Sixty years ago this month, the February 1957 issue of Popular Electronics
reported a first in transistor communication, with the first transatlantic amateur contact by W1OGU over a distance of 3800 miles. His transmitter is shown here. It used two Raytheon 2N113/CK761 fusion-alloy transistors.
Sixty years ago, the 1957 edition of Radio TV Experimenter showed how to make this combination lamp crystal set. It was billed as being useful not only as a lamp, but to provide Junior with a radio of his own. In an emergency, whether it was the big set being in the shop, or a power outage, it would be a source of information. And the headphones made it possible to listen late at night without disturbing others.
The crystal set circuit is unremarkable. The notable feature is the use of the electrical wiring for the antenna. The arrangment was safe, since the insulated lamp cord was simply wound a few turns around the main tuning coil, with no direct connection.
Seventy-five years ago this month, the February 1942 issue of Radio News contained one in a series of articles on the subject of homemade parts for radio construction. While the article appears to have been written before Pearl Harbor, it acknowledged that the present emergency could sharpen its teeth still further, in which case radio men might need to make their own parts. This article focused on variable capacitors, and offered a number of ideas, as well as specific details and even formulas for computing capacity.
The first idea given is shown here, a variable capacitor consisting of two cans. The inner can would be about 1/8 to 1/2 inch smaller than the outer one. A vertical support made of wood would allow the inner can to move up and down, varying the capacitance. Since adjustment was not particularly convenient, this scheme was recommended for things such as neutralization, where the adjustment only needed to be made once.
For tuning, two ideas were offered. The sliding plate condenser shown below allowed tuning by pulling one set of plates in and out.
The “book” or “barn-door” capacitor is shown at left. It consists of two hinged plates. The article notes that this idea was used commercially until about 1927. In fact, it allowed adjustment with a rotary knob, by using the scheme with a cam shown below. According to the article, this system was used by Crosley in 1926.
In most cases, the insulated portions of these condensers were made of wood, and the author offers pointers on selecting wood. Other insulators are also discussed, for use in capacitors and other applications. Cardboard was offered as a good base for coils, and the article explains how to treat the cardboard with beeswax, parafin, or other substances. For coil bases, the article recommends burnt out tubes, which it notes are discarded by most shops by the bushel.
Fifty years ago, sending an audio “letter” by tape was one way to keep in touch with servicemen overseas, but a home tape recorder was still a relatively rarity. So in this ad in the February 1967 issue of Popular Electronics, Radio Shack made an offer to send a tape to a GI anywhere in the world. The sender just had to come into the store, which would allow use of a recorder. They would even supply a free tape, mailer, and postage.
Happy Valentine’s Day! The wartime Valentine illustration here is from the cover of the February 1943 issue of Manitoba Calling, the program schedule published by CKY Winnipeg.
Sixty years ago this month, the February 1957 issue of Popular Science showed the best way to clean a typewriter. Yes, as the picture shows, ultimately, it’s just a matter of dunking it in the kitchen sink with some detergent and letting it soak.
Before you do this, however, you should read the article. It’s important to first strip down the machine of some components, to dry it thoroughly (which might involve placing it in the sun, or even in the warm oven, since you’re in the kitchen anyway), and then properly lubricating as soon as you’re done. The magazine tells you exactly how to do it.
Crystal set radio-phono, top. Middle row, compact portable set, left, one-tube set, right. Super-selective crystal set, bottom.
Seventy years ago, the venerable crystal set was old technology, but as the February 1947 issue of Popular Science pointed out that beginners and experimenters who liked to do a lot with a little skill still could do a lot with a little piece of galena. It presented the four deluxe crystal sets shown above.
Crystal set radio-phono.
The first was a crystal set radio-phono combination. The phonograph relied on cutting edge technology. Instead of a galena crystal, it used a piezoelectric crystal as the phonograph pickup. This pickup had sufficient output to drive a set of headphones directly. In fact, in some cases, the volume might be too loud, requiring the substitution of a softer needle. The radio employed a 1N34 fixed crystal, which could be tucked away inside the cabinet since it required no adjustment. The plans shown here called for an electric motor, but the article points out that a spring-wound motor could be used, resulting in a radio-phono with no need for power.
The second set, shown below, was a superselective model which allowed strong stations to be separated with the use of two tuned circuits.
The third set was the compact portable unit shown at the left, which made for an ideal travel companion. For use on camping trips, the article suggested bringing along a coil of wire and a metal stake that could be driven into the ground. To tune the entire broadcast band with one variable condenser, two sets of coils were needed, which could be wound on plug-in forms.
The final set, shown below, was for areas with weaker signals, or for use with a loudspeaker with strong signals. In addition to the crystal detector, it included a 1A5GT tube serving as audio amplifier.
A hundred years ago this month, the February 1917 issue of Popular Mechanics showed how a progressive second grade teacher used modern methods to teach her children spelling: She taught them by means of Morse Code.
As the article noted, it was a well-known truth that children learned more quickly through play than through dull hours of tedious instruction. The teacher, Miss Florence Biddle of Columbus, Ohio, discovered that she could make the children anxiously look forward to their daily spelling lesson by use of Morse code.
Miss Biddle would send words from a telegraph key at her desk. The children would then write down the dots and dashes and then translate them. Here, we can see that these children have correctly copied her send the word “fed.” The girl to the left has the dots and dashes written down, and the others have completed the process of translating. A variation in the lesson was having children send the code for words she dictated.
Miss Biddle’s method is explained in more detail in the April 1917 issue of Primary Education magazine.
According to that article, Miss Biddle’s method had spread from her own Spring Street School to other schools in the city. She originally got the idea four years earlier, and used a ruler to tap out the words. After Assistant Superintendent R.G. Kinkead saw the idea, he provided her with the telegraph instrument, and the idea spread.
That article noted that the children like to learn the code, because it “puts them in touch with the railroad and telegraph, two things which fascinate all children.” Here, from that article, we see one of your young students sending a message in response to her dictation.
If you look carefully at the dots and dashes written by the student on the left, you see that Miss Biddle was teaching American Morse, since .-. is written down for “F”. This stands to reason, since she is using a landline telegraph sounder, and American Morse would have been in use by the railroads and telegraph companies. If any of these students were inspired to get into wireless telegraph, then they would have had to learn International Morse, which varies slightly. But their minds appear resilient, and I’m sure they would have had little trouble making the transition.
A hundred years ago this month, the February 1917 issue of Boys’ Life gave some career advice to scouts who were busy working on the Electricity merit badge, by letting them know how they could become electrical engineers.
The railroads, for example, relied upon telephone and telegraph systems and power plants. The “untrained man” could start as a conductor or motorman, but would remain in the ranks of the unskilled unlesss he added to his limited daily experience by a course of study in an area such as electrical engineering.
Such study could be done through private study and reading and correspondence and night schools, as well as more formal trade and engineering schools. Even the poor boy was not necessarily barred, since the best schools were often not the most expensive.
The article noted that getting ahead after graduation meant hard, dogged work, since the graduate still had to learn many practical engineering skills to get his bearings. But there was no reason why a competent technical graduate wouldn’t be able to rise to $2000 per year.
It should be noted that the magazine’s proofreader apparently let one slip by. The Morse Code shown in the illustration reads, “BE PREPARED AND DO A GOOD TURN DAMLY.”
Seventy-five years ago today, February 9, 1942, the United States went on War Time, or year round Daylight Savings Time. At 2:00 AM that morning, all clocks were to spring forward an hour for the wartime measure, which was intended to conserve electricity.
The measure had been adopted by Congress nationwide, and was to remain in effect until six months after the end of hostilities.
Broadcasters welcomed the change. The January 19 issue of Broadcasting magazine noted that “broadcasting’s semi-yearly headache, partial daylight saving time” would disappear and that the new law “inadvertently fulfills an industry campaign favoring ‘fast’ time on a universal basis, preferably year-round.”
The clock had previously presented headaches to broadcasters, not only due to the twice yearly need to change the clock, but because daylight savings time had not been universally adopted. Some states and communities moved the clock ahead, but others didn’t. For the first time, the entire nation would follow the same scheme.
