Category Archives: World War 2

1942 Photocell Opportunities

1942SepRadioRetailingWith civilian radio production suspended for the duration in 1942, many radio dealers were in search of additional lines of business to fill the gap. The September 1942 issue of Radio Retailing offered a number of suggestions involving applications of photocells. Above, with the possibility of wartime blackouts, a business owner would need a way to shut off his electric sign quickly in case the order was given. One way to do it automatically would be to wire the sign to a photocell pointed at the closest streetlight. When the town shut off the streetlights, his sign would immediately go dark.

1942SepRadioRetailing2Various industrial applications were suggested, as well as, of course, use of electric eyes in security systems. Shown at right was a design used the by Cleveland Plain Dealer, to measure the pitching speeds of various pitchers. A trailer was equipped with the system shown here, and the player was to pitch into an opening in the back of the trailer. The ball would pass through two beams of light, and from the difference in time, the speed would be measured.

Of course, today, the aspiring major league pitcher can get the same thing surprisingly inexpensively. The device shown here uses radar to measure the ball’s speed and does not require an entire trailer to move around.



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Queen Elizabeth II, 1926-2022

PrincessElizabethQueen Elizabeth II of the United Kingdom died today at the age of 96.  She was preceded in death by her husband Prince Philip, the Duke of Edinburgh, Patron of the Radio Society of Great Britain.

She came of age during World War II, and it’s not surprising that her first public speech was on the radio.  In 1940 at the age of 14, the Princess addressed the children of Britain, especially those who were far away from home, having been evacuated to the countryside or the Empire or to America.

You can hear that speech here:

One of her last addresses was during the early days of the COVID lockdown, when she referred to that speech, and closed with the words of Vera Lynn’s “We’ll Meet Again.”



1942 Blackout Receiver

1942SepPSEighty years ago this month, the September 1942 issue of Popular Science showed how to construct this two-tube battery operated receiver. The low power consumption made the set especially useful in case of a blackout, an ever-present wartime possibility.

The set consisted of a 3A8-GT triode-pentode which served as RF amplifier and detector. This went to a 1E7-G dual pentode, which served as the push-pull audio amplifier, driving a loudspeaker. For best volume, 135 volts was recommended (three 45-volt batteries), but excellent results could be obtained with just 90 volts. Because sets of this type sometimes had difficulty tuning the entire broadcast band, there is a trimmer in parallel with the tuning capacitor. This was adjusted to the particular part of the band to be tuned, and then stations were tuned in with the main dial.

Eighty years ago, people took things in stride, and most people considered electricity to be a luxury. If the power went out, whether because of a storm, or to blackout in case of air attack, people were able to continue their life with little interruption. And for those who put together this radio, they still had the luxury of radio, even with the power out.

These days, people view electricity more as a necessity and not a luxury. Ironically, though, it’s much easier to prepare for blackouts today. Things like batteries, flashlights, and portable radios are incredibly cheap. For some pointers on how to prepare for blackouts, see our earlier post. And for pointers on how to prepare for winter power outages (which might be a true emergency), see this post.

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Maria Luisa Sierra, NBC Shortwave, 1942

1942Aug15RadioGuideShown here 80 years ago is NBC broadcaster Maria Luisa Sierra. The Mexico City native broadcast her commentaries from New York over the network’s shortwave service, covering the activities of American women in wartime.

The photo appeared in Radio Guide, August 15, 1942.



1942 Emergency Receiver

1942JulPSEighty years ago this month, the July 1942 issue of Popular Science showed how to make this compact emergency receiver, designed to meet the requirements of defense organizations. The key to the design was the elimination of bulky B batteries. Instead, the set used only about 9 volts of plate voltage, and also cut the filament voltage in half.

The circuit could be used with either metal 6SJ7 tubes or glass 1SA6GT interchangeably. The glass tubes provided better battery economy, but the metal tubes were more durable for rough service in the field. Filament votages were extremely critical. In fact, the circuit would not function at all at the tube’s normal filament voltage. A rheostat was used to get the exact voltage needed.

With suitable plug-in coils, the set could tune from 16 to 1000 meters. One tube served as detector, with the other two amplifying the audio.

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Patriotic Salvage Corps, Winnipeg, 1942

1942JuneCKYYour first guess is that this picture taken 80 years ago was taken in England. After all, the truck proclaims that it’s going to feed families in bombed-out areas. The truck was on its way to Britain, but the picture was taken in Canada, specifically at 755 Henry Avenue, Winnipeg, the then-headquarters of the Patriotic Salvage Corps.

Like Americans, Canadians were encouraged to collect scrap materials for the war effort.  In this case, the funds received from selling those materials to industry were used to purchase this truck, and others like it.

The building above is still standing, and can be seen in the Google Street View image below.  The picture above appeared in the June 1942 issue of Manitoba Calling, the program guide of CKY.

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1942 Air Raid Alarm

1942JuneServiceEighty years ago this month, the April 1942 issue of Service magazine carried this ad for the Model AR-101 Air Raid Alarm from National Union Radio Corp., 57 State Street, Newark, NJ.

For $5 plus installation, the small device was attached to “any type of radio set,” although I suspect the radio in question had to be a superheterodyne with AVC. But since most five-tube radios of the time fit that description, it was pretty close to “any type of radio set.”

During an air raid, radio stations would go off the air, so as not to serve as a beacon for incoming aircraft. According to the ad, the stations going off the air “are usually the first indications of attack.” The ad noted that during the early air raid alarms in Los Angeles, owners of radios with this device would have received warning six to ten minutes before the sirens sounded. And inside the house, the sirens might not be noticeable.

When the station went off the air, the radio equipped with this alarm would emit a “loud siren-like tone.”

According to the ad, the alarm was “sturdily constructed of the finest quality materials, and under normal conditions should last as long as the radio set and require no attention. In fact, the unit is sealed to prevent tampering, moisture, dust, or other deteriorating factors.”

And I suspect it was sealed for another reason–to conceal just how simple the circuit was, especially given the $5 price tag. The image in the ad shows a tiny box, with only a switch and what appears to be a potentiometer. The device had four wires that connected to easily accessible points in the radio.

1957ConelradI haven’t been able to find any more information about this device, but I suspect it’s very similar or identical to the 1957 “CONELRAD The Easy Way” circuit we featured previously. In that circuit, shown here, when the radio is set into the alarm mode, the AVC voltage is used to bias the first audio tube to cut-off, rendering the radio silent. But if the station goes off the air, the AVC voltage is zero, and the first audio stage comes back to life. The output from the final audio amplifier is fed back through the capacitor, resulting in feedback, or what the ad would call a “loud siren-like tone.”



1942 Airplane Detector

1942JuneRadioCraftCoverEighty years ago this month, the June 1942 issue of Radio Craft showed this walking airplane detector, then under development for use by the Aircraft Warning Service. The headset contained a parabolic microphone and headphones. When the operator heard the low-pitch rumbling of a plane, he could turn his body for the loudest sound, at which point he could look for the approaching aircraft with his binoculars.

The batteries and amplifier were contained in a case “smaller than the usual gas mask container.”



Battle of Dutch Harbor, 1942

Today marks the 80th anniversary of the Battle of Dutch Harbor, Alaska. On June 3-4, 1942, Japanese Aircraft attacked the naval base there, resulting in the deaths of 50 Americans.  The battle marked the first ever enemy air raid on the Continental United States.



1942 Anti-Theft Sign

1942MayRadioRetailingAs a public service, we present the image above. You can print it, and when your car is parked, you can display it, facing out, on the passenger side of your car. The idea is not ours. In fact, it originally appeared 80 years ago this month in the May 1942 issue of Radio Retailing.

Many radio men had written to the magazine lamenting the fact that even though theirs was a vital profession, they didn’t have any special priorities when it came to tires or gasoline. So when they went on a service call, their car parked out on the street was a sitting duck for thieves who could steal the spare tire. In some cases, the thieves were brazen enough as to jack up the car and steal the tires, wheels and all.

Several Western salesmen had come up with the idea of the sign shown here. It would alert passers by that the owner was absent, and anyone tampering with it was unauthorized. According to the magazine, the mere presence of such a sign would in many cases scare off the thieves from making an attempt. The magazine didn’t say so, but, of course, we doubt that any thief would dare target a car after learning that the owner was a radio man. We have no doubt that it would have the same effect today.