1961 Electronic Project Lab

Sixty years ago this month, the June 1961 issue of Radio Electronics posed the question, “how can I prepare my child for today’s electronic world?” The answer was shown on the cover. A kit such as this would not make a child an electronic genius overnight, but it would let the parent find out of the child had an interest in and aptitude for electronics.

Shown here is the Heathkit Electronic Workshop model SK-50, and the magazine reviewed a number of similar kits. This one allowed the young radio fan to build 19 different electronic projects, simply by wiring the components together according to the instructions. The magazine article doesn’t state the price, but the kit was still in Heath’s 1966 catalog for $19.95.

I sometime hear it lamented that these kits are no longer available, but that’s not true. First of all, from the picture above, it would be possible to recreate the kit shown above simply by looking at the picture. But if you want to buy a similar set for Junior, then one of the Elenco Snap Circuit kits shown below fits the bill:

Ration Challenge Update: Sunday

Today was my first day of the Ration Challenge. For this week, my diet consists of the same rations provided to Syrian Refugees in Jordan. This is a fundraiser for Church World Service. You can make your donation at this link:

https://www.rationchallengeusa.org/richard-clem

My first meal is shown above. I made soup from rice, lentils, and chicken bouillon. I served it with one flatbread (which I made yesterday), which contains about 1/4 cup of flour. I am allowed one spice for the challenge, and surprisingly, the bouillon qualifies as a “spice.” It is very helpful, since it will turn just about anything into chicken soup. As an added bonus, it also provides a few needed calories.

Since I have more rice than I have flour, I decided to use some of the rice for making a cake, shown here. Using an electric coffee grinder, I turned the rice into flour and added a little oil. I added enough water for a doughy consistency, and fried it on the griddle. It was a little bland, but should go well with soup, sardines, or beans.

Dinner consisted of the rice leftover from lunch, fried with 1/4 can of sardines (and the oil in the sardine can), along with the last piece of flatbread and a glass of (unsweetened) iced tea:

To prepare for tomorrow, I made another batch of rice cakes and put them in the refrigerator. This time, I remembered to add a little salt. I also put half of my chickpeas (garbanzo beans) in to soak overnight, and I’ll add them to my soup tomorrow.

If you are able, please make a donation to Church World Service at this link:

https://www.rationchallengeusa.org/richard-clem

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Ration Challenge Update: Saturday

Here’s the bulk of what I’ll be eating Sunday as I start the one week Ration Challenge. I won’t have time to cook in the morning, so I had to do some pre-cooking.

The flatbread isn’t bad, if I do say so myself. I used one cup of flour, a half cup from the house, and a half cup from my rations. So half is to test today, and the other two breads are for tomorrow.

The rice will mostly go in soup, since I’m allowed to use chicken bouillon as my “spice.” I also started soaking half of my lentils, which I’ll add to the soup as my protein for the day.

Thank you to those who have donated already. If you are able, please consider making a small (or large) donation. I’m about $72 away from getting the luxury of one (1) vegetable to enjoy during the week! So your generous early donations will prevent needless suffering. On the other hand, if you don’t like me and want me to suffer, then wait until next Sunday evening, and make a huge donation then!

Either way, your donation helps Syrian refugees who are going through the same exercise, through no fault of their own.

Donations go to Church World Service, which has an extremely good reputation for making sure donations efficiently go to where they are needed. You can make your donation at this link:

https://www.rationchallengeusa.org/richard-clem

Eclipse Report: June 10, 2021

Wikimedia Commons photo by Anthony Quintano from Mount Laurel, United States – Statue of Liberty Annular Solar Eclipse, CC BY 2.0.

As we previously reported, we travelled to near Grand Marais, Minnesota, on the North Shore of Lake Superior, to view the annular eclipse of June 10, 2021. You win some, and you lose some, and we lost this one, as the event was completely clouded out.

Local sunrise was at 5:05 AM, and we should have seen a view similar to the one above (but probably without the Statue of Liberty). Unfortunately, we awoke at about 3:00 to the sound of rain, and the weather within a hundred miles driving distance reported cloudy.

We set out in hopes of finding a hole in the clouds, but with no luck.

The photo above was taken by New Jersey photographer Anthony Quintano, whom we thank for releasing this image on a Creative Commons license. Prints are available at his website.

Ration Challenge Update

Here’s an update on the Ration Challenge I will be taking from June 13-19. Please consider donating to Church World Service to assist Syrian refugees. You can read more and donate at this link:

https://www.rationchallengeusa.org/richard-clem

1946 Two Meter Transceiver

Seventy-five years ago, this ham was just getting back on the air after a wartime hiatus, thanks to a two-tube two meter transmitter described in the June 1946 issue of Popular Mechanics. The magazine noted that for the ham licensed prior to Pearl Harbor, as well as the newly licensed, the simple set would provide an efficient way of getting on the air for local contacts while the big rig was still under construction.

The set used a 6N4 to serve as oscillator, with a 7C5 modulating. On receive, the 6N4 became a superregenerative detector, with the 7C5 serving as audio amplifier. Also shown above is a 300 volt power supply, although another supply, such as a vibrator supply in a car, could be used to power the rig. The recommended antenna was a folded diple constructed of 300 ohm twin lead.

1941 RCA BP-10 Portable

Eighty years ago today, the June 9, 1941, issue of Life magazine showed some of RCA’s offerings. The portable was the main feature, and was billed as the perfect Father’s Cay gift. The superhet weighed in at only 4-1/2 pounds, but was a full toned powerful set. It featured a built-in antenna in the lid, and the speaker was said to pay symphony music with amazing tone and volume. The set sold for $20, and if you acted fast, they would toss in the leather case.

The set appears to be model BP-10, a four-tube set powered by a 67.5 volt B battery and 1.5 volt filament battery.

Homemade Cardiac Monitor: 1961

If Junior is looking for a spectacular science project in the field of biomedical engineering, this one is a sure winner.

Sixty years ago, the June 1961 issue of Popular Electronics showed how to construct this simple cardiac monitor. The circuit was simple, amounting to a 4 transistor audio amplifier. The diagram called for 2N279 transistors, which are apparently unobtainium today, but this substitution guide lists the 2N2431 as equivalent, and it is available at a reasonable price.

The input comes from two electrodes, one of which is placed on each arm. In this position, they will pick up the currents from the heart, which are alternating currents of up to 100 kHz. The audio portions will be audible in the headphones, and also displayed on the meter. The magazine notes that you are not hearing the actual sound of the heart, merely the amplified voltage sent to the heart muscle. Other muscles can be monitored by placing the electrodes on either side of the muscle in question.

The electrodes are simply pieces of metal placed on the body. Prior to placing them, the skin needs to be scrubbed to improve the conductivity. This is done by scrubbing with Lava soap
or Ajax cleanser. (However, since Ajax is now billed as “non-scratching”, I’m not sure it would still work.) The article notes that the device is completely safe, even for children. First of all, it runs off only three volts. And the connection to the electrodes goes through a capacitor, so even that voltage has no pathway to the body.

More advanced versions are available today, but the advanced student will almost certainly bring home the blue ribbon in the science fair by building the medical device at home.

Emergency Portable Radio Batteries: 1951

This young woman shown above in Popular Mechanics 70 years ago this month, June 1951, is using her portable radio to pull in some entertainment at the beach. But she also realizes that in a civil defense emergency, the set might have a vital role to play if the bombs started falling.

The problem, of course, is that you need batteries for the radio, and many sets had oddball shapes and sizes, some of which might not be available in the runup to an emergency. Therefore, the magazine gives some pointers on substituting what’s available. Even though the batteries might not fit in the case, with a little thought, it was a relatively easy matter to power the radio for emergency information.

Annular Eclipse, June 10, 2021

Eclipse of May 31, 2003, Bavaria. Wikimedia Commons image by Sch, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

On Thursday, June 10, 2021, much of North America will experience a sunrise similar to the one shown above. As we previously reported, on that day, there will be an annular eclipse of the sun. Normally, this isn’t a really big deal, since enough of the sun remains visible so that it doesn’t get noticeably dark outside. But this one is an exception, since it takes place at sunrise. Depending on your location, as the sun rises Thursday morning, the sun will be either a crescent or a ring.

The map below (courtesy of Michael Zeiler, GreatAmericanEclipse.com) shows approximately what the sun will look like at sunrise. In some cities, such as Minneapolis and Chicago, there will be a noticeable chunk missing from the sun as it rises that morning. Other cities, such as New York, Philadelphia, Washington, and Toronto, will have only a tiny crescent sun come over the horizon.

This map shows simulated views of the partial eclipse at sunrise. To get this view, you’ll need approved solar viewers. In general, you will get the most dramatic views of the rising eclipse along the middle curve of the three curves in this map.

As the sun is rising, it’s as safe to view as any other sunrise. But as it goes above the horizon, if you want to keep watching, you’ll need eclipse glasses or an indirect viewing method. If you still have glasses from the 2017 eclipse, you’re all set. You can also use indirect methods, as we discussed in 2017.

My original plan was to view the eclipse near Longlac, Ontario at Macleod Provincial Park. Unfortunately, the border remains closed, and it looks likely that the park will remain closed to camping due to COVID. Therefore, the official OneTubeRadio.com eclipse headquarters will be located at Cascade River State Park, near Lutsen, Minnesota. While there probably won’t be a good view of the sunrise from the campground, we will use the day before the eclipse to scout out a spot along the shore of Lake Superior to view the sunrise. That campground is fully booked, but the last I checked, there were a handful of sites available at Judge C.R. Magney State Park and Gooseberry Falls State Park. There are also some hotel rooms available in the area.

Similarly, if you’re in Chicago or Detroit, it’s worth the drive to Sault Ste. Marie to view the crescent sunrise. And if you live in New York, Philadelphia, Toronto, or Washington, all you need to do is set the alarm clock early, and find a good place to watch the spectacular sunrise.