Here are some articles I found intersting. The first details a cheap way to teach kids (and adults, too!) about circuits….Dan

Scrappy circuits

The best dollar you can spend on a child’s STEAM education is to take them to the dollar store, buy an electronic item, and then take it apart. Learning how a handheld fan, LED light, remote control, or headphones work will help show how wind turbines, traffic lights, speakers, keyboards, and other modern devices function.

The next step is to take apart a dollar store item and make it better — combine two items, replace a switch, create something new and unique. Scrappy Circuits is the perfect way to get started.

I first developed Scrappy Circuits with Chris Connors and Eva Luna while working at Xraise, an education outreach program at Cornell University. What began as an exploration of DIY switches ended later as a self-made invention system sourced from a fifty-cent LED tea light. Educators can build it with their class for about $20. Anyone with access to office supplies and a dollar store can make the five Core Bricks for about $1. Here’s how to create each one.

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I think that we short-change ham radio’s usefulness in getting people to pursue STEM careers…..Dan

Ham radio inspired this Scranton University student to pursue engineering

Many college students participate in sports, listen to music, or play video games in their spare time, but IEEE Student Member Gerard Piccini prefers amateur radio, also known as ham radio. He’s been involved with the two-way radio communication, which uses designated frequencies, since his uncle introduced him to it when he was a youngster. His call sign is KD2ZHK.

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I’ve always been something of a measurement nerd……Dan

Why measurements are important

Practically everything you use in your everyday life works because of measurement science. Without precise measurements, your car wouldn’t run, your phone wouldn’t work, hospitals couldn’t function, and the ATM would fail.

NIST is the national measurement institute of the United States. Most people in the U.S. have no idea that there is a single organization within the federal government that makes sure all measurements in the U.S. are correct and trustworthy — and that they are accepted by other governments worldwide.

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Copper is one of those things that we take for granted…..Dan

Copper: Conductivity Benefits and Environmental Impact

Most circuit designers probably aren’t thinking about, much less worrying about, the metal copper. But as the electrification of the world continues, copper conductors used in applications from microchips, other components and circuit boards, to household, industrial, and automotive wiring, and critical workhorses like batteries and electric motors, points to the need to spotlight its starring role.

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W3LPL on HF propagation

At an hour and a half, this video is kind of long, but if you’re interested in propagation, it’s worth watching.

W2AEW on how to use a NanoVNA to measure a filter’s characteristics

Alan, W2AEW, shows how to use a NanoVNA, which is one of the most useful tools for characterizing RF components and circuits.

Hallicrafters World of SW Radio

Back in the day, Hallicrafters was arguably the biggest name in amateur and shortwave radio. Unfortunately, this is just an audio file, but I guess, radio is audio so just close your eyes and imagine that you’re listening to this on a Hallicrafters receiver.

Tuesday, my friend Paul, KW1L, texted me, and asked if I could come over to his house and help him with his new antenna. He had just purchased and installed a Cobra Ultra-Lite Junior, and he didn’t think that it was performing as well as it should.

I won’t go into all of the details, but one of the checks he had made was to measure the continuity of the feed line, which is 80 feet of 18-gauge, 450 Ω ladder line. To do this, he connected the jumper wire in the photo at right across the ladder line in his shack and then measured the resistance at the antenna feed point.

The measurement that he came up with was 16 Ω. Well, the National Institute of Science and Technology (NIST) says that the resistance of 18-gauge solid wire should be about .0064 Ω/ft. Using that figure, the resistance should be somewhere near 1 Ω.

So, Paul asked me to bring over my DMM, which I did yesterday. We dropped the antenna, put my Fluke 79 across the feed point, and measured close to 16 Ω.

It didn’t make much sense, but the only reasonable explanation was that the problem with this measurement was the jumper wire. This was somewhat troubling to Paul, as he had a sentimental attachment to this jumper wire. It was given to him by a fellow who worked for him at Xerox, and he pointed out to me how well-made it was. He noted, for example, that each end of the wire had been tinned before it was screwed to the alligator clip.

I agreed that it was well-made, but certainly one or both of the connections could have oxidized, resulting in a high-resistance connection. And guess what? When I measured the resistance of the jumper, it turned out to be about 15 Ω!

I then unscrewed the wire at one end and measured again. It measured 15 Ω. I unscrewed the wire at the other end, and voilá, I measured 0 Ω. I screwed the alligator clips back on, and the overall resistance was near 0 Ω again. My guess is that the second connection was a little loose, and that over the years, some oxidation built up on both the wire and the alligator clip.

Whenever we do something like this, Paul likes to ask, “So, what did we learn from this?” In this case, I think what we learned is that even jumper wires can go bad. It’s also a validation of the KB6NU Theory of Electronic Failures, i.e. at least 80% of the problems associated with electronic equipment are problems with cables or connectors.