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.

There 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.

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Admiral Model 12-B5, 1940

Eighty-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.

1950 Look at the H-Bomb

The first hydrogen bomb wasn’t tested until 1952, but two years earlier, readers of Life Magazine, January 30, 1950, got a pretty good idea of what it would be capable of. The above picture shows the blast radius for the A-bomb (small circle) compared to that of the H-bomb (large circle).

Colorado Senator Edwin C. Johnson had referenced the new bomb in a television broadcast, the press followed up, and President Truman had failed to either confirm or deny that the project was underway. The magazine noted that the nation was still trying to adjust itself to life with the A-bomb, but the new bomb, which would harness the same energy as the sun itself, would make the Hiroshima weapon look like a stick of dynamite.

Ohio Girl Builds Radio, 1925

One hundred years ago today, 13-year-old Grace Weaver of Oakwood Village, Ohio, near Dayton, made the front pages by putting together her own five-tube neutrodyne radio. On her first night, she pulled in Los Angeles.

She is shown here on the front page of the Radio section of the Indianapolis Times, January 29, 1925.

1965 Grid Dip Oscillator

Sixty years ago, the January 1965 issue of 73 Magazine showed how to make this simple Grid Dip Oscillator (GDO or “Grid Dipper”.)

The GDO is handy for quickly measuring the resonant frequency of a tuned circuit or of an antenna. The GDO’s coil is exposed, and it’s poked into the coil of the circuit in question. For an antenna, a small loop of wire attached to the antenna goes around the coil. The frequency is adjusted, and at the resonant frequency, the meter showing the grid current drops precipitously. If you need the exact frequency, you can find the signal of the GDO on a receiver, or use a frequency counter.

This example uses a 3S4 tube, and has the convenience of being able to run from batteries. Of course, these days, the same thing can be done with transistors. Even though transistors have no grid, many old timers still refer to the instrument as a Grid Dipper. Hams these days are more likely to use an antenna analyzer, but the Grid Dipper gets the job done in an elegant analog fashion.

1945 Four-Tube Portable Station

Eighty 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.

1950 Transistor Radio

For many radio hobbyists, this could very well have been the first transistor radio they had ever seen. The invention of the transistor was announced in 1948, and the first commercial example to hit the market was the Raytheon CK-703 later that year. The January 1950 issue of Radio News showed how to build this project, a crystal receiver, with three stages of audio amplification, courtesy of the new “crystal triodes.”

The new transistors resembled miniature tubes, and required sockets. The collectors and emitter terminals had pins, and the base connection was to the brass case of the device. Sockets had not yet hit the market, so the builder, Rufus Turner, K6AI (earlier W3LF), had to fabricate them himself.

He noted that the set would not drive a loudspeaker, but would “give a walloping good signal in high-impedance headphones.” He noted that “enterprising radio men undoubtedly will find a host of applications for this device.”

Turner is said to be the first African-American licensed amateur radio operator. He had no formal education in electronics, but managed to achieve Professional Engineer status in two states. He was involved in the development of the 1N34 diode with Sylvania. When he did go to college in the late 1950s, he received his degrees in English and became a professor of English at California State College, although he continued to publish in electronics.

1925 Paragon Radios

One hundred years ago this month, this couple were enjoying some dance music courtesty of their Paragon receiver. In this ad in the January 1925 issue of Radio Retailing, the manufacturer, Adams Morgan Co., 14 Alvin Ave., Upper Montclair, NJ, reminded retailers that if they were not featuring Paragon, they were missing out on profit opportunities.

1968 Grocery Prices

For a snapshot of grocery prices in 1968, this ad appeared in the Pittsburgh Post Gazette, January 22, 1968.

There’s been a lot of inflation since then. According to this online calculator, one dollar in 1968 is the equivalent of $9.07 in 2024. So the margarine is closer to $3 a pound, and the pork chops are over $6 per pound.

What would you make for dinner if you were buying the groceries in 1968?

Six Meter Mobile, 1965

Shown here, at the reins, is 73 Magazine publisher Wayne Green, operating some six-meter mobile. Seated next to him, in the raccoon coat, is Bob Cushman of Cushcraft, the maker of the Squalo antenna. Pulling the duo is Arabian stallion Alrun, said to be the pride of 73 farms.

The photo, taken by K2YDD, appeared on the cover of 73 Magazine, January 1965.