Basic Internet Connectivity And Modem Help

[bc13534]

Our modem (SB5101 - leased from Comcast) has been continually dropping the internet signal since we moved in.  Had a Comcast tech out to install everything a few weeks ago and was told we were good, didn't move up until this past weekend and the modem has dropped the signal numerous times each day.  I've spoken with a comcast rep online, cycled the power, disconnected the router, but still no fixes.  I've been told to go get a replacement modem, but this one was just installed by one of their techs, so I suspect that will just be a waste of my time.  Is there something else I need to be checking, or is hiking out to comcast the only possible solution.

Thanks in advance.

[i-am-nerdburg]

Please give us more information:

1) Please connect your computer directly to the modem via Ethernet ( no router, no wireless, no USB )
2) Run ShaperProbe and post your results. (It works with Win 7)
3) Post your upstream and downstream signal levels (click the link.) We are interested in your power levels (dBmV) and your Signal to Noise Ratio (SNR).
4) Let us know to what speed tier you subscribe.
5) Post the make a model of your modem.
6) Post your modem's error logs.

[bc13534]

Is it possible to run these tests while the internet is out?  My wife just told me she hasn't been able to connect all morning.

Speed tier - performance

Also, where do I find the error logs?

Thank you

[i-am-nerdburg]

You'll need some connectivity for the test to be avail or to work at all. Is there a router in the mix? Same problem w or w/o the router? What are the lights on the modem doing? You can find all your modem info from a local machine at http://192.168.100.1

[bc13534]

There is a router, the problem has persisted both with and without it (and we had comcast in Philly using that router and had no issues).  The lights today - power has been on, and it has fluctuated between receive blinking and receive solid while send blinks.  Over the past couple days its been mostly the same, with opccasionally all 4 green lights going solid.

dBmV = -8.5

SNR = 37.8db

I can't post the error logs right now, is there something specific I should look for?

[i-am-nerdburg]

What is the upstream power level?

[bc13534]

sorry its 55.0

[i-am-nerdburg]

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bc13534 wrote:

sorry its 55.0

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Ahh, there is your problem. Most commonly a high upstream power is the result of too many splitters. How's your wiring?

[bc13534]

From what I could tell, one split in the basement, a second split on the first floor at the tv/modem.  I'm not sure how to limit this other than having to run new cable all the way to the modem.

[i-am-nerdburg · Accepted solution]

Typically, you would have a two way splitter where the cable enters the house. One leg would feed the modem, the other would feed everything else. The length and quality of the coax also plays a part. If it's possible for you to relocate the modem, you might be okay on a different outlet. Your best solution is probably to have a tech run a separate line for you.

[bc13534]

I'll get in touch with Comcast and have them fix it - is this something they would normally do/check on the installation?

Thanks for all your help, I really appreciate it.

[i-am-nerdburg]

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bc13534 wrote:

I'll get in touch with Comcast and have them fix it - is this something they would normally do/check on the installation?

Thanks for all your help, I really appreciate it.

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Absolutely! If you had a tech install it, then he should have run a new line -that would be part of the installation fee you paid. Let us know how it goes.