Building an inexpensive 802.11 (AirPort) repeater; boosting your signal strength

Building a wireless 802.11 repeater device in your own home can save some money, but will cost some time and obviously not carry the same reliability as a store-bought product. For those adventurous enough to try, there are some viable options.

First, it is important to note that a from-scratch 802.11 repeater might work but it would likely not be FCC accepted and might cause interference to other people or services, which could pose legal ramifications among other problems.

Borrowing from the radio industry, one option that may work to extend AirPort is signals is a "leaky coax". Leaky coax antennas are used to cover an area with radio signals, but it keeps them fairly local. Leaky coax is often used in mines and hospitals for radio contact were normal antennas would not work. You could make your own for an AirPort network without even connecting it to any ports. Using any sealed copper wire, wrap a few turns around the AirPort base station and then run the wire to where you need the signal to get to. The more wraps the better. It could also be laid beneath the airport base as this would interfere with the regular operation of the Airport and would look better as well. By inductance some of the signal will be sent down the wire and travel to the end, getting signals into places that might be hard to cover. Signals would also be returned to the airport base the same way.

The benefits of this workaround are that it is very cheap to do, and the equipment is not being permanently modified. Remember to use a plastic covered wire and keep it away from power sources. Do not use a shielded wire such as coax, it is designed to keep RF signals in the line and outside RF signals out of the coax and simply will not work. Any single conductor, plastic coated copper wire will work.

In the MacFixIt Forums, poster "imkim" notes two sources of 2.4 GHz antennas:

• General purpose: http://www.hdcom.com/2.4ghzantennas.html
• A blade antenna that can attach to the laptop: http://www.hyperlinktech.com/web/re05e.php

Michael Oh, the WiFi Admin at NewburyOpen.net notes that you can use an 802.11 bridge and access point, such as the Linksys WET11 and Apple Airport or Linksys AP (together US $ 300). He writes:

"We use them to run our free Wi-Fi network and details on how to configure are available in our downloadable Tech Specs."

Feedback on this issue? Drop us a line at late-breakers@macfixit.com.

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