From the early days of broadcasting a century ago, the business had its outlaws. They built radio stations in border towns just across the Rio Grande and cranked their signals far beyond the 50,000-watt limit mandated by the U.S. government. They filled the air with stemwinders, spellbinders, conspiracy theorists and purveyors of quack remedies.

North of the border, radio created mass culture. Suddenly everyone was dancing to the same music, falling for the same crooners, tuning in at the same hour to the same dramas and comedies and political speeches. The rewards were tremendous for those artists who colored inside the lines of public taste.

South of the border was the land of rebels, titillaters and scandalizers. John Romulus Brinkley, a medical charlatan of epic proportions, opened the first Mexican mega-station, call letters XER, across the river from Del Rio, Tex., in 1931. The million-watt signal was so strong it could be heard in the barbed wire of nearby ranch fences and as far away as Canada. Speaking for hours on end, Brinkley rambled about topics ranging from the federal government’s machinations against him to the value of goat testicles for treating sexual dysfunction. There was music — XER was country music’s incubator, hatching the likes of Jimmie Rodgers and the Carter family. There was wild, passionate Pentecostal preaching. There was peddling of sketchy merchandise, including, for a time, autographed photos of Jesus.

Most of all, there was a voice, hypnotic and compelling.

For Don Imus, outlaw radio was the best kind. As a young man in the early 1960s, Imus didn’t tune his receiver to some cookie-cutter Top 40 station playing a rote rotation of two-and-a-half-minute pop hits. He dialed in XERF, a direct descendant of Brinkley’s border blaster, where a charismatic broadcaster known as Wolfman Jack did his strange and edgy business. The Wolfman’s music was good, but his talk was the thing. He howled. He rasped. He said things Mom and Dad would not approve of, speaking to the entire body: ears, brain, spine, gut, libido.

Imus, who died Dec. 27, was a radio revolutionary. What he perceived, earlier than most, was that the rise of television during his adolescent years meant that domestic radio was going to lose its role as the maker and arbiter of mass culture. The time was ripe for the outlaws to cross the border and seize the U.S. airwaves.

During a career that filled a half-century, the I-man — as he was known to his broad following — applied the lessons of outlaw radio to the evolving technologies of modern communication. He made radio interesting; not like a seminar is interesting, but like a bank robbery is interesting. Like emergency surgery is interesting. Like climbing a cliff with no rope is interesting.

As practiced by Imus, previously mainstream broadcasting became dangerous: subversive, irreverent, defiant of norms and undermining of conventions. Through all those years of growling and rasping and mumbling, he broke every rule, written and unwritten. He swore on the air, mused about his genitals and asked female callers if they were naked. He trafficked in racial stereotypes and epithets. He spoke disrespectfully of authority figures. He got suspended, got reprimanded, got fired and got rich on his way to the Broadcasting Hall of Fame.

I knew Imus only a little and found him an unsettled, unsettling character. We met at his New Mexico ranch, years after he ended his monstrous romance with booze and cocaine. I was auditioning for the role of ghostwriter of a little essay in his wife’s vegan cookbook — not a natural assignment given my devotion to barbecue, bratwurst and Buffalo wings.

Directed to a seat across the table from the brooding, shaggy legend, I broke a long silence by saying that I shared his interest in country music. By way of reply, Imus snatched a remote from the table and powered up a deafening stereo. For the next half-hour, he switched from one old recording to the next, border-blaster music, challenging me to name each artist. Only after I successfully sorted Ernest Tubb from Faron Young from Ray Price from Marty Stuart did he soften his disdainful sneer, just a little. I got the gig.

It was abundantly clear he would have preferred to catch me in a phony lie, to expose my insincerity. The essence of outlaw radio as practiced by Imus, by Howard Stern, by Rush Limbaugh, by Art Bell is authenticity. A man — it’s always a man — sits at a microphone and bares his soul, his body, his lust, his fear, his paranoia, his insecurities, his resentments, his biases, his megalomania, his mean streak, his sentimental side. The revelation is different for each broadcaster, but whatever it is, it must be real — and the assay of authenticity is his willingness to go too far.

The I-man was always willing.

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