32

3.0 Downstream channels

 

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

1                          Locked                40                       1418                            1521

2                          Locked                40                       1027                            551

3                          Locked                40                       1700                            1964

4                          Locked                40                       2567                            3589

5                          Locked                40                       2633                            3164

6                          Locked                40                       2322                            2926

7                          Locked                40                       2662                            3004

8                          Locked                40                       2510                            3045

9                          Locked                40                       2457                            3121

10                       Locked                40                       2406                            2890

11                       Locked                41                       2653                            2927

12                       Locked                40                       737                            1239

13                       Locked                40                       2295                            2565

14                       Locked                40                       2293                            2533

15                       Locked                41                       2124                            2667

16                       Locked                41                       2113                            2443

17                       Locked                41                       2082                            2606

18                       Locked                41                       570                            1242

19                       Locked                41                       2051                            2482

20                       Locked                41                       1950                            2421

21                       Locked                41                       1994                            2533

22                       Locked                41                       1560                            1647

23                       Locked                41                       389                            976

24                       Locked                40                       110                            138

25                       Locked                40                       1762                            2646

26                       Locked                40                       1300                            2164

27                       Locked                40                       1442                            1621

28                       Locked                40                       1303                            2227

29                       Locked                39                       1870                            2414

30                       Locked                38                       1780                            1625

31                       Locked                36                       10714                 918

3.1 Downstream channels

 

Channel              Channel Width (MHz)     FFT Type              Number of Active           Modulation        First Active

Subcarriers          (Active Profile) Subcarrier (Hz)

 

33                       94                                    4K                       1840                                 QAM 4096         1108

3.1 Downstream channels

 

Channel ID         Locked Status    RxMER Data       PLC Power   Corrected errors             Uncorrectable errors

(dB)                     (dBmV)               (Active Profile)                 (Active Profile)

 

33                       Locked                0                          0.0                            1132355454                    5923

 

3.0 Upstream channels

 

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

0                          49600000                        40.3      5120                                         QAM 64             1

1                          43100000                        39.5      5120                                         QAM 64             2

2                          36600000                        38.5      5120                                         QAM 64             3

3                          30100000                        38         5120                                         QAM 64             4

4                          23600000                        37.8      5120                                         QAM 64             5

3.0 Upstream channels

 

Channel              Channel Type     T1 Timeouts       T2 Timeouts            T3 Timeouts       T4 Timeouts

0                          ATDMA               0                          0                            4                          0

1                          ATDMA               0                          0                            6                          0

2                          ATDMA               0                          0                            7                          0

3                          ATDMA               0                          0                            4                          0

4                          ATDMA               0                          0                            3                          0

3.1 Upstream channels

 

Channel              Channel Width (MHz)     Power (dBmV) FFT Type             Modulation

6                          10.4                                 36.7                    2K                       QAM 256

3.1 Upstream channels

 

Channel              Channel Type     Number of Active              First Active Subcarrier (Hz)          T3 Timeouts              T4 Timeouts                                                Subcarriers

6                          OFDMA               208                                   74000000                                     5                          0

 

4 Replies

  • You can see the impairment: The sudden drop in receive power. Something is wrong. No question. :)

  • Client62's avatar
    Client62
    Alessandro Volta

    The Post RS Errors & Uncorrectable errors, affecting all Downstream channels,
    are a concern.

    3.0 Downstream Power Level of channels 30 & 31 are lower, 
    but still well with the -7 to +7 dBmV preferred range. 

    The 3.0 & 3.1 Downstream channels with power levels exceeding +10dBmV
    are above what is normal for regular service.



    • gitty's avatar
      gitty
      Tuning in

      You need to correlate the levels though. A sudden drop that big is not supposed to be there. That is also called a "suck out".

      The OFDM's MER says 0. That is also off.

  • Anonymous's avatar
    Anonymous

    So what has happened to the downstream channel on 387 MHz? Something odd has happened no? Look at its value compared to the others!

    And the 3.1 downstream channel, an MER of zero, now that just can’t be right. So either something has gone catastrophically wrong with their connection or the hub is misreporting