Researcher Ermanno Pietrosemoli has set what appears to be a new record for the longest communication link with Wi-Fi.
Pietrosemoli, president of the Escuela Latinoamerica de Redes (which means networking school of Latin America) established a Wi-Fi link between two computers located in El Aguila and Platillon Mountain, Venezuela. That's a distance of 382 kilometers, or 238 miles. He used technology from Intel, which is concocting its own long-range Wi-Fi equipment, and some off-the-shelf parts. Pietrosemoli gets about 3 megabits per second in each direction on his long-range connections.
Most Wi-Fi signals only go only a few meters before petering out. Conventional Wi-Fi transmitters, however, send signals in all directions. By directing the signal to a specific point, range can be increased.
Honing the signal, however, means that the receiver and transmitter have to be aligned. Trees, buildings and other objects that get between them can sever the link. The curvature of Earth, misalignment between the transmitter and receiver, as well as shaking and any sort of movement at the transmitting or receiving end can also impair the signal. (To ameliorate some of these factors, Intel has created a way to electrically steer the signal, which in turn increases bandwidth.)
Geography was on Pietrosemoli's side. El Aguila and Platillon Mountain sit in the Andes, which form fairly jagged peaks in this part of the range.
The old record was 310 kilometers. Swedish scientists made a link between a balloon and an Earth-bound station. We say "apparently" on Pietrosemoli's record, in case someone out there has set a better record about which we are unaware.
More details can be found in an article at the Web site for The Association for Progressive Communcations. (Inveneo, which is trying to bring PCs to emerging markets, told us about Pietrosemoli's achievement.)
Intel, along with organizations like Inveneo, are testing the feasibility of long-range Wi-Fi as a communication link in Uganda and other emerging nations. Long-range Wi-Fi isn't as robust at WiMax, but the towers cost a lot less. Some hobbyists have accomplished a long-range Wi-Fi connection with low bandwidth.
Similar experiments are being carried out in the United States as well. A long-range Wi-Fi link connects Intel Research's Berkeley Lab and a Sun Microsystems lab on the San Francisco Peninsula, more than 20 miles away.