Visitor

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21 Messages

Monday, August 17th, 2026 2:09 AM

Packet loss and uncorrectable codewords after a maintence

Ever since 8/13 Maintenance for my local area the packet loss has returned to haunt me while gaming and streaming videos. The uncorrectable codewords have been going up on a few channels and i reset the router to maybe resolve the issue since there might have been a security flaw or connection issue to my devices

I use Ethernet connected to the gateway (XB8)

tested new cables and i have had this problem in the past but the technician that came out said my house is "end of line" which makes it so tuning the downstream power levels back into spec is not possible and i have had 3 techs come out to check all in house connections and no flaws just the downstream power is out of spec but it has been fine until 8/13 hopefully others are experiencing the same issue as me

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Visitor

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21 Messages

11 days ago

Channel ID
12
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
193
Lock Status
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Frequency
453 MHz
387 MHz
393 MHz
399 MHz
405 MHz
411 MHz
417 MHz
423 MHz
429 MHz
435 MHz
441 MHz
447 MHz
459 MHz
465 MHz
471 MHz
477 MHz
483 MHz
489 MHz
495 MHz
765 MHz
771 MHz
777 MHz
783 MHz
789 MHz
801 MHz
807 MHz
813 MHz
819 MHz
900000000
SNR
39.6 dB
40.7 dB
40.4 dB
40.4 dB
40.3 dB
40.2 dB
40.2 dB
39.9 dB
39.9 dB
39.7 dB
39.8 dB
39.4 dB
39.3 dB
39.1 dB
38.9 dB
38.6 dB
38.8 dB
38.4 dB
38.6 dB
33.4 dB
33.4 dB
33.3 dB
33.2 dB
32.6 dB
32.4 dB
32.2 dB
31.9 dB
31.6 dB
29.6 dB
Power Level
-6.3 dBmV
-4.4 dBmV
-4.8 dBmV
-4.9 dBmV
-5.0 dBmV
-5.4 dBmV
-5.3 dBmV
-5.8 dBmV
-5.6 dBmV
-6.1 dBmV
-6.0 dBmV
-6.4 dBmV
-6.7 dBmV
-6.9 dBmV
-7.0 dBmV
-7.4 dBmV
-7.2 dBmV
-7.7 dBmV
-7.5 dBmV
-13.2 dBmV
-13.5 dBmV
-13.6 dBmV
-13.7 dBmV
-14.3 dBmV
-14.4 dBmV
-14.5 dBmV
-14.8 dBmV
-15.1 dBmV
-15.7 dBmV
Modulation
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
OFDM

Visitor

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21 Messages

this is my current power on downstream, it continues to increase and channel 22/23 are the ones coming up with uncorrectable codewords even after power cycling and resetting the gateway

Official Employee

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1.5K Messages

11 days ago

Howdy user_mz0496 👋 I know exactly how debilitating it is to deal with packet loss during gaming, so I appreciate you stopping by to let us know about the ongoing issue this has been for you! Especially with you being connected hardwired, you should be zooming without any issues. Accounting for the troubleshooting you've done up to this point along with the technicians that have already been to the home, I'd say we can take a deeper look on our end to see if anything is standing out.

 

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Expert

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120.3K Messages

10 days ago

@user_mz0496 There is a bad cable tilt (rolloff) condition. Not sure how the techs could leave it like that..... The downstream power is low/weak at the lower frequencies and way out of spec at the upper. The upper-frequency SNRs are out of spec as well. 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 any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/reconfigured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, 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, or animal chews.

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 !

(edited)

Visitor

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21 Messages

It's very strange how i've had about 5 techs come out and also have the cable from the street to the house replaced and its still in this condition. Its really annoying how every tech says they can't do anything about it

Visitor

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21 Messages

every tech says the last technician didn't do his job correctly and replace brand new connections even though they weren't even a month old so old equipment is out of the picture, all my tracerts i'm using (MTR) show packet loss beyond my modem to every hop in my traceroute

Contributor

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82 Messages

Exactly what is happenning to me. My 2 ofdm channels are drowning in some form of noise and I've had over 6 techs come out and a new main drop installed and my problem persists. 85% of all of the data coming into my apartment is damaged and has to be fixed by the rental modem. Comcast has built their business model around trying to hide and obfuscate their failing network infrastructure. They will spout the same thing to you. Is there a splitter on the line? Are the cables tightened? They are losing so much money that I'm pretty sure they overloaded my neighborhood tap to save money instead of installing a new one or even replacing this old one that has been hit by a tornado and constantly rained on. The cover barely fits on top of it and I'm in Florida. It's just sad at this point.

Visitor

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21 Messages

@DebLev86​ this is exactly whats happening to me, im in California and after every maintenance they seem to overload my lines to cover up poor quality updates....so many flaws and i have no other options in services until ATT eventually installs Fiber in my area, ive been dealing with poor quality service for 3 straight years

(edited)

Expert

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120.3K Messages

@user_mz0496​ 

They indeed can fix it. They can use a tilt compensator pad, an amp, or both.

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.

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Visitor

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21 Messages

1 day ago

well to come back on this post, Tech said he couldn't do anything once again and had to put a maintenance ticket in. The "maintenance" never happened and now im back to square one with high downstream power and terrible service

Visitor

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21 Messages

23 hours ago

5 tech visits and all of them can't do a single thing about it so they lie to me about setting up a maintenance ticket to fix the lines on the street and it never happens. This is ridiculous. the tech also said that he would get in touch with me after the "maintenance" happened but i have not received anything in 3 days
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