Even though the war was over, it appears that aluminum was still in somewhat short supply, or at least expensive, in 1948, since it’s not unusual to see radios from that era using permeability tuning, which means that a variable capacitor was not required.

Here’s one such example from the January 1948 issue of Popular Science. This little one-tube set uses a 12BA6 as a regenerative detector, with a 35W4 rectifier and “curtain burner” cord to run the filaments.  Tuning is accomplished by moving a slug through the coil, changing the inductance.  The complete coil assembly was  available as a commercial part, and was listed on the parts list as merely a “permeability tuning unit for regenerative circuit.”

The accompanying article didn’t include an explanation for hooking up the dial string, since the entire assembly was commercially available, and the other parts were simply squeezed in.

Shown here on the cover of the January 1928 issue of Radio Digest is Eunice Johnson of KOA Denver, described as “the most beautiful artist” in radio.  According to the magazine, she was “still in her teens, but she sings and talks to her audience like an old timer.”

The GE station signed on in 1924 with 5000 watts, increasing to 12,500 watts in 1927.  It went to its current power of 50,000 watts in 1934.

Eighty years ago, the January 1938 issue of Shortwave and Television magazine carried the plans for this two-tube regenerative shortwave receiver.  With plug-in coils, the set would cover 550 through 9 meters. The set used two 1.5 volt tubes: The RK42 triode served as regenerative detector, and a dual RK43 provided two stages of audio amplification.

The set was capable of pulling in stations from around the world, and “there is practically no limit to which this receiver will cover. So long as general receiving conditions are favorable, this little set will work wonders.”

The use of two variable capacitors allowed for bandspread tuning, and a variable resistor was used for regeneration.

75 years ago this month, the January 1943 issue of Radio Craft carried this hint for winding coils.

The idea was sent in by one Tony Calabrese of White Plains, NY, and was billed as a good method for anyone to get a professional looking coil.

One end of a designated length of wire was attached to the wall or some other fixed object, with the other end attached to the coil form. After a couple of turns, the weight was placed on the wire to maintain tension.

When the coil was complete, the weight was slipped off, resulting in a neat coil with evenly spaced turns.

Fifty years ago this month, the January 1968 issue of Electronics Illustrated offered just the thing for aspiring spooks, namely, this homemade electronic bug. Housed in the ubiquitous cigarette pack, the tiny device transmitted on the AM band, and could be picked up 10-50 feet away.

It was billed as suitable for listening in on “your neighbor, close friend, worst enemy, bookie, business partner, the business competition, or even you.”

As shown here, the parts had a price tag of about $20, although the article noted that the price might be lower if slightly larger components would be acceptable.

The circuit used four Motorola transistors, three 2N4123’s and one MPS3646 handling the RF output duties. It was constructed on a circuit board with holes drilled for the components, with wiring on the other side.

The battery shown here is a Burgess H-177 9.8 volt battery, although the article pointed out that a standard 9 volt battery could be used if the slightly larger size were acceptable.