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.
Five athletics world records were broken in Beijing (three by Usain Bolt) but only seven were broken at the previous four Games. The oldest track and field record still standing belongs to Jarmila KratochvÃ­lovÃ¡ from what was then Czechoslovakia, who set the 800m mark back in July 1983.