Category Archives: Radio history

1949 Combination Receiver/Signal Generator

Screenshot 2024-01-12 12.43.23 PMThis utilitarian-looking three-tube British device appeared in Practical Wireless 75 years ago this month, January 1949. It has considerable utility, as it functions as both a regenerative receiver and signal generator.

The regenerative receiver, of course, causes oscillation that can be radiated through the antenna jack. But this circuit does one better, because it turns the audio amplifier into an oscillator, which modulates the signal. Therefore, when working on another piece of equipment, you have a handy source of tone modulated RF. And when you’re done troubleshooting your other device, you can tune in programs from 3000 to 10 meters. Thanks to the second harmonic, you can use it as a signal generator up to five meters.

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1924 One-Tube Loudspeaker Set

 

1924JanPSThe plans for this handsome one-tube receiver appeared a hundred years ago this month, in the January 1924 issue of Popular Science. The regenerative set, when used with a high-quality loudspeaker, was capable of producing volume to fill a large room, with but a single tube. The secret was the antenna coil, which served as an autotransformer to boost the signal in the regenerative circuit.

The set was both sensitive and selective. When tested in New York City, within a couple of miles of some strong broadcast stations, it easily pulled in more distant stations. And with a 100 foot antenna, the author reported pulling in Chicago with loudspeaker volume.

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1944 Intercom

1944JanPSEighty years ago, there was a war going on, but in his workshop, this gentleman had a power supply capable of putting out 250 volts and six volts. He also had a few tubes lying around, so he put together this audio amplifier, which he used as an intercom. The master station was down in the shop by his power supply, and he mounted a speaker in the kitchen. It was fed with a single wire, with water or steam pipes serving as the second conductor.

From the shop, he could monitor what was going on in the kitchen. And when his wife announced that lunch was almost ready, he let her know he was on the way up. The amp could also be used for a phonograph, as shown in the schematic.

The circuit appeared in the January 1944 issue of Popular Science.

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1924 Air-Way and Savoy Jr. Radios

1924Jan18WashEveStarIf you were in the market for a very nice radio a hundred years ago, you couldn’t go wrong with this four-tube Air-Way receiver. For only $114.50, you would get everything you needed, including a Perfectone speaker, a complete antenna, and both of the batteries. You could get it at The Hecht Co., 624 F Street, Washington. Of course, that was a lot of money, according to this inflation calculator, over $2000 in 2024 money.

1924Jan18WashEveStar2If you couldn’t swing that much, you could head down to Haverford Cycle Sales Co., 522 10th St. NW (conveniently across the street from Ford’s Theater), and get this one-tube Savoy, Jr., which was guaranteed to pull in the DX stations clear and strong. It also came with everything you needed–radio, tube, batteries, antenna, and headphones. And with a small down payment, you could take it home with a promise to pay a dollar a week.

The ads appeared in the Washington Evening Star, January 18, 1924.



1949 RCA Victor FM

1944Jan17LifeSeventy-five years ago today, the January 17, 1949, issue of Life magazine showed these two FM offerings from RCA Victor.

The nine-tube model 8V90 stood only 33-1/4″ high and 31=1/4″ wide, but included standard broadcast and FM with “RCA Victor’s own simpler, more sensitive Frequency Modulation circuits.” The fine record changer featured a sapphire pickup with no needles to change. The 18th Century-style cabinet also featured a record storage compartment.

For those looking for an FM table radio, the seven-tube model 8X71 was beautifully styled in rich maroon or antique ivory-finish plastic.



Police Radio Car, 1924

1924JanRadioNewsFor the last hundred years, criminals might have been able to outrun the police, but they can’t outrun the radio, as shown by the cover of Radio News, January 1924.

The accompanying article by Armstrong Perry describes this radio car employed by Scotland Yard. While the truck runs at 40 MPH, the officer in back can chat with headquarters, other cars, or even an airplane overhead. The receiver had six tubes, and the transmitter was said to get out 30 miles.



1924 Crystal Set

Screenshot 2023-12-30 5.07.16 PMOne hundred years ago this month, the January 1924 issue of Popular Mechanics showed how to put together this simple crystal set, which had been submitted by one F.L. Brittin of Chicago. In the 1950s and 1960s, it appears the Brittin went on to become the magazine’s radio editor.

The set was said to cost about 65 cents to build, and had excellent results pulling in stations up to 20 miles away. The honeycomb coil is homemade, and the insulation is carefully removed along a path for the slider, which tunes in the stations.

If you want to duplicate this design, be sure to check out our crystal set parts page.



On The Radio 1924

1924Jan11WashTimesA hundred years ago today, these were your choices for radio listening, according to the January 11, 1924, issue of the Washington Times.

At 6:15 PM, for example, you could tune in an organ recital on KDKA Pittsburg on 326 meters (920 kHz). Or, if you preferred, WOR in Newark was running a lecture on Mouth Hygiene on 405 meters (741 kHz).

At 10:30, you could pull in Paul Specht and his orchestra on WJZ, New York, 455 meters (659 kHz). If you happened to have missed the show, you can buy his CD on Amazon.



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1939 Combination Radio-Lamp

1939JanPSThis woman appears to have a high level of admiration for her lamp. And the admiration is well deserved, since it’s not just a lamp. Instead, it has a four-tube radio receiver in its base, with the loudspeaker at the top. A single plug-in cord provided power to both the radio and the lamp, and the lamp was available in several color combinations.

It was shown 85 years ago this month in the January 1939 issue of Popular Science.



1939 British Two-Tube SW Receiver

1939JanPracMechEighty-five years ago this month, the January 1939 issue of the British magazine Practical Mechanics carried the construction plans for this two-tube shortwave receiver.  The exact circuit is a little hard to follow, since the magazine included no schematic diagram.  Instead, only the pictorial diagram below is shown.  But the left knob served as coarse tuning, with the center knob for fine tuning.  The control on the right appears to control regeneration.

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