Speed up your cable internet

Is your internet connection through the cable company? Are you getting the speed you're paying for? Do you know how to improve your speed?

My local cable company, smelling some competition in the wind, sped up my connection from 50Mb/s to 100Mb/s. That's when the trouble began for me. Sometimes I got 100Mb/s, sometimes I got as little as 6Mb/s. After working through the problem, I'm now consistently getting 108Mb/s downloads and about 11Mb/s up.

You can test your speed at http://www.speedtest.net among other places. Test at different times of day, as speed can be affected by traffic and temperature. My slowest speeds were in the late afternoon, the hottest part of the day.

Assuming you've tested and found your speed lacking, read on. What follows is what I've learned about debugging an internet connection through a cable modem. You may or may not need the help of the cable company. It depends on how handy you are and who owns your wiring and your modem. My house cable wiring was done by my builder, and I bought my own modem awhile ago to avoid the rental fee.

Whose problem is it?

The basic question is: Where is the problem? Hopefully you can sort it out from what follows and either fix it or help direct your cable repair person.

Do you have your own modem, or are you using a rented modem? If you are renting the cable company's modem, call them. You'll have to work with them to solve the problem. (But keep reading for suggestions.)

If you have your own modem, look at the modem status page. For my Motorola modem, it's http://192.168.100.1 and click the "signal" tab. I have four channels bonded for download, 4 channels bonded for upload. (My Motorola SB6141 modem allows up to eight download channels to bond, and four upload channels.)

My problem was that one download channel was marginal. The allowable ranges for each download channel are 30dB or greater signal-to-noise ratio, and +/- 15dBm signal strength. In my case, one channel was consistently low, close to -13dBm. In the afternoon, probably related to temperature, the signal dropped to -15 or -16dBm, which caused massive errors and turned my 100Mb/s downloads into about 6Mb/s. This was really ugly.

Can I fix this?

Then my question was: Can I fix this or do I need the cable guy? To discover this, I connected to the cable at the point where it enters my house. In my case, there is a box there that I needed to open, which in my neck of the woods is OK if you're not defrauding the cable company. (Yes, I pay the cable company for everything I get from them.) You may need a special tool to get into the box. Once you have access, take your modem and your laptop (or wireless router) and connect it at that point. (I needed to drag an extension cord out to that point to plug stuff into.) Fire everything up, then check the modem status page. If your signal at that point has greater than 30dB signal to noise ratio and greater than -15dBm signal power, then it's possibly your problem.

If it's less than these values, it's their problem: Call them. Or, if you can't access the cable at the entrance point, again, call the cable company. You'll need to work with them. But keep reading for ideas on things to try...

Okay, it's my problem. Now what?

What you can do depends on how handy you are. At this point, you could have bad wiring, too much wiring, or too many or badly placed splitters.

1. You could have too many splitters. If you also get cable TV, you should have one high-quality 2-way splitter at the entrance to your house. One leg of the split signal goes to your modem, the other one goes to your cable boxes, TVs and other stuff. TVs are not as picky as the modem. In any case, keep the modem as close to the entrance as you can. If you only get internet service, you should have no splitters: Remove them and set up a straight run to your modem.
2. Your house's cable wiring could be bad. Yes, wiring can go bad, especially in an attic. People walk around attics and step on things, including cable. Squish enough of the center insulator and you get more loss. Sharp bends in cables can pinch the insulator, also adding loss.
3. The wiring specification may have changed. Currently, cable wiring should use RG6 cable (preferably quad-shielded). My house was wired with RG59, which was fine for analog cable but isn't as good for higher frequency digital cable and cable modems. You should have a good clean run of RG6 from the entrance point to your modem.
4. Check your connections. Connectors corrode. Loosen and retighten connectors. Connectors (including barrel connectors) should be zero-loss. If you have access, check each connector in series for loss from the entrance. If you want to be paranoid (and are handy) cut off all the existing connectors and replace them with new compression connectors.
5. You could have signal loss due to too much wiring. Move the modem closer to the entrance.

When I looked at my cables, I found my house had been wired with RG59. I also found loose and corroded connections. And I had way too much wiring. In my case, the thing that made the most difference was changing to a short run of RG6: I moved the modem to the room closest to where the cable enters the house, and I did a straight run from the demarcation box to my modem, replacing old RG59 with RG6, shortening the run from about 50ft to 20ft with no splitters. I gained 3 or 4 dBm, which is enough to keep the weak channel above the -15dBm lower limit all the time.

Internet bliss

Well, maybe not bliss, but I'm pretty happy with the new speeds and I don't have afternoon drop-outs as before.

You may be wondering: If I moved the modem to the room nearest the cable entry, how do I get a connection to my computer? I put my wireless router right next to the modem. Even so, I'm kind of old school on this. I don't like WiFi. Too much possible interference, and slow speeds as you get away from the router. So, for most connections in the house, I've run Cat5e wiring and I have a local gigabit network, which is much quicker than WiFi and doesn't slow down with the distances in a house. But that's another kettle of fish.