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Visitor

 • 

5 Messages

Sat, Apr 30, 2022 5:28 PM

Constant Disconnects

Hi all,

Having constant disconnects at the modem with XFINITY. Here are my modem (Netgear CM1150V) stats.

Upstream channel has power that looks slightly higher than spec (59 vs 57), but all else seems within reason (downstream within -15 to +15, SNR > 33, all within ~3 of each other).

Walking the line, I have one extension adapter that looks fine from visual inspection but several spots where the cable goes near internal power lines, etc. In all the cable travels ~80 feet from front left corner of the house (where the street wire comes in) to the back right corner of the house (where the cable modem sits in my office).

Any obvious red flags? I have a tech coming out Monday.

Thanks,

Michael

Downstream Bonded

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 13 507000000 Hz -10.5 dBmV 39.3 dB 3782 0
2 Locked QAM256 14 513000000 Hz -11.9 dBmV 38.6 dB 31207 15
3 Locked QAM256 15 519000000 Hz -11.9 dBmV 38.7 dB 18233 9
4 Locked QAM256 16 525000000 Hz -11.5 dBmV 38.9 dB 10569 0
5 Locked QAM256 17 531000000 Hz -10.3 dBmV 39.4 dB 3112 0
6 Locked QAM256 18 537000000 Hz -11.2 dBmV 38.9 dB 4130 0
7 Locked QAM256 19 543000000 Hz -11.4 dBmV 38.8 dB 8580 6
8 Locked QAM256 20 549000000 Hz -12.1 dBmV 38.5 dB 10145 1
9 Locked QAM256 21 555000000 Hz -10.8 dBmV 39.1 dB 2942 0
10 Locked QAM256 22 561000000 Hz -11 dBmV 38.9 dB 1878 0
11 Locked QAM256 23 567000000 Hz -11.2 dBmV 38.9 dB 10640 9
12 Locked QAM256 24 573000000 Hz -13.1 dBmV 37.8 dB 12826 3
13 Locked QAM256 25 579000000 Hz -11.7 dBmV 38.5 dB 5736 0
14 Locked QAM256 26 585000000 Hz -11.3 dBmV 38.7 dB 2411 0
15 Locked QAM256 27 591000000 Hz -10.1 dBmV 39.1 dB 1300 0
16 Locked QAM256 28 597000000 Hz -12.3 dBmV 38.1 dB 5336 0
17 Locked QAM256 29 603000000 Hz -12.3 dBmV 38.1 dB 9557 3
18 Locked QAM256 30 609000000 Hz -12.6 dBmV 37.9 dB 5187 0
19 Locked QAM256 31 615000000 Hz -10.8 dBmV 38.6 dB 885 0
20 Locked QAM256 32 621000000 Hz -12.5 dBmV 37.8 dB 2432 0
21 Locked QAM256 33 627000000 Hz -13.7 dBmV 37.3 dB 10264 0
22 Locked QAM256 34 633000000 Hz -14.3 dBmV 37 dB 9583 0
23 Locked QAM256 35 639000000 Hz -11.6 dBmV 38.3 dB 1753 0
24 Locked QAM256 36 645000000 Hz -10.6 dBmV 38.5 dB 792 0
25 Locked QAM256 37 651000000 Hz -11.6 dBmV 38.1 dB 2971 0
26 Locked QAM256 38 657000000 Hz -12.7 dBmV 37.8 dB 4779 0
27 Locked QAM256 39 663000000 Hz -12 dBmV 38.1 dB 2959 0
28 Locked QAM256 40 669000000 Hz -10.8 dBmV 38.6 dB 574 0
29 Locked QAM256 41 675000000 Hz -11.8 dBmV 37.5 dB 829 0
30 Locked QAM256 42 681000000 Hz -13.2 dBmV 37.4 dB 3116 0
31 Locked QAM256 43 687000000 Hz -12.9 dBmV 37.6 dB 3830 0
32 Locked QAM256 44 693000000 Hz -11.4 dBmV 38.2 dB 549 0

Upstream Bonded

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 5 5120 Ksym/sec 35600000 Hz 59 dBmV
2 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
3 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
4 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Accepted Solution

Visitor

 • 

5 Messages

2分前

Issue resolved with Tech visit.

The root cause was the barrel extension connecting the 50 and 25ft cables. Though it didn't look off to my (untrained) eyes, after the tech recut the ends of the wires and installed a new extension, it worked fine. That plus adjusting or removing the filters at the street box and adding a passive splitter (to tweak the last ~3.5 dBmV of power so that I'm now at ~0 downstream and ~42 upstream) has me locked on 4 channels.

Thanks for the guidance on what to look for. The tech said it was useful to have datapoints that aligned to his hypothesis.

EG

Expert

 • 

94.3K Messages

2分前

The downstream power levels are out of spec. And the upstream power level is far out of spec ! It's so bad that only one upstream is locked in. Should be 3 to 5 channels.

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, 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 let the tech investigate and correct.


Good luck with it !

(edited)

Visitor

 • 

5 Messages

@EG​ Thank you for the advice. The upstream locking only 1 channel seems fairly new, as the light on the upstream is usually green (meaning 2+ channels locked on this modem), but it has been amber since this last outage started.

Past the street to house 2-way splitter, there's only 1 other extension adapter inside the house. It looks like a 50 and a 25 foot RG6/U were pieced together using that one extension. Eliminating it would most likely require getting a 100ft cable (with ~25 ft of slack) or custom rolling the cable from a spool (beyond my ability, for a tech to do). I'll take a look at the adapter when everyone's gone to bed and another internet outage won't cause a house panic.

Only 3 "right angles" in the line: once at the front right of the house, once to get around a garage wall feature, once vertically to bring it up through the floor into the office. Of the 3, only the small one around the garage wall feature could be described as an "angle", the other 2 are "curves". Otherwise a fairly straight shot. Not sure if any of those constitute a sharp bend. Otherwise the line seems fine.

The other thread I'm monitoring is that there's a fair amount of discussion on the NetGear CM1150V forum re: that modem, in particular, having Upstream locking issues (vs. XFINITY or other 3P modems). We'll see what the tech thinks. Thanks for the help.

EG

Expert

 • 

94.3K Messages

2分前

A right "angle" would indeed be a *sharp bend*. If so, it's not good.

Please circle back here after the tech visit with how things turn out.

EG

Expert

 • 

94.3K Messages

2分前

@user_677409 

My pleasure ! Glad that it got squared away ! 

(edited)

Visitor

 • 

5 Messages

2分前

In this post here I detailed issues we were having re: our line, which seemed to be fixed by replacing a barrel extension. At the time, all power was in the ideal range: downstream at ~0, upstream at ~42.

Within 8 hours we've had 2 more sustained outages, with our current stats still showing just-barely-acceptable downstream/upstream (off by ~10 from ideal in each case). We have a new XV7 router/modem on the way (giving up on my own modem) to try to eliminate one source of issues.

Any thoughts about how a setup could revert, so quickly, after a tech has just visited and gotten the system to an acceptable state?

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 37 651000000 Hz -11.2 dBmV 38.1 dB 7132785 5998735
2 Locked QAM256 13 507000000 Hz -9.6 dBmV 39.6 dB 7171867 6049318
3 Locked QAM256 14 513000000 Hz -10 dBmV 39.4 dB 7492730 6544700
4 Locked QAM256 15 519000000 Hz -9.8 dBmV 39.5 dB 7738543 6935040
5 Locked QAM256 16 525000000 Hz -9.9 dBmV 39.4 dB 7353715 6141366
6 Locked QAM256 17 531000000 Hz -9.4 dBmV 39.5 dB 7397480 6327423
7 Locked QAM256 18 537000000 Hz -9.5 dBmV 39.3 dB 7448503 6341137
8 Locked QAM256 19 543000000 Hz -9.2 dBmV 39.4 dB 7800539 6783755
9 Locked QAM256 20 549000000 Hz -9.6 dBmV 39.2 dB 7446869 6341454
10 Locked QAM256 21 555000000 Hz -9.4 dBmV 39.3 dB 7390918 6245949
11 Locked QAM256 22 561000000 Hz -10 dBmV 39 dB 7808728 6686596
12 Locked QAM256 23 567000000 Hz -9.6 dBmV 39.2 dB 7900632 7149294
13 Locked QAM256 24 573000000 Hz -10.6 dBmV 38.7 dB 7213296 5918187
14 Locked QAM256 25 579000000 Hz -10.1 dBmV 38.9 dB 7391795 6279454
15 Locked QAM256 26 585000000 Hz -10.7 dBmV 38.6 dB 7327388 6138397
16 Locked QAM256 27 591000000 Hz -9.6 dBmV 39 dB 7407024 6267468
17 Locked QAM256 28 597000000 Hz -10.7 dBmV 38.5 dB 7288010 6092010
18 Locked QAM256 29 603000000 Hz -10.7 dBmV 38.5 dB 7203950 5929869
19 Locked QAM256 30 609000000 Hz -11.5 dBmV 38.1 dB 7534560 6341202
20 Locked QAM256 31 615000000 Hz -10.8 dBmV 38.3 dB 7308818 6133627
21 Locked QAM256 32 621000000 Hz -11.6 dBmV 37.7 dB 7170293 5855897
22 Locked QAM256 33 627000000 Hz -11.5 dBmV 37.8 dB 7226316 5931831
23 Locked QAM256 34 633000000 Hz -12.5 dBmV 37.4 dB 7205773 5925951
24 Locked QAM256 35 639000000 Hz -11.5 dBmV 38 dB 7321807 6103268
25 Locked QAM256 36 645000000 Hz -10.9 dBmV 38.1 dB 7273159 6024666
26 Locked QAM256 38 657000000 Hz -12 dBmV 37.7 dB 7365482 6144780
27 Locked QAM256 39 663000000 Hz -11.8 dBmV 37.8 dB 7051719 5530306
28 Locked QAM256 40 669000000 Hz -11.4 dBmV 38 dB 7261633 5940381
29 Locked QAM256 41 675000000 Hz -12 dBmV 37 dB 7333929 6105399
30 Locked QAM256 42 681000000 Hz -12 dBmV 37.6 dB 7431464 6192496
31 Locked QAM256 43 687000000 Hz -11.1 dBmV 38 dB 7186544 5771980
32 Locked QAM256 44 693000000 Hz -11.3 dBmV 37.9 dB 7412399 6128219
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 2 5120 Ksym/sec 16400000 Hz 51 dBmV
2 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 52 dBmV
3 Locked ATDMA 4 5120 Ksym/sec 29200000 Hz 52 dBmV
4 Locked ATDMA 5 5120 Ksym/sec 35600000 Hz 52.5 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Note: This comment was created from a merged conversation originally titled Continued outages, even after tech visit
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