How can I boost the wi-fi signal of the router?

Channel selection is very important. the wrong channel on your wireless router can cause you to pull you hair out thinking what cna be wrong with the wireless setup. Interference in the home is a real threat to your home Wi-Fi Metwork. Selecting the correct channel can asave you hours of grief.

The table below lists the ETSI specified frequencies and corresponding channel for European operation of Direct Sequence Spread Spectrum:

Channel No.    European Frequencies
1    2401 - 2423 MHz
2    2406 - 2428 MHz
3    2411 - 2433 MHz
4    2416 - 2438 MHz
5    2421 - 2443 MHz
6    2426 - 2448 MHz
7    2431 - 2453 MHz
8    2436 - 2458 MHz
9    2441 - 2463 MHz
10    2446 - 2468 MHz
11    2451 - 2473 MHz
12    2456 - 2478 MHz
13    2461 - 2483 MHz

Each Channel is 22 MHz wide and uses a 1 MHz carrier frequency. As you can see from the diagram, the channels are spaced at 5 MHz intervals.
e.g. Channel 1 operates from 2401-2.423 GHz

Out of the 13 Channels available in most European countries under the ETSI standard in the 2.4 GHz ISM band (which covers 802.11b and 802.11g) only 3 channels at any one time are unique. 1, 7, 13 (preferred) do not cross over at all against each others frequencies, and for this reason we tend to use these most as the preferred channels for transmissions.

Channels 2, 3, 4, 5, 6, 8, 9, 10, 11, 12 all overlap into other channels beside themselves, and this can cause interference to any other transmission signal.

Note: 1, 6, 11 are also unique, however for ETSI and this guide we will use 1, 7, 13 as they are the furthest apart as well.

When setting up your wireless network you should take into consideration other wireless Cells active in your area, and change SSID and Channels to accommodate you and your neighbours.

Further more there are also a few things to tweak your wireless router to get the best out of the signal without loosing connection.

Position the Router in the highest place possible. Don't put it in the basement this will affect wireless signal strength.

If your wireless devices are all 54G then if possible set your router to G only. if not set Wireless to B only (unless you have B and G devices) though B mode will give better signal than G

Adjusting the "RTS Threshold" can help alleviate Packet loss. If one of the Wireless computers can obtain an IP address but can not ping, then set the "RTS Threshold" to something lower. (no lower than 2304 though)

Adjusting the "Beacon Interval" can help association problems. If there is a wireless adapter that is able to see the access point, but is unable to get locked, try adjusting the "Beacon Interval" to 50

Adjusting the "Fragmentation Threshold" can help association problems. If there is a wireless adapter that is able to see the access point, but is unable to get locked, try adjusting the "Fragmentation Threshold" to something lower. (no lower than 2304 though)

If you have just one or two clients enabling frameburst will help. Make sure CTS is disabled. (WRT54G/GS only)

Also adding a Directional Antenna to your wireless PC's will help in reception. The DLink DWL-M60AT is a very good example of a Directional antenna that can be added to most Wireless PCI Network cards with easy and gives better reults than boosting a signal via a firmware upgrade.

WRT54G/GS and WAP54G ONLY

You can adjust the signal strength output of the routers. The default for most linksys Routers is 18mW. You can increase this drastically with upto a max of 251mW (outside use only)

Putting the transmission rate beyond 100mW is illegal in ETSI/FCC standards. 251mW is obtainable from the WRT54G chipset but this can affect your health. don't do this unless it is outside and you are broadcasting long distances. Also Heat is an issue of the radio chip set when putting the power up to 251mW, and the signal gets "dirty" and channels either side of the one you have slect can be affected.

One other thing:

The signal strength maybe adequate but the reception is the problem. You can sometimes gain better signal strength by adding a reflector than adding any bigger antennas.

For more information about making a reflector checkout this website.

Free Antennas

Here are is a short list on common causes of interference:

WINDOW IN BRICK WALL = 2dB

METAL FRAME, GLASS WALL INTO BUILDING = 6dB

OFFICE WALL = 6dB

METAL DOOR IN OFFICE WALL = 6dB

CINDER WALL = 4dB

METAL DOOR IN BRICK WALL = 12.4dB

BRICK WALL NEXT TO METAL DOOR = 3dB

Linksys suggests that you place your Access Point as high as possible. If your network goes through multiple floors, try to place the Access Point on the upper floor. If you want to connect while you're outside, place the AP near a window. Keep it away from large metal objects such as filing cabinets. Also, try to keep the AP's away from operating microwave ovens and 2.4GHz cordless phones. In addition, if you use 2.4 GHz phones and experience interference, try using a different channel on the phone.