Ham radio
Ham radio, also known as Amateur radio, is a hobby enjoyed by severalhundred thousand people in the United States and by over a million people worldwide. Amateur radio operators call themselves “radio hams” or simply”hams.”
To become a radio ham, you must pass an examination. Wirelessamateur communication is done on numerous bands (relatively narrow frequency segments)extending from 1.8 MHz (a wavelength of about 160 meters) upwards through several hundredgigahertz (wavelengths in the millimeter range). There are several license classes. The more privileges a class of license conveys, the more difficult is theexamination that one must pass to obtain it.
Amateur radio operation is fun, and that is one of the main reasons hamsdo it. But ham radio can provide communication during states of emergency. Hamradio works when all other services fail. After Hurricane Andrew struck SouthFlorida in 1992, the utility grid was destroyed over hundreds of square miles. Allcellular towers and antennas were blown down.
Ham is an informal term for an amateur radio operator, and, by extension, “ham radio” refers to amateur radio in general. This use of the word first appeared in the United States during the opening decade of the twentieth century .
Radio amateurs use various modes of transmission to communicate. Voice transmissions are most common, with some such as frequency modulation (FM) offering high quality audio, and others such as single sideband (SSB) offering more reliable communications when signals are marginal and bandwidth is restricted.
Radiotelegraphy using Morse code is an activity dating to the earliest days of radio. Technology has moved past the use of telegraphy in nearly all other communications, and a code test is no longer part of most national licensing exams for amateur or HAMradio.