SDRs have been a game changer for radio hobbyists, but for ham radio applications, they often need a little help. That’s especially true of SDR dongles, which don’t have a lot of selectivity in the HF bands. But they’re so darn cheap and fun to play with, what’s a ham to do?

[VK3YE] has an answer, in the form of this homebrew software-defined radio (SDR) helper. It’s got a few features that make using a dongle like the RTL-SDR on the HF bands a little easier and a bit more pleasant. Construction is dead simple and based on what was in the junk bin and includes a potentiometer for attenuating stronger signals, a high-pass filter to tamp down stronger medium-wave broadcast stations, and a series-tuned LC circuit for each of the HF bands to provide some needed selectivity. Everything is wired together ugly-style in a metal enclosure, with a little jiggering needed to isolate the variable capacitor from ground.

The last two-thirds of the video below shows the helper in use on everything from the 11-meter (CB) band down to the AM bands. This would be a great addition to any ham’s SDR toolkit.

We’re not very far into the AI revolution at this point, but we’re far enough to know not to trust AI implicitly. If you accept what ChatGPT or any of the other AI chatbots have to say at face value, you might just embarrass yourself. Or worse, you might make a mistake designing your next antenna.

We’ll explain. [Gregg Messenger (VE6WO)] asked a seemingly simple question about antenna theory: Does an impedance mismatch between the antenna and a coaxial feedline result in common-mode current on the coax shield? It’s an important practical matter, as any ham who has had the painful experience of “RF in the shack” can tell you. They also will likely tell you that common-mode current on the shield is caused by an unbalanced antenna system, not an impedance mismatch. But when [Gregg] asked Google Gemini and ChatGPT that question, the answer came back that impedance mismatch can cause current flow on the shield. So who’s right?

In the first video below, [Gregg] built a simulated ham shack using a 100-MHz signal generator and a length of coaxial feedline. Using a toroidal ferrite core with a couple of turns of magnet wire and a capacitor as a current probe for his oscilloscope, he was unable to find a trace of the signal on the shield even if the feedline was unterminated, which produces the impedance mismatch that the chatbots thought would spell doom. To bring the point home, [Gregg] created another test setup in the second video, this time using a pair of telescoping whip antennas to stand in for a dipole antenna. With the coax connected directly to the dipole, which creates an unbalanced system, he measured a current on the feedline, which got worse when he further unbalanced the system by removing one of the legs. Adding a balun between the feedline and the antenna, which shifts the phase on each leg of the antenna 180° apart, cured the problem.

We found these demonstrations quite useful. It’s always good to see someone taking a chatbot to task over myths and common misperceptions. We look into baluns now and again. Or even ununs.

When all else fails, there’s radio. Hurricane Helene’s path of destruction through Appalachia stripped away every shred of modern infrastructure in some areas, leaving millions of residents with no ability to reach out to family members or call for assistance, and depriving them of any news from the outside world. But radio seems to be carrying the day, with amateur radio operators and commercial broadcasters alike stepping up to the challenge.

On the amateur side, there are stories of operators fixing their downed antennas and breaking out their field day gear to get on the air and start pitching in, with both formal and ad hoc networks passing messages in and out of the affected areas. Critical requests for aid and medication were fielded along with “I’m alright, don’t worry” messages, with reports from the ARRL indicating that Winlink emails sent over the HF bands were a big part of that. Unfortunately, there was controversy too, with reports of local hams being unhappy with unlicensed users clogging up the bands with Baofengs and other cheap radios. Our friend Josh (KI6NAZ) took a good look at the ins and outs of emergency use of the amateur bands, which of course by federal law is completely legal under the conditions. Some people, huh?

Also scoring a win were the commercial broadcasters, especially the local AM stations that managed to stay on the air. WWNC, an AM station out of Nashville, is singled out in this report for the good work they did connecting people through the emergency. As antiquated as it may seem and as irrelevant to most people’s daily lives as it has become, AM radio really proves its mettle when the chips are down. We’ve long been cheerleaders for AM in emergencies, and this has only served to make us more likely to call for the protection of this vital piece of infrastructure.

Windows 10 users, mark your calendars — Microsoft has announced that you’ve got one year to migrate to a more profitable modern operating system. After that, no patches for you! If Microsoft holds true to form, the scope of this “End of Life” will change as the dreaded day draws nearer, especially considering that Windows 10 still holds almost 63% of the Windows desktop market. Will the EOL announcement inspire all those people to migrate? Given a non-trivial fraction of users are still sticking it out with Windows 7, we wouldn’t hold our breath.

Speaking of Microsoft, for as much as they’re the company you love to hate, you’ve got to hand it to them for one product: Microsoft Flight Simulator. It seems like Flight Simulator has been around almost since the Wright Brothers’ day, going through endless updates to keep up with the state of the art and becoming better and better as the years go by. Streaming all that ultra-detailed terrain information comes at a price, though, to the tune of 81 gigabytes per hour for the upcoming Flight Simulator 2024. Your bandwidth may vary, of course, based on how you set up the game and where you’re virtually flying. But still, that number got us thinking: Would it be cheaper to fly a real plane? A lot of us don’t have explicit data caps on our Internet service, but the ISP still will either throttle your bandwidth or start charging per megabyte after a certain amount. Xfinity, for example, charges $10 for each 50GB block you use after reaching 1.2 TB of data in a month, at least for repeat offenders. So, if you were to settle in for a marathon flight, you’d get to fly for free for about 15 hours, after which each hour would rack up about $20 in extra charges. A single-engine aircraft costs anywhere between $120 and $200 to rent, plus the cost of fuel, so it’s still a better deal to fly Simulator, but not by much.

And finally, we were all witness to a remarkable feat of engineering prowess this week with the successful test flight of a SpaceX Starship followed by catching the returning Super Heavy booster. When we first heard about “Mechazilla” and the idea of catching a booster, we dismissed it as another bit of Elon’s hype, like “full self-driving” or “hyperloops.” But damn if we weren’t wrong! The whole thing was absolutely mesmerizing, and the idea that SpaceX pulled off what’s essentially snagging a 20-story building out of the air on mechanical arms was breathtaking. While the close-up videos of the catch are amazing, they don’t reveal a lot about the engineering behind it. Luckily, we’ve got this video by Ryan Hansen Space of the technology behind the catch, lovingly created in Blender. The work seems to have been done before the test flight and was made with a lot of educated guesses, but given how well the renders match up with the real video of the catch, we’d say Ryan nailed it.