Monthly Archives: May 2024

1944 One Tube Receiver

1944MayRadioCraftEighty years ago this month, the May 1944 issue of Radio Craft carried this circuit for a one-tube receiver. It had been sent in to the magazine by one Bob Smith of Montclair, NJ, who pointed out that standard plug-in coils could cover the shortwave and broadcast bands. He added one word of caution, “do not ground set.” This, of course, is because it was running straight off the AC line, and if you grounded it, there would be a 50/50 chance that you would short out the power. We, of course, will add another word of caution, namely, not to touch anything. The headphones are hot, strapped right to your head. So if you touch a grounded object nearby, there’s a 50/50 chance that the resulting current would run right through you.

A 70-watt lightbulb is used to drop the filament voltage to 12.5 volts to light the filament of the 12A7 tetrode/diode tube.



Crystal Sets for the Poor and Needy, 1924

1924May16WashA hundred years ago today, the May 16, 1924 issue of the Washington Star carried this item. Many listeners had graduated to tube sets, and radio executive Le Roy Mark wanted to see to it that their old crystal sets made it into the hands of the poor and needy of Washington. He had begun an ongoing campaign to collect old crystal sets at Piggly Wiggly and Peoples Drug stores in the District, from whence they would make it into the hands of the needy. 400 names had already been collected, but Mark requested that clergymen and physicians send him the names of others who might benefit.

The Boy Scouts of the District had volunteered to install the sets. The only expense would be the cost of antenna wire, and contributions were being solicited for that purpose.

According to his 1938 obituary, Mark was a pioneer of radio broadcasting in Washington, as well as the insurance industry. The obituary still remembered him as “a leader in the campaign to provide funds to furnish radio sets to all shut-ins, particularly to make available a sufficient number of sets to enable all hospitalized World War veterans to listen to radio programs.”



1939 Shortwave Broadcasting

1939LifeMay15a1939LifeMay15bEighty-five years ago, all of the countries that would soon be at war were gearing up for the inevitable propaganda battles, and the May 15, 1939, issue of Life magazine explained some of the technical issues involved. The Germans had an advantage when it came to broadcasting to South America, since their beam could be only half the width required by the Americans to cover the major population centers.

But as far as broadcasting to the respective homelands, the Americans had the advantage. They could blanket Europe with a narrow beam, whereas the signal from Berlin would need to be extremely wide to cover all of the United States.



1939 Portable Radios

1939MayRadioTodayThis gentleman’s technique with the canoe paddle leaves something to be desired, but his girl doesn’t even notice, because she is enthralled with the portable radio he had the foresight to bring along on their date.

Eighty-five years ago, portable radios were a hot commodity, and the May 1939 issue of Radio Today carried some pointers for selling them. In addition to the normal ideas of direct mail, window displays, etc., it suggested some other ideas. For example, it recommended to “have a clown or a fairy-story character carry a battery-operated radio playing around the streets, with appropriate signs. Thousands of people don’t yet know there is such a radio.” If the clown didn’t work out, the magazine suggested having a man with a battery-operated portable meet all he trains, or lending a radio to prominent people in the community and taking their picture.



1944 British Car Radio Installation

Screenshot 2024-04-25 11.39.45 AMEighty years ago, somewhat to the surprise of many in the industry, the British government lifted the sartime ban on radio receivers installed in cars. This was welcome news to those who still drove a car for essential purposes. And it meant that the price of secondhand auto radios in dealer’s stocks suddenly increased in price.

Because both automobile and radio dealers were swamped with work, it probably meant that the owner of a car who wanted a radio installed would need to do it himself. This, the May 1944 issue of Practical Wireless contained an article outlining the basics. The car radio installation shown above appeared on this issue’s cover.

The magazine did stress the need for a license.  The license for the receiver in your home would not cover the additional set in your car, and you would need to secure a license at the post office before tackling the installation.



1964 Radio Control Truck

1964MayEISixty years ago this month, the cover of the May 1964 issue of Electronics Illustrated shows Dad putting the finishing touches on this remote-control vehicle that he’ll be surprising Junior with. The transmitter puts out 100 mW on CB channel 23 for good range without the need for a license. One push of the button steers the truck to the right as long as the button is held down, and two pushes steers it to the left.

The editors couldn’t find any vehicles with steerable front wheels, so they bought the Tonka truck shown here and modified it by adding a steerable front axle.

Complete circuits for transmitter and receiver are included. The receiver employs five transistors, and the transmitter, three.



1924 One Tube Broadcast Receiver

1924MayBLA hundred years ago this month, the May 1924 issue of Boys’ Life showed scouts how to put together this one tube broadcast receiver. The design was the winner of a contest put on by the magazine as the very best one-tube receiver. The winner was C.H. Brown of Edgewood, Maryland.

The magazine noted that the set was not regenerative. That was good, in that it wouldn’t break into a squeal to the consternation of listeners living nearby. It could be used for ‘phone signals, modulated CW, and spark transmissions. It was, however, no good for those newfangled CW signals that were showing up on the air.

A number of tubes could be used in the set, such as a UV-199, C-299, UV-201A, or C-301A. The set used a reflex design, meaning that the tube had two functions. It first amplified the incoming RF signal, which was then detected by a crystal detector. It was then fed back to the same tube which amplified the audio. This design accounted for the extraordinary distance and volume of which the set was capable.

Total cost was said to be about $18.00.

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Schmoller & Mueller Piano Company, Omaha, 1924

19240506OmahaBeeIf you were in the market for a phonograph in Omaha, then the place to go would be the Schmoller & Mueller Piano Company, as shown in this ad from the Omaha Bee, May 6, 1924.

It wasn’t unusual for piano dealers to sell phonographs.  This made sense, since they were hedging their bets–if phonographs meant people would stop buying pianos, they were covered either way.  But this dealer took it a step further–just in case radio marked the end of phonographs, they had that covered, too.  If you bought a phonograph from them, they would throw in a free crystal set.



1924 One Tube Regen

1924MayPM01924MayPM1The plans for this unusually designed one-tube regenerative receiver appeared a hundred years ago this month in the May 1924 issue of Popular Mechanics. Nothing about the circuit, using a UV199 tube, is particularly remarkable, other than the way it’s put into effect. The main coil is stationary, but the antenna coil and ticker coil are adjustable. They are all wound spiderweb style. To increase antenna coupling, you move the antenna coil closer to the main coil. To increase regeneration, you move the tickler coil closer.

According to the article, the set could be constructed of the odds and ends that can be found on any radio enthusiast’s worktable.

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