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daz28
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Mixed Upstream Modulation

I’m seeing a nice variety of upstream modulation, 16, 32 and 64 QAM. Does this signify an issue?

Channel

Frequency (Hz)

Power (dBmV)

Symbol Rate (ksps)

Modulation

Channel ID

1

60300020

51

5120

64 qam

1

2

53700000

52

5120

16 qam

2

3

39400000

51

5120

32 qam

4

4

46200000

50.3

5120

32 qam

3

 

My Downstream Power levels seem a bit off also:

Channel

Frequency (Hz)

Power (dBmV)

SNR (dB)

Modulation

Channel ID

1

138750000

-6.5

36

256 qam

1

2

146750000

-6.5

36

256 qam

2

3

154750000

-6.5

37

256 qam

3

4

162750000

-6.5

37

256 qam

4

5

170750000

-6.5

37

256 qam

5

6

178750000

-6.7

37

256 qam

6

7

186750000

-6.5

36

256 qam

7

8

194750000

-6.5

37

256 qam

8

9

202750000

-6.5

37

256 qam

9

10

210750000

-6.5

37

256 qam

10

11

218750000

-6.9

37

256 qam

11

12

226750000

-7

36

256 qam

12

13

234750000

-7.5

36

256 qam

13

14

242750000

-8

36

256 qam

14

15

250750000

-7.9

36

256 qam

15

16

258750000

-7.2

37

256 qam

16

17

266750000

-6.5

37

256 qam

17

18

274750000

-6.5

37

256 qam

18

19

282750000

-6

37

256 qam

19

20

290750000

-5.9

37

256 qam

20

21

298750000

-5.5

37

256 qam

21

22

306750000

-5.5

37

256 qam

22

23

314750000

-5.2

37

256 qam

23

24

322750000

-5

37

256 qam

24

 

Also a lot of RS errors:

Channel

Locked Status

RxMER (dB)

Pre RS Errors

Post RS Errors

1

Locked

36.6

92815

29403

2

Locked

36.6

77382

23038

3

Locked

37.3

22753

47366

4

Locked

37.3

5340

48228

5

Locked

37.3

3387

44554

6

Locked

37.3

4177

43362

7

Locked

36.6

3501

40929

8

Locked

37.3

3140

40311

9

Locked

37.6

3144

40311

10

Locked

37.3

3048

40208

11

Locked

37.3

32080

41025

12

Locked

36.6

46324

43673

13

Locked

36.6

3716

37887

14

Locked

36.6

18908

145112

15

Locked

36.6

4407

15008

16

Locked

37.6

6798

91457

17

Locked

37.3

5940

92829

18

Locked

37.3

2872

33468

19

Locked

37.6

3280

33926

20

Locked

37.3

4924

103146

21

Locked

37.6

31732

128681

22

Locked

37.6

53512

113035

23

Locked

37.3

22336

148223

24

Locked

37.6

6031

86982

 

The actual service is still pretty fast most of the time, but unreliable with periods of no service every few days that normally needs a reboot to fix. Any advice?

 

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AlexisMori
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Message 2 of 11
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Re: Mixed Upstream Modulation

Hi...my point some time recently was a TDMA carrier wouldn't be reinforced based on the data I posted. In case you're bonding a channel that's implied for 1.1 DOCSIS modems and 3.0 modems appears like a destitute plan choice the Return range possibly has as well much clamor to back different 64QAM channels . In case both your LED's are blue DS and US, i will concede i'm blown absent.
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lotharmat
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Message 3 of 11
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Re: Mixed Upstream Modulation

Power levels are well out of spec!

You'd need a tech visit to remedy!

You can either wait a couple of days on here or call it in on 150 (0345 454 1111)

It'll ask you to reboot the hub (as you already have done - don't)
You will then be cut off
Wait a couple of minutes
Call 150 again - report a broadband fault - The system will recognise that you called before and transfer you to a person!



------------------------------------------------------------------
Hub 3 - Modem Mode - TP-Link Archer C7

Zoie_P
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Message 4 of 11
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Re: Mixed Upstream Modulation

Hi Daz28,

Thanks for your post, I have managed to find your account and can see you are affected by a congestion outage, the estimated fix date is 21 JUL 2021 12:55

Thanks,

Zoie

Zoie
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jpeg1
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Message 5 of 11
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Re: Mixed Upstream Modulation

That doesn't look much like congestion, far more like a very local connection problem.  But you won't get a technician visit to rectify it while there is an area problem. 

As soon as the congestion is fixed you will need to phone it in as a fault. 

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jem101
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Message 6 of 11
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Re: Mixed Upstream Modulation

Also this thread was started six months ago so it's very likely that the OP has long since either left VM or had an engineer visit to fix it. No it wasn't a congestion issue but a connectivity (or lack thereof) problem.

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daz28
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Re: Mixed Upstream Modulation

Actually I temporarily fixed it myself by unplugging the splitter that divided the cable between my modem and one of my TiVo boxes that I don’t use often and that made the modem much more reliable, at the expense of not having Virgin TV in that room. I should book an engineer, but my house is up for sale and I hope to be moving out in three months.

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jpeg1
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Re: Mixed Upstream Modulation

So it was very likely a poor connection that you removed with your wiring changes. 

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David_Bn
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Re: Mixed Upstream Modulation

Feel free to come back to us beyond 21/07/21 and we'll be happy to book an engineer for you, if this is still required

 

Kindest regards,

 

David_Bn

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daz28
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Message 10 of 11
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Re: Mixed Upstream Modulation

No, I think the signal level is too low coming from the street box, but by removing the splitter, the signal reaching the modem is now sufficient. If I plug the splitter and TiVo box back in, I can see the numbers returning to their previous poor levels. I think the signal level when everything is connected is out of spec, but marginal, so it works a lot of the time, but changes in temperature / weather push it over the edge.

The cable from the street is split three ways, serving a TiVo V6 on the ground floor, a TiVo V6 on the first floor, and then finally going to the third floor, where it splits again to feed the cable modem and an original TiVo box. Thus the cable modem is the furthest away from the point of entry, has the longest cable run, and goes through two splitters.

This has worked fairly reliably for 16 years, so I suspect that I’ve been moved onto a different tap point at some stage, or the cable has deteriorated over time. The cabinet is just outside my house, so I can imagine an engineer visiting would assume I need the lowest level tap point, whereas the cable layout is such that there is more cable up the side of my house than from the cabinet to the house.

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