Hi everyone. I have Xfinity's Gig speed Internet plan and recently purchased the Nighthawk CAX80. Currently, its cable connection status shows as poor. I did a quick search in the forums and I come across multiple responses that state to have the ISP come out to check the line up to the modem. Before I do that, I was wondering if anyone had any interpretation on the diagnostic results below: Startup ProcedureProcedure Status Comment Acquire Downstream Channel405 MHzLockedConnectivity StateOKOperationalBoot StateOKOperationalSecurityEnabledBPI+ Downstream Bonded ChannelsChannel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables 1Locked256 QAM38405000000 Hz12.4 dBmV40.8 dB002Locked256 QAM1483000000 Hz12.3 dBmV40.8 dB003Locked256 QAM2489000000 Hz12.2 dBmV40.8 dB004Locked256 QAM3495000000 Hz12.1 dBmV40.8 dB005Locked256 QAM4501000000 Hz12.0 dBmV40.8 dB006Locked256 QAM5507000000 Hz12.0 dBmV40.9 dB007Locked256 QAM6513000000 Hz11.9 dBmV40.9 dB008Locked256 QAM7519000000 Hz11.9 dBmV41.1 dB009Locked256 QAM8525000000 Hz11.9 dBmV41.2 dB0010Locked256 QAM9531000000 Hz11.8 dBmV41.2 dB0011Locked256 QAM10537000000 Hz11.8 dBmV41.3 dB0012Locked256 QAM11543000000 Hz11.6 dBmV41.3 dB0013Locked256 QAM12549000000 Hz11.6 dBmV41.3 dB0014Locked256 QAM13555000000 Hz11.6 dBmV41.3 dB0015Locked256 QAM14561000000 Hz11.5 dBmV41.3 dB0016Locked256 QAM15567000000 Hz11.5 dBmV41.7 dB0017Locked256 QAM16573000000 Hz11.3 dBmV41.6 dB0018Locked256 QAM17579000000 Hz11.4 dBmV41.7 dB0019Locked256 QAM18585000000 Hz11.5 dBmV41.6 dB0020Locked256 QAM19591000000 Hz11.4 dBmV41.7 dB0021Locked256 QAM25459000000 Hz12.3 dBmV40.6 dB0022Locked256 QAM34465000000 Hz12.2 dBmV40.7 dB0023Locked256 QAM35471000000 Hz12.3 dBmV40.8 dB0024Locked256 QAM36477000000 Hz12.3 dBmV40.8 dB0025Locked256 QAM39411000000 Hz12.3 dBmV40.7 dB0026Locked256 QAM40417000000 Hz12.3 dBmV40.7 dB0027Locked256 QAM41423000000 Hz12.3 dBmV40.7 dB0028Locked256 QAM42429000000 Hz12.4 dBmV40.7 dB0029Locked256 QAM43435000000 Hz12.4 dBmV40.6 dB0030Locked256 QAM44441000000 Hz12.2 dBmV40.5 dB0031Locked256 QAM45453000000 Hz12.3 dBmV40.6 dB0032Not LockedUnknown00 Hz0.0 dBmV0.0 dB00 Upstream Bonded ChannelsChannel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1LockedATDMA85120 Ksym/sec16400000 Hz35.0 dBmV2LockedATDMA55120 Ksym/sec35600000 Hz36.0 dBmV3LockedATDMA65120 Ksym/sec29200000 Hz36.0 dBmV4LockedATDMA75120 Ksym/sec22800000 Hz35.8 dBmV5LockedATDMA101280 Ksym/sec39600000 Hz41.8 dBmV6Not LockedUnknown0000.0 dBmV7Not LockedUnknown0000.0 dBmV8Not LockedUnknown0000.0 dBmV Downstream OFDM ChannelsChannel LockStatus Modulation /Profile ID ChannelID Frequency Power SNR /MER Active SubcarrierNumber Range UnerroredCodewords CorrectableCodewords UncorrectableCodewords 1Locked0 ,1 ,2 ,337690000000 Hz13.28 dBmV41.6 dB1108 ~ 2987769890445474258702Not Locked000 Hz0 dBmV0 dB0 ~ 4095000 Upstream OFDMA ChannelsChannel Lock Status Modulation / Profile ID Channel ID Frequency Power 1Not Locked000 Hz0 dBmV2Not Locked000 Hz0 dBmV

Your power levels are to high. You need a 3-6db attenuator or a 3-4x splitter in line to get the power down a bit. The power level should be between-7.5dbmv and 7.5dbmv. You're above 12.

brownbear55

Guide

Mar 08, 2023

Solved

CAX80: Poor Cable Connection Status

Hi everyone. I have Xfinity's Gig speed Internet plan and recently purchased the Nighthawk CAX80. Currently, its cable connection status shows as poor.

I did a quick search in the forums and I come across multiple responses that state to have the ISP come out to check the line up to the modem. Before I do that, I was wondering if anyone had any interpretation on the diagnostic results below:

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	405 MHz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enabled	BPI+

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	256 QAM	38	405000000 Hz	12.4 dBmV	40.8 dB	0	0
2	Locked	256 QAM	1	483000000 Hz	12.3 dBmV	40.8 dB	0	0
3	Locked	256 QAM	2	489000000 Hz	12.2 dBmV	40.8 dB	0	0
4	Locked	256 QAM	3	495000000 Hz	12.1 dBmV	40.8 dB	0	0
5	Locked	256 QAM	4	501000000 Hz	12.0 dBmV	40.8 dB	0	0
6	Locked	256 QAM	5	507000000 Hz	12.0 dBmV	40.9 dB	0	0
7	Locked	256 QAM	6	513000000 Hz	11.9 dBmV	40.9 dB	0	0
8	Locked	256 QAM	7	519000000 Hz	11.9 dBmV	41.1 dB	0	0
9	Locked	256 QAM	8	525000000 Hz	11.9 dBmV	41.2 dB	0	0
10	Locked	256 QAM	9	531000000 Hz	11.8 dBmV	41.2 dB	0	0
11	Locked	256 QAM	10	537000000 Hz	11.8 dBmV	41.3 dB	0	0
12	Locked	256 QAM	11	543000000 Hz	11.6 dBmV	41.3 dB	0	0
13	Locked	256 QAM	12	549000000 Hz	11.6 dBmV	41.3 dB	0	0
14	Locked	256 QAM	13	555000000 Hz	11.6 dBmV	41.3 dB	0	0
15	Locked	256 QAM	14	561000000 Hz	11.5 dBmV	41.3 dB	0	0
16	Locked	256 QAM	15	567000000 Hz	11.5 dBmV	41.7 dB	0	0
17	Locked	256 QAM	16	573000000 Hz	11.3 dBmV	41.6 dB	0	0
18	Locked	256 QAM	17	579000000 Hz	11.4 dBmV	41.7 dB	0	0
19	Locked	256 QAM	18	585000000 Hz	11.5 dBmV	41.6 dB	0	0
20	Locked	256 QAM	19	591000000 Hz	11.4 dBmV	41.7 dB	0	0
21	Locked	256 QAM	25	459000000 Hz	12.3 dBmV	40.6 dB	0	0
22	Locked	256 QAM	34	465000000 Hz	12.2 dBmV	40.7 dB	0	0
23	Locked	256 QAM	35	471000000 Hz	12.3 dBmV	40.8 dB	0	0
24	Locked	256 QAM	36	477000000 Hz	12.3 dBmV	40.8 dB	0	0
25	Locked	256 QAM	39	411000000 Hz	12.3 dBmV	40.7 dB	0	0
26	Locked	256 QAM	40	417000000 Hz	12.3 dBmV	40.7 dB	0	0
27	Locked	256 QAM	41	423000000 Hz	12.3 dBmV	40.7 dB	0	0
28	Locked	256 QAM	42	429000000 Hz	12.4 dBmV	40.7 dB	0	0
29	Locked	256 QAM	43	435000000 Hz	12.4 dBmV	40.6 dB	0	0
30	Locked	256 QAM	44	441000000 Hz	12.2 dBmV	40.5 dB	0	0
31	Locked	256 QAM	45	453000000 Hz	12.3 dBmV	40.6 dB	0	0
32	Not Locked	Unknown	0	0 Hz	0.0 dBmV	0.0 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	8	5120 Ksym/sec	16400000 Hz	35.0 dBmV
2	Locked	ATDMA	5	5120 Ksym/sec	35600000 Hz	36.0 dBmV
3	Locked	ATDMA	6	5120 Ksym/sec	29200000 Hz	36.0 dBmV
4	Locked	ATDMA	7	5120 Ksym/sec	22800000 Hz	35.8 dBmV
5	Locked	ATDMA	10	1280 Ksym/sec	39600000 Hz	41.8 dBmV
6	Not Locked	Unknown	0	0	0	0.0 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	Modulation / Profile ID	Channel ID	Frequency	Power	SNR / MER	Active Subcarrier Number Range	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	0 ,1 ,2 ,3	37	690000000 Hz	13.28 dBmV	41.6 dB	1108 ~ 2987	76989044	54742587	0
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

plemans
Mar 08, 2023
Your power levels are to high.

You need a 3-6db attenuator or a 3-4x splitter in line to get the power down a bit.

The power level should be between-7.5dbmv and 7.5dbmv. You're above 12.

10 Replies

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plemans
Guru - Experienced User
Mar 08, 2023
Your power levels are to high.

You need a 3-6db attenuator or a 3-4x splitter in line to get the power down a bit.

The power level should be between-7.5dbmv and 7.5dbmv. You're above 12.
- brownbear55
  Guide
  Mar 08, 2023
  By using a coaxial splitter to slightly reduce the power, would I then see increased speeds or at least in theory?
  - Kitsap
    Master
    Mar 08, 2023
    brownbear55 wrote:
    By using a coaxial splitter to slightly reduce the power, would I then see increased speeds or at least in theory?
    You are way too hung up on throughput (speed).
    
    If your cable input signal power levels are not within specification, the modem will not have a chance to do the job it was designed to do.
    
    Give your modem a chance to do it's job. If you still have throughput problems, work your way downstream to find the problem.
Kitsap
Master
Mar 08, 2023
Technically the power level is the responsibility of the ISP. More frequently today, end users that own their own modems find the ISPs are less than responsive to requests for support.

plemansrecommendation to add a splitter or attenuator to the line is action you can take. If you do not have either of these items, they are available for a reasonable cost from Amazon. If you use a splitter, be sure and buy caps to cap off any unused connections. Make sure both the splitter and attenuator are specified for cable TV frequency range, usually up to 3 GHz.
- brownbear55
  Guide
  Mar 08, 2023
  I used the Xfinity app and walked through the prompts for slow connection and using a variety of responses, Xfinity always places the responsibility of slow connection speeds on not themselves.
  - Kitsap
    Master
    Mar 08, 2023
    brownbear55 wrote:
    I used the Xfinity app and walked through the prompts for slow connection and using a variety of responses, Xfinity always places the responsibility of slow connection speeds on not themselves.
    Surprise! Surprise! NOT

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CAX80: Poor Cable Connection Status