shortwave radio, transmission and reception of information by means of electromagnetic waves about 10 to 80 m (33 to 262 feet) in length having frequencies of approximately 29.7 to 3.5 megahertz .
Read moreshortwave radio, transmission and reception of information by means of electromagnetic waves about 10 to 80 m (33 to 262 feet) in length having frequencies of approximately 29.7 to 3.5 megahertz .
Read more