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C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

elb85
Guide

C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

I'm hoping to get some insight. 

 

I have the C7000v2 Nighthawk AC1900 Cable Modem Router. 

 

Xfinity service - 1000mbps download/35 mbps upload plan

 

The Nighthawk app under Wifi Analytics -> Home Testing shows the signal is coming in around 850 Mbps.

 

When I'm downloading over ethernet/Wifi, the speeds aren't near that, but completely fine for me - around 200 Mbps (which may be related to the issue). However, the upload is consistently around 0.2-0.5 Mbps on any speed test platform I run.

 

I've had Comcast replace my line, I've reset the router many times, firmware is V1.03.01 which is current according to Netgear website. I'm trying to figure out what I need to do next to troubleshoot why my upload is so slow. I've also searched the community posts and have seen others with similar issues. I've attempted the steps in those posts but no luck.

 

I also have the Comcast line coming into the house, it goes to a subscriber amplifier and I'm attaching to the wall outlet for my router/moded. There are no splitters in between and my thought is that the 850 Mbps being read by the router/modem means there shouldn't be an issue before the router?

 

Appreciate any help.

Model: C7000|Nighthawk - AC1900 WiFi Cable Modem Router
Message 1 of 9

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plemans
Guru

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

they either need to check the amp, the line again, or the tap. you have a lot of dynamic range window violations which is when power goes out of spec. Plus t3 errors. 

I'd remove that amp and see how it does. 

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Message 7 of 9

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plemans
Guru

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

I wasn't aware the C7000 could hit 850mbps on comcast. I though it was only spec'd up to 600mbps on comcast. 

Comcast requires docsis 3.1 for gigabit lines. 

when you say "home testing" do you mean the tech hooked up to the line or you hooked a laptop/pc to it and hit those speeds? 

 

Regardless, you should be able to get faster upload speeds. 

do you have a screen snip of the cable connections page and the logs? That helps us to check the line. 

Message 2 of 9
elb85
Guide

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

So that 850 Mbps number came from the Nighthawk app. Not sure if it was relevant.To be honest, I just upgraded from a 300/10 Mbps plan from Xfinity. I was on the phone with them about why I was only getting around 0.05-0.2 Mbps (at that time) for upload speeds and they wanted to 'save me money' by upgrading to the gigabit plan - 1000/35 Mbps.I didn't need that speed for download, but need the upload to be higher. I figured with a max increase in speed, I might see some increase on the lower end.

 

I've attached the screenshots for the Cable Screen.

cableScreen1.pngcableScreen2.png

Message 3 of 9
elb85
Guide

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

Not sure why, but the screenshots aren't showing so I'm including them as links for the Cable Screen. First reply has the first screenshot and this reply has the second half.

Message 4 of 9
plemans
Guru

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

You said theirs an amplifier in line? 

I'd remove that, move the modem to right where the coax enters the home, and try it. 

Reason why is that if the signal isn't good coming in, the amp just increases a bad signal. 

And if there's an amp issue, when the modem sends out a signal (upstream) it can block/cause issues. 

 

Do you have the modem logs as well? The cable connection page is just taken when you open the page. The logs show underlying/longer term issues. 

Message 5 of 9
elb85
Guide

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

So I attached a screenshot of the Event Log. It seems there have been some issues and, looking them up, maybe directly related to wiring?

I'm going to connect directly to the line coming into my house to see if that corrects the issue. It's in a difficult spot so going to take a bit. I'll post what I found though.

 

Appreciate all the help.

Message 6 of 9
plemans
Guru

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

they either need to check the amp, the line again, or the tap. you have a lot of dynamic range window violations which is when power goes out of spec. Plus t3 errors. 

I'd remove that amp and see how it does. 

Message 7 of 9
elb85
Guide

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

So I ended up bypassing the amplifier and that did the trick. I did also end up going back down to a 300/10 Mbps plan because you were correct in that Comcast requires Docsis 3.1 for gigabit and it might have been a secondary issue.

 

Appreciate the help.

Message 8 of 9
plemans
Guru

Re: C7000v2 Nighthawk AC1900 Cable Modem Router - Extremely slow upload speed

Glad to hear you got it resolved!

Let us know if you have futher issues and we're happy to help

Message 9 of 9
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