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Bradliam1
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Message 1 of 14
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Modem power levels all over the place

Just got 1gig with the hub 4, we had a 6db attenuator on the previous hub but when connected the power levels were -18dbmv, with no attenuation they are +14dbmv,We also have a 3db attenuator that I tried that gives -13dbmv. Something seems to be a bit strange with the power levels

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Richw1982
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Message 2 of 14
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Re: Modem power levels all over the place

Your forward levels should be between -6/+10.  If your forwards are +14 then the 6db should make it around +8.  Your return levels should be between 33 and 51 and work opposite to the forward path.  Assuming you have a 6 wideband attenuator if your return is at 40 the attenuator will bring the level down to around 46.  If its affecting the signal by more than the face value it sounds like a failed part

I work for Virgin Media - but all opinions posted here are my own
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Bradliam1
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Message 3 of 14
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Re: Modem power levels all over the place

Do you think i should get an engineer out? as the attenuator dont seem to be working properly, the download speed is capping out at around 750mbps so its not getting max speed.

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Bradliam1
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Message 4 of 14
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Re: Modem power levels all over the place

This is without any attenuation

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

24 322750000 13.300003 38.605377 QAM256 24

1 138750000 11.599998 37.636276 QAM256 1

2 146750000 11.800003 37.636276 QAM256 2

3 154750000 11.800003 37.355988 QAM256 3

4 162750000 11.900002 37.636276 QAM256 4

5 170750000 11.800003 37.355988 QAM256 5

6 178750000 11.699997 37.636276 QAM256 6

7 186750000 11.800003 37.636276 QAM256 7

8 194750000 11.900002 37.636276 QAM256 8

9 202750000 11.800003 37.636276 QAM256 9

10 210750000 11.800003 37.636276 QAM256 10

11 218750000 11.800003 37.636276 QAM256 11

12 226750000 11.699997 37.355988 QAM256 12

13 234750000 11.500000 37.355988 QAM256 13

14 242750000 11.400002 37.636276 QAM256 14

15 250750000 11.400002 37.355988 QAM256 15

16 258750000 11.300003 37.636276 QAM256 16

17 266750000 11.800003 37.636276 QAM256 17

18 274750000 12.199997 37.636276 QAM256 18

19 282750000 12.699997 37.636276 QAM256 19

20 290750000 13.099998 37.636276 QAM256 20

21 298750000 13.099998 37.636276 QAM256 21

22 306750000 13.099998 37.636276 QAM256 22

23 314750000 12.900002 38.605377 QAM256 23

25 330750000 13.400002 37.636276 QAM256 25

26 338750000 13.500000 38.605377 QAM256 26

27 346750000 13.500000 38.605377 QAM256 27

28 354750000 13.400002 37.636276 QAM256 28

29 362750000 13.199997 38.605377 QAM256 29

30 370750000 12.599998 37.355988 QAM256 30

31 378750000 12.099998 37.636276 QAM256 31

This is the downstream with the 6db forward attenuator that was working fine with the previous hub 3

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

24 322750000 -16.799999 31.072100 QAM256 24

1 138750000 -22.900002 26.820402 QAM256 1

2 146750000 -22.700001 27.067228 QAM256 2

3 154750000 -22.400002 27.275312 QAM256 3

4 162750000 -22.599998 27.170025 QAM256 4

5 170750000 -22.500000 27.275312 QAM256 5

6 178750000 -22.299999 27.465942 QAM256 6

7 186750000 -21.799999 27.843828 QAM256 7

8 194750000 -21.200001 28.462973 QAM256 8

9 202750000 -20.900002 28.605377 QAM256 9

10 210750000 -20.700001 28.905008 QAM256 10

11 218750000 -20.400002 29.103352 QAM256 11

12 226750000 -20.299999 29.103352 QAM256 12

13 234750000 -20.599998 28.943958 QAM256 13

14 242750000 -20.599998 29.062952 QAM256 14

15 250750000 -20.700001 28.462973 QAM256 15

16 258750000 -20.500000 29.062952 QAM256 16

17 266750000 -20.400002 28.943958 QAM256 17

18 274750000 -19.500000 29.397188 QAM256 18

19 282750000 -18.900002 29.619953 QAM256 19

20 290750000 -18.299999 30.001997 QAM256 20

21 298750000 -17.900002 30.206408 QAM256 21

22 306750000 -17.599998 30.646576 QAM256 22

23 314750000 -17.599998 30.589052 QAM256 23

25 330750000 -16.299999 31.136440 QAM256 25

26 338750000 -16.200001 31.335388 QAM256 26

27 346750000 -15.900002 31.688669 QAM256 27

28 354750000 -16.000000 31.688669 QAM256 28

29 362750000 -15.900002 31.688669 QAM256 29

30 370750000 -16.599998 31.136440 QAM256 30

31 378750000 -17.099998 30.823864 QAM256 31

 

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Bradliam1
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Message 5 of 14
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Re: Modem power levels all over the place

So after fiddling with the cable and attenuator, lossening them both has made it work, now getting +5 downstream. Don't know what's got a dodgy connection, could be the cable

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Eeeps
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Message 6 of 14
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Re: Modem power levels all over the place

Take a close look at the end of the incoming cable that connects to the attenuator.
Is that a screw on or push fit type?

The inner conductor is simple the exposed end of the cable. If this has been cut a little short it may make connection when directly fitted to the SH4 but not when fitted to the attenuators.

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Tudor
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Message 7 of 14
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Re: Modem power levels all over the place

I presume they are VM cables, not one you have installed yourself. The crimped plugs very rarely give problems.


Tudor
There are 10 types of people: those who understand binary and those who don't and F people out of 10 who do not understand hexadecimal c1a2a285948293859940d9a49385a2
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Bradliam1
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Message 8 of 14
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Re: Modem power levels all over the place

Yeah these are all the ones installed by an engineer

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Hayley_S
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Message 9 of 14
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Re: Modem power levels all over the place

Hello @Bradliam1.

 

I am sorry to see that you have been having some issues with your services recently.

 

Thank you for reaching out to us!

 

I have located your account using your forums details, I can see you rang us yesterday and was given advice and told to allow 24hours for an update? 

 

Look forward to your response.

Hayley
Forum Team



New around here? To find out more about the Community check out our Getting Started guide


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Bradliam1
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Message 10 of 14
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Re: Modem power levels all over the place

Hi, the problem has still not been resolved, would it be possible to get an engineer to come round?

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