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.

…read more

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.

…read more

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.

…read more

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.

…read more

Three new radios were introduced last month at this year’s Japan Amateur Radio Leage (JARL) Ham Fair, including:

• the Icom IC-7760
• the Yaesu FTX-1F
• a new mobile VHF/UHF transceiver from Kenwood

Icom IC-7760

Icom tried to get hams talking about the new IC-7760 by displaying a bunch of prototype board under a plexiglass case at the Dayton Hamvention. It generated some buzz, but in general, most hams here in the U.S. took a wait-and-see attitude.

When it was finally unveiled, many were disappointed, mostly because of the price, I think. DXZone reported that “the initial price in Yen was approximately $6000 or 5400 €. Just a few weeks later, European dealers began publishing the official IC-7760 price at around 6650 €, significantly higher than the original estimate.” None of the U.S. dealers has published a price for the radio yet.

The radio does have some interesting features, including:

• 200 W output
• Separable control head and RF deck
• In-house remote operation through a wired LAN
• Two displays, 7-inch wide and 2.4-inch

The question is whether theses features justify the high price. Members of the IC-7610 mailing list don’t seem to think so. One of them noted, “I think the biggest competition to the 7760 will be the 7610, at nearly half the price and with very similar features, my guess is that few will opt for a 7760 unless they ‘just have to have one….'”

Yaesu FTX-1F

The FTX-1F is Yaesu’s replacement for the very popular FT-817/818. Its features include:

• SSB, CW, AM, FM and C4FM digital modes
• SDR technology and 3DSS (3-Dimensional Spectrum Stream) on a 4.3-inch high-resolution full-color touch display panel
• Two independent receivers for true simultaneous dual-band operation, whether in the same band or in different bands.
• USB ports support CAT operation, audio input/output and TX control
• 9 hours battery life on HF bands, 8 hours on V/UHF bands

Like the IC-7760, it’s not currently available from U.S. dealers, so the pricing isn’t set yet, but the word is that it’s going to cost around $2,000 when it’s finally released sometime in 2025. That’s quite a bit higher than the price of the FT-817/818, but it does have more features, and presumably, better performance.

Like the IC-7760, the question is whether these features justify the higher price. There are lots of interesting comments about this on qrper.com.

Kenwood mobile transceiver

The last announcement from the JARL Ham Fair is a new mobile radio from Kenwood. Details on this radio are sketchier than for the other two, but hamlife.jp reports the following:

• Compatible with D-STAR and APRS. 
• Separate controlunit and RF deck.
• Built-in GPS receiver
• USB ports on both the control panel and the radio body.
• Currently developing it for release in 2025.

They also report that, “Price is expected to be higher than the TH-D75.” That puts the price north of $750.

The question that I have with regard to these new radios is are they making ham radio better? This is only a partly-baked idea, but please stick with me on this. I can see where these new radios might make Icom, Yaesu, and Kenwood more money, but I don’t really think that they make ham radio better.

First, how many hams can actually afford a $6,000 radio? And of those, how many will actually buy one? I’d love to see Icom’s marketing study for the IC-7760. Same goes for the Yaesu FTX-1F and the yet-unnamed Kenwood radio.

Second, I teach a lot of ham classes, and work with a lot of new hams, so I have a particular point of view here. That being the case, I’m not so sure that I’d counsel a new ham to buy one of these three radios. These are not radios for people just getting started in the hobby.

I think that what we need are more radios like the HF Signals sBitx. The sBitx is a reasonably-priced radio that offers reasonable performance at a price that’s affordable. And, it’s hackable, too!  It’s not the perfect radio, but it’s certainly more accessible.

As I say, this is just a partly-baked idea, so I’d love to hear what you think. What features should a radio have to make the hobby better for all radio amateurs.

Last week, I attended DEFCON, where I gave my “Ham Radio for Hackers” talk and mingled with a number hacker types. This talk seems to have struck a chord. It was featured on Hack-a-Day, and recently, Steve Stroh, N8GNJ, commented that I am “fast becoming the Amateur Radio Evangelist of techies / hackers / makers.”

All this has got me thinking, though, that perhaps I’m not really walking the walk, so to speak. After all, I’m using an Icom IC-7610 in the shack and an Elecraft KX-3 out in the field. I am using a K3NG keyer that I built as my main keyer, and I have been building my own antennas and baluns, but to really earn the title “ham radio hacker” perhaps I need to step up a little more.

So, how do I really earn that title? What comes to mind is that I could sell my current closed-source gear (dare I say appliances) and go with all homebrew and/or open-source gear. For example, for the shack, I could sell my IC-7610 and purchase an HF Signals sBitx. The sBitx is a 40 W, fully open source, high performance HF SDR transceiver with built-in digital modes, including FT8, RTTY, PSK31, and more, in addition to CW and SSB. Based on a Raspberry Pi 4, this radio is very hackable.

For VHF/UHF operation, I could go with any of the radios that support OpenRTX. Open RTX supports M17 on some radios, too. There’s also the Quansheng UV-K5. There are many open-source firmware hacks for this radio.

Antennas I pretty much have covered. I bought a Buddipole about 15 years ago, but aside from HT antennas, that’s the only commercial antenna that I currently own.

These are all just partly-baked ideas at this point. I don’t know if I’ll ever actually do this, but now that I’m retired, I certainly have the time to do it. Please let me know what you think. Are there other cool open-source/homebrew projects out there that I should also consider?

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Field Day gets many mentions

This year, Field Day got more publicity this year than any year that I can remember. My Google Alerts was almost overflowing with links to stories in local newspapers. One of the stories that got mentioned a lot was “Colorado’s ham radio operators are ready for an emergency—just don’t call them amateurs.” It’s worth reading.

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.

On Thursday, May 16, I attended Four Days in May (FDIM), an event put on by the QRP Amateur Radio Club International (QRP ARCI). The first FDIM was held in 1996, and QRP ARCI has held it every year since, excluding the Covid years. This year, nearly 300 people attended the event.

Like the name implies, there are FDIM events on Thursday, Friday, Saturday, and Sunday, but the main event is the series of talks on Thursday. These start at 8 am and run until 5 pm. This year, the talks included:

• The Construction and Use of a WhoZat by Jack Purdum, W8TEE. Jack is a retired professor from Purdue University, a frequent speaker at FDIM, and the designer of many microcontroller-powered ham radio projects, including transceivers and antenna analyzers. This year, he talked about his latest design, the WhoZat. WhoZat is a portable, battery-powered device that allows an operator to type in a call sign prefix and obtain information about the country associated with the callsign. It will give you the country name, and the azimuthal bearing from your location to that country. One of the takeaways from this talk is that the WhoZat is powered by a Raspberry Pi Pico, and Jack encouraged everyone to consider the Pico for future projects because it has more computing power and more memory than most Arduinos.In addition to talking about the WhoZat, Jack was promoting his latest book, Digital Signal Processing and Sofware Defined Radio. It’s available on Amazon for $45.
• Top 10 Junkbox Projects by Hans Summers, G0UPL. Hans is the genious(?), madman(?), entrepreneur(?) behind QRP Labs. In this talk, he extolled the virtues (as I have done) of a well-stocked junkbox. The project that resonated the most with me is the one-tube transmitter.The reason it resonates with me is that I’ve been threatening to build one for years myself. Hans actually did it, though. In fact, he made his first QSO with a transmitter he built from an ECL82 tube.At the end of his talk, Hans gave a little plug for his newest transceiver, the QMX+. The embedded SDR rig covers 160 – 6m, in a slightly bigger form factor than the QMX, for only $125. It’s incredible, really.
• zBitx–A Portable Station for the CW Operator by Ashar Farhan, VU2ESE of HF Signals. In this talk, Ashar described his zBitx, a portable CW/FT8 SDR transceiver. This isn’t a radio that Ashar is selling (yet!), but it does look like a complete design. And, of course, that design is completely open source, something he ribbed one of the other presenters about.

  

  This radio is powered by a Raspberry Pi, specifically the Raspberry Pi Zero 2 W. This module costs $15 and runs Linux. Ashar says, “If Arduino was a matchbox RC car, this Raspberry Pi is an Airbus A380, both in terms of size and speed. It can run WSJT X, fldigi, and full-stack SDR.” The radio also takes advantage of the WiFi capablity of the RPi. There’s an app that runs on a smart phone that acts as a front panel.

  At the end of his talk, instead of flogging a product, Ashar passed out a small PCB assembly called the sBitx Hat. Designed to plug into a Raspberry Pi, it includes an Si5351 clock generator and a 96 kbps, dual-channel audio codec. It looks it will be a fun thing to play with.

• Adventures of a QRP Evangelist by Cliff Batson, N4CCB, proprietor of the QRP School YouTube channel. Cliff gave us a primer on QRP operation and on how to make YouTube videos. He encouraged us all to go out and make videos. I’m not so sure about this myself. It seems to me that there is already too many ham radio videos to watch.
• Amplifying Your Adventures, Minimizing Your Power by noted YouTuber Tom Witherspoon, K4SWL. In his presentation, Tom concentrated on the personal and operating aspects of QRP, not the technical. The conclusion published in the proceedings does a good job of summarizing his talk. It reads, “Since my journey into ham radio began in 1997, I’ve encountered countless naysayers proclaiming, ‘That won’t work’ or ‘Life’s too short for QRP.’ These discouraging words often came from individuals who lacked firsthand experience in the field. Rather than accepting the pessimistic views, I’ve treated them as a checklist of challenges to overcome. my approach has been simple: get out there, experiment, and fully immerse myself in the moment. It’s through this hands-on exploration that I’ve discovered the true joy and potential of QRP operations.”
• Designing the Elecraft KH1: From Vision to Reality by Wayne Burdick, N6KR. Wayne certainly needs no introduction. His talk concentrated on how he made some of the decisions he made in designing the Elecraft KH1 hand-held HF transceiver. It was a great talk that gave quite a bit of insight into the design process. Personally, I’m not sold on the KH1, but Elecraft can’t make them fast enough, so I guess that tells you how valuable my opinion is.
• The Amazing Thermionic Valve by Greg Latta, AA8V. Greg is a professor emeritus of electrical engineering from Frostburg State University. He delved into some of the theory of how vacuum tubes work and some of the practical applications.
• Stealth Operation from Hotel Rooms and Other Unlikely QTHs by Ross Ballantyne, VK1UN.

Unfortunately, Ross was unable to present, either in person or via Zoom. According to the paper in the proceedings, Ross was part of several peace-keeping missions to remote spots around the world. On these trips, he operated from many hotel rooms and gained quite a bit of experience doing so. For example, he writes that virtually all of his antennas are made from wirewrap wire, which he gets from Ali Express. To couple the wire antenna to the transmitter, he uses a Z-match tuner or a modified Z-match tuner called the FRI match ATU. It’s a shame that Ross wasn’t able to adress us in person, as he sounds like quite an interesting fellow.

A walk with VU2ESE

After the talks, I decided to take a walk and stretch my legs. Just as I got to the street, I ran into a friend of mine, Arun, W8ARU, and Ashar, VU2ESE. We decided to walk together, and ended up walking about a mile and a half or so.

Arun and Farhan have been friends for many years. In fact, Arun hired Ashar to work for a company that Arun owned when he lived in India. (Arun now lives in Ann Arbor, MI, which is how I got to know him.) Arun once told me the taught Farhan how to solder. I confirmed that story at Hamvention last year when Ashar visited the ARDC booth.

In addition to all his development activities, Farhan recently joined the board of directors of Amateur Radio Digital Communications (ARDC), the private foundation that I retired from last May. We had a great chat about the future of ARDC and amateur radio in general, among other topics. It will be interesting to see in which direction the new board members take ARDC.

Vendor Night

Thursday evening, FDIM holds Vendor Night. It’s a great deal for vendors. There’s no charge to participate as a vendor, and it’s a lot of fun. A couple of years ago when I did Vendor Night, I also shared a booth with the Dayton Makerspace on Friday and Saturday at Hamvention and ended up selling more books in 2 hours at the FDIM Vendor Night than I did in 2 days of Hamvention.

This year, I sold about $150 worth of books. What was even better was meeting everyone, including those who have used my books to get licensed or to upgrade. For example, Tom, K4SWL, came over and shared his story with me.

He said that one year his wife said that she would also get her ticket as an anniversary present. He gave her my study guide and ten days later, she had her license. How cool is that?

Kudos to QRP ARCI for another successful FDIM. If you’d like to get a copy of this year’s proceedings, you can contact them by emailing toystore@qrparci.org or n8et@woh.rr.com. QRP ARCI also has some other goodies, if you’re interested, in their Toy Store.