CASE HISTORY
Title Example 01in Venezuela
Although this Case Study is several years old now, we have left it in this version of the book as it still to this day is the longest ever successful point to point outdoor 802.11 test. Here you will find the pioneering work of those who are still authoring this book. And in fact some of the preparation work involved in the setup of this test is still relevant for those planning long distance outdoor links. Enjoy reading!
BACKGROUND

Thanks to a favourable topography, Venezuela already had some long range WLAN links, like the 70 km long operated by Fundacite Mérida between Pico Espejo and Canagua. To test the limits of the WiFi technology, it is necessary to find a path with an unobstructed line of sight and a clearance of at least 60% of the first Fresnel zone.

While looking at the terrain in Venezuela, in search of a stretch with high elevation at the ends and low ground in between, I first focused in the Guayana region. Although plenty of high grounds are to be found, in particular the famous "tepuys" (tall mesas with steep walls), there were always obstacles in the middle ground. My attention shifted to the Andes, whose steep slopes (rising abruptly from the plains) proved adequate for the task. For several years, I have been travelling through sparsely populated areas due to my passion for mountain biking. In the back of my head, I kept a record of the suitability of different spots for long distance communications. Pico del Aguila is an outstanding place for long distance communication. It has an altitude of 4100 m and is about a two hour drive from my home town of Mérida. For the other end, I finally located the town of El Baúl, in Cojedes State. Using the free software Radio Mobile

Image Description - Guatemala FIG.02

Thanks to a favourable topography, Venezuela already had some long range WLAN links, like the 70 km long operated by Fundacite Mérida between Pico Espejo and Canagua. To test the limits of the WiFi technology, it is necessary to find a path with an unobstructed line of sight and a clearance of at least 60% of the first Fresnel zone.

While looking at the terrain in Venezuela, in search of a stretch with high elevation at the ends and low ground in between, I first focused in the Guayana region. Although plenty of high grounds are to be found, in particular the famous "tepuys" (tall mesas with steep walls), there were always obstacles in the middle ground. My attention shifted to the Andes, whose steep slopes (rising abruptly from the plains) proved adequate for the task. For several years, I have been travelling through sparsely populated areas due to my passion for mountain biking. In the back of my head, I kept a record of the suitability of different spots for long distance communications. Pico del Aguila is an outstanding place for long distance communication. It has an altitude of 4100 m and is about a two hour drive from my home town of Mérida. For the other end, I finally located the town of El Baúl, in Cojedes State. Using the free software Radio Mobile

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Thanks to a favourable topography, Venezuela already had some long range WLAN links, like the 70 km long operated by Fundacite Mérida between Pico Espejo and Canagua. To test the limits of the WiFi technology, it is necessary to find a path with an unobstructed line of sight and a clearance of at least 60% of the first Fresnel zone.

While looking at the terrain in Venezuela, in search of a stretch with high elevation at the ends and low ground in between, I first focused in the Guayana region. Although plenty of high grounds are to be found, in particular the famous "tepuys" (tall mesas with steep walls), there were always obstacles in the middle ground. My attention shifted to the Andes, whose steep slopes (rising abruptly from the plains) proved adequate for the task. For several years, I have been travelling through sparsely populated areas due to my passion for mountain biking. In the back of my head, I kept a record of the suitability of different spots for long distance communications. Pico del Aguila is an outstanding place for long distance communication. It has an altitude of 4100 m and is about a two hour drive from my home town of Mérida. For the other end, I finally located the town of El Baúl, in Cojedes State. Using the free software Radio Mobile

The 2006 experiment was performed by Ermanno Pietrosemoli, Javier Triviño from EsLaRed, Carlo Fonda, and Gaya Fior from ICTP. With the help of Franco Bellarosa, Lourdes Pietrosemoli, and José Triviño. For the 2007 experiments, Dr. Eric Brewer from Berkeley University provided the wireless routers with the modified MAC for long distance, as well as enthusiastic support through his collaborator, Sonesh Surana. RedULA, CPTM, Dirección de Servicios ULA Universidad de los Andes and Fundacite Mérida contributed to this trial. The second experiment work was funded by Canada's IDRC. References: Fundación Escuela Latinoamericana de Redes, Latin American Networking School, http://www.eslared.org.ve/ Abdus Salam International Centre for Theoretical Physics, http://wireless.ictp.it/
OpenWRT Open Source firmware for Linksys - openwrt.org/ www.idrc.ca
Fundacite Mérida - www.fundacite-merida.gob.ve