Category Archives: Radio history

1947 GE Radios

Seventy-five years ago, the January 13, 1947, issue of Life magazine carried this ad showing General Electric’s radio offerings, especially its FM offerings, such as the model 417 console.

1947Jan13LifeSince there were still prewar FM stations on the air, the deluxe set tuned both FM bands, 42-50 MHz and 88-108 MHz. It also tuned two shortwave bands in addition to standard broadcast. The set’s ten tubes drove a 12 inch dynamic speaker.

The ad featured actress Virginia Mayo, who had most recently appeared in The Best Years of our Lives.



1942 Radio Repairman Short Story

1942JanRadioServiceDealer1This interesting short story appeared 80 years ago in the January 1942 issue of Radio Service Dealer. The story appeared in the magazine’s “Serviceman’s Diary” feature written by contributing editor John H. Potts.

The story must have been written days after Pearl Harbor, and the author is fantasizing about an air raid warning. Ordered to shelter by a police officer, a radio repairman found himself in front of a big apartment building. Somewhat counter-intuitively, he remembered that the safest place would be on the third or fourth floor, so he went to the third floor and rang the bell of the first apartment he saw. An attractive woman answered the door, and the story has its happy ending when she falls for him after he is able to fix the radio.

It’s an interesting prediction of home front life early in the war, and makes an interesting read:



Hoosier Radio Company, Indianapolis, 1922

Pembroke Arcade. Image, historicindianapolis.com.

Pembroke Arcade. Image, historicindianapolis.com.

1922Jan9IndianaA hundred years ago today, the January 9, 1922, issue of the Indiana Daily Times carried this feature describing a radio store, Hoosier Radio Company of Indianapolis.
RADIO CREATES NOVEL BUSINESS
Wireless Telephone and Telegraph Open New Field.

Radio telegraphy, which a few years ago was regarded by the general public as only for real experts when operated on a big scale, for youngsters to amuse themselves with on a small scale, now has come to assume an important place in the life of the community, and the radio telephone Is In far more general use than the average person realizes.

This new science, developed along lines all its own, has resulted in the growth of an entirely new business, the supply business for radio equipment, according to L. H. Smith, president of the Hoosier Radio Company, 108 Pembroke Arcade.

“When radio work was Just becoming popular users of equipment found it difficult in the extreme to buy supplies. Supplies of this character were handled by only a few shops as a sideline, the clerks knew very little about them and the technical nature of the equipment made it almost impossible for anyone not enthusiastic about radio work to deal
intelligently with the trade,” Mr. Smith said.

“This led me to establish a store handling nothing but supplies for radio telephone and radio telegraph equipment. My patronage comes from about every part of Indianapolis and Includes persons of all ages from the enthusiastic school boy to the business man, who is interested in radio work. I believe that at present there are more than 1,000 persons actively interested in radio work in this city and the number is steadily Increasing.

“There has been a genera! misunderstanding In the public mind as to the expense of a radio plant. Contrary to the general belief it is not at all prohibitory. A receiving set with a range of 4OO to 500 miles under favorable conditions may be purchased for $15, and no great amount of study is necessary to use these machines.

“Radio telephony is growing more popular every day, a popularity that is increased by the concerts sent out nightly by the Commonwealth-Edison Company of Chicago. These concerts are given by the Chicago Grand Opera Company and are heard in this city and all over the country. Dally concerts are sent out by the Westinghouse Company at Pittsburgh at the same time, and by simply tuning the instrument the owner of a wireless telephone plant has his choice of the music to which he desires to listen.”

The building in which this shop was located, shown above, the Pembroke Arcade, was located in downtown Indianapolis and built in 1895. It was what we would call today a shopping mall–an enclosed building with a large number of stores inside. It was torn down in 1943.



Motorola Playmate Junior, 1947

1942JanRadioNewsSeventy-five years ago, these youngsters, shown on the cover of the January 1947 issue of Radio News, had been especially good, since Santa had brought them, among other gifts, this Motorola Playmate Junior portable radio (Model 51M1U).

The four-tube (1R5, 1U4, 1U5, 3S4) portable covered the broadcast band, and ran off batteries or AC. On AC, the set used a selenium rectifier.

Actress Jeanne Crain had apparently also been a good girl, since she is also shown with the same model in the ad below, which noted that the set was the company’s most compact portable and had excellent signal pickup and shock-resistant tubes.  It also notes that the antenna is conveniently built in to the cover.  Since the ad mentions the film “Take Care of My Little Girl,” it must have been from about 1951, meaning that the set remained in production for quite some time.



Jewel Model 5050: 1951

1952JanRadioRetailingSeventy years ago this month, the January 1951 issue of Radio Retailing carried this ad for Jewel’s combination table model/portable set, the model 5050.  The ad notes that whether on a table or being carried, the dial is always in a convenient position, and the sound is always pointing in the right direction.

The set operated on household current or battery, and featured a ferrite core antenna. The set had four tubes, 1R5, 1U4, 1U5, and 3V4



1942 Code Practice Oscillator

1942JanPMCPOEighty years ago, these gentlemen probably realized that they would soon be serving in the armed forces, and their stint would probably be more comfortable if they came to their induction in possession of a skill useful to Uncle Sam. Therefore, they have undertaken to learn Morse Code, thanks to this one-tube oscillator described in the January 1942 issue of Popular Mechanics.

The set used a single 117L7-GT tube, whose 117 volt filament meant that it could run straight off the AC power lines, without worrying about dropping resistors or transformers. It had plenty of volume, which could be controlled with a volume control, to drive a speaker or up to 20 pairs of headphones for group practice.

1942JanPSCPOschematic



William F. “Billy” White III, K5CBZ

I am not old enough to have to have worried about contracting polio, but I am old enough to have known people who suffered from the effects of polio. Amateur radio has always served as a window on the world for those with many types of disabilities, and I had the pleasure of meeting many hams who were handicapped as the result of polio.

Thanks mostly to the vaccines of the 1950s, North America saw its last case of polio in the 1970s, and children and their parents no longer had to worry about contracting it. But there were still many survivors of the disease when I was growing up in the 1960s and 1970s, and largely because I was a ham, I had the pleasure of meeting many of them.

One example was profiled in the December 1961 issue of QST, thirteen-year-old William F. “Billy” White III, K5CBZ, of Corpus Christi, Texas. White had been confined to an iron lung for eight years, and it was from that location where he spent all of his time, doing his school work, reading, and watching television. But recently, he had added to his repertoire the magic of amateur radio.

His first novice station was installed by a group of local hams, but could be operated only when he was out of the respirator, meaning that the time on the air was extremely limited. When he passed the Conditional test, a permanent solution had to be found. And thanks to the local hams, it was. It was decided that a Collins KWM-2 transceiver would be a good choice since it was relatively lightweight at 18 pounds and completely self contained. It was possible to mount the transceiver directly on the iron lung using fittings that were normally used for items such as mirrors and book holders. The set was mounted vertically, and could be removed and reinstalled in a matter of seconds.

Billy was able to operate the controls using a spatula held in his mouth. The only exceptions were the band switch and transmitter tuning. But when those were set, he could operate the set by himself.

During Hurricane Carla, Billy handled a considerable amount of emergency traffic from his station. When power at his house failed, the local hams delivered a generator, which powered both the radio and the iron lung.

Billy died in 1967 at the age of 19. But for the last six years of his life, as the article notes, “daily he traveled the airwaves, visiting friends, meeting new people, and filling his time through the magic of amateur radio.”

For people with disabilities who are interested in learning more about amateur radio and other assistive technology, we recommend you contact the Courage Kenny HandiHam Program, which has carried out that mission since 1967.



KIRO Seattle; Milton Shaw, 1917-1944

1941Dec29BCEighty years ago today, the December 29, 1941, issue of Broadcasting showed Private Milton Shaw of Cleveland, Georgia, standing guard over the 50,000 watt transmitter of KIRO, Seattle, sited on Vashon Island. The soldier was one from the 41st Division. The magazine claimed that the station was “located in the center of a large colony of Japanese nationalists.” The magazine noted that the station was the only 50,000 watt station north of San Francisco and Salt Lake City.

free-vector-poppy-remembrance-day-clip-art_106032_Poppy_Remembrance_Day_clip_art_smallAccording to this source, Shaw was killed in Action in New Guinea on June 17, 1944, and his remains are buried at Oakwood Cemetery, Oakwood, Georgia.



Worldwide TV: 1951

1951DecPMSeventy years ago this month, the December 1951 issue of Popular Mechanics carried a feature with the byline of RCA Chairman of the Board David Sarnoff discussing the prospects of international television. He predicted that before long, viewers would be able to bring exciting events from distant lands to their armchairs with a flick of the dial, all at the instant they’re taking place.

He outlined the ways this might happen, but interestingly, he fails to mention the technology that did make it happen, namely orbiting satellites.

His most promising idea is shown above, namely a network of microwave relays about 20-50 miles apart. This network was already taking shape in the US, and Sarnoff pointed out that it could easily be expanded from Patagonia to Alaska. And since it was only 40 miles acroos the Bering Strait, there was no technological reason why the network couldn’t be thus extended into Eurasia, and from there to Africa. He notes that there were plans for a telegraph land line along the same route 90 years earlier, which was abandoned only after the success of the transatlantic telegraph cable.

Another idea for connecting America and Europe was a string of artificial islands in the Atlantic, 200 miles apart, each with a 1000 foot tower.

We’ve previously mentioned the idea of stratovision, namely, using aircraft both to broadcast and relay programs. Sarnoff hinted at a possible expansion of this system to link America and Europe. He noted that there were already enough commercial flights flying the route, and that if these planes were fitted with television relays, they could provide a permanent microwave link across the Atlantic.



Science Fair Idea: Electrostatic Precipitator

1946DecPS1946DecPS2Seventy-five years ago this month, this young woman undoubtedly took home the blue ribbon of the 1946 Science Fair with this experiment in which she constructed an electrostatic precipitator to fight air pollution.  In the photo above, a column of smoke is rising.  But the moment she flips the power switch on her precipitator, the smoke ceases.  An electrostatic precipitator, known at the time as a Cottrell precipitator after its inventor Frederick Gardner Cottrell, removes particulate matter from the air through an electric charge, but does not affect the flow of gas. The same principle is used in home air purifiers such as this:

In the 1946 experiment, a column of polluted air passes through a mailing tube, where it passes through a high voltage electric field. Particulate matter clumps together as a result of the electric charge, and falls to the bottom of the tube.

We enjoy providing inspiration for projects such as these, and we hope modern school children can do the same experiments. And for this project, your young scientist will need the following items. Where available, we have provided links to Amazon:

As you see, Amazon no longer has all of the needed parts. The Model T spark coil is apparently out of production. And while this young woman had no problem bringing a pack of Chesterfields to school and nonchalantly lighting one up in the science classroom to show off her invention, it’s no longer 1946. If a kid did that today, they would probably get expelled. So if Junior wants to do this experiment today, some modification is necessary.

Fortunately, as long as your young scientist has some creativity, substitutions shouldn’t be a problem. In place of the cigarette, the original 1946 experiment allows for the use of an incense stick, and as long as Junior has the teacher’s permission, this shouldn’t be a problem.

The Model T spark coil, however, is a bit more problematic. The spark coil from a Model T was known as a trembler coil.  The device was a transformer. To be able to operate with DC, the coil operated in interrupter: When voltage was applied to the coil, the magnetic field opened the contacts of the interrupter, which turned off the coil. With the coil off, the contacts closed, allowing the coil to re-energize. The result of this on-off action was an alternating current, and the voltage of this alternating current was stepped up to thousands of volts with the transformer.

The Model T spark coil remained in production for many years after the last Model T rolled off the assembly line, and many of them found their way into things other than cars. When this experiment was published in Popular Science in December 1946, there was apparently no question that if you wanted a Model T spark coil, that finding one wouldn’t be a problem. One popular use of the coil in the early days of radio was for use in a spark-gap transmitter.

But if you walk in to the parts counter of your local Ford dealer today, they probably don’t have them any more. (On the other hand, there are still Model T’s on the road, and if you want to buy a new spark coil, they are still being made, but they’re probably too expensive, such as this one.)

The advanced student should be able to build their own induction coil. They will need a transformer and a method of interrupting the current. Experimentation with a filament transformer and mechanical buzzer will probably prove fruitful. Our earlier post describing a spark coil should give the advanced student enough information to construct one that is essentially identical to the Model T version.

The school might already have the equivalent stashed away in the back room of the science lab, or you could convince the teacher to spend some of the science budget on one of these:

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