Uncorrectable Codewords and Slow Speeds

Question

Hello, I recently bought a CM1000 and have it hooked to an Orbi router with satellite. After some configuration of the Orbi, I was getting great speeds for what I'm paying for (700Mbps wired, 300 wireless, and I'm paying for 600). This lasted for a couple days, but then I noticed extremely slow speeds (40 - 60Mbps wired, 20 - 30 wireless), constantly dropped connections, and difficulty in even getting my modem to connect to the internet.

After a lot of troubleshooting, I pulled this from the log:

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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	495000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enable	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

Downstream Bonded Channels (Partial Service)

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR / MER	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	QAM256	17	495000000 Hz	-1.1 dBmV	30.6 dB	27881984	7332094	7056
2	Locked	QAM256	13	471000000 Hz	-1.2 dBmV	31.3 dB	31891416	2162843	61
3	Locked	QAM256	14	477000000 Hz	-1.0 dBmV	31.1 dB	31137492	2920508	184
4	Locked	QAM256	15	483000000 Hz	-0.9 dBmV	30.9 dB	29974885	4086048	714
5	Locked	QAM256	16	489000000 Hz	-1.5 dBmV	30.8 dB	28407285	5655476	2785
6	Locked	QAM256	18	507000000 Hz	-1.6 dBmV	30.3 dB	22901983	11124052	42993
7	Locked	QAM256	19	513000000 Hz	-1.5 dBmV	30.2 dB	19111799	14812909	148120
8	Locked	QAM256	20	519000000 Hz	-1.9 dBmV	29.8 dB	14607041	18970555	499027
9	Locked	QAM256	21	525000000 Hz	-2.2 dBmV	29.5 dB	9436862	22950882	1690979
10	Locked	QAM256	22	531000000 Hz	-2.0 dBmV	29.4 dB	6607042	24253937	3222860
11	Locked	QAM256	23	537000000 Hz	-1.9 dBmV	29.2 dB	4206773	24133856	5741616
12	Locked	QAM256	24	543000000 Hz	-1.8 dBmV	29.3 dB	2731744	22833002	8515849
13	Locked	QAM256	25	549000000 Hz	-1.9 dBmV	29.1 dB	1907106	21247830	10902643
14	Locked	QAM256	26	555000000 Hz	-1.4 dBmV	28.9 dB	1180093	18880984	14007281
15	Locked	QAM256	27	561000000 Hz	-0.7 dBmV	29.1 dB	845951	17200561	16019783
16	Locked	QAM256	28	567000000 Hz	-1.1 dBmV	29.1 dB	719180	16389074	16965015
17	Locked	QAM256	29	573000000 Hz	-0.6 dBmV	29.2 dB	777377	16803610	16495101
18	Locked	QAM256	30	579000000 Hz	-0.5 dBmV	29.0 dB	424983	14004230	19647388
19	Locked	QAM256	31	585000000 Hz	-0.3 dBmV	29.0 dB	387057	13642956	20055384
20	Locked	QAM256	32	591000000 Hz	0.1 dBmV	29.1 dB	629216	15799247	17663066
21	Locked	QAM256	33	597000000 Hz	0.1 dBmV	29.1 dB	493746	14696502	18914606
22	Locked	QAM256	34	603000000 Hz	0.6 dBmV	29.2 dB	322847	12917789	20854298
23	Locked	QAM256	35	609000000 Hz	-0.1 dBmV	29.0 dB	245496	11887225	21982438
24	Locked	QAM256	36	615000000 Hz	-0.3 dBmV	29.2 dB	363311	13396316	20355649
25	Locked	QAM256	37	621000000 Hz	0.8 dBmV	29.2 dB	498406	14786284	18835234
26	Locked	QAM256	38	627000000 Hz	0.5 dBmV	29.2 dB	259057	12126089	21740231
27	Locked	QAM256	39	633000000 Hz	0.7 dBmV	29.2 dB	211295	11455797	22461011
28	Locked	QAM256	40	639000000 Hz	1.2 dBmV	29.2 dB	197886	11051140	22120456
29	Locked	QAM256	41	645000000 Hz	1.3 dBmV	29.1 dB	364710	13454329	20322305
30	Locked	QAM256	42	651000000 Hz	1.3 dBmV	29.3 dB	435393	14214767	19471029
31	Locked	QAM256	43	657000000 Hz	1.0 dBmV	29.5 dB	378663	13636884	20116802
32	Locked	QAM256	44	663000000 Hz	1.4 dBmV	29.3 dB	271649	12339230	21524185

Upstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power
1	Locked	ATDMA	9	16400000 Hz	50.0 dBmV
2	Locked	ATDMA	10	22800000 Hz	50.0 dBmV
3	Locked	ATDMA	11	29200000 Hz	51.0 dBmV
4	Locked	ATDMA	12	35600000 Hz	51.5 dBmV
5	Locked	ATDMA	13	40400000 Hz	52.0 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

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	159	690000000 Hz	0.4 dBmV	26.8 dB	1126 ~ 2969	28958633	28958630	0
2	Not Locked	0	0	0 Hz	-5.1 dBmV	0.0 dB	0 ~ 4095	0	0	0

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

All those unncorrectable codewords... that's a problem from what I understand, right? And it's probably a problem with the cabling? I don't have any splitters between my wall outlet and the modem, but some of the cables where the outside cable comes into my house look pretty old.

I should add that this all started happening the day I had a tankless water heater installed mere inches from where the outside cable enters my house, goes to a splitter, and sends the five or so other cables to other parts of my house. I didn't put the two and two together immediately, but after looking at the logs, is it possible or likely that they knicked a cable or somehow disturbed them, and that's what's causing my issues? I made sure all the cables are tight, and I don't notice anything obviously wrong, but I feel like it's the only explanation. I've been in this house 2.5 years with no issues up til now.

I have a technician from my ISP coming on Monday, but one tech already confirmed over the phone that the "signal is strong" on their end when he was pinging my modem. I guess what I'm wondering is: assuming the the ISP technician concludes that the problem is in my house and not on their end, is it reasonable to ask the company that installed the water heater to pay for getting this fixed? I feel like it is, but I want a gut check.

And apart from replacing the cabling right now, is there anything else I should be doing in the meantime to get better speeds?

FURRYe38 · Answer

Ya there should be very little or zero un correctables or correctables.
&nbsp;
Have the ISP check the signal and line quality UP to the modem.&nbsp;Be sure the ISP provisions the modem correctly. Make sure the tech looks at these logs.Be sure there are no coax cable line splitters in the between the modem and ISP service box.&nbsp;Be sure your using good quality RG6 coax cable up to the modem.&nbsp;Be sure to power OFF the modem for 1 minute then back ON.https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

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Uncorrectable Codewords and Slow Speeds

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