A Career in Wireless: 1920

1920NovBLA hundred years ago this month, the November 1920 issue of Boys’ Life asked scouts to ponder the question of whether they should pursue a career in radio.

The article was an excerpt from the merit badge pamphlet for “Wireless Electricity.”  I’ve never run across this name before, but it’s used throughout the article.  According to Wikipedia, Wireless merit badge was discontinued in 1923 and replaced by Radio, and I didn’t find any reference to the name Wireless Electricity.

The article talks about the advantages of a career in radio, such as the possibility of traveling the world as a shipboard radio operator.  It also points out that there was a demand for persons to fill these lucrative positions.  While the article pointed out that there were a number of good schools, it also made clear that most in the profession were self-trained as amateurs, and that this was one of the rare cases where one could get a good job based on such self-education.

The magazine also included some pointers for building a detector, shown at the bottom of the page.



Product Review: Opinel Pocket Knife

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Bottom Line:  The Opinel is a very inexpensive and unpretentious high quality knife for your everyday carry needs.

Pre-pandemic, I very rarely carried a pocket knife. When I needed a cutting tool, I looked around the garage or kitchen and found something suitable. In the car, I would find a cheap utility knife in the toolbox which would usually serve the purpose.


But with the pandemic, it seemed that I needed a knife multiple times per day. More often than not, it was to open a box from Amazon or Walmart. I like to do this outside, so that I can immediately discard the outer packaging into the recycling bin. Thus, it became convenient to keep a knife in my pocket. I had several around the house, many of which had been given to me as gifts over the years. The first one I stumbled upon was the Opinel No. 6 Stainless Steel folding knife.

As you can see from the picture, the Opinel is a nondescript knife with a wooden handle. It looks like a tool, which, of course, is exactly what it is. It doesn’t have a camouflage handle. It doesn’t have a built-in screwdriver or can opener. It’s benign looking, and designed for cutting things, a goal which it accomplishes remarkably well. It’s well made, and it seems to keep a cutting edge well. I’ve sharpened it a couple of times with a whetstone, and the edge seems to last.

My version came in stainless steel, and the knife is also available in carbon steel. Apparently, the carbon steel blade holds an edge a bit better, but is more prone to rust. The stainless steel (marked on the blade in French, Inox, short for inoxidable) seems the more practical choice.

The Number 6 in the product name indicates the length of the blade, the number 6 being 2.87 inches. The sizes range from a tiny Number 2, up to a Number 12 with a 4.84 inch blade. The number 6 seems to be the perfect size for the occasional jobs I use it for. In addition to opening boxes, I’ve used it to cut food while camping, strip wire, cut cords, and do the normal variety of tasks for which one would use a pocket knife. It’s big enough to do the jobs I need it for, but as it weighs only about an ounce, I hardly notice it in my pocket.  The blade meets the “under three inches” standard which is important for some regulatory purposes.  (On the other hand, at such time as it becomes safe to fly commercially, I’ll have to remember to leave it at home or in my checked baggage.)

Locking mechanism. Wikipedia photos.

Locking mechanism. Wikipedia photos.

The knife has a simple locking mechanism, which allows the blade to be locked open or closed. It’s simplicity itself–namely, a notched ring which can be twisted to hold the blade in place. In my opinion, most locking mechanisms are annoying and dangerous. If you’re using a knife in such a way that the blade might inadvertently close, then in my opinion, you are using it wrong. And most locking mechanisms I’ve seen require some contortion to disable them, such as holding down a button while moving the blade toward your finger.  In most cases, in my opinion, the “safety” feature of a locking blade makes the knife less safe.   In the case of the Opinel, however, the locking mechanism needn’t be used at all.  In fact, I carried the knife around for quite some time before even realizing that the blade could be locked.

On the rare occasions when I might want to lock the blade on the Opinel, the mechanism and easy and safe to use. You merely rotate the ring to lock or unlock the blade.

Joseph Opinel began making knives in 1890 in Savoie, France, and the knife has always been the quintessential working man’s knife. Picasso reportedly used one as a sculpting tool. Today, about 15 million knives per year roll off the company’s assembly lines.

The Opinel knife is quite inexpensive, but high quality and useful. It’s unpretentious and looks like a tool, so it won’t draw the ire of those who are squeamish about knives. It’s the perfect knife to keep in your pocket. You’ll find you wind up using it several times per day.

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1945 Selective Crystal Set

1945NovPM11945NovPM2Seventy-five years ago, this crystal set experimenter was pulling in a station, even though he was in a congested radio area, and even though there was another strong station very close to it on the dial. He was able to do this thanks to the crystal set shown in the November 1945 issue of Popular Mechanics.

The set featured two tuned circuits to give it such good selectivity. It was mounted on a chassis made of wood, and the two coils were mounted below the chassis. They could be wound on cardboard tubes or on wooden dowels.

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Science Fair Idea: Jacob’s Ladder

1960NovEE5This young woman undoubtedly took home the blue ribbon in the 1960 science fair. And she certainly earned herself considerable street cred as a mad scientist by putting together this Jacob’s ladder, by carefully following the plans in the November 1960 issue of Electronics Illustrated.

As revealed by the schematic diagram below, the circuit is simplicity itself. It simply takes normal household current and runs it into a transformer which steps it up to 12,000 volts, which is fed into two electrodes. One way or another, there is going to be an arc between the two conductors. It will follow the path of least resistance, and thus starts out at the bottom, where the two metal rods are closest together.

The arc heats the air right above it, which ionizes the air. The ionized air thus becomes the new path of least resistance, and the arc moves upward. The process repeats until it reaches the top, at which point a new arc forms at the bottom.

The critical component, of course, is the high voltage transformer. In 1960, it was available in the form of a neon light transformer, for $12 plus shipping. Of course, neon signs still exist, and you can buy the transformers on Amazon.  This modern replacement is rated at “only” 10,000 volts, but it seems like that should be sufficient.

The 1960 article includes a number of important safety features. First of all, the electrodes are safely behind a sheet of 1/32″ clear acetate. This also appears to be available on Amazon.

And the choice of switch ensures that the device isn’t turned on accidentally. The power switch is a momentary switch, meaning that when you let go of the switch, it turns off. It’s a SPDT switch, meaning that when it’s off, another contact is energized. This is wired to a green pilot light that indicates that the device is plugged in. The switch has a safety cover, meaning that one needs to consciously lift the cover to flip the switch.

The article begins by saying that “if the directions given in this article are followed to the letter, there is no danger of shock. Don’t take short-cuts or omit the built-in safety features of this model; it is poor economy to leave out relatively inexpensive components that might prevent a nasty shock.”

These days, when one reads safety warnings, there’s a tendency to ignore them. But in 1960, when a warning like this was included, it’s because the activity in question was, indeed, dangerous, and you really needed to be careful. So I believe this project is suitable for mature students, working under the supervision of a competent adult. But this contraption is potentially lethal, and great care must be taken in its construction and use.  In 2016, a Michigan teen was killed trying to build one, and we don’t want any of our readers to suffer the same fate.  So please be careful.

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1940 Clock Radio

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The humble clock radio hit the scene shortly after the war, but as we can see from this self-explanatory drawing in the November 1940 issue of Popular Mechanics, one John L. Story of Washington, D.C., had come up with the idea. He mounted a small toggle switch on the back of a wind-up alarm clock not unlike the one shown at left, still available on Amazon.

When this type of clock rings, the key for winding the clock unwinds.  The switch is carefully placed so that the unwinding key trips it, turning on the radio or other small appliance.  For students interested in the history of technology, this would be an interesting science fair project to duplicate Story’s invention and answer the question, “what is the simplest clock radio?”



1920 Voting Machine

1920NovPSA hundred years ago, on November 2, 1920, this gentleman was casting his vote, for either Warren G. Harding or James M. Cox in the 1920 Presidential Election. (I suppose he might have been voting for Eugene Victor Debs, but he doesn’t look like a socialist.)

Whoever he voted for, he cast his vote on a lever-type voting machine, probably manufactured by the U.S. Standard Voting Machine Company. These were commonly in use for many decades thereafter, and when I first voted in 1979, it was in a machine that looked almost like this one. The voter pulled a lever to close the curtain, which unlocked the voting levers. When the voter is finished he (or she, since this was the first election after the ratification of the 19th Amendment) opened the curtain, which caused a counter at the back of the machine to increment for the candidate selected. When the polls closed, the election official unlocked the back of the machine (which locked the levers on the other side) and looked at the count for each candidate.

The picture appeared on the cover of Popular Science, November 1920, and the accompanying article proclaimed that the machines would insure an honest election. The article detailed all of the nefarious things someone could do with paper ballots, and proclaimed that “the machine is honest, and its honesty is fully protected from those who would destroy it.”



1940 One Tube Broadcast Receiver

1940NovPS1This young man is pulling in a local station with loudspeaker volume using the circuit shown 80 years ago this month in the November 1940 issue of Popular Science. The set uses a 1E7G dual pentode. One half is an RF amplifier, and the other half serves as the detector, but with enough output to drive a speaker with no further amplification. For stations within ten miles, and indoor antenna can be used, and for local stations further away, a good outdoor antenna is necessary. Selectivity was said to be very good, with the circuit able to separate strong stations only 30 kHz apart.

The set is a TRF, meaning that each stage had its own tuning dial. Two ganged variable capacitors could be used, but the separate dials allow each stage to be tweaked for maximum sensitivity. The 90 volt plate voltage was supplied by two 45 volt B batteries, with a 3 volt A battery lighting up the filaments.

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Halloween Broadcast

1915HalloweenHappy Halloween from OneTubeRadio.com!

For Halloween, I am doing a special broadcast for the neighborhood.  If you discovered this page from that broadcast, welcome to OneTubeRadio.com, a blog covering mostly radio history, but also other eclectic topics.  If you are outside of our broadcast range, you can listen to the full broadcast by clicking the play button below:

Tonight’s broadcast features War of the Worlds, originally broadcast on CBS radio on October 30, 1938.  It also includes Halloween music from French artist Chez Mon Plaisir, who has graciously placed the music in the public domain under a Creative Commons 0 license.  It is available for download at FreeMusicArchive.org.

We are transmitting with our  InfOspot Talking House transmitter, which I previously reviewed at this link.  It is an FCC-certified transmitter for the AM band and operates with 100 milliwatts to a 3-meter antenna.  Tonight, we are broadcasting at 1610 kHz on your AM dial.  It has fairly solid coverage for about two blocks, and in a few spots, can be heard over a mile away.  During COVID-19, I have used this transmitter for drive-in educational programs for my continuing legal education business.  It is also suitable for other socially distanced activities, such as church services and meetings of community organizations.  It could potentially be an important community resource in emergencies.  And tonight, I hope it’s providing some Halloween entertainment to the neighborhood.

Reception reports are welcome.  You can contact us at como-radio@usa.net.

Happy Halloween!

Happy Halloween from OneTubeRadio.com!

The Windy City youngsters shown here have been collecting Social Security for a few years now, but in 1960, they were celebrating Halloween at Jackie Robinson Park, Chicago.

And in 1947, the young women shown below were participants in the Anaheim, CA, Halloween Slick Chick Beauty Contest.