Let’s face it. PBS is never going to produce an “American Masters” documentary on The Grateful Dead. But personal essays like “Box of Rain,” movies about the fan experience, the phenomenon of the “family” — their tribal, migrant fanbase — point to a serious blindspot on the Brit soap opera-obsessed Public Broadcasting Service.

If Deadheads aren’t an “American Experience” waiting to be remembered, I don’t know what is.

Lonnie Frazier’s “Box of Rain” isn’t definitive. It doesn’t have Grateful Dead music or concert footage in it. There’s a Dead-ish twangy score that could have been made by “the family” in “the parking lot scene,” the musical street fair/festival/market fans nicknamed “Shakedown Street.” She and her interview subjects skate past the druggy nature of the culture, underplaying it to a disingenuous degree. And they downplay the tragedies at Dead shows. More than a few concerts were marred by fan deaths.

But this warm, embracing little film — catching up with old friends from “the road,” remembering epic road trips following the band, chatting with other, even-more-devoted fans and even the director of another Deadhead documentary — vividly creates a sense of the community that the band inspired, with its own economy, values and shared creed.

“I Need a Miracle,” aka “Who’s got tickets to the next show?”

Frazier personalizes the Dead by saying her first show, an ’80s cross-country trek as a teen in her Chevette, “saved my life.” A victim of gang-rape, she’d figured out the small town in Maryland where she grew up was “not my home.” At a Dead concert at Red Rocks in Colorado, she found a new one.

Frazier and her friends found themselves in the ongoing cosplay counterculture of the 1980s, a world that was “the opposite” of that “Valley Girl, big hair Reaganomics” era. Here was Woodstock — tie-dyed, turned-on and dropped-out and touring — sometimes taking over for several shows cities and towns all across America in the middle of the “Greed is Good” decade.

“The worst day on tour still beats the best day at work,” one fellow traveler enthuses. They’d pile into colorfully-decorated VW Microbuses, camp out and live hand to mouth for days, weeks or months on end, traveling from venue to venue because this “electric Dixieland” “jam band” never put on the same show twice, never played a song the same way twice. Before the concert began, and after it ended, the parking lot “Shakedown Street” (a Dead tune) kept the musical/fraternal good times going.

Here’s wheelchair-bound James LeBrecht, seen in the documentary “Crip Camp,” marveling at the acceptance, the pre-Americans with Disabilities Act wheelchair-access (handmade ramps and platforms built by fans and the crew).

Filmmaker Brian O’Donnell, who filmed his own years-in-the-making Dead-and-their-fans-on-tour documentary, is leaned on to categorize the fanbase. There were “The spinners,” dancers in the audience who twirled through shows “like whirling dervishes,” first song to last, “the tapers” who’d use band-provided audio feeds to cassette-record every show, “the listers,” fans who kept meticulous set lists of every concert, and so on.

Older fans demonstrate the dervish spinning thing with tie-dyed capes. Others recall that one “magic” moment or concert that distilled the experience for them.

“The music of life,” one aficionado calls their jams, because “life is improvisational.”

Not having access to the Dead’s music seriously undercuts the motivation for this devotion. But there’s a four hour Netflix “Long Strange Trip” doc, and others, to cover that.

There’s a chuckling admission that sometimes shows were musical “trainwrecks” due to the nature of the improvisations that they built their shows on, or in my case — a terrible sound mix at the Minneapolis Metrodome.

And there’s recognition that after the band’s “Touch of Grey” Top 40 hit, a rougher, dumber and more drunken element started filling the shows, suggesting that the best days had passed.

“We got to see America” following the tours, one fan says, “the good, the bad and the ugly.”

But there’s no denying the cultural phenomenon that developed around the Dead, one of almost cultlike devotion, with priorities out of step with the rest of society.

I got my first job in media because the other top candidate — my fellow summer intern at a public TV station — told our supervisors he’d “pass” on the gig because “I’m hitting the road with the Dead.”

Our long-haired bosses looked genuinely disappointed — at not being free enough to go along with him, at having to give the job to somebody who wasn’t willing to take similar risks for what “Box of Rain” reveals was a youthful adventure-of-a-lifetime experience.

Movies like “Box of Rain” and the Rick Springfield fan doc “An Affair of the Heart” may not give us the complete experience, sharing the music that so enchants fans that they devote huge chunks of their lives to the performer and the concert experience provided.

But the Deadheads were the generation-defining inventors of this long-term phenomenon. Without Deadheads, there are no Parrotheads, or Phish Heads. Without Deadhead stickers, a VW van is just an antique.

In or out of the tribe, Deadheads were every bit as emblematic of the American Experience of the ’80s as pastel suits and trickle down economics. “Box of Rain” might be too narrow in focus to pass broadcast muster, but PBS should consider this a gauntlet-thrown, and this time the glove is florescent and tie-dyed.

Rating: unrated

Cast: Elizabeth Abel-Talbott, Kelley L. Condon, Brian O’Donnell, James LeBrecht, Joey Talley, Tim Zecha and Lonnie Frazier

Credits: Directed and narrated by Lonnie Frazier. A Mutiny release.

Running time: 1:18