Router reports low downstream power

My router (Netgear Nighthawk CAX80)'s diagnostic is reporting that my downstream connection's power level is poor (13.8 dBmV with the recommended range being under -10 to 10). Speed test from the router itself only clocks about half the bandwidth I'm paying for. I've tracked the cabling from my router, to the wall, to where the cable comes in from the telephone pole and there are no splitters being used along the way (only extenders). Is there anything else I can do from my end to fix this? Not seeing anything on Xfinity's automated support.

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Accepted Solution

EG

Expert

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110K Messages

3 years ago

It's not too low. It's actually too high. Is there an amplifier on the coax cable line leading to the modem. If so, try removing it and see. If not, you can try using a minus -6 dB attenuator pad like this to knock that downstream power level down;

https://www.amazon.com/6db-Attenuator-Pad-1-each/dp/B0013L48XA

There's no guarantee that this is the root cause of the speed issue, something else may be going on, but this should be addressed regardless,

(edited)

3

C

cynicalbliss

Visitor

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4 Messages

@EG Interesting. Yeah, I see that now--used to interpreting "poor" as "low". Will give it a whirl and see what happens. Thank you.

3 years ago

0

EG

Expert

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110K Messages

Quite welcome ! Please post back about how things go.

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.

Was your question answered? Please mark an Accepted Answer! tick

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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3 years ago

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cynicalbliss

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4 Messages

I did manage to get my hands on a 6db attenuator, and my router is now reporting the signal as being in spec. Download speed was about 800mbps over ethernet, which was an improvement.

3 years ago

0

EG

Expert

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110K Messages

3 years ago

Please copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

Is this a WiFi connection ?

1

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cynicalbliss

Visitor

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4 Messages

From my router's diagnostic:

Downstream Status: Poor

Downstream Power Level: Poor
Downstream power is poor (14.2dBmV). The recommended level is between -10dBmV to 10dBmV.

Downstream SNR: Good

Upstream Status: Good

Upstream Power Level: Good

Current time: Thu Mar 31 06:35:51 2022

Startup Procedure
Acquire Downstream Channel: 579 MHz Locked
Connectivity State: OK Operational
Boot State: OK Operational
Security: Enabled BPI+

Downstream Bonded Channels
Channel LockedStatus Modulation ChannelID Frequency Power SNR Correctables Uncorrectables
1 Locked 256 QAM 13 579000000 Hz 13.1 dBmV 41.9 dB 0 0
2 Locked 256 QAM 1 489000000 Hz 11.6 dBmV 41.3 dB 0 0
3 Locked 256 QAM 2 513000000 Hz 12.2 dBmV 41.6 dB 0 0
4 Locked 256 QAM 3 519000000 Hz 12.3 dBmV 41.9 dB 0 0
5 Locked 256 QAM 4 525000000 Hz 12.4 dBmV 41.7 dB 0 0
6 Locked 256 QAM 5 531000000 Hz 12.4 dBmV 41.8 dB 0 0
7 Locked 256 QAM 6 537000000 Hz 12.4 dBmV 41.9 dB 0 0
8 Locked 256 QAM 7 543000000 Hz 12.4 dBmV 42 dB 0 0
9 Locked 256 QAM 8 549000000 Hz 12.5 dBmV 42 dB 0 0
10 Locked 256 QAM 9 555000000 Hz 12.6 dBmV 42 dB 0 0
11 Locked 256 QAM 10 561000000 Hz 12.8 dBmV 42.1 dB 0 0
12 Locked 256 QAM 11 567000000 Hz 12.8 dBmV 41.9 dB 0 0
13 Locked 256 QAM 12 573000000 Hz 13 dBmV 42 dB 0 0
14 Locked 256 QAM 14 585000000 Hz 13.2 dBmV 42.1 dB 0 0
15 Locked 256 QAM 15 591000000 Hz 13.3 dBmV 42.1 dB 0 0
16 Locked 256 QAM 16 597000000 Hz 13.6 dBmV 42.1 dB 0 0
17 Locked 256 QAM 17 603000000 Hz 13.5 dBmV 41.9 dB 0 0
18 Locked 256 QAM 18 609000000 Hz 13.6 dBmV 42 dB 0 0
19 Locked 256 QAM 19 615000000 Hz 13.4 dBmV 41.8 dB 0 0
20 Locked 256 QAM 20 621000000 Hz 13.2 dBmV 41.6 dB 0 0
21 Locked 256 QAM 21 627000000 Hz 13.4 dBmV 41.4 dB 0 0
22 Locked 256 QAM 22 633000000 Hz 13.9 dBmV 41.6 dB 0 0
23 Locked 256 QAM 23 639000000 Hz 14 dBmV 41.6 dB 0 0
24 Locked 256 QAM 24 645000000 Hz 14.1 dBmV 41.6 dB 0 0
25 Locked 256 QAM 25 651000000 Hz 14.2 dBmV 41.6 dB 0 0
26 Locked 256 QAM 26 657000000 Hz 14.1 dBmV 41.5 dB 0 0
27 Locked 256 QAM 27 663000000 Hz 13.9 dBmV 41.5 dB 0 0
28 Locked 256 QAM 28 669000000 Hz 13.7 dBmV 41.4 dB 0 0
29 Locked 256 QAM 29 675000000 Hz 13.8 dBmV 40.9 dB 0 0
30 Locked 256 QAM 30 681000000 Hz 13.4 dBmV 41.3 dB 0 0
31 Locked 256 QAM 31 687000000 Hz 13.6 dBmV 41.3 dB 0 0
32 Locked 256 QAM 32 693000000 Hz 13 dBmV 41.1 dB 0 0

Upstream Bonded Channels
Channel LockedStatus ChannelType ChannelID SymbolRate Frequency Power
1 Locked ATDMA 1 2560 Ksym/sec 10400000 Hz 41.3 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 16400000 Hz 37.3 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 37.3 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 29200000 Hz 37.8 dBmV
5 Locked ATDMA 5 5120 Ksym/sec 35600000 Hz 37.8 dBmV
6 Locked ATDMA 6 2560 Ksym/sec 40400000 Hz 39.8 dBmV
7 Not Locked Unknown 0 0 0 0.0
8 Not Locked Unknown 0 0 0 0.0

Downstream OFDM Channels
Channel LockedStatus ProfileID ChannelID Frequency Power SNR/MER ActiveSubcarrier Unerror Correctable Uncorrectable
1 Locked 0 ,1 ,2 ,3 159 805000000 Hz 11.18 dBmV 40.7 dB 1126 ~ 2969 1396334894 87901395 0
2 Not Locked 0 0 0 Hz 0 dBmV 0 dB 0 ~ 4095 0 0 0

Upstream OFDMA Channels
Channel LockedStatus ProfileID ChannelID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

3 years ago

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cynicalbliss

Router reports low downstream power

EG

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EG

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