The squat, bland, concrete-block building on a side street in St. Louis Park looks like it could be a meat locker, an auto parts warehouse or a CIA safe house hidden in plain sight.

But step inside, and it hits you like Morse Code hitting a Marconi coherer: This place is nerd heaven.

In the dim, cavernous interior of the Pavek Museum of Broadcasting, the history of radio and TV is laid out in all its scientific rigor and showbiz glamour. The technically minded can geek out on circuits, amplifiers and tuners; the celebrity-hungry can take in publicity shots of early Twin Cities TV stars, bathed in the soft glow of neon signs spelling out the call letters of broadcast stations. And everyone can enjoy radio and TV shows that range from Warren Harding to Roundhouse Rodney.

In an age when we carry supercomputers in our pocket or purse, the Pavek reminds us how we unlocked the secrets making that possible. In farmhouses and industrial laboratories, by accident and by design, brilliant scientists and regular tinkerers more than a century ago discovered how to beam sound and light through the air.

And life would never be the same. For the first time, the world could be instantly brought to the individual.

During the 20th century, radio and television helped transform America from a collection of far-flung regions to a nation knit together with a common culture. The Pavek museum is jammed with broadcasting artifacts that tell the story.

Radios and tubes line the walls. TVs, microphones and phonographs vie for floor space with build-your-own radio kits and commemorative ashtrays. In one corner is a camera crane used to broadcast the 1952 political conventions that introduced Walter Cronkite to America and coined the term “anchorman.” In another is the early tape deck used by Bing Crosby in the 1940s to prerecord his radio program — and create the first laugh track.

More than 100,000 students have visited the museum since it opened in 1988, learning about broadcasting and recording their own programs. On a recent visit, a group of grade-schoolers listened to a scratchy Edison cylinder recording and squealed with more delight than you’d ever expect to hear from kids raised on 3-D Imax movies.

And it all started with a hardware salesman from Hopkins.

Pacemaker inspired by radio

Joe Pavek sold nuts and bolts throughout the Midwest after World War II. His work brought him to hundreds of small towns, where he had time to poke around in search of old radios and parts. Over the years, his collection of broadcasting memorabilia began to overwhelm his ability to store and care for it. As Pavek aged, he began looking for an “angel” who could ensure that his collection lived on.

An angel did appear — one whose early love of radio led to an inventing career that saved countless lives.

Earl Bakken built his first crystal radio when he was 8 years old. “When my parents thought I was sleeping, I was actually listening to ‘Lights Out’ [an early radio suspense show],” said Bakken, now 91, by phone from his Hawaii home. “All through high school, I was madly searching for radio books.”

When Bakken joined the military during World War II, “I told them I had gotten a radiotelephone license when I was 17 years old, and they said, ‘Good — you’re a radar instructor,’ ” he chuckled. Bakken spent the war teaching bomber pilots and crews about radar. After the war, he graduated from the University of Minnesota and began servicing medical devices at the university hospital. He called his company Medtronic.

In 1957, a power outage at the hospital resulted in the death of a young heart patient on a pacemaker. Dr. C. Walton Lillehei asked Bakken if he could build a battery-powered pacemaker. Bakken turned to his collection of radio magazines to learn more about then-new transistorized circuits. A month later, he delivered his first pacemaker. Bakken’s invention freed patients from the need to be plugged into a wall socket and led to today’s pacemakers, which can be as small as a vitamin pill. About 600,000 people get a pacemaker every year, according to the American Heart Association.

“All of this came from my work in radio,” Bakken said. He helped create the museum from Pavek’s collection and has been a generous supporter ever since. It’s at his urging that the museum has made youth education a major focus.

“Getting kids interested in radio at a young age gives them something to work toward that may lead them to very advanced electronics,” Bakken said.

‘A sanctuary of moments’

The names of the old radios lining the walls at the Pavek Museum evoke a sense of wonder. There’s the Gilfillan Neutrodyne. The Cleratone. The Aeriola, the Radiotron, the Inverse-Duplex. Their shiny dials, flickering lights and humming tubes are the precursors of the Web videos we stream today. In the 1920s and 1930s, the Twin Cities had a thriving radio manufacturing industry. More than 60 radio makers were headquartered here, with St. Paul’s University Avenue as the hub.

Steve Raymer has been managing director of the Pavek since the beginning. Asked how the museum can retain its relevance in the Internet era, he paused for a moment.

“With any collection and any collector, it starts off just because they like the stuff,” he said. “And then as it grows, you start looking for a justification. For me, it’s a sanctuary. It’s a sanctuary of moments and time. And it’s a place to come to get some grounding.”

Danny Henry, the museum’s audio/video manager, said it represents “how far we’ve come in a short amount of time. For me, it’s a way to piece together history.”

This weekend, radio fans from throughout the Midwest and Canada will descend on the Pavek to get a piece of that history. On Friday and Saturday, the museum is having a garage sale, disposing of some of its excess inventory. Radios, tape decks, projectors, magazines, posters and other memorabilia will be sold off.

Bakken won’t be among the crowd. He doesn’t travel much anymore. But he’ll be there in spirit.

“There are just so many people who are interested in not just using their iPhones,” he said. “This is still an area that is of great interest. It’s still there.”