Personal Device CM3000 States "Downstream power is poor (-13.3dBmV). The
recommended level is between -10dBmV to 10dBmV."
I have a simple setup, one CM3000 which is fed from the street pole, through a splitter (installed by Xfinity) to a drop on the main floor in my house. From that I have an Orbi WiFi system which feeds my home WiFi. When I log into the router I see the following
Below are my detailed specs:
Advanced Information
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
Startup Procedure
Procedure
Status
Comment
Acquire Downstream Channel
549000000 Hz
Locked
Connectivity State
OK
Operational
Boot State
OK
Operational
Security
Enabled
BPI+
IP Provisioning Mode
Honor MDD
IPv6 only
Downstream Bonded Channels
Channel
Lock Status
Modulation
Channel ID
Frequency
Power
SNR
Correctables
Uncorrectables
1
Locked
QAM256
28
549000000 Hz
-11.6 dBmV
38.6 dB
629192
120
2
Locked
QAM256
1
375000000 Hz
-9.3 dBmV
40.3 dB
621237
639
3
Locked
QAM256
2
381000000 Hz
-9.5 dBmV
40.5 dB
635909
33894
4
Locked
QAM256
3
387000000 Hz
-9.5 dBmV
40.6 dB
629720
537
5
Locked
QAM256
4
393000000 Hz
-9.6 dBmV
40.6 dB
623219
550
6
Locked
QAM256
5
399000000 Hz
-9.9 dBmV
40.4 dB
182673546
64194667
7
Locked
QAM256
6
405000000 Hz
-10.3 dBmV
40.2 dB
628418
543
8
Locked
QAM256
7
411000000 Hz
-10.6 dBmV
40.1 dB
633605
561
9
Locked
QAM256
8
417000000 Hz
-10.5 dBmV
40.2 dB
627263
646
10
Locked
QAM256
9
423000000 Hz
-10.4 dBmV
40.2 dB
616597
599
11
Locked
QAM256
10
435000000 Hz
-10.5 dBmV
40.1 dB
625213
563
12
Locked
QAM256
11
441000000 Hz
-10.4 dBmV
40.0 dB
695069
539
13
Locked
QAM256
12
447000000 Hz
-10.4 dBmV
40.0 dB
615854
541
14
Locked
QAM256
13
453000000 Hz
-10.6 dBmV
39.6 dB
646163
526
15
Locked
QAM256
14
459000000 Hz
-10.9 dBmV
39.6 dB
663587
581
16
Locked
QAM256
15
465000000 Hz
-11.2 dBmV
39.3 dB
673100
614
17
Locked
QAM256
16
471000000 Hz
-11.8 dBmV
38.7 dB
658073
613
18
Locked
QAM256
17
477000000 Hz
-12.4 dBmV
36.9 dB
622623
637
19
Locked
QAM256
18
483000000 Hz
-13.0 dBmV
37.2 dB
40992207
206930
20
Locked
QAM256
19
489000000 Hz
-13.3 dBmV
37.3 dB
1415933
951
21
Locked
QAM256
20
495000000 Hz
-12.7 dBmV
37.9 dB
472218
518
22
Locked
QAM256
21
507000000 Hz
-11.8 dBmV
38.7 dB
64761047
1200223
23
Locked
QAM256
22
513000000 Hz
-11.8 dBmV
38.7 dB
49965718
54477
24
Locked
QAM256
23
519000000 Hz
-11.7 dBmV
37.9 dB
568283
660
25
Locked
QAM256
24
525000000 Hz
-11.2 dBmV
38.0 dB
583702
644
26
Locked
QAM256
25
531000000 Hz
-11.2 dBmV
38.4 dB
547941
457
27
Locked
QAM256
26
537000000 Hz
-12.2 dBmV
37.9 dB
517582
0
28
Locked
QAM256
27
543000000 Hz
-12.7 dBmV
37.7 dB
511703
5
29
Locked
QAM256
29
555000000 Hz
-11.1 dBmV
38.9 dB
495190
497
30
Locked
QAM256
30
561000000 Hz
-11.4 dBmV
33.8 dB
503519
502
31
Locked
QAM256
31
567000000 Hz
-12.0 dBmV
36.8 dB
507394
483
32
Locked
QAM256
32
573000000 Hz
-11.4 dBmV
35.5 dB
485066
478
Upstream Bonded Channels
Channel
Lock Status
US Channel Type
Channel ID
Symbol Rate
Frequency
Power
1
Locked
ATDMA
6
2560 Ksym/sec
10400000 Hz
49.8 dBmV
2
Locked
ATDMA
2
5120 Ksym/sec
22800000 Hz
50.8 dBmV
3
Locked
ATDMA
3
5120 Ksym/sec
29200000 Hz
51.3 dBmV
4
Locked
ATDMA
4
5120 Ksym/sec
35600000 Hz
51.5 dBmV
5
Locked
ATDMA
5
2560 Ksym/sec
40400000 Hz
51.8 dBmV
6
Locked
ATDMA
1
5120 Ksym/sec
16400000 Hz
50.5 dBmV
7
Not Locked
Unknown
0
0
0
0.0 dBmV
8
Not Locked
Unknown
0
0
0
0.0 dBmV
Downstream OFDM Channels
Channel
Lock Status
Profile ID
Channel ID
Frequency
Power
SNR / MER
Active Subcarrier Number Range
Unerrored Codewords
Correctable Codewords
Uncorrectable Codewords
1
Locked
0 ,1 ,2 ,3
193
690000000 Hz
-13.12 dBmV
37.1 dB
1108 ~ 2987
17490535535
17285095209
8447749
2
Not Locked
0
0
0 Hz
0 dBmV
0 dB
0 ~ 4095
0
0
0
Upstream OFDMA Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
1
Not Locked
0
0
0 Hz
0 dBmV
2
Not Locked
0
0
0 Hz
0 dBmV
Extended Upstream Transmit Power
Current System Time:Thu Sep 04 10:10:48 2025
System Up Time:61 days 14:36:20
I am looking for help on how to make this inline with specs. Thank you!
The upstream power is too high 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.
Thank you for your post. I have checked everything that I can reach (can't get to the pole). I did have my lines from the pole to my house buried a while back. The splitter that Xfinity installed (the only one I have) is a CommScope SV-3BG which is rated for 5-1002Mhz.
Quite welcome ! If there is nothing that can be done to improve the connection quality, then you'll need a tech visit as stated.
Bear in mind that if the premises-facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.
@EG So in talking with Xfinity support they are stating that "everything is fine on their end" and since it's a personal device (I own my own router) that I need to talk to NetGear. OMG this is terrible. I had to explain to the agent that 'A "poor downstream status" on a cable connection often indicates a problem with the signal coming from your internet service provider'...after several rounds of telling them it's an issue with their connection....I got a tech scheduled. I'll let you know what I find out.
Hello @determs I'm sorry to hear about your connection concerns. @EG mentioned some great tips to assist, since the issue hasn't been resolved I'll be happy to take a further look. If a technician is needed, let's get you scheduled. Please send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account.
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there
- As you are typing a drop-down list appears. Select "Xfinity Support" from that list
- An "Xfinity Support" graphic replaces the "To:" line
Type your message in the text area near the bottom of the window
Press Enter to send it.
I am an Official Xfinity Employee. Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation. Was your question answered? Please, mark a reply as the Accepted Answer.
EG
Expert
•
113.3K Messages
10 days ago
The upstream power is too high 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 !
1
EG
Expert
•
113.3K Messages
9 days ago
@determs
Quite welcome ! If there is nothing that can be done to improve the connection quality, then you'll need a tech visit as stated.
Bear in mind that if the premises-facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.
Good luck !
2
EG
Expert
•
113.3K Messages
8 days ago
I'm not surprised to hear that...... 🙄
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