Category Archives: World War 2

Recharging Flashlight Batteries: 1945

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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.

1945MayPS2



1940 DX’ing

1940AprRadioNewsIt wasn’t until June 5, 1940, that the FCC completely banned amateurs from working foreign stations.  And it wasn’t until after Pearl Harbor that amateur radio was put off the air entirely. But even before the ban on foreign contacts, U.S. amateurs had been prohibited from communicating with any of the belligerent countries, and even some neutral countries had shut down amateurs as a precaution. So there wasn’t much DX to be found, as the ham in this cartoon from the April 1940 issue of Radio News has discovered.



Laying Telephone Wire by Air, 1945

1945AprilPMIn 1945, the U.S. Army had ben using as much as 235,000 miles of wire per month for communications. Despite the role of radio, it was often advisable to use telephone communications. Among other things, radio might disclose positions to the enemy.

There was the matter of laying all that wire, and one method is shown here, on the cover of Popular Mechanics, April 1945. A “grasshopper” plane was fitted so that it could skim the ground and 200-250 feet. At one end, probably closest to the front, it would drop a parachute bearing a telephone unit, attached to the wire. The wire was wound binder twine fashion, to play out without tangling, and with minimal resistance. Rolls were 1-1/2 miles long, and three to five miles of wire could be layed in a flight at 65-70 miles per hour.

By this method, patrols cut off from communications could be swiftly reached.



1940: War Comes to Norway, Denmark, and Greenland

1940April22Life

Eighty-five years ago, on April 8-9, 1940, Germany invaded Denmark and Norway.  This was of particular concern to the United States, since the war was now creeping closer to America, since the Danish colony of Greenland was geographically part of North America. A year later, Greenland became a de facto protectorate of the United States, and when America entered the war, Greenland became a combatant.

President Roosevelt suggested that it would be “a good thing for the American people to learn a great deal about Greenland.”  According to Life Magazine, April 22, 1940, from which suggested that most Americans’ only knowledge was the hymn beginning “from Greenland’s icy mountains to India’s coral strands.”  The magazine also reminded readers that during the last war, the U.S. bought the Virgin Islands from Denmark to keep them from falling into hostile hands.

While orders came to Greenland from Copenhagen, via radio and via neutral Portugal, these orders were ignored. Instead, local officials came to taking orders from the Danish Ambassador to the U.S., Henrik Kauffmann, who became nicknamed as the “King of Greenland.” He was charged by the Danish government with treason, but the sentence was revoked after liberation in 1945.

That issue of Life devoted fifteen pages to the expansion of the War to the Nordic Countries. Shown above is an Inuit Greenland girl flirting with two Danes. The magazine noted that the Inuit had a good deal of white blood, and the Danes have no objection at all to marrying them, since there were “considered more useful wives in this hard climate than the thin-blooded white women. They are extremely courteous, for Greenlanders know they must get along with one another to survive at all.”



1945 One Tube Radio

1945MarRadioCraftEighty years ago, the March 1945 issue of Radio Craft showed this circuit for a one-tube radio that actually had four stages. The tube is a 1D8GT, which appears to be at first glance a double tube.  But it’s actually a triple tube.  On the left is a pentode and on the right is a triode.  Down in the lower right side of the tube there is what appears to be a cathode, but it’s actually the plate of the third part of the tube, a diode.

The circuit first amplifies the RF signal with the pentode, and then sends it to the diode to be detected.  Then, the pentode is reflexed and serves as AF amplifier.  Finally, the triode is used as a second stage of AF amplification.  So the single tube actually takes the place of four tubes.

The circuit had been sent in to the magazine by one Sgt. L.R. Blattner, of Tinker Field, Ohio.



Happy Valentine’s Day!

1945Feb14PghHappy Valentine’s Day from OneTubeRadio.com!

Eighty years ago, it was the last Valentine’s day of the war, and for many GI’s, this cartoon probably summed it up. Let’s hope that Valentine’s Day 1946 was happier.

The cartoon appeared on the front page of the February 14, 1945, issue of the Pittsburgh Post-Gazette.



1945: Keeping Your Name Before Customers

1945FebRadioRetailingEighty years ago there was still a war going on. But people knew that it wouldn’t last forever, and there was a pent-up demand for consumer products like radios that had been unavailable for the duration.

The cover of the February 1945 issue of Radio Retailing reminded dealers of the importance of keeping their names in front of consumers. When the war ended, and products were available, you wanted them to come to you to buy them.



1940 Homemade Batteries

Eighty-five years ago, Britain was at war, and that meant shortages of many things, including flashlight batteries. Undaunted, many Britons took to making their own, and the February 1940 issue of Practical Mechanics showed them how to do it.

Screenshot 2025-01-23 9.14.31 AMThere was a learning curve involved, but the magazine assured readers that the task was well within the capabilities of amateurs. The costs of materials were low, and once you were set up, you could laugh at the Nazis trying to deprive you of batteries.

The article pointed out that filling the cells, at least initially, was a messy process. But once you got into a routine, it was relatively easy. The article suggested getting together a quantity of zinc containers and carbon rods, and then commencing the filling process. Surrounding the carbon rod was a “depolarizing paste” consisting of a mixture of approximately equal quantities of carbon or plumbago powder and manganese dioxide (pyrolusite) made into a paste with a 1 per cent. solution of gum tragacanth. The electrolyte consisted of about 85 per cent. of plaster of Paris and 15 per cent. of ordinary flour mixed to a just-wet paste with a strong solution of sal ammoniac,

For the student looking for a science fair project, making a battery is always a worthwhile option.  In addition to this set of instructions, we have many other  similar ideas on this site.



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.

Admiral Model 12-B5, 1940

1940FebRadioRetailingEighty-five years ago, the War was still over a year away for America, but it was raging in Europe. With a shortwave receiver, you could pull in the war news directly from Europe. And thanks to the Admiral model 12-B5, you could do so for the unheard of price of only $12.95. Of course, there’s been a lot of inflation since 1940, and according to this inflation calculator, that works out to $290 in 2025 dollars. But we think it would be worth the investment.

This ad appeared in the February 1940 issue of Radio Retailing.



1945 Four-Tube Portable Station

1945JanQST11945JanQSTEighty years ago, there was still a war going on, and hams were off the air for the duration. But more than a few of them were itching to get back on the air as soon as possible, and one of them was apparently Sheldon W. Gates, W8VWK, who designed this portable station, described in the January 1945 issue of QST.

The three-band (80, 40, and 20 meters) station was housed in a small vanity case which measured 11.5 by 6.5 by 7 inches, and which set him back $2.49. He originally considered designing the set for battery operation, but since he described himself as a city boy who rarely went farther than the power lines, he settled on AC power. The transmitter used a single 117N7 tube, and the receiver was a three-tube Meissner Student Midget Kit that he cut down to fit the available space. Since the receiver used 1 volt tubes, he included a dry cell to run those filaments.

The cover of the case included plenty of room for logbook, key, crystals, and headphones. At the end of the article, he reminded readers that the transmitter could not be operated on the air at the present time.