Jack Diamond, front left, in the “Jack Diamond Morning Show” studio. (Lisa Anne)

On summer evenings in his early 20s, worried by the challenges of adulthood, Christian Hamaker would slip outside, pop a cigar in his mouth and switch on his Walkman radio.

He’d turn the dial to the D.C.-based channel Mix 107.3. He’d clear his mind. He’d stroll through his neighborhood in Vienna for an hour or so, puffing and listening.

“When you’re at that stage of life, [and] I was single at that time, you’re thinking about, ‘What’s next for me? Am I ever going to get married?’” Hamaker said. “So I’d listen to a lot of radio, a lot of Mix 107.3. They’d play a lot of love songs, get you thinking about marriage.”

Hamaker married a few years later — now 48, he has a wife and four children — and, pretty soon, he stopped taking nighttime neighborhood walks (ditto for smoking cigars). But he never stopped listening to Mix 107.3. Hamaker kept tuning in to the station, which offered adult contemporary music and a morning talk show, the “Jack Diamond Morning Show,” right up until its last airing on May 31.

A Washington-area staple, Mix 107.3 last month ended its 30-year run to make way for a national Christian program piped in from Rocklin , Calif. Long time radio programmer Steve Allan, who has worked in the industry — including several stints in D.C. — for over three decades, called the station a “legendary set of call letters ” and said its demise marks the end of an era.

Educational Media Foundation, a nonprofit more commonly known as K-LOVE that broadcasts contemporary Christian music, took Mix 107.3 off the air a few months after it bought the channel from longtime owner Cumulus Media Inc. K-LOVE paid Cumulus $103.5 million for Mix 107.3 and five other stations.

Joseph Miller, the vice president of signal development at K-LOVE, said his company has been looking to buy a station in D.C. for at least 10 years. He said K-LOVE purchased Mix 107.3, “one of the best signals in Washington,” in a bid to “reach as many people as we can.” K-LOVE never considered keeping Diamond’s show , he said.

“That was a decision made at a corporate level from the company buying us — the goal wasn’t to continue to employ local people, have local personalities,” said Jack Diamond, the titular host of the show who was born in D.C. and has lived in the area almost his entire life. “We continued doing the very best we could for every single listener listening until the very last day.”

Alan Burns, a radio consultant for 34 years, predicts the replacement Christian station will draw listeners.

“There’s a wide spectrum of people who listen to Christian music, but the plurality is women between the ages of about 35 and 54, and the D.C. area is rich in that market,” he said. “Washington is one of the largest markets in the country.”

For now, though, some are struggling to process the change.

University of Virginia student Cara McClure, 19, said she still has Mix 107.3 programmed as a set station in her car. Driving to and from school and to the pool where she works as a lifeguard, she sometimes forgets the “Jack Diamond Show” ended and “reflexively” hits the button.

“Then it’s gospel music and it makes me so sad,” McClure said. “[Mix 107.3] was around for a while, everybody knew it; when my friends found out it was gone, everyone was really upset.”

McClure said she started listening to Mix 107.3 as a child growing up in Darnestown, Md. Before she earned her driver’s license, her parents played the station — and, after she got behind the wheel, Mix 107.3 was her go-to.

McClure said she listened to the station for its “versatile” music selection and because she enjoyed Diamond’s chatter in the mornings. In her later teens, she loved it for another reason: Whenever Jack Diamond’s voice sounded in the car, McClure could close her eyes and picture herself, a kid again, riding inside her mother’s navy blue Mazda to gymnastics practice.

“It made me feel sentimental, happy, safe,” McClure said of the station.

Sonora Bostian-Posner, who grew up in Leesburg, also said Mix 107.3 allowed her to relive childhood. Bostian-Posner, 33, said the show conjured summer drives to a favorite fishing lake. She remembered sitting on the maroon seats of her mother’s car as her parents navigated, listening to the station and feeling pure “contentment.”

Bostian-Posner, now a resident of Arlington, said she will miss Diamond’s personality.

“Those memories associated with it are more than just music, it was also the intros and outros of the station,” she said. “It’s sad — that personal element is going away.”

Diamond said he tried to ensure his show remained relevant to local listeners. After working inside the studio from 5:30 a.m. to roughly 1 p.m. every day, he would head outside — equipped with his iPhone “Notes” app — and jot down events or people that struck him: overpriced avocados in the supermarket, a stranger’s decision to help an unknown woman cross the street, or a perfectly blue sky.

If something resonated with him, Diamond reasoned, it might interest his audience.

“The whole day, those things that you had an emotional reaction to would be those things you would talk about the next day on the air,” he said. “A really important component was to get out of the building, walk the streets, go to lunch, talk to your friends and family — just see what was going on.

“Go live your off-air life,” he added.

Diamond, who began working part-time radio gigs in the D.C. area at 14 and scored his first job as a full-time radio show host at 16, wants to keep doing what he loves in the city he loves. He hopes to relaunch the “Jack Diamond Morning Show,” staffed by the same four people including his wife, Lisa Anne, on another local station.

That may be difficult. Burns said Diamond’s kind of show — locally focused, helmed by someone with deep roots in the region he covers — is on its way out. Many radio stations are converting to national formats, Burns said — programs, like K-LOVE’s Christian station, that are broadcast from a single site to scores of towns across America.

“There’s more and more national syndication and national networking and operation of radio stations remotely,” Burns said. “It’s profitable, it saves money, you can produce it once and distribute it many times.”

P. Kenneth Burns (no relation to Alan Burns), a longtime listener of Mix 107.3 who grew up in Adelphi, Md., said he is willing to give K-LOVE’s national programming a chance. But he called the loss of Diamond’s banter and know-how devastating.

As a teenager, P. Kenneth Burns would descend to his basement bedroom every Saturday evening and blast Mix 107.3 — the station offered a “retro Saturday night disco playlist” — while playing video games. He said it was the “ultimate teenage boy’s paradise.”

Even after P. Kenneth Burns, now 38, moved away (he now lives in New Jersey), he kept listening to Diamond. Whenever he drove back to Maryland to visit family, he would flip, at some point, to Mix 107.3.

“Now, when I go home to Maryland, I will not have comfort, knowing that, when I turn on 107.3, there’s no Jack, there’s no Mix,” P. Kenneth Burns said. “Jack Diamond is not there — and just having a familiar presence on the radio, even as the world changes around us . . . I will miss that.”