In 1973, the Citizens Band radio (aka the CB radio, aka a collection of short-distance radio communications) grew so popular that it attracted millions of people throughout the entire decade — not at all unlike the way social media attracts users today. This weekend, ’70s on 7 pays tribute to the fad by welcoming American country singer C.W. McCall, who is best known for his ’75 chart topper, Convoy, a hit song Rolling Stone recently included in its 100 Greatest Country Songs Of All Time list. On writing Convoy, McCall reminisced: “When we wrote the song, we went out and...