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View Full Version : Cox Cable - Modem Troubleshooting



Lithorn
09-13-20, 01:45 PM
I've two Netgear Modems, and had an Arris modem on our account for a time. The first Netgear is a NightHawk C7800 (IIRC as its gone now), and it started throwing T2-4 Errors, Disconnects, Packetloss, and Dynamic Range Violations all day long.
We got an Arris and it worked great, it only spit out a few errors every now and then but never dissconncted. Well the Misses didnt like having two machines and wanted to go back to an all in one so we got another Netgear Nighthawk, C7000V2. It worked great for about a week and began spitting the same errors the first Netgear did. It also began dissconnecting as well.

I've contacted netgear, who can do nothing according to them. I've contacted Cox, who can do nothing with it according to them (Repeatedly, and I mean weve been in contact with them over 30 times about this crap.). I've read a bit on cox's forums about other users with the same modems having issues, and end up resolving it by them doing something in a hub or programing and what not. When I ask about such things I either get hung up on or they don't know what im talking about. Instead they try to push their hardware and Homecare products which after another agent truthfully told me may not even do anything.

I've a log of the errors, a picture of the channels to boot at the craziest of times. Is there anyone who could look at things and tell me where im going wrong? The modem "Should" be directly connected to the outside line to the pole. There "Was" splitters on the line (3 of them, one amplified) but have been removed. The first netgear had many issues while the splitters was on, and many issues with them being off.

This is an old photo

https://ibb.co/7Q8QN0v

https://ibb.co/68R9PYm

https://ibb.co/pZyrCH2

Here is a current snap of the modem after a reboot last night, seems to be doing ok.

https://ibb.co/vXt2fjD

https://ibb.co/ZLSC96n


Any advice, or help, or what to say to cox to even get the right help would be apreciated.

(Edit, aparently the img tags didnt work. Sorry)

Philip
09-13-20, 09:05 PM
Your signal levels seem ok, your downstream power is a bit high but still ok. You can even add one more two-way splitter and be ok, but you don't want your upstream power to get much higher. You shouldn't be running any amlifiers/boosters, as they also amplify noise. Here is some info on what is good for your reference: https://www.speedguide.net/faq/what-cable-modem-signal-levels-are-considered-good-78


Other than that, different modems react differently to the same signal levels, some are more sensitive than others, their firmwares are different, etc. Also signal levels fluctuate throughout the day depending on weather and who else is using the network in your neighborhood. When you are experiencing issues with errors/etc. are the signal levels, SNR etc. the same?

Lithorn
09-25-20, 11:12 PM
Your signal levels seem ok, your downstream power is a bit high but still ok. You can even add one more two-way splitter and be ok, but you don't want your upstream power to get much higher. You shouldn't be running any amlifiers/boosters, as they also amplify noise. Here is some info on what is good for your reference: https://www.speedguide.net/faq/what-cable-modem-signal-levels-are-considered-good-78


Other than that, different modems react differently to the same signal levels, some are more sensitive than others, their firmwares are different, etc. Also signal levels fluctuate throughout the day depending on weather and who else is using the network in your neighborhood. When you are experiencing issues with errors/etc. are the signal levels, SNR etc. the same?


The SNR is usually the same but the power levels tend to be higher. I've seen them as high as 11. This is tonights. We had a few dissconnects today. We have a few every day, or a lot. Its really random. https://ibb.co/SJpfVmw and today's event log
https://ibb.co/yq0LqQn

Philip
09-26-20, 11:19 AM
Downstream Power level should be closer to zero.. You may have some coax issue. If you want to tackle this yourself, I would buy a "Forward Path Attenuator", probably in the 6dB range, this should bring the downstream power down close to zero without affecting the upstream much, it should reduce disconnects. Even better if you can get a tech from the cable company to test the incoming coax line for issues.

These two FAQs may shed a bit more light on the T3/T4 errors
https://www.speedguide.net/faq/unicast-dsid-psn-startup-error-514
https://www.speedguide.net/faq/docsis-t1-t2-t3-t4-timeout-errors-515

Also, keep in mind that different brands/models modems may have slightly different upstream signal characteristics, causing more/fewer T3 timeouts.