Author Archives: clem.law@usa.net

1942 Popular Mechanics Phono Oscillator

Seventy-five years ago this month, the March 1942 issue of Popular Mechanics carried a construction article for this portable phonograph oscillator. Mounted in the always available cigar box, the one-tube record player used a 117L7-GT tube to produce a signal that could be tuned in on any nearby radio.

The tone arm could be removed when not in use, and plugged in with two phone tip plugs to hold it in place and make the electrical connection.

Since the phono oscillator only required one tube, and didn’t need an expensive speaker or transformer, they were quite popular for playing records for those who already had a radio.

For use right next to the radio, no external antenna was required. For a bit more range, a short piece of wire could be added. The coil inside was wound on a one-inch piece of cardboard, and a variable condenser could be tuned to a blank spot on the dial.

1937 Snow Speaker

March is the snowiest month, so there should still be plenty of time to construct the speaker shown here. This speaker was shown 80 years ago in the March, 1937, issue of Radio Craft, and had a number of technical advantages. Since the packed snow has no resonant frequency of its own, the overall frequency characteristics of such a speaker would be excellent. And since the construction material is free for the taking, it allowed a large true exponential curvature.

To construct, simply take a snowball and roll it around until it’s about five feet in diameter. Then, you take your previously prepared “drill,” the exponentially-shaped board, and push it into the snowball untill a cone-shaped hole has been cut. You smooth out the interior by hand, and then place an 8 inch speaker at the back of the snowball (using wax paper or cloth to separate the speaker from the snow).

The magazine suggested that this speaker would be ideal at venues such as skating rinks, hockey games, toboggan slides, or winter carnivals. You can construct a number of them and connect them to a suitable radio or PA amplifier.

Not only will such a snow speaker produce a fine quality of reproduction, but it attracts a great deal of interest.

U.S. Marine Corps Mimeograph, 1942

75 years ago today, this ad in the March 2, 1942, issue of Life magazine reminded readers that there was a war to be won, and the United States Marines were busy doing just that. And you can’t win a war without making sure your duplicating needs were taken care of.

The Marine shown here “stands for no nonsense, asks no quarter and gives none when the honor of the Corps is at stake. But he keeps a fatherly watch on the young recruits, start them off on the was to promotion and pay, sees that they stay on the track.”

Corps equipment, like the Corps itself, had to be rugged and ready. And that’s why the busiest, most trusted means of communications in the Corps was the Mimeograph duplicator. It had accuracy and speed, and its black-and-white crispness stodd up when the going got tough. “With its integrated stencil sheets and inks, it is on duty wherever Marines are stationed.”

1942 Popular Mechanics “Little Giant” Receiver

Each March, Popular Mechanics carried plans for a receiver dubbed the “Little Giant,” and the 1942 version is shown here.

With a war going on, this one differed in that it had been stripped of all unnecessary frills and designed for economy. But the little four tube AC-DC set still offered high grade performance with its superheterodyne circuit, featuring automatic volume control, an electro-dynamic speaker, and vernier tuning. The set’s open chassis construction also made it easier to build than earlier models. It tuned from the bottom of the broadcast band to 18 MHz, with three plug-in coils used to change bands.

Erec-Tronic Kit, 1957

Sixty years ago this month, the February 1957 issue of Radio Electronics featured this electronic kit for beginners, the Erec-Tronic. The magazine noted that similar outfits had been around for a long time, but they usually amounted to a wooden breadboard with a few rows of Fahnestock clips. But the Erec-Tronic was the ultimate in educational kits, thanks to the Jiffy-Clip, which could be used horizontally as an alligator clip, as shown on this illustration. But it could also be slid over the pins banana-plug style for quick assembly and disassembly.

The set was touted as a natural for the boy who was just taking an interest in things electronic. It quickly de-mystified schematic diagrams, since the parts could simply be placed right on top of the schematic template to form circuits, such as the code practice oscillator shown here.

The Jiffy connector also removed the necessity for the “mess, dirt, or danger” of solder for the young electronic experimenter. The set shown here sold for about $17, and a transistor version was also available for $13. But these sets were not limited to beginners. Big kits for industry or education were also available with over 300 resistors, 100 capacitors, and scores of sockets and potentiometers, with large basis for assembling advanced circuits. These sold for up to $395.

1937 Popular Mechanics Hurricane Receiver

Eighty years ago this month, the February 1937 issue of Popular Mechanics carried the plans for this “hurricane receiver.”

Even though it required only about $5 worth of parts to build, the ultracompact set would serve as a rugged portable set which could pull in news during emergencies such as hurricanes. The set, both B+ and filaments, required only 6 volts, and could be run off dry cells for about 12 hours, or from a 6 volt car battery for about 75 hours.

The circuit was a regenerative detector followed by one stage of audio amplification to drive headphones. A 25 foot antenna was recommended, and the set was able to pull in stations up to 500 miles away.

If this set looks familiar, it’s because we’ve featured it here before. After the plans were published in Popular Mechanics, the set was available as a kit from the 1939 Allied Radio catalog, as we featured in an earlier post. We’ve also covered an updated 1943 version of the set, which was billed as a wartime emergency blackout set.

Justice William O. Douglas, 1947

Shown here 70 years ago at the soda fountain of a drug store near the U.S. Supreme Court is Associate Justice William O. Douglas.

The 17 year old soda jerk serving him is his daughter, Mildred Douglas, and the picture appeared in the February 24, 1947, issue of Life magazine. According to the magazine, she was somewhat abashed by the publicity, and announced that she took the job for the money, earning 65 cents per hour. Her younger brother, Bill, 14, had a paper route.

Douglas was four times married and three times divorced. He divorced Mildred’s mother, also named Mildred, in 1953. The children were subsequently estranged from their father, and the younger Mildred was later quoted as saying that the Justice “never talked to us like we were people” that “when he got angry at us, which was often over the slightest things, he would simply not speak to us for days on end,” and that she “didn’t like him very much because of the way he treated my mother.”

When the elder Mildred died, the Justice was not immediately informed, since neither sibling felt the desire to inform him.

1947 Two Meter Handie Talkie

Seventy years ago this month, the February 1947 issue of Radio News carried the plans for this handie talkie for two meters.

The author was C.T. Haist, Jr., W6TWL, and this was the his third version of the set, with earlier ones appearing in the June 1944 and April 1946 issues of QST. Those earlier versions had one bug that still needed to be worked out: Since they used the same oscillator tube for both the transmitter and receiver, the result was that the transmit and receive frequencies were slightly offset. This didn’t pose a problem when working a fixed station, since the other station would probably be using a separate transmitter and receiver. But when two portable sets were used, the result was that each station would need to retune after each transmission, resulting in the two stations chasing one another around the band.

This set solved the problem by using separate tubes for transmit and receive, with a third tube used in common in both circuits. Transmit-Receive switching was accomplished with a three pole double throw switch.

The compact set had room for a 67-1/2 volt B battery and 2 flashlight batteries running the filaments. The built-in antenna was a repurposed telescoping automobile antenna. The set drew about 15 mA on transmit, meaning that the total input power was about one watt. At 8-10 miles line of sight, the set gave good signal reports. With batteries, it weighed in at about three pounds, and measured 2-1/4 x 2-3/4 x 9-1/4″

Win the War: Learn How To Type!

On this date 75 years ago, the February 23, 1942 issue of Life Magazine contained this advertisement from Smith Corona telling the nation’s eleven million girls that there was indeed something they could to to help with the war. And they could do it by learning how to type!

Things had to be kept going while the boys were away, and that meant there were countless ways that women always found to help. Volunteers were needed for the Red Cross, civilian defense, draft boards, auxiliary services, and vital social work.

Knowing how to type was always important in peace time, but it was even more useful during war. “Twice-welcome is the girl who brings with her not only the will to serve, but the skill to save precious hours of working time.”

The ad pointed out that typing skill came quickly to women’s deft fingers. They didn’t need the blazing speed of the expert, since all that was needed was the speed sufficient for the workaday world.

All a girl needed was a typewriter, a simple manual, and a few days of practice, and she would be twice as able to help!

Perhaps the ad sounds like hyperbole, but elsewhere in the magazine, we see this woman who brought her typewriter to war. Shown here is Life researcher Shelley Smith Mydans, at work in China. Her husband, Carl Mydans, was a Life photographer, and the two last checked in with the magazine the day after Christmas from Manila. After the fall of Manilia, they were presumed by the magazine to be in a Japanese concentration camp.

The magazine’s presumption was correct, since they were interned in Manila for about a year before being transferred to another camp in China. They were released in 1943 as part of a prisoner of war exchange. After their release, they quickly made their way to Europe to resume their duties, and then returned to the Philippines to cover the liberation of those islands.

Bombardment of Ellwood, 1942

Goleta Valley Historical Society image, via American Oil and Gas Historical Society.

On this night 75 years ago, the mainland United States saw its first attack of the war, in the Bombardment of Ellwood, near Santa Barbara, California, on February 23, 1942.

The event served to trigger a scare of a West Coast invasion, and was a major factor in the decision to intern Japanese-Americans.

The shelling was done by the Imperial Japanese Navy submarine I-18, under the command of Kozo Nishino. Four days earlier, on the night of February 19, the ship covertly landed on Point Loma, San Diego, to determine its position. It then headed north along the California coast.

At about 7:00 PM on February 23, the sub came to a stop off the Ellwood oil field. At 7:15, iit fired its first shot at an oil storage tank. Very little damage was done, and some of the shells landed as far as a mile inland. There was some damage to the pier, and a derrick and pump house were destroyed. There were a total of about 20 shots, after which the sub headed south toward Los Angeles.

One witness reported that the sub had flashed signal lights toward the shore. While this probably did not happen, it was used to support the internment of Japanese-Americans.

The next night, February 24, was the “Battle of Los Angeles,” in which anti-aircraft guns were used against probably nonexistent enemy aircraft.

Commander Nishino had been to Ellwood previously. Before the war, he had commanded a merchant ship, which had taken on fuel at Ellwood. While walking to a formal welcoming ceremony, he tripped and fell onto a patch of prickly pear cactus. Apparently, nearby oil workers laughed at the sight of the commander having cactus pulled from his buttocks. Most of the shelling took place within a thousand yards of the spot where he had visited.

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