Same Router, Extreme Power
Francis D'sa | 22 June 2010
Same Router, Extreme Power
You can use alternative firmware to increase the transmission power of your router and ensure a longer range. CHIP shows you how to use DD-WRT.
By Francis D'Sa
You’re constantly frustrated while surfing over a wireless network because your wi-fi range is simply too low. Signals are weak, and connections either constantly break off or can’t be established in the first place. You’ve tried tweaking all possible settings and changing the router’s position, but it just won’t satisfy your needs. What do you do? Get a new router with longer antennae, or add multiple access points, which would burn holes into your wallet?
You can choose to replace the router’s firmware (its operating system and configuration options) with a third-party, unsupported version. One open source option is called dd-wrt. It’s free and you can use it to increase transmission power and thus, the range of certain wi-fi routers over and above their default available values. Dd-wrt can help increase your router’s capabilities and revive an old failing router by infiusing it with additional uses.
Apart from the option of boosting the transmission power, the extendable dd-wrt linux firmware system offers a host of cool functions, such as running servers and clients for various functions, control via ssh commands, file transfer protocols (ftp) and smb hosting, and also the option of switching on your home pc using its wake-on-lan feature (wol) from the internet and then accessing files on it from wherever you are. Moreover, you have a server and client for openvpn on board, which you can use to configure a virtual, encrypted link between multiple computers on the internet.
In this workshop, the router we'll be using is a linksys wrt54gl with hardware revision 1.1. The wrt54gl is an 802.11 b/g router and cannot match up to the high range of modern routers, which use the new n standard. The radio network barely manages a 30-meter range when used indoors. Its default signal strength amounts to roughly -74 dbm. At times, the wi-fi signal is still detectable at 40 meters with -80 dbm, but surfing becomes impossible. Although the embedded (original) firmware from linksys offers numerous setting options, the transmission power cannot be increased.
Important note: if you download an inappropriate firmware version or make a mistake during the installation, the router may quickly and irreparably be damaged. It is very important that you look precisely for your router’s model number on the ‘www.dd-wrt.com’ website in the ‘router database’ section, inclusive of the correct hardware revision. There are precise installation instructions for every supported model on the ‘www.dd-wrt.com/wiki’ website, which you'll need to follow without errors. Even if the firmware upgrade works, the increase in transmission power will increase operating temperatures, which can affect the life of the router. Added tweaking of the router might be required to help cool it. Also note that the firmware replacement procedure is irreversible and will certainly void any warranty. Do this at your own risk.
Step 1: the firmware
Go to the website ‘www.dd-wrt.com’, click on the ‘router database’ and look for ‘wrt54gl’ (in your case, look for the model number of your router). Download the file ‘dd-wrt.v24_mini_generic.bin’ and save it on the desktop.
Step 2: disconnecting
Before installing the new firmware, detach all lan cables from the router, except for the lan cable of the pc that has the firmware file that you have just downloaded. Also disconnect any devices connected via wi-fi.
Step 3: hard reset
You will now need to hard-reset the router using the physical reset button located on its rear panel. You might require a pin as the reset switch is usually hidden inside the chassis and only a tiny hole is provided to reach it. Check your instruction manual if you cannot locate the reset button. You will need to keep the reset button pressed for at least 90 seconds for the complete hard-reset. Now carefully read these instructions before actually starting the procedure: pull out the power connector after the first 30 seconds, wait for another 30 seconds and re-connect the power again. After another 30 seconds, release the reset button. If you have made any mistakes during this procedure, repeat the whole step.
Step 4: flashing
Now that you have completely reset the router, it is time to start configuring the router. To do this, you will need to open your web browser and enter the address ‘http://192.168.1.1’ and press [enter].
Note: certain routers have a different default ip address. Make sure you have your user manual at your disposal.
Once inside, go to the firmware section and select ‘upgrade’. Browse and select the downloaded firmware file from your desktop (in our case it is the ‘dd-wrt.v24_mini_generic.bin’ file). Click on the upgrade button. Once the process completes, restart the router.
Step 5: configuring
You are almost there. Before you start the dd-wrt configuration, you will need to repeat the hard-reset procedure described in step 4. Once completely done, enter the configuration page of the router using the above ip address in the web browser. Firstly, assign a username and a strong secure password for the router before you proceed into any other configuration steps. Then safeguard your network with a wpa2 key under ‘wireless’ so nobody can intrude into your router at this time as your network is presently in an open state and can be easily hacked.
Step 6: tweaking
Now you can connect all the lan cables again. Configure your router as per your requirements. You can increase the specified value in the ‘tx power’ field under ‘wireless | advanced settings’ from around 71 mw to a higher value in small steps. Up to 100 mw is allowed by default, even though you can boost it to more than 200 mw with further tweaking. But be careful; increasing this value will force your router’s components to run at higher power levels, thus producing more heat, which could damage them permanently. Hence, increase these values gradually and stop when they are just about enough to serve your needs. If you increase the power more than you need, you also run the risk of boosting the wi-fi range enough for others in the vicinity to hook on to it. Trust us; you don’t want that to happen.
Now that you have successfully upgraded your router with the dd-wrt firmware, you have opened up a treasure chest of settings and features that were previously hidden. Browse through the features and enable any that you might want.