Category Archives: Radio history

1946 Bendix Radios

1946Jul22LifeSeventy-five years ago today, the July 22, 1946, issue of Life magazine carried this ad showing the postwar radio lineup from Bendix, manufactured by the radio division of Bendix Aviation Corporation.

One of the sets, the model 646A, was dubbed an “invisible radio,” whose “phantom dial” would disappear when turned off, turning it into a beautiful end table. You can see a nicely restored specimen at this link.

The dial is covered by wood grain, and without the dial illuminated, it does indeed blend in to the rest of the furniture. The speaker grill is at the rear, helping with the illusion. The set originally sold for $84.95.



1946 Washington Radio Listings

1946Jul20WashEveStarSeventy-five years ago today, here is what you would have heard on the radio in the nation’s capital. These listing are from the Washington Evening Star, Saturday, July 20, 1946.

Click on the image to view it full size.



1921 KDKA Organ Concerts

1921Jul19BismarckOne hundred years ago today, the July 19, 1921, issue of the Bismarck (ND) Tribune
carried this article about the organ concerts being broadcast by KDKA Pittsburgh, featuring “Famous Concert Organist” Charles Heinroth.

Heinroth was the director of music and concert organist at the Carnegie Institute. His Saturday evening and Sunday afternoon recitals were carried by telephone line to KDKA across town, and then over the airwaves by the recently licensed station. The newspaper noted that the concerts were listened to by a large list of amateurs in nearly all sections of the country.

The article predicted, correctly it turns out:

In the future, if the present developments keep on at their present pace, good music can be easily obtained by every citizen. It is fairly possible that small receiving sets will be installed in homes, in such a manner that by merely inserting a plug, recitals of the same standard as Mr Heinroth’s can be heard. That this is not a far-fetched idea is attested to by the fact that radio engineers are working on the problem at this very moment. Perfections and new adaptations have come very swiftly in the past two years so it is very probable that the individual radio set for the home is an article of the very near future.

Heinroth went on to become a professor at the City College of New York in 1932, and died in 1963 at the age of 89.

1936 Two Tube Regen

1936JulPS21936JulPSEighty-five years ago, this gentleman was showing off the two-tube broadcast receiver that he constructed according to the plans shown in the July 1936 issue of Popular Science. The set’s main claim to fame was that it didn’t require expensive and heavy B batteries. The two-tube regenerative set ran off of just nine volts on the plates, plus an additional 1.5 volt battery to light the filaments of the type 30 and type 40 tube.

The simple circuit required only nine commercial parts–a transformer, an RF choke, two variable condensers, the tubes and sockets, and a switch. The “pancake” coils were easily wound at home.

The article noted that the layout of the circuit was quite critical, but over the course of a few months, the author pulled in more than 50 stations as far as 1500 miles away, with just a 12 foot indoor antenna and no ground.

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Safely Fixing Your TV: 1951

1951JulPMSeventy years ago this month, the July 1951 issue of Popular Mechanics gave some pointers on how to safely do some repairs to your television. The magazine noted that sets were much more complex than radios, but even inexperienced owners were often able to bring a radio set back to life by swapping tubes, and there was no reason that they couldn’t do the same thing with a television.

Of course, the first step was to make sure you knew which tube went in which socket, and the magazine provided sources for this information. The second issue was the high voltages, which could prove lethal, and the magazine noted how to make sure the capacitors were discharged before tackling the job.

If the picture tube had to be replaced, one important safety factor to keep in mind was that the tube could implode if dropped, sending chards of glass all over the room. As shown above, when doing this delicate job, it was important to wear gloves and safety goggles. To dispose of the old tube, it was put in the box in which the new one came. Then, it was taken to the back yard, and a crowbar was used to smash it to smithereens inside the box, so it didn’t risk implosion when the garbage man hauled it away.



Diode Quiz

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Today’s quiz comes from the July 1961 issue of Popular Electronics. It’s tougher than it appears at first glance. The answers will appear tomorrow.



Vic Clark, W4KFC

1951JulBLSeventy years ago this month, the July 1951 issue of Boys’ Life carried a biography of Vic Clark, W4KFC.  Clark later went on to become president of the ARRL from 1982 until his death in 1983.  He was, however, already a well known ham in 1951.  His biggest claim to fame was taking first place in the 1948 November Sweepstakes.

According to the article, Clark’s interest in radio came when he happened to hear some hams on his family’s broadcast radio, and incident he said fired his interest.  He was licensed soon thereafter, as shown in the illustration above.  He went on to a career with the Civil Aviation Administration, later the Federal Aviation Administration.



1941 Code Oscillator

1941JunePMaEighty years ago, these young men were mastering the Morse code, thanks to a battery-powered code practice oscillator shown in the July 1941 issue of Popular Mechanics.  The set used a single 1Q5GT tube and was powered by two inexpensive batteries.  A 1.5 volt dry cell lit up the filaments, and a 45 volt battery provided the B+ voltage.

The magazine noted that the country had an increased need for trained radio men for the national defense program. While a buzzer and dry cell would do the trick for code practice, the smooth high-pitched tone of a vacuum tube oscillator was much preferable.

While headphones could be used, an inexpensive permanent magnet speaker is shown, which would provide ample volume for group code practice.

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