U

Sunday, October 1st, 2023 2:20 AM

Closed

slow speed latency spikes

I have the 1000Mbps service. I have an Arris SB8200. I was having some quality / speed issues and got into the Web dashboard of the modem. I compared with the recommended spec numbers and see differences in power and SNR for download. Seems like my power numbers are way out of spec? My modem is as close to where I can get to cable entering house.

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
29 Locked QAM256 663000000 Hz -18.0 dBmV 33.2 dB 187846 21218
13 Locked QAM256 567000000 Hz -15.8 dBmV 35.0 dB 0 0
14 Locked QAM256 573000000 Hz -15.8 dBmV 33.2 dB 0 0
15 Locked QAM256 579000000 Hz -15.7 dBmV 33.5 dB 0 0
16 Locked QAM256 585000000 Hz -16.2 dBmV 34.8 dB 0 0
17 Locked QAM256 591000000 Hz -16.5 dBmV 34.6 dB 0 0
18 Locked QAM256 597000000 Hz -16.7 dBmV 34.5 dB 0 0
19 Locked QAM256 603000000 Hz -17.2 dBmV 34.2 dB 0 0
20 Locked QAM256 609000000 Hz -17.1 dBmV 34.1 dB 0 0
21 Locked QAM256 615000000 Hz -17.3 dBmV 33.8 dB 0 0
22 Locked QAM256 621000000 Hz -17.3 dBmV 33.8 dB 0 0
23 Locked QAM256 627000000 Hz -17.7 dBmV 33.4 dB 0 0
24 Locked QAM256 633000000 Hz -18.0 dBmV 33.3 dB 0 0
25 Locked QAM256 639000000 Hz -17.8 dBmV 33.3 dB 0 0
26 Locked QAM256 645000000 Hz -17.8 dBmV 33.4 dB 0 0
27 Locked QAM256 651000000 Hz -17.8 dBmV 33.4 dB 0 0
28 Locked QAM256 657000000 Hz -17.9 dBmV 33.3 dB 0 0
30 Locked QAM256 669000000 Hz -18.2 dBmV 33.0 dB 0 0
31 Locked QAM256 675000000 Hz -18.3 dBmV 32.0 dB 0 0
32 Locked QAM256 681000000 Hz -18.3 dBmV 32.9 dB 0 0
33 Locked QAM256 687000000 Hz -18.6 dBmV 32.9 dB 0 0
34 Locked QAM256 693000000 Hz -18.5 dBmV 32.8 dB 0 0
35 Locked QAM256 699000000 Hz -18.9 dBmV 32.5 dB 0 0
36 Locked QAM256 705000000 Hz -19.1 dBmV 32.3 dB 9 0
37 Locked QAM256 711000000 Hz -19.2 dBmV 32.3 dB 0 0
38 Locked QAM256 717000000 Hz -19.5 dBmV 32.0 dB 0 0
39 Locked QAM256 723000000 Hz -20.1 dBmV 31.5 dB 0 0
40 Locked QAM256 729000000 Hz -20.4 dBmV 30.9 dB 19 0
41 Locked QAM256 735000000 Hz -20.5 dBmV 30.6 dB 56736 148
42 Locked QAM256 741000000 Hz -21.2 dBmV 29.8 dB 278010 1092
43 Locked QAM256 747000000 Hz -21.7 dBmV 0.0 dB 3150423 645431
44 Locked QAM256 753000000 Hz -22.4 dBmV 27.9 dB 3857901 594079
159 Locked Other 762000000 Hz -22.0 dBmV 23.0 dB 218181155 32795551


Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 1 Locked SC-QAM Upstream 35600000 Hz 6400000 Hz 42.0 dBmV
2 2 Locked SC-QAM Upstream 29200000 Hz 6400000 Hz 41.0 dBmV
3 3 Locked SC-QAM Upstream 22800000 Hz 6400000 Hz 40.0 dBmV
4 4 Locked SC-QAM Upstream 16400000 Hz 6400000 Hz 40.0 dBmV
5 5 Locked SC-QAM Upstream 39600000 Hz 1600000 Hz 42.0 dBmV

I used the Xfinity app to check signal but doesn't seem to do anything? Please help



Gold Problem Solver

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26.5K Messages

2 years ago

... 1000Mbps service ... Arris SB8200 ...

Note that the SB8200 is not approved for use with the gigabit Internet tier. If you visit https://www.xfinity.com/support/devices and scroll down to the "All Compatible Devices" link you'll see that Comcast rates the SB8200 for use with plan speeds "Up to 957 Mbps". Using devices on Internet speed tiers for which Comcast has not approved them tends to produce unexpected results. Consider picking up one of the devices that is approved for Gigabit service, or dropping back to a lower tier. But besides that . . .

... Seems like my power numbers are way out of spec? ...

Yep. Upstream power levels look good, but the downstream power levels and SNR values are indeed out of spec. Signal problems like these are often due to poor coax connections or damaged coax cable, usually in or near your home. Running the cable through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power. 

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it and an employee does not respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Gold Problem Solver

 • 

26.5K Messages

2 years ago

"... Please send a dm to XFINITY SUPPORT ..." means, from any forums.xfinity.com page:

  • Click "Sign In" if that prompt is visible  

  • Click the "Direct Messaging" icon above or https://forums.xfinity.com/direct-messaging  

  • On the DM page click the "New message" (pencil and paper) icon 

  • The "To:" line prompts you to "Type the name of a person" but don't do that. It won't work.

      Instead, type Xfinity Support there. As you are typing a drop-down list appears.

  • Select "Xfinity Support" from the list. An "Xfinity Support" graphic replaces the "To:" line.

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

  • Press Enter or tap the > icon to send it

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

Regrettably the "pencil and paper" icon is a pale grey that is active even though it does not look active. If a red circle-slash appears when you try to select the icon it means that DMs are disabled in your user Profile. To enable them go to your Profile Settings, clear the "Opt Out from Direct Messaging" checkbox, click Save, and try again.

(edited)

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