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.
Category Archives: Radio history
Four 1947 Crystal Sets
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.
Teaching Morse Code To Second Graders: 1917
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.
1917 Career Advice for Scouts: Electrical Engineering
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.”
US Goes on War Time: Feb. 9, 1942
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.
1937 Popular Mechanics Crystal Set
Eighty years ago this month, the February 1937 issue of Popular Mechanics showed how to put together this simple crystal set, noting that most of the parts could be found in the experimenter’s junk box.
The set was housed in a homemade wooden cabinet with the tuning dial, crystal detector, and headphone connections on the front plywood panel. The article noted that the set, which was sensitive and selective enough to pull in most local stations, “looks something like a regular tube-type receiver.”
The set’s circuit, as revealed by the diagram below, is a typical crystal set, although the switching arrangement for the coil appears a bit more complicated than necessary. However, I guess the second switch makes it look more like a regular tube type receiver.
If you’re thinking of duplicating a crystal set such as this one, please check out my Crystal Set Parts Page for some ideas on where to track them down.
1917 New Jersey Amateur Station
A hundred years ago today, the February 6, 1917 edition of the Philadelphia Evening Public Ledger carried this picture of an unidentified New Jersey amateur radio station.
The photo’s caption notes that there were more than 200 such stations in the seven New Jersey counties adjoining Philadelphia.
1947 Radio-Phono Service Call
If you think something untoward is happening in this picture from 70 years ago, then you’re wrong. This radio-phono serviceman is simply making an ordinary service call, and it was important for him to bring the right parts. This ad from Astatic reminds him that it was always best to use exact manufacturer replacement parts, and that was especially true when it came to phonograph pickup cartridges.
To keep a service call from getting out of hand, the serviceman was advised to carry in his service kit a wide variety of pickups.
The ad appeared in the February 1947 issue of Radio Maintenance.
SWL’ing 1957
Sixty years ago this month, the cover of the February 1957 issue of Popular Electronics showed this avid SWL tuning the foreign shortwave bands with her Hammarlund HQ-110 receiver.
She was able to tune in numerous English-language programs thanks to the extensive listing of broadcasts contained in the magazine. Among the selections was Radio Moscow as shown in the photo below of these comrades working the console.
Groundhog Day 1942: Last Prewar Automobile
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Seventy-five years ago today, America celebrated its first Groundhog Day of the war. But because of wartime censorship, the groundhog’s report was not made public. Here, the Chicago Tribune, February 2, 1942, announces that the reports will not be available.
During the war, weather reports could have proven useful to the enemy, and were largely prohibited. Newspapers were allowed to print the Weather Bureau’s official forecast, but no other commentary was allowed. Certainly, an accurate prediction of whether or not the country would endure another six weeks of winter would not be permitted, as this information would be vitally important to the enemy.
Broadcasters even had to be careful with any mention of the weather. For example, even sports announcers were supposed to refrain from giving the weather conditions affecting the game. With enough such reports, an enemy listener would be able to piece together conditions throughout the nation. The idea was simply to deprive them entirely of that possible source of information.
The requirements for broadcasters were printed in the January 19, 1942, issue of Broadcasting:
Weather reports for use on radio will be authorized by the United States Weather Bureau. This material is permissible. Confirmation should be obtained that the report actually came from the Weather Bureau. Special care should be taken against inadvertent references to weather conditions during sports broadcasts, special events and similar projects.
Information concerning road conditions, where such information is essential to safeguarding human life, may be broadcast when requested by a Federal, State or municipal source.
Groundhog Day 1942 also saw the end of prewar auto production, as the U.S. auto industry geared up for war. The photo at the top of the page is the last automobile to be produced until the war ended. This gray Buick rolled off the assembly line at 1:31 PM, February 2, 1942, as shown in the February 16, 1942 issue of Life magazine.
The groundhog at work during peacetime.