Field Day is an annual amateur radio exercise sponsored by the American Radio Relay League which encourages emergency communications preparedness.

Since the first Field Day in 1933, Amateur radio operators throughout the United States have practiced the rapid deployment of radio communications equipment in environments ranging from operations under tents in remote areas to operations inside Emergency Operations Centers (E.O.C). Operations using emergency and alternative power sources are highly encouraged, since electricity and other public infrastructures are often among the first to fail during a natural disaster or severe weather.

To determine the effectiveness of the exercise and each participant's operations, there is an integrated contesting component.

In the Western Hemisphere the ARRL Field Day is held annually the fourth full weekend in June. The IARU Region 1 sponsors an Amateur Radio Field Day for Europe , and other national Amateur Radio societies sponsor them in other countries.
 

Early Arrivals.