Seventy-five years ago this month, the July 1951 issue of Radio Electronics carried this circuit for a four-tube shortwave regenerative receiver. The circuit was provided by the editors in response to an inquiry from a reader, who specified these specific tubes. They are familiar as coming from an “All-American Five” AM radio, so they were, and still are, easy to find.

Shown here 80 years ago is radio man B.F. Headrick of The Ideal Radio Service of Pueblo, Colorado, in the June-July 1946 issue of National Radio News.  Headrick had taken the National Radio Institute course, and by the 20th lesson, he started taking in some jobs in his home attic workshop. As he gained more experience, the business kept rolling in, and he charged regular prices for his work.

He later enclosed his house’s porch as his shop, and soon bought a shop of his own in the business district. He hired two more servicemen, and all three of them stayed busy 8 hours a day, 6 days a week. He had earned the reputation as the best and most honest radio repair man in town.

These 1960 obituaries for one Bueford F. Headrick seem to be the same person, and reveal that he died at about age 44.

Sixty years ago this month, the July 1966 issue of Electronics Illustrated showed how to make this 40-watt transmitter for 40 meters. It was geared mostly to the needs of the Novice, but a General-class operator could certainly make good use of it. The main feature was the fact that ten crystals were mounted internally, meaning that one could quickly change frequency with the flip of a switch.

It uses a 6CL6 oscillator and 6DQ5 final. No power transformer is required, since it uses a voltage-doubler circuit to supply the B+. Voltage is kept off the key with a relay. It is equipped with a spotting switch to quickly find your new frequency after switching crystals.

Eighty years ago this month, the July 1946 issue of Popular Science carried the plans for this simple one-tube superregenerative receiver for ten meters. Ten meters was one of the first bands allowed by the FCC after the war, and as a result, the magazine noted that hams were busily firing up their ten-meter transmitters and getting on the air. The band was hot at that time, and the magazine promised that you were likely to hear stations 5000 miles away, often more than you would be able to hear stations 500 miles away. With just a handful of parts, the magazine promised that you could be listening the same day.

Eighty years ago, Hallicrafters came out with the venerable S-38 receiver. It was essentially an “All American Five” circuit, but covered three shortwave bands in addition to the broadcast band, up to 32 MHz. And it had six tubes, since one served as a BFO for reception of CW or SSB signals. It was announced in this ad from the June 1946 issue of Radio News, with a retail price of $39.50.

The receiver was a very basic communications receiver, but got the job done for many a beginning shortwave listener.  While not ideal, it was pressed into service by many beginning hams, often paired with a simple homemade transmitter.  Hallicrafters released five more versions of the S-38, dubbed S-38A through S-38E, until 1961.

Sixty years ago, ARRL Technical Editor Doug DeMaw, W1CER (later W1FB) had a transistor radio that resisted all of his attempts to fix an intermittent problem somewhere in the RF or IF sections. Undaunted, he decided to convert the radio into a 2 meter receiver. He stripped out the offending parts of the circuit, and used that portion of the circuit board to install a superregenerative detector for 2 meters. He replaced the tuning capacitor with a smaller one and used the same mount. And the earphone jack was placed into service as the antenna jack.

The circuit here uses an NPN transistor. Depending on the existing circuit, it would be necessary to use a PNP transistor for a positive ground.  The circuit is shown in QST for June, 1966.

Seventy five years ago this month, the June 1951 issue of the British publication Radio Constructor carried this idea for fabricating a switch that would turn a circuit on when the lid was opened. It was originally built for a cocktail cabinet, to turn on the lights when the lid was opened. But the author noted that it could be used for any circuit.

The cost was basically zero, since the author used an old volume control which was going to be thrown away. The volume control itself was not used (in fact, the slider was removed to make it turn more easily). Instead, only the switch was used. A spring held the switch in the off position, but when the lid was raised, the spring stretched and allowed the switch to rotate back to the on position.