Seventy years ago, the March 1956 issue of QST featured this two-transistor transmitter for 40 meters. The author, Laird Campbell, W1CUT, noted that the QRP rig probably wasn’t going to get a top score in any contest. It was strictly for experimenters who wanted to get up to speed on the new transistors that had recently become available. He also noted that this was probably the first time ever that QST had shown pictures of a transmitter full size!

The circuit used to CK761 transistors, running on 8 penlight batteries. Since different parts of the circuit required different voltages, multiple taps were used. Campbell reported that the set had worked many contact over the prior months, including 8 states worked. The best DX was 800 miles. All of this was accomplished by simply calling CQ, without any prearranged schedules, which he deemed unsporting. He did not the problem, though. Another station hearing his call might assume that the path was simply not there, even though the QRO signal would get through just fine. He dismissed calling “CQ QRP,” as this would be interpreted as wanting to make contact with other QRP stations. He proposed something that never caught on, namely, calling CQ TR to let the other guy know that the weak signal was the result of a transistorized QRP rig.

Seventy-five years ago, the cover of the March 1951 issue of Radio Electronics featured Robert Gunderson, W2JIO,  in his radio lob, sound studio and ham shack at the New York Institute for
the Education of the Blind.  We’ve previously seen Gunderson as the mentor, in 1941, of deaf-blind ham Leo Sadowsky, W2OFU.  But Gunderson was a remarkable figure in his own right.  He started at the Institute as a student in 1928.  Upon graduation in 1937, he was put to work heading the school’s radio vocational department.  You can see a complete biography at this link.  You can also find a good look at his work in the March 1951 issue of QST.

The magazine included an article by Gunderson regarding adaptation of test equipment for the blind.  But as the cover hints, it wasn’t just a matter of accessibility for the blind.  Gunderson made the instruments better for sighted individuals as well.  Most of his adaptations involved audible signals, showing when a Wheatstone bridge was in balance, or when two signals were zero beated.  Since these phenomena involved extremely precise measurements, they were beneficial to all servicemen.  And since the feedback was audible, even a sighted repairman benefited, since he could keep his eyes on the work while making the measurement.

One hundred years ago this month, the March 1926 issue of Popular Mechanics showed how to build this crystal set, which the magazine said could be put together for just fifty cents. A unique feature was the tuning. The coil, wound honeycomb style, was rotated through two tin plates. According to the magazine, the set would provide good volume on local stations.

One hundred years ago this month, the cover of the March 1926 issue of Radio News announced the magazine’s drawing contest, in which readers would show their ideas for the ideal radio set. I’m sure the women were delighted to see that there were special prizes reserved for them. But wait a minute….

That’s right.  Women don’t qualify for the big prizes, and “special” apparently means smaller.

These young women are now in their 90’s, but they undoubtedly have an appreciation for good music, thanks to their parents’ foresight in putting a six-tube GE model L-678 radio phonograph in their room. This ad, which appeared 85 years ago today in the March 10, 1941, issue of Life magazine, points out that they can listen to the music their mother wants them to hear, whether it’s on records (much of which was specially arranged for children) or on the radio. For only $39.95, the set had excellent tone, and it could be operated by even a three year old.

The ad also highlights the L-500 table radio for $9.95, and the JB-410 portable for $19.95.

Seventy years ago, transistors were new, and the March 1956 issue of Popular Electronics carried a number of projects to get the beginner up to speed with the new technology.  The magazine had five different projects (with more to follow the next month), all of which could be assembled with the parts shown at left.  The heart of all of them was a 2N35 transistor.  They were powered by a 9 volt battery, although the familiar version was apparently not yet on the market, six penlight cells could be used.  They could go in a holder, or simply connected together with soldered wires and tape.

The first circuit, where very little can go wrong, is the code oscillator shown below, to learn the “sound and touch of a ham’s second language.”

The next three projects are receivers.  The first is a crystal set with the transistor serving as audio amplifier.  The second is a solar-powered set using the transistor as detector.  And the third one goes back to nine volts to work as a regenerative receiver.

The final project is a transmitter, a slight variation on the regenerative receiver.  It is put into oscillation to generate the RF, and the frequency of the modulation is set by the time constant of an RC circuit.