Monthly Archives: May 2019

Communicating with Mars, 1919

1919MayPSA hundred years ago this month, the May 1919 issue of Popular Science tackled the topic of communications with Mars. The magazine quoted Prof. Percival Lowell as saying that Mars is much older than Earth, and therefore it was reasonable to assume that the Martians had more time to evolve into creatures far superior to ourselves.

The magazine seemed to believe that radio waves wouldn’t do the trick. It noted that radio engineers on Earth require about 400 kilowatts to communicate 4000 miles. Thus, to make the millions of miles to the red planet, it looked bleak for wireless telegraphy.

1919MayPS2A suggested alternative was to use light, and the magazine proposed setting up a lighted display of the Pythagorean theorem in the Sahara desert. “The Martians ought to recognize that Euclidean theorem, and reply with another. Picture would follow picture, until at last some kind of interstellar code would be established.”



Wartime Diversification for Radio Dealers

1944MayRadioRetailingWith manufacture of civilian radios being suspended for the duration of the war in 1942, radio dealers had to seek other avenues to augment their income. Of course, servicing sets became especially important, but dealers also diversified, and that often meant selling records. Shown here, on the cover of the Radio Retailing for May 1944 is the colorful record display at Paramus Tire Exchange, 150 E. Ridgewood Ave., Ridgewood, N.J. The unusual name for a radio store (much less a kids’ record store) is explained by the fact that owner Cy Jacoby had diversified into the radio business in the 1920’s. The article noted that he was one of the many automotive men who took on radio way back when lots of music merchants were not interested.”

The address proved to be a good one from a merchandising point of view. With the inability to sell radios (or tires) during the war, Jacoby put together this display. In fact, since the shop was wired with intercoms, he even put a speaker behind the display and would speak to kids as the looked at the display of books and records.

1944MayRadioRetailing2The magazine warned of another kind of diversification that was illegal. Some dealers were buying broken radios and using the parts to rebuild new sets. In some cases, the rebuilding consisted of putting a refurbished chassis into a new cabinet. But the magazine reported that the War Production Board had taken the position that this was illegal.

There had apparently been no prosecutions, although the magazine did note that there had been several cases of action taken against dealers who had converted automobile sets to home use. Presumably, making the conversion at home (as described at this post and this post) were OK, but a dealer could not do the conversion and sell the set.



Electric Fences: 1939

1939MayRadioRetailingFenceThe May 1939 issue of Radio Retailing offered some advice for radio men thinking of diversifying their business–the electric fence.  The magazine pointed out that a fence needs to be “pig tight, horse high, and bull strong,” but that this ideal has never been fully arrived at.  But a small electrical jolt will encourage all animals to shun the fence completely, at a much lower cost.

The article noted that the concept of an electric fence was fairly new, and that a Wisconsin survey showed that only about ten percent of the farmers in that state were employing them.  Many states had adopted regulations prohibiting the direct connection to the electrical mains, so even in areas of rural electrification, the dealer would be able to sell batteries and chargers to satisfy the need.



1896 Phonograph “Concert”

1919MayTalkingMachineWorldToday, we take a nostalgic look back a hundred years to the May 1919 issue of Talking Machine World, which was itself taking a nostalgic look back 23 years to 1896.

The magazine reproduced this poster advertising a “concert” at the Methodist Church in Chagrin Falls, Ohio. The benefit event (with admission of either 10 or 20 cents) featured Edison’s Most Wonderful Invention, namely the phonograph. The poster pointed out that the device would reproduce “the human voice, bands, whistling, etc., etc.” And this was not some puny device that could be heard only through an ear tube. The phonograph was one which could be heard by hundreds at the same time. The concert included a recording of the chimes “by the Bells in St. John’s Cathedral,” although it’s not clear which church of that name is being referenced.

The concert was to take place at 7:30 on February 14, 1896.  The current United Methodist Church of Chagrin Falls traces its roots back to the 1830s, and reports that it built on its current site in 1884.  So it appears that the concert took place at that church’s current location of 20 S. Franklin St.

At the beginning of the 20th century, phonographs rapidly became common.  Even before most people owned one, they had an opportunity to listen.  But in 1896, the instrument was still quite a novelty, and it’s likely that most Americans had never heard one.  So it was probably well worth a dime or two to go listen to a concert featuring the greatest invention of the century.



1959 Two Transistor Portable

1959MayPM1Sixty years ago this month, the May 1959 issue of Popular Mechanics showed how to put together this two transistor receiver. While within the capabilities of the beginner, the set was a good performer. According to the article, the set was capable of pulling in stations 10-15 miles away with only the built-in antenna.

The RF amplification was handled by a 2N168A transistor. It operated as a regenerative amplifier, with a 1N66 diode serving as detector. The audio was then fed back to the same transistor, which was “reflexed” to serve as the first AF stage. A 2N170 transistor served as a second stage of audio amplification to drive the high-impedance earphone. The set was powered by four penlite cells wired in series.

1959MayPM2



Electronics Quiz from 1959

1959MayPEquizSixty years ago this month, the May 1959 issue of Popular Electronics contained these electronic brain teasers. We’re confident that most of our readers can figure them out, but just in case, we’ll show the answers tomorrow.

If you need a larger version, from most browsers, click twice on the image above.



Science Fair Idea: Does a Flame Conduct Electricity?

1939MayPSIf Junior’s science fair project is due tomorrow, there’s still time to whip together a meaningful project, and this one from the May 1939 issue of Popular Science should fill the bill. You probably have all of the necessary parts at home. If you don’t, you should be able to find them at the trusty dollar store.

This experiment answers the question, “does a flame conduct electricity?” It turns out that it does, and this experiment proves it. All Junior needs (in addition to the obligatory poster board and magic markers) is a battery (a 9-volt battery should work fine), a pair of headphones (a cheap pair of stereo earbuds will do the trick), a few short pieces of wire, and a candle.  And, of course, don’t forget to give Junior some matches or a lighter!

One terminal of the battery is hooked to the headphones. The other terminal of the battery and the other terminal of the headphones are each hooked to a piece of wire. Remove the insulation for the other end of those two wires. When Junior sticks the two wires into the flame of the candle, a clicking will be heard in the headphones, confirming that electrical current is flowing.

If Junior has more time to prepare his entry, he might want to consider more complex versions, such as the flame audion or the flame speaker.

1939MayPS2If you don’t trust Junior with matches, then the same magazine also shows the experiment shown here.  Junior will need a piece of glass, an iron, a lamp (with an old-fashioned incandescent light bulb) and a thermometer.  The glass will effectively block the heat from the iron.  The radiant heat from the lamp, however, has a shorter wavelength and will pass through the glass.  So when the iron is used, the thermometer won’t budge.  But with the lamp, the temperature will rise quickly.



1944 Car Tune-Up

1944May5MilJourA few weeks ago, we showed a snapshot of wartime grocery prices. Today, we show how much it cost to have your auto serviced 75 years ago. This ad appeared in the Milwaukee Journal on May 5, 1944.

Because of gasoline and tire shortages, it’s likely that most cars spent most of the war parked.  But even if they got little mileage, they would need occasional service.  And Sears Roebuck was there to help, with its Milwaukee service stations open until 9:00 every night except Sunday at 1337 W. Forest Home Ave. and 2100 W. North Ave.

A tune-up was $2.39 and included cleaning and inspecting the distributor, testing the coil condenser caps, and checking the spark plug wires for breakdown.  The spark plugs would be cleaned and the gap checked.

In addition, the service included inspection of the fuel pump and adjusting the carburetor.  The battery would be cleaned and refilled, and the generator, fan belt, and radiator would be inspected.

 



1969 Two Tube Superhet/Regen

1969MayEE1Fifty years ago this month, the May-June 1969 issue of Elementary Electronics showed how to put together this two-tube receiver. The set covered 1.7-30 MHz with plug-in coils. And despite having only two tubes, it had excellent performance thanks to its design, which combined a superheterodyne and regenerative receiver.

The set used two dual tubes. A 6CQ8 served as mixer and IF amplifier, with a 12AT7 serving as regenerative detector and audio amplifier. The power supply consisted of transformer and solid-state diode.

1969MayEEschematic