Besides the fun of assembling and operating communications equipment, and making friends around campus as well as around the world, there are practical benefits. Engineering, computer, and physics projects can be designed to take advantage of the privileges, services, and equipment available to hams. Future teachers can include their ham abilities to effectively engage students in subjects of language, geography, astronomy, history, political science, and more. Hams may design, build, modify, and operate their own equipment. Hams may use earth based and orbiting signal repeaters.
Signals bounce between the earth's ionospheric layers.
Sunspot cycle, solar activity, and the time of day and year, all contribute, although differently, to the propagation on each particular band. VHF signals are also bounced off meteor trails during meteor showers, aurora, the moon, and orbiting links or to other frequency bands, including short waves. Global communication from a hand-held transceiver is possible. The UHF bands are not as crowded. Experimenters and TV operators are found here more than on other bands.