Hello,
I have noticed some occasional network issues. I currently have the 1200/40 cable internet plan and utilize a Motorola B12 modem with a Ubiquiti Express 7 router/gateway.
My modems logs indicate I am having trouble maintaining an upstream lock, I seem to have a lock at least as of looking today, but my upstream power levels definitely seem to be on the high end which is leading me to believe that when this spikes out of spec, my upstream lock gets dropped. My downstream data seems to be okay, although channels 25 and 32 do concern me as 25's corrected number is definitely not valid and I seem to have uncorrected errors on 32.
Anyone know what I can do to fix this? I live in an apartment building so my access to the line into my building is quite limited. Would it be possible for xfinity to run some sort of signal check or maybe evaluate the health of the line I am on? I am going to try and replace the Coax cable I can access with new cables to see if that helps as well...
| Downstream Bonded Channels |
 |
|
|
|
| Channel |
Lock Status |
Modulation |
Channel ID |
Freq. (MHz) |
Pwr (dBmV) |
SNR (dB) |
Corrected |
Uncorrected |
| 1 |
Locked |
QAM256 |
1 |
489.0 |
-3.0 |
40.8 |
0 |
0 |
| 2 |
Locked |
QAM256 |
2 |
495.0 |
-2.5 |
41.1 |
0 |
0 |
| 3 |
Locked |
QAM256 |
3 |
507.0 |
-2.2 |
41.6 |
0 |
0 |
| 4 |
Locked |
QAM256 |
4 |
513.0 |
-2.8 |
41.2 |
0 |
0 |
| 5 |
Locked |
QAM256 |
5 |
519.0 |
-3.2 |
41.0 |
0 |
0 |
| 6 |
Locked |
QAM256 |
6 |
525.0 |
-3.5 |
40.7 |
0 |
0 |
| 7 |
Locked |
QAM256 |
7 |
531.0 |
-3.4 |
40.7 |
0 |
0 |
| 8 |
Locked |
QAM256 |
8 |
537.0 |
-3.0 |
41.0 |
0 |
0 |
| 9 |
Locked |
QAM256 |
9 |
543.0 |
-2.7 |
41.1 |
0 |
0 |
| 10 |
Locked |
QAM256 |
10 |
549.0 |
-2.6 |
41.1 |
0 |
0 |
| 11 |
Locked |
QAM256 |
11 |
555.0 |
-2.6 |
41.2 |
0 |
0 |
| 12 |
Locked |
QAM256 |
12 |
561.0 |
-2.6 |
41.3 |
0 |
0 |
| 13 |
Locked |
QAM256 |
13 |
567.0 |
-2.2 |
41.4 |
0 |
0 |
| 14 |
Locked |
QAM256 |
14 |
573.0 |
-1.9 |
41.4 |
0 |
0 |
| 15 |
Locked |
QAM256 |
15 |
579.0 |
-1.7 |
41.3 |
0 |
0 |
| 16 |
Locked |
QAM256 |
16 |
585.0 |
-1.9 |
41.2 |
0 |
0 |
| 17 |
Locked |
QAM256 |
17 |
591.0 |
-2.3 |
40.6 |
0 |
0 |
| 18 |
Locked |
QAM256 |
18 |
597.0 |
-2.5 |
40.8 |
0 |
0 |
| 19 |
Locked |
QAM256 |
19 |
603.0 |
-2.2 |
40.9 |
0 |
0 |
| 20 |
Locked |
QAM256 |
20 |
609.0 |
-1.6 |
41.4 |
0 |
0 |
| 21 |
Locked |
QAM256 |
21 |
615.0 |
-1.0 |
41.6 |
0 |
0 |
| 22 |
Locked |
QAM256 |
22 |
621.0 |
-0.8 |
41.8 |
0 |
0 |
| 23 |
Locked |
QAM256 |
23 |
627.0 |
-1.2 |
41.5 |
0 |
0 |
| 24 |
Locked |
QAM256 |
24 |
633.0 |
-1.5 |
41.4 |
0 |
0 |
| 25 |
Locked |
OFDM PLC |
25 |
780.0 |
-1.0 |
40.2 |
-482878171 |
0 |
| 26 |
Locked |
QAM256 |
26 |
639.0 |
-1.8 |
41.1 |
0 |
0 |
| 27 |
Locked |
QAM256 |
27 |
645.0 |
-1.5 |
41.2 |
0 |
0 |
| 28 |
Locked |
QAM256 |
28 |
651.0 |
-1.2 |
41.3 |
0 |
0 |
| 29 |
Locked |
QAM256 |
29 |
657.0 |
-1.4 |
40.9 |
0 |
0 |
| 30 |
Locked |
QAM256 |
30 |
663.0 |
-1.3 |
41.1 |
0 |
0 |
| 31 |
Locked |
QAM256 |
31 |
669.0 |
-1.5 |
41.2 |
0 |
0 |
| 32 |
Locked |
QAM256 |
32 |
675.0 |
-1.1 |
41.3 |
86 |
510 |
|
| Upstream Bonded Channels |
|
|
|
|
| Channel |
Lock Status |
Channel Type |
Channel ID |
Symb. Rate (Ksym/sec) |
Freq. (MHz) |
Pwr (dBmV) |
| 1 |
Locked |
SC-QAM |
8 |
5120 |
16.3 |
50.8 |
| 2 |
Locked |
SC-QAM |
9 |
5120 |
22.8 |
50.8 |
| 3 |
Locked |
SC-QAM |
10 |
5120 |
29.2 |
51.0 |
| 4 |
Locked |
SC-QAM |
11 |
5120 |
35.6 |
51.5 |
| 5 |
Locked |
SC-QAM |
12 |
2560 |
40.4 |
51.8 |
|
Thanks,
Matt
BruceW
Gold Problem Solver
•
26.9K Messages
17 hours ago
The downstream power levels look good. The upstream levels are borderline (too high). This is 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.
The negative Corrected count shown for channel 25 is most likely a bug in the modem's software. A large Corrected count with a low Uncorrected count is considered normal for the OFDM channel. When a binary counter reaches a number higher then the code reporting that number is expecting, it is reported as a negative number (see "two's complement overflow"). This, by itself, is probably cosmetic and not causing any actual connection issues.
If you can't find the cause of the high upstream levels 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.
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(edited)
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