Monthly Archives: May 2025

V-E Day

Today marks the 80th anniversary of V-E Day, May 8, 1945. You can hear how it was covered on NBC Radio at this video, which includes addresses by President Truman and Prime Minister Churchill:



1940 Phonograph Stroboscope

1940MayRadioService DealerEighty-five years ago this month, the May 1940 issue of Radio Service Dealer provided this handy stroboscope for testing the speed of record players.

The included instructions explained how to place it on a piece of cardboard, or an old record. If a record was used, it was critical to make sure the hole was exactly in the center. Then, it was placed on the platter, and illuminated with a neon bulb powered by 60 Hz. At exactly 33-1/3 RPM, the outer segments would remain stationary, and at 78.26 RPM, the inner ones would do the same. If the speed were too fast or too slow, the segments would appear to move forward or backward.



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Recharging Flashlight Batteries: 1945

1945MayPSFlashlight batteries were sometimes in short supply during the war, and the May 1945 issue of Popular Science gave some pointers on how you could get some extra life out of them by recharging them. If the battery was already dead, there was little hope, and if they were bulging or pitted, they were beyond hope. But by recharging them before they were completely dead, you could give a low battery a new lease on life.

The idea was to zap them with about twice their voltage. So for a flashlight battery, you could put two in series, and then charge them with a six-volt battery from the car. You would wire them as shown below, but then carefully monitor them. After two to five minutes, they would start to get warm, at which point you would disconnect them and let them cool. This process would be repeated two or three time. It was important not to allow them to become hot. When done, the cells could be put back in use. They wouldn’t last as long as new batteries, but new batteries might not be available.

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1965 Headlight Reminder

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Screenshot 2025-04-10 12.23.17 PMSixty years ago this month, the May 1965 issue of Popular Electronics showed this simple circuit for a headlight reminder. I remember that starting in the 1970s, cars started including a noisemaker to remind you of various things, such as not wearing your seat belt. But the one helpful thing it could be used for would be to prevent leaving your headlights turned on.

The circuit shown here is simplicity itself. All you needed was a buzzer, a diode (the cheapest one you could find) and a resistor (unless you had a 6-volt car, in which case the resistor could be omitted). You connected one side to the light switch, and the other two the ignition switch. If both the lights and the ignition were turned on, then there would be zero voltage difference, and the buzzer would be quiet. If the ignition were on and the lights were off, then the diode would block the flow of current. But if the lights were on and the ignition was off, then current would flow and the buzzer would sound.



Make Money Selling Magazines, 1965

1965MayEISixty years ago, if you needed a job, you could always sell magazines. You could sell them to your friends; you could sell them over the phone; you could go door to door. You would be your own boss, and there was really no investment involved. If you could sell, the sky was the limit.

This ad appeared in the May 1965 issue of Electronics Illustrated, and it invited you to sell that magazine, along with other leading publications. All you had to do was send them a postcard, and they would send you everything you needed to get started. You would just start selling new and renewal subscriptions, and you would get a commission for each sale.

In college, I had one friend who was involved with something similar. He was given a stack of business reply postcards, and the idea was to get people to send them in to subscribe. He would get a commission. He did this by placing hundreds or thousands of postcards into school lockers. Apparently, one or two people subscribed, and he once got a check for a couple of dollars.

I don’t think it’s really viable to sell magazines door to door these days. For one thing, paper magazines are rapidly becoming a dying breed. And I’m not aware of any magazines that will send you postcards to stuff in people’s lockers.

But there is a thing called affiliate marketing, and this site engages in it. Occasionally, we make a few pennies. We haven’t made our first million yet, but it does keep this site self-sustaining. If you click on any of the Amazon links on this site, and then make a purchase (even if it’s not for the item you clicked on), then this site earns a commission. And Amazon sells everything, including magazine subscriptions (both print and online).

If you are interested in making money online, I do have some ideas of how you can do so, at this link. You won’t make huge amounts of money fast, but you can make some money online. Some of those ideas are somewhat out of date, but there are things you can do to make money.



1940 Camera Radio

1940MayRadioNews1Unless you happened to see the headphones, you would think this gentleman 85 years ago was fiddling with his camera. But he’s actually listening to the radio hidden in an old camera case, as described in the May 1940 issue of Radio News.

The two-tube regenerative set could be used with a loudspeaker (mounted where the lens used to be) for strong local stations, or with headphones as shown here. Both the A and B batteries were concealed within the camera.

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1955 RDF Receiver

1955MayRadioElecSeventy years ago this month, this gentleman was aligning the radio direction finding (RDF) receiver he had constructed according to plans in the the May 1955 issue of Radio-Electronics. The magazine noted that ferrite loop antennas had simplified the design considerably. It even recommended going ahead and building one even if you didn’t have a boat: “You can build one and use it yourself or give it to a cruising friend, thus insuring yourself of a boating trip anytime you want. This model has been designed with the simplest of construction and can be made of surplus and junkbox parts. But it will give bearings as good as the fanciest job afloat.”

By turning up the gain, the set could also copy CW signals, which shared the same frequency range as beacons. It also pointed out that A-N Beacons for aviation could be found in that band.

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