Category Archives: Radio history

1956 Custom Hi-Fi

Seventy years ago this month, this high fidelity enthusiast was making adjustments to the H. H. Scott control panel of a custom installation, put together by Custom Sound Systems of Orange, New Jersey.  The two lower drawers contained a De Jur tape recorder and Audiosphere stereophonic tape player.  The upper drawers contained a Rek-O-Kut record player and an Altec amplifier.

This deluxe setup is in the home of one Robert Ossorio of New York City.  But while this young woman appears at ease with the equipment, she’s actually a model, Mona McHenry, hired for the photo shoot.  The photographer is by Dan Rubin, and the photo appeared on the cover of the April 1956 issue of Radio-Electronics.

 



Getting the Antenna Higher: 1941

If you need to get the end of your antenna up a few more feet, you might try this idea sent into QST 85 years ago this month, April 1941. The idea is self-explanatory–you just hoist a new section of mast up your existing mast. The bottom of the new section contains a ring of heavy wire. The idea was submitted to Hints and Kinks by Bernard S. Shields, W5AJJ, who noted that if the guy wires are added to the top section, an appreciable height could be achieved.



Build Your Own Scope: 1951

Seventy-five years ago, the April 1951 issue of Radio Electronics showed how to construct your own oscilloscope. The magazine pointed out that many were daunted by the prospect, but a basic scope for work on AM and FM radios was well within the capabilities of the average builder. The model they show used five tube, including rectifier, plus the CRT.

These days, you don’t need to break out the soldering iron or track down those five tubes. You can go to Amazon and get a pocket-sized version.



Some links on this site are affiliate links, meaning that this site earns a small commission if you make a purchase after using the link.

Motorola 3A5 “Playboy”, 1941

Eighty-five years ago this month, the April 1941 issue of Radio News showed the Motorola model 3A5 “Playboy.” The four tube (plus rectifier) portable radio was said to play anywhere, and the manufacturer backed up that promise: The set would play where other personal portables failed, or the customer’s money would be refunded.

The set measured 6-1/4 x 4-5/8 x 3-1/2 inches, and weighed in at 4-1/4 pounds. It started playing automatically when the lid was snapped open, and shut off when closed. It was “encased in a crackle finish metal case of modern design with shimmering chrome trim and a front cover of Polystyrene, the new plastic.”



Free Energy–Harness the Power from Radio Broadcasts, 1951

Seventy-five years ago this month, this curious ad appeared in the April 1951 issue of Popular Science. It invites you to send $5 ($62.84 in 2026 dollars) to Scientific Products of Indianapolis (conveniently headquartered in a Post Office box), and they will send you copyrighted instructions showing you how to build this radio powered motor. You turn the motor until voices or music are heard from it, courtesy of the proverbial strong local station. At that point, you can listen to it like a radio, but it keeps spinning, thanks to the energy taken from that station.

The skeptic will note that this device doesn’t provide very much energy. It can keep feebly spinning, and you can probably listen to the broadcast at low volume indefinitely, assuming you’re close enough to the station. But they thought of that. They did the impossible by making the tiny prototype, and now it’s up to you to make it more practical. And you can earn “$10,000” if you can pull it off. They include a “royalty agreement,” meaning that if they can commercialize your idea, you will make money. And more importantly for them, they will make money from your hard work.

We’re sure that many of our readers have independently come up with the same idea–using power from a nearby radio station to power up a small device. But we also know that there’s a limit to it.  The only references to “Scientific Products of Indianapolis” were similar ads in other magazines during about the same time frame.  They must have had a bit of capital to run all of those ads.  Let’s hope that not too many suckers sent them $5.



1946 Solar Capacitors

This ad appeared 80 years ago in Radio Craft magazine, April 1946. We decided to get at the real backstory of how this young woman found her way into a capacitor ad, so we asked Google Gemini, who delivered this logical explanation:

In 1946, the world was finally trading in its olive drab for something with a bit more chrome. But for the boys down at the local radio shop, the “atomic age” was more than just a headline—it was sitting right there on the counter in a tailored trench coat.

Her name was Sarah, though behind her back, the consensus was that she was a total bombshell. She had a way of walking into a room that made every vacuum tube in the shop feel like it was about to red-plate.

She stepped up to the counter, reached into her pocket, and pulled out a cigarette. Before anyone could reach for a Zippo, “Sparky” Pete leaned over with his soldering iron. He offered the hot, tinned tip with a steady hand; she leaned in, took a light, and blew a cool plume of smoke toward the “No Smoking” sign.

“My portable,” she said, her voice like velvet. “It’s got a hum that won’t quit.”

She reached into her other pocket and pulled out a radio so small it seemed impossible. It was a sleek little set, the kind of miracle the magazines promised once the factories stopped making tanks.

Sparky popped the back off the set and whistled. “I see the problem, Miss. Someone tried to fix this with some old-fashioned, oversized wax paper caps. They’re crowding the chassis. In a set this small, that’s just asking for a meltdown.”

He reached for a yellow-and-black box on the shelf labeled Solar. He pulled out a handful of “Little Giant” MINICAPS. They were tiny, gleaming, and looked like they belonged in a watch, not a radio.

“You see these?” Sparky said, holding one up to the light. “These Solars are the real deal. During the war, they were the only thing tough enough and small enough to go into the proximity fuses of the actual bombs we dropped. If they could survive being shot out of a cannon and still trigger an explosion at the right microsecond, they can certainly handle your favorite swing station.”

He went to work, his iron dancing across the terminals. He cleared out the bulky, outdated components and tucked the Solar units into the tight corners of the chassis. They fit like they were born there.

“The military spent millions perfecting these so they wouldn’t fail under fire,” Sparky explained as he snapped the case shut. “Now, they’re the only reason you can fit a five-tube performance into a pocket like yours.”

He tuned it to the local station, and the music came through crystal clear—no hum, no hiss.

Sarah tucked the radio back into her coat. The lines of her pocket remained perfectly smooth, thanks to the space saved by the Solar tech. She gave the boys a wink that was more dangerous than a high-voltage rail.

“Thanks, boys,” the bombshell said, heading for the door. “It’s good to know the same stuff that won the war is now keeping me in tune.”

“Well,” Sparky muttered to the guys, “I guess it’s true what they say: it takes a set of those ‘bomb’ capacitors to keep a bombshell from having a blowout.”

Google Gemini was also kind enough to supply these Amazon affiliate links.  If you make any purchase after using one of these links, this website earns a small commission.

Gear Up Your Workbench

If you’re looking to do some “bombshell” level restoration of your own, here are a few essentials for the modern radio bench:




1941 Receiver Using Rectifier Tube

Eighty-five years ago this month, the April 1941 issue of Popular Science showed how to build this receiver. It’s essentially a crystal set, but instead of a crystal, it uses a 25Z5 rectifier tube. Since there is no B+ voltage in use, the magazine assures that there will be absolutely no hum. Also, it’s safe to ground the set, because there is no connection to the power, other than to light the filament.

Instead of 25 volts, the filament is powered with 5 or 6 volts, which is obtained by dropping resistors, and/or a “curtain burner” cord.



1966 Homemade Headphones

If you need a pair of headphones today, you can run down to the dollar store and find some that are quite adequate. Or you can go to Amazon, such as this link of headphones with free shipping, sorted by price.

But sixty years ago, they could be rather pricey. Fortunately, the April 1966 issue of Radio-Television Experimenter showed you how to make a set yourself. The idea is pretty self-explanatory. You started with a couple of two-inch speakers, and the remaining components could be found at a variety of locations. You needed some wire coat hangers, some small plastic enclosures, some padding, and a little bit of ingenuity, and you would be the first on your block with a pair of stereo headphones.

The total cost was said to be $4, and the project would take about three hours.



Some links on this site are affiliate links, meaning this site earns a small commission if you make a purchase after using the link.

1956 Shortwave Converter

Seventy years ago this month, the April 1956 issue of Popular Electronics showed this extremely simple shortwave converter. It consisted of little more than a diode and tuned circuit, and the output went to the antenna terminals of an AM radio, or looped around the coil. (The loop antenna would pick up too many broadcast stations, so the author recommended replacing it with a small loopstick.)

The author doesn’t explain how it works, and I don’t know either, other than perhaps by brute force on strong signals. But according to the author, he was able to pick up foreign broadcast stations and amateurs on 40 and 80 meters. Even though it appeared in the April issue, I’m inclined to believe that it worked through brute force. We previously covered a similar idea for making prewar FM radios pick up signals on the new FM band.



1941 “Powerless” Keying Monitor

Eighty-five years ago, the April 1941 issue of QST included this hint (or perhaps it was a kink) sent in to the magazine by C. Ray Wagner, W2FEN, for a “powerless” (other than filament) keying monitor. It uses a 117L7GT tube, half of which is a simple audio oscillator.  The rectifier half of the tube is powered by a pickup from the transmitter, and this RF is rectified to supply the B+ for the oscillator.  The result is that when the circuit is powered up (in other words, when there’s RF coming from the transmitter), the oscillator puts out a side tone.