This document discusses various applications of ham radio. It begins by defining ham radio as a hobby where operators can communicate across long distances without the internet or cell phones by using radio frequencies allocated by the FCC. It then discusses how ham radio is used for emergency communication when other forms of communication fail during disasters. Several digital applications of ham radio are also outlined, including Automatic Packet Reporting System (APRS) for tracking locations, packet radio, Software-Defined Radio (SDR), amateur radio high altitude ballooning, D-STAR digital voice/data protocol, and using ham radio to access the internet. The document provides examples of ham radio use in space, agriculture, and during various emergency situations.