Ham radio, also known as amateur radio, is a form of communication using radio waves that allows individuals to communicate with each other across distances using a variety of frequencies, power levels, and modulation techniques. Ham radio operators, or "hams," use radios to communicate with other hams for a variety of reasons, including personal enjoyment, emergency communication, experimentation, and community service.

The history of ham radio can be traced back to the late 19th century, when radio technology was first being developed. In the early days of radio, wireless telegraphy was used primarily for commercial purposes, such as ship-to-shore communication and the transmission of news and weather reports. However, as the technology developed, hobbyists began experimenting with radio equipment to communicate with each other over longer distances.

The first known use of the term "ham" to refer to amateur radio operators dates back to the early 20th century. At the time, many professional telegraphers considered amateur radio operators to be unskilled and incompetent, and referred to them as "ham-fisted" or "ham-handed." However, the term was eventually adopted by the amateur radio community and is now used as a badge of honor among hams.

Ham radio played an important role during World War I, as amateur radio operators were recruited to help with communications and intercepting enemy transmissions. Following the war, the popularity of ham radio grew rapidly, as more and more people became interested in the hobby. The first amateur radio license in the United States was issued in 1912, and by the 1920s, there were tens of thousands of licensed hams around the world.

During the 1930s and 1940s, ham radio operators continued to play an important role in emergency communication and disaster response efforts, particularly during natural disasters such as hurricanes and earthquakes. Hams also used their radios to communicate with friends and family members around the world, and to experiment with new technology and techniques.

In the decades following World War II, the popularity of ham radio continued to grow, and new advancements in technology allowed hams to communicate over longer distances and on a wider range of frequencies. However, the rise of television and other forms of entertainment in the 1950s and 1960s led to a decline in the popularity of ham radio.

Despite this decline, ham radio remains a popular hobby around the world, with millions of licensed hams operating in over 200 countries. In addition to providing a fun and rewarding hobby for enthusiasts, ham radio continues to play an important role in emergency communication and disaster response efforts, and is often used by hams to provide community service and support local organizations and events.