SAN JOSE, Calif. — Walk into a nondescript building in Alameda — which happens to have once been the first telephone exchange on the island, circa 1900 — and you’ll find yourself plunged into an electronic wonderland of Inspector Gadget-type widgets and gizmos.

Vacuum tubes the size of baby dolphins rest on shelves near radios of all shapes and eras, clad in snakeskin, aglow with neon and disguised as Scotch whiskey bottles. Transmitters from World War II bombers are stacked next to CIA communications gear, and a replica of Amelia Earhart’s airplane radio. A telegraph machine clicks away in one corner, and elsewhere are unlikely treasures, like the largest black-and-white TV ever made and a recording of the Beatles that a peevish John Lennon tried to sabotage by repeatedly flushing a toilet.

This is the Bay Area Radio Museum and Hall of Fame, an institution devoted to everything under the sun related to wireless communication, stretching back some 120 years to the invention of radio. The museum is run by volunteers from the California Historical Radio Society, who open it to the public on Wednesdays and Saturdays for tours and classes.

During these events, you might see visitors pointing to refrigerator-sized speakers and exclaiming, “Oh God, an old Ampex! That’s where my dad worked!” You can peek into a six-bench repair lab, where hunched-over workers with flashlights on their heads poke at the guts of old radio boxes to save them from landfills, looking like tech-obsessed creatures from the world of Harry Potter. If you have old 8-tracks or wax phonograph cylinders from Grandma you found in a closet, you can bring them in — they’ll digitize them as part of their audio-transfer service.

The museum has led a rather itinerant lifestyle. Its thousands of mostly donated artifacts were located in Berkeley’s old KRE radio station before moving here in 2014. For much of its existence, the building has functioned as a social club and hangout space for die-hard radio collectors. But this summer, it plans to open as a full-fledged museum, with rotating exhibits and a burning mission to teach the public that radio is anything but dead.

“Radio was the fastest-adopted technology ever — including the internet and cellphones and television,” says Rachel Lee, executive director of the California Historical Radio Society. “That’s probably my favorite factoid, because these days people are like ‘Ehhh, radio.’ But it really was culture-changing — the ability to have this kind of news communication and entertainment was just huge in a time when you didn’t have widespread communication.”

It turns out that radio has a unique history in the Bay Area. The first entertainment broadcasts in the United States came out of San Jose in 1912, when Charles “Doc” Herrold started broadcasting musical concerts by dangling a microphone in front of a windup gramophone. Herrold’s cutting-edge transmitter involved a water-cooled mic and arcs burning in alcohol-filled tubes, and the broadcasts were only really available in the San Jose area. Nevertheless, the “Doc” is remembered as a radio pioneer, and his station later went on to become KCBS in San Francisco.

In the 1920s, radio experienced a growth spurt nationwide, expanding from a couple dozen stations to more than 450. San Francisco led the pack among all cities, with seven operating stations. The local stations included 6XG/KDN, which broadcasted player-piano music, weather reports and the price of eggs and butter from a wooden shack atop the Fairmont Hotel in Nob Hill.

The station broadcast live concerts by international opera stars and, on one memorable night, an orchestra that apparently forgot to listen to the weather report.

“There wasn’t enough room in the operator’s shack for the orchestra, so they stationed themselves on the roof while (radio operator Alan) Cormack positioned his microphone in the doorway,” writes radio historian John F. Schneider. “Just as the broadcast got underway, it began to rain. But the show must go on, and the little group played its entire concert in the downpour, although, as (Cormack) recalled, the violins sounded a bit ‘soggy’ towards the end.”

The nonprofit California Historical Radio Society began its journey from a collectors’ group into an authentic historical society in the early 1970s.

“There were a bunch of engineers, mostly who worked in what we called the Electronic Gulch — before it was Silicon Valley— for companies like Fairchild and Ampex. These guys collected antique radios, and in 1974, they formed a group that was basically a radio collectors organization,” says Steve Cushman, former president and current director for the radio society. “They would meet in parking lots, and they would exchange radios and parts and schematics and books.”

If you don’t understand the appeal of this hobby, well, maybe you grew up deprived.

“I was fascinated by radio as a kid,” Cushman says. “I had a little crystal set and was always running around the house with an alligator clip, clipping onto things that would be my best antenna. In those days, in the early ’50s, the finger stop on a dial telephone — which was a little piece of metal — you could hook your antenna up to that, and you’d have the whole telephone company as your antenna.”

Most of the artifacts in the Bay Area Radio Museum and Hall of Fame are donations. On the bottom level is the largest communications library west of the Mississippi, with a whole section of novels that have something to do with radio, wartime communications or spies, including the “The Radio Boys and Girls” series of books popular in the 1940s.

The oldest piece in the collection might be a 1900 oak-clad phone booth with a telephone that can still dial out. There is British Spark equipment — one of the earlier wireless technologies, sometimes used on antisubmarine planes — and radio-station jackets from Bay Area personalities like KFOG’s Dave Morey and KOFY-TV’s Celeste Perry.

There is also one of two remaining functional NBC chime machines. Starting about a century ago, these devices initiated and closed every NBC broadcast with a tritone “bing-bing-bong” — a sound so distinctive, it got the first audio trademark in the country. The tritone was originally played by announcers physically hitting metal chimes, which led to inaccurate timing and sour notes by those who didn’t study enough in band class. So the process was automated by the Rangertone company, which built machines for places such as NBC’s New York Radio City and the West Coast Radio City at 420 Taylor St.

“We have it opened up and working, so you can see the chimes going around and see how it worked for the hundreds of thousands of plays on the air that this machine was used,” Cushman says.

And you can actually buy radios here. Volunteers salvage old 1950s and ’60s-era radio boxes, clean them up and install Bluetooth connectivity, so you can listen to music wirelessly in your kitchen.

The museum also has a ham-radio room, which is going to be hooked into the Alameda emergency network, and a soon-to-deploy station at 1570 AM that will play old jazz records on old equipment. (The signal will only reach a few blocks out into Alameda but can be heard streaming worldwide on Radio Sausalito.) It has ancient TVs ranging from the 1950s IMAX of the day to a 3-inch 1940s screen, which are all wired up to play episodes of “I Love Lucy.”

The collection of recordings includes an interview with the Beatles by San Francisco talk-radio pioneer Hilly Rose, then at KCBS, who caught them in 1964 at their Hilton suite during the band’s whirlwind tour of the country.

“I showed up at the appointed time, which I remember was somewhere around 3 p.m., and all four were in their underwear lounging around,” Rose told a radio-museum curator. “John and Ringo didn’t want to do the interview, but happily Paul and George did. John was so annoyed, he went into the bathroom and flushed the toilet continuously, attempting to foil the sound. I was using a recorder that was unidirectional and blocked out peripheral sound, so it foiled his efforts, as you can tell by the quality of the recording.”

Why is it important to preserve such history? Cushman has some thoughts.

“When a class of kids come in here, I hold up my cellphone and say, ‘All right, you guys, you know what this is?’ They say, ‘It’s your phone’ — they’ll never say telephone, because they don’t know what that is. I say, ‘No. Let me tell you the story about why this isn’t a phone, it’s a radio.’ I trace wireless communications from where we are today and work backward, so they understand what all those big brown boxes with lights are in the room.”

If three out of 20 kids take an interest in what he’s talking about, Cushman believes he’s doing a good job: “Because we’re doing what the schools aren’t doing. We’re teaching about what a great portion of society grew up with — and kids today don’t even know what a knob is.”

If you go: Bay Area Radio Museum and Hall of Fame

Where: 2152 Central Ave. in Alameda, Calif.

When: 10 a.m. to 3 p.m. on Wednesdays and Saturdays

Admission: free and open to the public

Info: bayarearadio.org