Mohammad Sharif Walid, BBC World Service presenter,
in the studio. Courtesy Mohammad Sharif Walid
OTTAWA, Ontario — With the advent of radio in the 20th century, the shortwave band (1710–30,000 kHz) soon became a hotbed of long-distance radio broadcasting. Used primarily by state-run international broadcasters, plus ham radio operators and ship-to-shore radio communications, the shortwave band was prized due to its astoundingly broad reach.
That reach was — and is still — made possible by the tendency of ground-based shortwave radio transmissions to bounce off the ionosphere and back to earth; allowing shortwave broadcasts to “hop” repeatedly, increasing a broadcast’s range while minimizing its decay. This writer once heard BBC World Service on 6175 kHz coming to him from both directions at once; a phenomenon proven by the “echo” he heard caused by the…
