OFDM Channel not locked - Downstream light consistently blinking now

Hi Bruce, I appreciate the response.

I am not sure why I don't have 8 upload channels locked but at this point Cox has decided that now my brand new modem is also the "Issue".   The issue has been consistent through my Netgear CM1200 as well as the Netgear CM2000 modem I just purchased two weeks ago.    The concerning part for me is they installed one cox modem and it actually wouldn't lock the downstream channels either.  They said their modem must have an issue as well.   So now we are on a forth modem(another cox modem) to see if they can pinpoint the issue.    After provisioning it did lose connection but I was told it was probably upgrading the firmware so that is why it was down. 

I hate to sound negative but I find it very hard to believe that 3 out of 4 different modems(including one of cox's) are the issue and not something with the signal.  

I now seem to have the ODFM channel locked as of this morning (after 12 hours) but there the SNR and power levels don't have any readings.  Shouldn't there be some kind of signal information?

Any thoughts on this? This is from cox modem model # CGM4140COM

Downstream	Channel Bonding Value
Index	13	1	2	3	4	5	6	7	8	9	10	11	12	14	15	16	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	159
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	855 MHz	783 MHz	789 MHz	795 MHz	801 MHz	807 MHz	813 MHz	819 MHz	825 MHz	831 MHz	837 MHz	843 MHz	849 MHz	861 MHz	867 MHz	873 MHz	357 MHz	363 MHz	369 MHz	375 MHz	381 MHz	387 MHz	393 MHz	399 MHz	405 MHz	411 MHz	417 MHz	423 MHz	429 MHz	435 MHz	441 MHz	447 MHz	300000000
SNR	42.3 dB	43.5 dB	43.4 dB	43.4 dB	43.3 dB	43.1 dB	43.3 dB	43.1 dB	42.9 dB	42.9 dB	42.7 dB	42.7 dB	42.4 dB	42.2 dB	42.1 dB	41.7 dB	45.0 dB	45.4 dB	45.2 dB	45.2 dB	45.3 dB	45.3 dB	45.4 dB	45.4 dB	45.4 dB	45.3 dB	45.3 dB	45.2 dB	45.2 dB	45.2 dB	45.1 dB	45.2 dB	NA
Power Level	2.2 dBmV	3.8 dBmV	3.7 dBmV	3.7 dBmV	3.7 dBmV	3.5 dBmV	3.7 dBmV	3.5 dBmV	3.3 dBmV	3.3 dBmV	2.8 dBmV	2.7 dBmV	2.4 dBmV	2.0 dBmV	1.9 dBmV	1.5 dBmV	4.1 dBmV	4.1 dBmV	4.2 dBmV	4.1 dBmV	4.3 dBmV	4.3 dBmV	4.3 dBmV	4.3 dBmV	4.4 dBmV	4.5 dBmV	4.5 dBmV	4.6 dBmV	4.5 dBmV	4.5 dBmV	4.4 dBmV	4.2 dBmV	NA
Modulation	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	OFDM

Upstream	Channel Bonding Value
Index	1	2	3	4	5	6	7	8
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	16 MHz	23 MHz	29 MHz	36 MHz	60 MHz	67 MHz	74 MHz	81 MHz
Symbol Rate	5120	5120	5120	5120	5120	5120	5120	5120
Power Level	40.5 dBmV	41.5 dBmV	41.0 dBmV	41.0 dBmV	41.8 dBmV	42.5 dBmV	42.5 dBmV	43.0 dBmV
Modulation	QAM	QAM	QAM	QAM	QAM	QAM	QAM	QAM
Channel Type	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA

Hi Nathanc34,

We can certainly investigate this issue for you. Please email our team at cox.help@cox.com with this post, your full name, and complete address. You can also reach out to us on Twitter and Facebook through the links below:

www.facebook.com/.../

https://twitter.com/CoxHelp

Maria
Cox Support Forum Moderator

Hi Maria, 

I just sent the team an email with my contact information regarding this post. 

I appreciate the response and look forward to hearing back from your team to hopefully figure out what's going on. 

Thank you 
Nathan 

As far as I know, very few areas have 8 upstream channels. Most have 4, and a few have 5 (really more like 4 1/2) due to congestion. Gigablast only supports up to 35 Mbit upstream so 4 channels is more than enough for that. As you pointed out it's odd that the OFDMA channel isn't locked since I think all of Cox is on DOCSIS 3.1 now. That's something a tech would need to investigate. As mentioned, it could be caused by noise issues in the 300 MHz band used by OFDMA.

Moral of the story is that Cox always blames the modem because it's a quick way to get customers off the phone and keep call times down. And very rarely a modem does break down. But it's almost never the modem. It's a good idea to keep up with new technology and upgrade your modem every few years but most of the time when Cox blames the modem they're just plain wrong.