http://lifehacker.com/5563196/turn-your-old-router-into-a-range+boosting-wi+fi-repeater
Har klippt bort allt som inte har med själva inställnignen att göra.
Setting Up the Repeater
Now that you've got your oldie-but-goodie router set up with DD-WRT, you can set it up to pick up the signal from your primary router and re-broadcast it within its own radius. Here's how to do that.
With your computer still hooked up to the now-secondary router, head into the DD-WRT setup screen. It will ask you to set a better password and username at first, so go ahead and do that—you'll probably want to set up the same admin/password as your primary router to avoid confusion. Once you're in, your setup screen will look something like this, as my Micro setup on my Linksys appears:
First up, click on the Wireless tab, then choose Basic Settings. Switch "Wireless Mode" to "Repeater," and the "Wireless Network Name" to the same as the main router you're going to be re-broadcasting. Don't worry about the bridged/unbridged radio buttons—they'll set themselves later. Hit the "Save" button at the very bottom, but do not hit "Apply Settings" just yet.
In the "Virtual Interfaces" section, below that main "Wireless Physical Interfaces" section you just modified, hit the "Add" button, then enter a new name for your repeater—don't use the same as your router, or else suffer the wrath of confused devices. Adding "Repeater" or "2" to the end of your main router's name is pretty sensible in most cases. If you prefer an access point that doesn't broadcast its name, save that for switching off later—while we're testing our repeater, we'll be using basic settings to make sure the connection goes through. Hit the "Save" button at the bottom again.
With the main Wireless tab still selected, head to the "Wireless Security" sub-tab to the right. You'll see two interfaces again—a "Physical Interface" and a "Virtual Interface." In the "Physical Interface" section at the top, fill in the same exact security settings as your primary router—the security mode, the algorithm (TKIP or AES, generally), and the password any device would use to connect. You might need to jump back into your primary router settings to confirm these—that's fine, but do so from another device. Under the "Virtual Interface" section, set up the same exact security settings as your primary router, again. Hit the "Save" key at very bottom again and, again, avoid "Apply Settings" for the moment.
Jump over to the Setup tab at the very top, then scroll down to the Network Setup section under Basic Setup. The main thing to do here is slightly alter the "Local IP Address" from what your primary router is. If you connect to your main router at 192.168.1.1, for example, set this repeater router to something like 192.168.2.1, or another number that you can remember in the second-to-last position. Hit (you guessed it!) Save.
Finally, head to the Security tab up top, and in the Firewall section, disable the "SPI Firewall," and un-check everything under the "Block WAN Requests," except "Filter Multicast." Hit "Save" at the bottom one last time. Finally, head over to Administration, double-check that you've got your administrator password written down or remembered, and hit "Apply Settings" at the very bottom. Your router will reset itself now, so give it time to do so.
Unplug your computer's Ethernet cable, turn on a wireless device, and see if you can find your new repeater bridge. Connect to it, use the same password you'd use for the main router, and you should have success. If not, run through the steps and double-check your settings. DD-WRT's wiki page for WLAN Repeaters has a good deal of troubleshooting advice, so check there too.
You've now got a second Wi-Fi station in your house that picks up signal from the main router and offers it out to devices that are farther out. It's likely not as fast a connection between devices—it's wireless G, in most cases, as opposed to N. Then again, at this point, there are very, very few services or streaming applications that make full use of Wireless N's crazy bandwidth potential, so your Hulu streaming, web browsing, and other usual internet life will likely be unaffected.
In my own case, my wife and I don't have to use modern-day divining tricks in our very non-linear Victorian home to keep a spotty Wi-Fi signal to an iPod touch or Android phone, and a side patio has just become a preferred secondary home office for the summer. As a bonus, my closest neighbors now know that I'm a serious, serious nerd when they fire up their laptops. Here's hoping you find similarly fun and free uses for a Wi-Fi repeater.