The above description is the basic idea of what is going on with the Yagi-Uda antenna. Yagi antenna design is done most often via measurements, and sometimes computer simulations. For instance, let's look at a two-element Yagi antenna (1 reflector, 1 feed element, 0 directors).
Though there are no detailed records of when the sport of track and field began, experts say that track and field history can be traced back to 776 B.C. Track and Field History Experts say that track and field history can be traced back to 776 B.C when a cook named Koroibos, from Elis, won a race that was run over 600 feet distance. It is believed that this was the only athletic event for the initial 13 Olympic Games.
Like running, it can take place on a track or as a road race. The main competitions take place at the Summer Paralympics which wheelchair racing and athletics has been a part of since 1960. Competitors compete in specialized wheelchairs which allow the athletes to reach speeds of 30 km/h or more.