1938 Two-Tube Pushbutton Set

1938OctPM2This handsome little two-tube receiver graced the pages of Popular Mechanics 85 years ago this month, October 1938. It uses two dual tubes, so it has the performance of a four-tube set. One tube appears to serve as RF amplifier and detector, with the other one providing two stages of AF amplification to drive the speaker. The set was billed as being perfect for an extra set around the house, as a traveler’s companion, for the sick room, or for the office desk.

Tuning was accomplished with a (now unobtainium) pushbutton unit, which contained trimmers for individual stations. An alligator clip connected to the antenna (through a fixed capacitor and without a ground, as the chassis was hot).

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2023 Post-Eclipse Report

image000000 (3)My son and I were in Corpus Christi, Texas, for the annular eclipse on Saturday, October 14, 2023.  Our original plan was to view it from the Padre Island National Seashore, which we had scoped out the day before.  But when we woke up Saturday morning, it was cloudy in Corpus Christi, and weather maps showed clouds over most of the region.

There was a large break in the clouds to the north, and we decided to head that direction.  Weprojected decided to head to Rockport Beach, and this proved to be an excellent spot to view the eclipse.  This was the first time I experience an annular eclipse.  Basically, it’s a 99% partial eclipse, with the remaining 1% of the sun forming a “ring of fire”.  The photo above was taken with my son’s cell phone, using the filter from a pair of eclipse glasses.  The photo at right is using an expedient projection method.  With the pair of “cheaters” reading glasses in my pocket, I simply projected the image onto the picnic table.

rockportbeachThe phenomenon was very different from total eclipse.  It was worth the trip, but considerably less dramatic.  I could tell that it didn’t seem as bright outside as usual, but if I hadn’t known there was an eclipse in progress, I might have dismissed it as haze.  No stars were visible, although the sun didn’t seem as hot as it should.  As you can see from the photo at the left, it’s still obviously daytime.  This is very different from the total eclipse, where at least one star (the planet Venus) was visible, and there was a sunset on the horizon for 360 degrees.

The moral of the story is that if you are in an area with a 99% total eclipse, you should definitely drive a few miles to where it is 100%.  It’s worth the drive.

There was a fairly large crowd at Rockport Beach.  It was obviously smaller than they would have on a hot summer day, but I’m sure it was much larger than a typical windy October morning.  Everyone seemed to have eclipse glasses, and one group played “Ring of Fire” during annularity, which seemed like a nice touch.
image000000 (4)After annularity, most other eclipse chasers on the beach started packing up to head home, even though the partial eclipse was still ongoing.  I made an effort to operate on the radio during the Solar Eclipse QSO Party on 40 meters CW.  Unfortunately, I had an extremely marginal antenna, as there wasn’t much to attach an antenna from my location.  As you can see, I used two broomsticks taped together as the center support.  The ends, I staked into the ground.  In Minnesota, there are always plenty of sticks on the ground to use to tie down the antenna.  South Texas, with its palm trees, doesn’t have convenient sticks on the ground.  Fortunately, I had two pencils in the car, and I used them.

But my makeshift antenna was only a few feet off the ground, and I didn’t manage to make any contacts, nor was I heard by the Reverse Beacon Network.  I made a list of calls heard, and I guess I’ll submit them.

 



October 14, 2023 Annular Eclipse

You might have noticed that we’ve been kind of incommunicado lately and not posting any new content. That’s because my son and I have been on the road, selling eclipse glasses for the annular solar eclipse, which will be visible in most of North and South America on Saturday, October 14, 2023. If you still need a pair of glasses, you can find them at one of the retailers we’ve sold to from Nevada to Texas, listed at this page.

If you don’t have glasses, see our post from 2017 showing safe projection methods of viewing the eclipse.

Our official headquarters for the eclipse will be near Corpus Christi Texas, probably at the Padre Island National Seashore, as we watch the annular eclipse leave the United States and head toward Central and South America.

For hams, please listen for us (W0IS) during the Solar Eclipse QSO Party on 40 meters CW.  We will try to set up and look for contacts, probably after annularity, or shortly after noon central time.  We will be calling CQ looking for contacts, as well as making ourselves visible on the Reverse Beacon Network.  After the eclipse, other citizen scientists will analyze the data generated to see how the eclipse affects the ionosphere.  You should be able to see where we are heard at this link.  Since we will be in a National Park and on an island, we’ll also submit our logs for POTA and WWFF, as well as US Islands and/or IOTA.

For information about the exact times that the eclipse can be viewed in your area, visit this page.  For information from NASA on safely viewing the eclipse, visit this page.



1953 Transistor Radios

1953OctPMSeventy years ago this month, this electronics hobbyist is undoubtedly the first on her block to own a transistor radio of her own construction. She is showing off three coveted CK722 transistors, complete with red dots. They had been developed by Bell Labs only five years earlier, and they were still costly devices. But the venerable CK722 was “only” $7.60 each ($87.39 in 2023 dollars).  As such the well-heeled experimenter could start using them in simple circuits.

The October 1953 issue of Popular Mechanics shows two radio receivers using the new transistor. The one-transistor set is within the grasp of the beginner. And for the advanced student, the three transistor set could drive a loudspeaker. It was assumed that the expensive devices would be re-used in other circuits, so they plugged in to transistor sockets. The magazine noted the importance of marking the sockets so that the transistor was plugged in correctly. It warned that before turning on the power, to check the polarity, and then check it again. Turning it on with the wrong polarity would prove costly, since the transistor junctions would be destroyed immediately.

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1953 Novice Transmitter

1953SepRadioElec2Seventy years ago this month, the September 1953 issue of Radio-Electronics carried the plans for this economical two-tube transmitter for the novice. It ran 35 watts input power, which the author, Richard Graham, W1VJV, acknowledged was less than the legal limit of 75 watts. But the advantage was cost. At the lower power level, common TV parts could be used, making it singificantly less expensive. And on the receiving end, the difference was only half an S unit, which wasn’t even discernible by the human ear.

The rig employed a 6C4 as Pierce oscillator, driving a 6BQ6-GT final. With the coils shown, it could tune both 80 and 40 meters. At the time, the Novice did not have privileges on 40, but would be ready the moment they upgraded to General.

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Coke Ad: 1953

1953SepBLSeventy years ago, America’s youth knew how to make a party click, thanks to the spin of a record, the cut of a caper, and, of course, a bottle of Coke.

This ad appeared in the September 1953 issue of Boys’ Life.



1938 Two Tube Regen

1938SepRadioNews2Eighty five years ago this month, the September 1938 issue of Radio News carried detailed construction details for putting together this two-tube shortwave receiver. It used a 1B4 as regenerative detector, followed by a 1F4 as audio amplifier.

The set tuned 160 through 10 meters, and the author advised that the beginner should start on 160 meters, since most signals will be relatively local and easy to tune in. He also gave pointers on which bands would work best at different times of day.

The article concludes by noting that once the reader becomes acquainted with the operation of the set, it would be a reliable and consistent way to bring to your headphones most of the DX signals of the world.

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Total Solar Eclipse of September 10, 1923

1923SepSciInvA hundred years ago this month, the cover of the September 1923 issue of Science and Invention was celebrating the total solar eclipse that was to take place on September 10, 1923.

1923SepSciInv2In the U.S., the path of totality covered only a tiny sliver of southern California, including the city of San Diego, as well as Santa Catalina and the Channel Islands. The best view, however, was in Mexico, since the path extended from Baja California to Yucatan. The Mexican National Government, as well as the governments of San Luis Potosi and Mexico City were heavily involved. The National Observatory and the Mexican National Railway were also assisting in preparations, and astronomers from around the world were preparing to descend upon the country.

Of course, we have two eclipses coming up in short order. The warm-up act will be the annular eclipse of Saturday, October 14, which will extend from Oregon to Texas, then into Mexico and Central and South America. It will also be visible as a partial eclipse in most of North and South America. Since the moon is currently too far from the earth for a total eclipse, the sun will appear to be a “ring of fire” along the path. While this phenomenon is certainly interesting, it’s not really spectacular.

The spectacular event is coming up on Monday, April 8, 2024, when a total eclipse will be visible along a line from Mazatlan, Mexico, and then in the United States and Canada, along a path from Texas through Maine. While the annular eclipse isn’t worth a special trip for most people, the total eclipse certainly is, just as it was a hundred years ago.

For the annular eclipse, and for all but a few minutes of the total eclipse, you will need eye protection to view the partially eclipsed sun. Our sister site, MyEclipseGlasses.com, has approved eclipse glasses available for only $3.99, with free shipping anywhere in the world. Just like eclipse glasses in 2017 (and just like toilet paper in 2020), they’ll be in short supply, so the time to order is now.



1948 3-Tube Shortwave Receiver

1948SepPracWirSeventy-five years ago this month, the British Practical Wireless carried the plans for this handsome three-tube shortwave receiver. It used homemade coils. It would drive a speaker, but for pulling in weak stations, or for amateur radio use, headphones could be used.

The coils are mounted under the chassis, and were switchable from the front panel.

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Emerson 747 Pocket Radio, World’s Smallest Radio: 1953

Emerson7471953SepRadioElecAt first glance, the radio above appears to be a transistor radio from the late 1950s or early 1960s. But it’s not. While the transistor had been invented when this radio came out in 1953, it didn’t use any. Instead, it’s a four-tube radio, employing flat miniature tubes. While most often used in hearing aids, this radio made use of those tubes, and for $40, you could have what was rightly the world’s smallest radio. While other radios might have been smaller, they were essentially novelties, requiring headphones and often an external antenna. This four-tube superhet pulled in the stations with an internal ferrite antenna, and the sound from the 2-1/2 inch speaker could be heard across a large room.

The announcement at left appeared 70 years ago this month in the September 1953 issue of Radio Electronics. The ad above is courtesy of Joe Haupt from USA, CC BY-SA 2.0, via Wikimedia Commons. The set retailed in 1953 for $40. You can learn more about it and view a pristine example at the video below.