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Broz1
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Wednesday, May 17th, 2023 3:26 AM

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Very low speeds, Arris SB8200

Have the 1200 plan, on a SB8200. These results are connected straight into the modem:

Downstream:

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
41 Locked QAM256 669000000 Hz -18.4 dBmV 33.4 dB 7 0
13 Locked QAM256 501000000 Hz -15.6 dBmV 36.5 dB 0 0
14 Locked QAM256 507000000 Hz -13.7 dBmV 37.8 dB 0 0
15 Locked QAM256 513000000 Hz -10.6 dBmV 39.3 dB 0 0
16 Locked QAM256 519000000 Hz -7.6 dBmV 40.4 dB 0 0
17 Locked QAM256 525000000 Hz -7.6 dBmV 40.3 dB 0 0
18 Locked QAM256 531000000 Hz -13.1 dBmV 37.9 dB 0 0
19 Locked QAM256 537000000 Hz -16.1 dBmV 35.9 dB 0 0
20 Locked QAM256 543000000 Hz -18.6 dBmV 33.3 dB 0 0
21 Locked QAM256 549000000 Hz -21.3 dBmV 31.7 dB 1 0
22 Locked QAM256 555000000 Hz -23.0 dBmV 30.3 dB 195 0
23 Locked QAM256 561000000 Hz -25.2 dBmV 28.4 dB 159151 0
24 Locked QAM256 567000000 Hz -26.2 dBmV 26.4 dB 44560517 25837582
25 Not Locked Unknown 573000000 Hz -27.8 dBmV 0.0 dB 0 0
26 Locked QAM256 579000000 Hz -28.3 dBmV 0.0 dB 32115 0
27 Locked QAM256 585000000 Hz -28.2 dBmV 0.0 dB 73559 0
28 Locked QAM256 591000000 Hz -29.5 dBmV 0.0 dB 1129 0
29 Not Locked Unknown 597000000 Hz -30.0 dBmV 0.0 dB 0 0
30 Not Locked Unknown 603000000 Hz -30.3 dBmV 0.0 dB 0 0
31 Not Locked Unknown 609000000 Hz -30.2 dBmV 0.0 dB 0 0
32 Locked QAM256 615000000 Hz -29.0 dBmV 0.0 dB 31449 0
33 Locked QAM256 621000000 Hz -28.9 dBmV 0.0 dB 27088 0
34 Locked QAM256 627000000 Hz -28.7 dBmV 0.0 dB 34593 0
35 Locked QAM256 633000000 Hz -28.9 dBmV 0.0 dB 14882 0
36 Locked QAM256 639000000 Hz -27.6 dBmV 0.0 dB 9026853 31185588
37 Locked QAM256 645000000 Hz -25.3 dBmV 27.7 dB 1803425 116
38 Locked QAM256 651000000 Hz -24.2 dBmV 28.7 dB 56207 0
39 Locked QAM256 657000000 Hz -23.2 dBmV 29.5 dB 3668 0
40 Locked QAM256 663000000 Hz -21.7 dBmV 30.5 dB 74 0
42 Locked QAM256 675000000 Hz -14.1 dBmV 36.2 dB 5 0
43 Locked QAM256 681000000 Hz -9.6 dBmV 38.6 dB 6 0
44 Locked QAM256 687000000 Hz -11.2 dBmV 37.8 dB 9 0
159 Locked Other 722000000 Hz -28.3 dBmV 17.2 dB 179947321 60588899


Upstream:
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 9 Locked SC-QAM Upstream 10400000 Hz 3200000 Hz 47.0 dBmV
2 10 Locked SC-QAM Upstream 16400000 Hz 6400000 Hz 47.0 dBmV
3 11 Locked SC-QAM Upstream 22800000 Hz 6400000 Hz 47.0 dBmV
4 12 Locked SC-QAM Upstream 29200000 Hz 6400000 Hz 48.0 dBmV
5 13 Locked SC-QAM Upstream 35600000 Hz 6400000 Hz 48.0 dBmV
6 14 Locked SC-QAM Upstream 40400000 Hz 3200000 Hz 48.0 dBmV

Question

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Updated 

2 years ago

 • Edited

575

4

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Accepted Solution

Broz1

Visitor

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7 Messages

2 years ago

Tech came out, laid new cable. Results:

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
41 Locked QAM256 669000000 Hz 1.7 dBmV 38.9 dB 127 0
13 Locked QAM256 501000000 Hz 0.3 dBmV 40.3 dB 0 0
14 Locked QAM256 507000000 Hz 0.3 dBmV 40.2 dB 226 779
15 Locked QAM256 513000000 Hz 0.2 dBmV 40.1 dB 389 1782
16 Locked QAM256 519000000 Hz 0.2 dBmV 40.0 dB 128 692
17 Locked QAM256 525000000 Hz -0.1 dBmV 39.7 dB 130 714
18 Locked QAM256 531000000 Hz -0.1 dBmV 39.5 dB 167 717
19 Locked QAM256 537000000 Hz -0.1 dBmV 39.5 dB 165 775
20 Locked QAM256 543000000 Hz -0.2 dBmV 39.5 dB 466 2081
21 Locked QAM256 549000000 Hz 0.0 dBmV 39.7 dB 288 767
22 Locked QAM256 555000000 Hz -0.3 dBmV 39.2 dB 1316 706
23 Locked QAM256 561000000 Hz -0.3 dBmV 38.7 dB 11650 817
24 Locked QAM256 567000000 Hz -0.4 dBmV 38.6 dB 144551984 1605247
25 Locked QAM256 573000000 Hz -0.2 dBmV 38.2 dB 638153322 255890933
26 Locked QAM256 579000000 Hz -0.4 dBmV 37.1 dB 140910738 245131
27 Locked QAM256 585000000 Hz -0.2 dBmV 37.3 dB 103277638 20913
28 Locked QAM256 591000000 Hz 0.1 dBmV 38.1 dB 90433287 19145
29 Locked QAM256 597000000 Hz 0.1 dBmV 38.7 dB 3986068 556
30 Locked QAM256 603000000 Hz 0.2 dBmV 39.0 dB 5455693 1653
31 Locked QAM256 609000000 Hz 0.3 dBmV 39.3 dB 1036297 743
32 Locked QAM256 615000000 Hz 0.5 dBmV 39.5 dB 268507 673
33 Locked QAM256 621000000 Hz 0.5 dBmV 39.3 dB 29076 654
34 Locked QAM256 627000000 Hz 0.5 dBmV 39.2 dB 45893 732
35 Locked QAM256 633000000 Hz 1.0 dBmV 39.2 dB 1035 652
36 Locked QAM256 639000000 Hz 1.1 dBmV 39.0 dB 293 665
37 Locked QAM256 645000000 Hz 1.2 dBmV 38.6 dB 229 713
38 Locked QAM256 651000000 Hz 1.3 dBmV 38.6 dB 296 673
39 Locked QAM256 657000000 Hz 1.5 dBmV 38.6 dB 272 643
40 Locked QAM256 663000000 Hz 1.7 dBmV 38.8 dB 269 730
42 Locked QAM256 675000000 Hz 1.6 dBmV 38.8 dB 341 624
43 Locked QAM256 681000000 Hz 1.6 dBmV 39.0 dB 335 610
44 Locked QAM256 687000000 Hz 1.8 dBmV 38.8 dB 450 648
159 Locked Other 722000000 Hz 3.0 dBmV 33.2 dB 72777664

116305129

2

0

EG

Expert

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110.3K Messages

@Broz1​ 

The QAM channels downstream power levels and the SNR's look good now but there are still a large amount of corrected and uncorrected bit errors. And the SNR on the OFDM (Other) channel is out of spec. What do the upstream power levels look like now ?

(edited)

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2 years ago

0

Broz1

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7 Messages

@EG​ I hadn't actually power cycled the modem at the time. The corrected/uncorrected I believe was the accumulation from before. Here's the logs now, fresh restart plugged directly in.

From what I understand channel 159 will always be having corrected errors because it's something with the modem (Arris SB8200) and Xfinity. Saw a lot of reports about that.

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
41 Locked QAM256 669000000 Hz 2.3 dBmV 39.5 dB 0 0
13 Locked QAM256 501000000 Hz 0.5 dBmV 40.9 dB 0 0
14 Locked QAM256 507000000 Hz 0.6 dBmV 40.9 dB 0 0
15 Locked QAM256 513000000 Hz 0.3 dBmV 40.7 dB 0 0
16 Locked QAM256 519000000 Hz 0.4 dBmV 40.6 dB 0 0
17 Locked QAM256 525000000 Hz 0.1 dBmV 40.3 dB 0 0
18 Locked QAM256 531000000 Hz 0.0 dBmV 40.0 dB 0 0
19 Locked QAM256 537000000 Hz 0.1 dBmV 40.0 dB 0 0
20 Locked QAM256 543000000 Hz 0.0 dBmV 40.1 dB 0 0
21 Locked QAM256 549000000 Hz 0.2 dBmV 40.2 dB 0 0
22 Locked QAM256 555000000 Hz -0.1 dBmV 39.7 dB 0 0
23 Locked QAM256 561000000 Hz -0.1 dBmV 39.1 dB 0 0
24 Locked QAM256 567000000 Hz -0.1 dBmV 39.1 dB 0 0
25 Locked QAM256 573000000 Hz 0.0 dBmV 38.9 dB 0 0
26 Locked QAM256 579000000 Hz -0.2 dBmV 37.8 dB 0 0
27 Locked QAM256 585000000 Hz 0.1 dBmV 37.5 dB 0 0
28 Locked QAM256 591000000 Hz 0.4 dBmV 38.4 dB 0 0
29 Locked QAM256 597000000 Hz 0.5 dBmV 39.1 dB 0 0
30 Locked QAM256 603000000 Hz 0.6 dBmV 39.4 dB 0 0
31 Locked QAM256 609000000 Hz 0.7 dBmV 39.9 dB 0 0
32 Locked QAM256 615000000 Hz 0.9 dBmV 39.9 dB 0 0
33 Locked QAM256 621000000 Hz 1.0 dBmV 40.0 dB 0 0
34 Locked QAM256 627000000 Hz 1.0 dBmV 39.9 dB 0 0
35 Locked QAM256 633000000 Hz 1.5 dBmV 39.8 dB 0 0
36 Locked QAM256 639000000 Hz 1.6 dBmV 39.6 dB 0 0
37 Locked QAM256 645000000 Hz 1.7 dBmV 39.3 dB 0 0
38 Locked QAM256 651000000 Hz 1.9 dBmV 39.2 dB 0 0
39 Locked QAM256 657000000 Hz 2.1 dBmV 39.3 dB 0 0
40 Locked QAM256 663000000 Hz 2.3 dBmV 39.3 dB 0 0
42 Locked QAM256 675000000 Hz 2.3 dBmV 39.3 dB 0 0
43 Locked QAM256 681000000 Hz 2.2 dBmV 39.3 dB 0 0
44 Locked QAM256 687000000 Hz 2.5 dBmV 39.0 dB 1 0
159 Locked Other 722000000 Hz 3.8 dBmV 33.5 dB 18049554 0

2 years ago

0

EG

Expert

 • 

110.3K Messages

2 years ago

The downstream power is way out of spec as are most of the SNR's. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


Good luck with it !

5

Broz1

Visitor

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7 Messages

@EG​ Another ISP came and was laying down fiber in the area 2 months ago. Any idea if that would do something like this?

2 years ago

0

EG

Expert

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110.3K Messages

@Broz1​ 

It's possible. If they happened to damage the Comcast coax cable line somewhere in the process of doing their work.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

2 years ago

0

Broz1

Visitor

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7 Messages

@EG​ I don't know exactly what they did. All I know is they came and started digging in our backyard because we have a utility pole and our internet went out. We asked if that was normal since we needed our internet (Work from home) and they said it would be back up shortly. Came up in the next 5 minutes or so.

(edited)

2 years ago

0

EG

Expert

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110.3K Messages

@Broz1​ 

They may have severed the line and then jerry-rigged it back together again. The proper fittings must be used. You should get a tech out to investigate !

(edited)

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

2 years ago

0

CCGina

Official Employee

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800 Messages

Hey @Broz1! 

 

@EG has given you great information and steps to take! 

 

If you would like for us to get a tech appointment set up, please use the following instructions to send us a direct message, and we'll be glad to get that taken care of for you :) 

(Full credit to @BruceW for this excellent explanation and @Again for the picture!) 

"Search for Xfinity Support" won't work. To send a "Direct Messaging" message to Xfinity Support:

 • Click "Sign In" if necessary

 • Click the "Direct Messaging" icon:

 

 

or https://forums.xfinity.com/direct-messaging

 • Click the "New message" (pencil and paper) icon

 • The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there

 •  - As you are typing a drop-down list appears. Select "Xfinity Support" from that list

 •  - An "Xfinity Support" graphic replaces the "To:" line

 • Type your message in the text area near the bottom of the window

 • Press Enter to send it

See https://forums.xfinity.com/conversations/email/cant-create-a-new-email-address/605e52b726aa974d63032d02?commentId=606107ea738c7f46a02b830e for an example.

I no longer work for Comcast.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

2 years ago

EG

Expert

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110.3K Messages

2 years ago

You didn't post the current upstream power levels.

1

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Broz1

Visitor

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7 Messages

@EG​ Ah sorry, took a screenshot of the entire modem page last night

2 years ago

0

EG

Expert

 • 

110.3K Messages

2 years ago

@Broz1 

The upstreams look good ! The bottom line. Live with it a while now and see. Best of luck !

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