Question Modem has intermittent connection - drops randomly

CBrando89

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Sep 28, 2014
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ISP: Spectrum
Router: Netgear Nighthawk AC1900 (my own - flashed with ExpressVPN firmware)
Modem: Arris TM1602 (Spectrum-supplied)

I've been having this issue since moving into this new place and it's driving me NUTS!

Our connection will drop and be intermittent, especially at certain times of the day (2PM, 5PM typically). Other than those times, it seems purely random. The lights on my modem drop down to just the power (which is solid blue) and the US/DS (Upstream/Downstream, blinks blue). From doing some research, I understand that means my modem isn't getting a signal from the coaxial cable, thus everything else drops (internet, phone, etc). The connection will re-establish after about 5 minutes, but most times, it will continue to drop minutes afterwards. Even a reset will not solve the problem, the connection will drop intermittently immediately after. I originally thought it was my router causing these issues, due to the fact that the drops are short and totally random (and that I'm using a VPN and flashed firmware), but after observing my modem, I'm starting to think that is the cause of my problems.

We've had Spectrum out about 20 times in the past couple of months, if not more. They have changed out modems, installed new cabling throughout the house and outside, and checked just about everything they could think of. They will leave, and it will work fine for about a few hours, then the problem always comes back. I'm starting to think this problem will never get fixed. I wanted to post this here to see if it's something that we are doing wrong, and if so, how can we fix it?

Is this an infrastructure issue with Spectrum? Or something else?

Thank you for taking the time to read this thread.
 

dorsai

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Nov 23, 2013
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Have you tried going straight from the modem to your PC without using the router ?

Have you looked at the modem signal levels while your service is interrupted ? Usually the modem will have an IP address like 192.168.100.1 on the bottom with a default password to access the modem.

You'd want to check downstream signal Pwr (dBmV) looking for anywhere between 0 and 10. You'd also want to check the SNR (dB) looking for between say 35 and 50.

Each CATV company sets different signal level requirements for their systems but in general most fall within the ranges above.

If either of the readings are low then you possibly have a low power/signal input issue...if either are above the range then you may actually be getting hit with too much signal.
 
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CBrando89

Honorable
Sep 28, 2014
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10,510
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Have you tried going straight from the modem to your PC without using the router ?

Have you looked at the modem signal levels while your service is interrupted ? Usually the modem will have an IP address like 192.168.100.1 on the bottom with a default password to access the modem.

You'd want to check downstream signal Pwr (dBmV) looking for anywhere between 0 and 10. You'd also want to check the SNR (dB) looking for between say 35 and 50.

Each CATV company sets different signal level requirements for their systems but in general most fall within the ranges above.

If either of the readings are low then you possibly have a low power/signal input issue...if either are above the range then you may actually be getting hit with too much signal.
Ok, I can check this out when I get home today. I wasn't aware I could access the modem directly. We have a Spectrum Tech coming out later on today, but I will try to check it before he gets here.
 

kanewolf

Titan
Moderator
Yeah, open a browser and enter 192.168.100.1 -- That will bring up status pages from your modem. You want the downstream power to be -3db to +3db optimally. You want the SNR to be around 40db. For upstream you want numbers around 40db also.

First thing I would do is bypass the in-house wiring and connect the modem to the ISP splitter on the outside of the house with a temporary coax cable run through a window opening. Then use a long ethernet cable to connect to your router. That gets the signal out of the radio frequencies ASAP and into ethernet.

I have that modem and no login/password is required with Spectrum to access the status page.
 

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