WokFi

Lore & Background

WokFi antennas are fabricated from commonly available concave metal kitchen dishes or dish covers, which need not be perfectly parabolic; Asian woks are favored because their shapes are closest to parabolic. A commercial Wi-Fi antenna, usually a USB Wi-Fi dongle, is suspended in front of the dish and attached by cable to the computer. The design is considered simpler and cheaper than other home-built antenna projects such as the popular cantenna.

A significant advantage of the WokFi approach is that with a USB modem the RF signal is converted to a conventional digital signal at the antenna. By using standard USB extension cables, the antenna can be located five meters or more from the computer without concerns over microwave signal losses that would occur in an RF coaxial cable feedline of that length. Chaining active USB repeaters allows the antenna to be placed at much greater distances, useful when line-of-sight obstacles require rooftop placement.

The performance of low-powered Wi-Fi dongles (typically 30–40 mW transmitter power) can be boosted with little more than cheap cookware or pot lids. The 'sweet spot' on such ad hoc reflectors can be found by taping a small mirror on the dish surface to see where the sun's rays focus. Interference from nearby 2.4 GHz signals can be nulled out, a useful feature in crowded RF spectrum.

Reader's Guide

The WokFi antenna's significance lies in its extreme simplicity and low cost, enabling anyone with a USB Wi-Fi dongle and a metal kitchen dish to dramatically extend wireless range. Its legacy is as a grassroots, DIY solution that democratized long-range Wi-Fi access, particularly in situations where professional equipment is unavailable or unaffordable. By converting the RF signal to digital at the antenna via a USB dongle, it avoids the signal losses that plague long coaxial cable runs, and allows the antenna to be placed remotely using USB extension cables or repeaters. This makes it practical for overcoming line-of-sight obstacles like vegetation and walls by mounting the antenna on a roof. The WokFi concept also popularized the use of mesh reflectors (with grid under 5 mm) for lighter weight and reduced wind load. While not as precise as a commercial parabolic dish, its typical gain of 10+ dB and range of 3–5 km (or up to 20 km with larger satellite TV dishes) made it a viable tool for auditing coverage, establishing WLAN viability, and even point-to-point links approaching 10 km. The technique remains a notable example of frugal innovation in wireless networking.

Did You Know?

• WokFi is a portmanteau of 'wok' and 'Wi-Fi'.
• The sweet spot on the reflector can be found by taping a small mirror on the dish to see where the sun's rays focus.
• Using mesh reflectors with a grid under 5 mm makes the antenna lighter and reduces wind load.