Howto on Cable Modem Connection

A friend of mine has Comcast Internet, and is experiencing numerous "stalling" occurrences during her Internet sessions. Her XP Pro PC is hardwired to a Linksys BEFW11S4 router, which also feeds a laptop and a TiVo wirelessly. Router is connected to a SurfBoard modem.

I tried to trace the route of the incoming cable back to the entrance point on the house today (having some problems because the entire basement has a drop ceiling). It appears the incoming cable runs to a Regal DS4DGH10 splitter. From there, a lead goes to a Regal GRS3DGH

110db EMI Isolator, and the lead to the cable modem takes off from there.

She called Comcast this week, and the tech who showed up said he couldn't find anything wrong (he didn't look at anything in the basement, though). The TiVo, which is using a DLink USB wireless adapter, was showing Poor (24%) to Marginal (28%) connectivity most of the time I was there, with an occasional jump to Fair (58%).

I downloaded a firmware upgrade for the Linksys router, and the download speed started out at 113 kbps, and gradually went up, never breaking 200 kbps. Applied the upgrade, but no change. Noticed the Internet light was flashing constantly on the router, which looks odd to me (my Linksys WRT54G, on a DSL line, has a constant Internet light).

Any suggestions as to what might be wrong gratefully appreciated. John Jones, Detroit

Reply to
John Jones
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Comcast lights flash.

Reply to
f/fgeorge

Access the cable modem statistics page at 192.168.100.1 and check signal to noise ratios and signal levels. The cable modem faq at

formatting link
will provide the basis for determining if there are line quality issues from the signal levels.

Q
Reply to
Quaoar

Best to not go through more than one splitter.

Reply to
KenW

I have a cable connection also and I also had a BEFW11S4 router. I switched to a WRT54GS router. It made a difference. Steve

Reply to
Steve

I happen to have a new WRT54G router laying around, so I may try swapping it into her network if I can't find anything else wrong. I still think her cable wiring isn't right, so I want to change that first. John Jones, Detroit

Reply to
John Jones

Finally had a chance Sunday to do this. Stats are:

Downstream SNR: 36 dB Power Level: -1 dBmV

Upstream Power Level: 56 dBmV

According to the FAQ, only the Upstream Power Level number looks bad. Guess I'll start looking for the right kind of splitter to feed the cable modem, and do some rewiring. John Jones, Detroit

Reply to
John Jones

It is always best to split the line only once prior to the modem and the installation techs know this. the 56 dbmv is certainly not good, shoot for 35-40 dbmv range. If you are doing your own wiring, consult the faq for coax specs. Radio Shack is *not* the best source. Buy the best coax type you can afford, and know that the connectors and install techniques have a significant influence on signal quality. IOW, you might contract a professional installer.

Q
Reply to
Quaoar

I responded above, but you toggled a memory cell or two: you have 56 dBmv upstream at the modem. A typical double splitter is -3dBmv loss. Unless you have a bunch of splitters in front of your modem, the 56dBmv is from my experience as a customer indicative of a line drop issue that only the ISP's techs can correct.

Reply to
Quaoar

I agree! The 56dBmv upstream sounds like a level issue between him and the node. I had a 55dBmv for quite some time and experiences random disconnects. It took several attempts to get Comcast to find a problem at the node. I now have a 36dBmv upsteam, 8dBmv downstream and a 39dB SNR. I'm very happy with them.

Reply to
Dave

The incoming line goes through one splitter, then a second one. The cable modem is connected to the second one. I'm thinking I'll try to locate a good splitter to replace the first one with, and connect the cable modem to the proper tap on that. If that doesn't help, I'll tell my friend to have Comcast get involved again. John Jones, Detroit

Reply to
John Jones

In your search for the perfect splitter, consider dropping by your local cable office. So far, everywhere I've lived, they gladly hand out splitters as well as reasonable lengths of terminated cable, just for asking.

Reply to
Bill M.

Here in Los Angeles, the field tachnicians are generous "judiciously". If you're a customer, they'll give you up to 100' of RG6 quad-shield cable and they'll even cut it and attach connectors. That's because it's in their interest to keep you happy and using good cable that prevents leakage into and out of their network. But the business office can't be bothered. In such instances, it helps to just walk into the field ops truck yard and speak to a supervisor and explain that you're a customer and sound you know what you're doing. Using terms like "RG6 quad-shield", "Snap-N-Seal F-connector", "2-way splitter good for

1 gigahertz" does help. I once did that. At first the techs denied that they had any splitters in their trucks. But after a brief conversation, they were giving me stuff that I hadn't even asked for. *TimDaniels*
Reply to
Timothy Daniels

The smarter cable office have learned (are learning) that giving out a

20 splitters that costs them $1 in bulk can save a service call that costs $200 (after accounting for overheard).

After an installer in Chapel Hill, NC dropped off a cable modem for a new house I mentioned getting a powered splitter to handle all the prewired drops. He handed me a new one from his truck. :)

Reply to
DLR

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