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Internet Crashing, High upstream power levels

Regular Visitor

Internet Crashing, High upstream power levels

I have recently upgraded to the Xfinity Gigabit plan. Upon initial installation the tech had replaced the line to my home from the pole. That day the levels were great and I was getting about 950mbps down and 40 up through ethernet directly to router. But the next day the internet would crash multiple times throughout the day. I had done resets on the modem, checked and reconnected all connections. The signal would last about 5 minutes before crashing again. I have replaced the modem and router twice since. Both with the same issues. A tech had replaced the splitter and the coax cable. Comcast says everything is fine but my modem is the problem. But every modem I use has the same issue. The comcast site states that the modem I use is compatible with their service and should obtain the gigabit speeds. I currently have the Netgear CM1000 modem and Netgear AC1900 router. I had checked my modem status and the upstream power level is high. I purchased a PCT 1 active return amplifier. It brought my upstream power down to normal levels but my downstream then was too high so it did not fix my crashing issue. I have had 3 techs at my home with  no resolve.  What should I do?

 

Cable Connection
 
 
 
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 669000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels (Partial Service)
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 32 669000000 Hz 2.4 dBmV 40.2 dB 63466791 0 0
2 Locked QAM256 1 483000000 Hz 1.2 dBmV 32.3 dB 1174980 73237 6590
3 Locked QAM256 2 489000000 Hz 1.3 dBmV 41.5 dB 61807601 0 0
4 Locked QAM256 3 495000000 Hz 1.6 dBmV 41.6 dB 61816494 0 0
5 Locked QAM256 4 501000000 Hz 2.3 dBmV 41.4 dB 61825677 0 0
6 Locked QAM256 5 507000000 Hz 2.9 dBmV 29.7 dB 61835107 183 0
7 Locked QAM256 6 513000000 Hz 3.2 dBmV 34.5 dB 61844689 0 0
8 Locked QAM256 7 519000000 Hz 3.4 dBmV 40.7 dB 61853913 0 0
9 Locked QAM256 8 525000000 Hz 3.5 dBmV 41.4 dB 61863558 0 0
10 Locked QAM256 9 531000000 Hz 3.6 dBmV 41.6 dB 61882490 0 0
11 Locked QAM256 10 537000000 Hz 3.6 dBmV 41.5 dB 61896327 0 0
12 Locked QAM256 11 543000000 Hz 3.4 dBmV 41.5 dB 61946059 0 0
13 Locked QAM256 12 549000000 Hz 3.4 dBmV 41.5 dB 61974834 0 0
14 Locked QAM256 13 555000000 Hz 3.8 dBmV 41.5 dB 61984870 0 0
15 Locked QAM256 14 561000000 Hz 4.2 dBmV 41.6 dB 61993272 0 0
16 Locked QAM256 15 567000000 Hz 3.0 dBmV 41.3 dB 62002501 0 0
17 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
18 Locked QAM256 17 579000000 Hz 2.1 dBmV 31.3 dB 28965056 2275138 9025
19 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
20 Locked QAM256 19 591000000 Hz 3.1 dBmV 31.1 dB 53001872 8921310 104716
21 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
22 Locked QAM256 21 603000000 Hz 3.5 dBmV 30.5 dB 58308390 3725507 6201
23 Locked QAM256 22 609000000 Hz 2.9 dBmV 40.9 dB 62049776 0 0
24 Locked QAM256 23 615000000 Hz 1.7 dBmV 40.6 dB 62059129 0 0
25 Locked QAM256 24 621000000 Hz 1.7 dBmV 40.4 dB 62068931 0 0
26 Locked QAM256 25 627000000 Hz 2.0 dBmV 40.4 dB 62078006 0 0
27 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
28 Locked QAM256 28 645000000 Hz 2.0 dBmV 39.5 dB 62088780 0 0
29 Locked QAM256 29 651000000 Hz 2.3 dBmV 39.6 dB 62098710 0 0
30 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
31 Locked QAM256 31 663000000 Hz 2.2 dBmV 30.5 dB 53417018 8671659 23192
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 17 35800000 Hz 52.5 dBmV
2 Locked ATDMA 18 29400000 Hz 52.3 dBmV
3 Locked ATDMA 19 23000000 Hz 54.5 dBmV
4 Locked ATDMA 20 16600000 Hz 56.0 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 1 33 720000000 Hz 2.1 dBmV 7.0 dB 1108 ~ 2987 642 0 644
2 Not Locked 0 0 0 Hz -1.5 dBmV 0.0 dB 0 ~ 4095 0 0 0

<tabindex=-1>Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV
Expert

Re: Internet Crashing, High upstream power levels

You could try a "return path only" type of amp;

 

https://www.amazon.com/Electroline-4100-Reverse-Path-Amplifier/dp/B00JJX32LI

 

FWIW, some of the downstream channels SNR's are low and some of them are not locking.



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Expert

Re: Internet Crashing, High upstream power levels

Your OFDM channel has a massive amount of noise on it while it’s scattered accross the 256QAM channels. Your upstreams are too high as well. Is there any splitters before the modem? If so, bypass them. I would also bypass the amp as well to bypass everything, if possible, to see how it looks after that. However, I think it might be good to get another technician out and figure it out.

EDIT: Is the modem the CM1000-1AZNAS model?

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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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Regular Visitor

Re: Internet Crashing, High upstream power levels

This is several minutes after removing the splitter and no amp. Modem is directly to wall. Also the modem is the CM1000-100NAS

 

Cable Connection
 
 
 
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 669000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels (Partial Service)
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 32 669000000 Hz 5.4 dBmV 40.0 dB 11337430 0 0
2 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
3 Locked QAM256 2 489000000 Hz 4.1 dBmV 41.1 dB 9630912 0 0
4 Locked QAM256 3 495000000 Hz 4.7 dBmV 41.5 dB 9639028 1 0
5 Locked QAM256 4 501000000 Hz 5.2 dBmV 41.2 dB 9636701 0 0
6 Locked QAM256 5 507000000 Hz 5.7 dBmV 30.1 dB 9659603 18 0
7 Locked QAM256 6 513000000 Hz 6.1 dBmV 34.5 dB 9669102 0 0
8 Locked QAM256 7 519000000 Hz 6.4 dBmV 40.5 dB 9678408 0 0
9 Locked QAM256 8 525000000 Hz 6.6 dBmV 41.0 dB 9687018 0 0
10 Locked QAM256 9 531000000 Hz 6.7 dBmV 41.6 dB 9696371 0 0
11 Locked QAM256 10 537000000 Hz 6.7 dBmV 41.5 dB 9705642 0 0
12 Locked QAM256 11 543000000 Hz 6.7 dBmV 41.1 dB 9714900 0 0
13 Locked QAM256 12 549000000 Hz 6.6 dBmV 41.3 dB 9723871 0 0
14 Locked QAM256 13 555000000 Hz 6.6 dBmV 41.3 dB 9733078 0 0
15 Locked QAM256 15 567000000 Hz 6.8 dBmV 41.3 dB 9781222 0 0
16 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
17 Locked QAM256 17 579000000 Hz 7.0 dBmV 30.7 dB 9082301 788702 203
18 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
19 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
20 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
21 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
22 Locked QAM256 22 609000000 Hz 6.6 dBmV 40.9 dB 9922956 0 0
23 Locked QAM256 23 615000000 Hz 6.4 dBmV 40.7 dB 9932658 0 0
24 Locked QAM256 24 621000000 Hz 6.3 dBmV 40.6 dB 9941978 0 0
25 Locked QAM256 25 627000000 Hz 5.8 dBmV 40.6 dB 9950656 0 0
26 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
27 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
28 Locked QAM256 28 645000000 Hz 5.7 dBmV 39.7 dB 9964700 0 0
29 Locked QAM256 29 651000000 Hz 5.9 dBmV 39.9 dB 9971956 0 0
30 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
31 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 17 35800000 Hz 49.0 dBmV
2 Locked ATDMA 18 29400000 Hz 48.8 dBmV
3 Locked ATDMA 19 23000000 Hz 50.8 dBmV
4 Locked ATDMA 20 16600000 Hz 54.5 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 1 33 720000000 Hz 5.7 dBmV 9.8 dB 1108 ~ 2987 399 0 401
2 Not Locked 0 0 0 Hz 1.0 dBmV 0.0 dB 0 ~ 4095 0 0 0

<tabindex=-1>Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV
 
Expert

Re: Internet Crashing, High upstream power levels

I think you might need a tech to investigate it. I think either the line from your pole or the underground tap to the modem isn’t good or it might be a problem beyond your premises

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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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