Retrotechtacular: Nuvistor, Vacuum’s Last Gasp

In 2021 all our electronics are solid state, in that they exclusively use semiconductor devices as their active components. Some of us may experiment with vacuum tubes, but only for curiosity or aesthetic purposes. Semiconductors have overtaken vacuum devices in all but the rarest of niche applications due to their easier design requirements, greater reliability, lower cost, and increased performance.

It was not always this way though, and there was a period at the start of the semiconductor era when transistors and vacuum tubes existed together side-by-side and competed directly. Vacuum tube manufacturers continued to create new devices into the 1970s, and in doing so they pushed the boundaries of their art in unprecedented directions. [David W Knight] has a page dedicated to the Nuvistor, something his calls the “final evolution of the thermionic valve”. His comparison photo seen above shows a Nuvistor on the left — a miniature vacuum tube you’ve likely never seen before.

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The Story Behind Ohm’s Law

Do you ever wonder how much of what we do you could figure out from scratch? Tying your shoe might seem simple now, but kids have trouble mastering the skill, and dreaming it up for the first time is even harder. The same holds true for a lot of technology we use every day. Would you think up the computer mouse or even the computer if they didn’t already exist? Surely, though, one of the simplest and most useful math equations that is fundamental to electronics — Ohm’s law — would be easy to figure out, right? It is often the first thing you learn about electronics, but figuring it out that first time turned out to be quite difficult.

The fellow who discovered the relationship was Georg Ohm, a high school math and physics teacher from Köln. What you might not know is that the first time he published it, he got it wrong. But, lucky for us, he figured out his mistake and was able to correct it.

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This Group Of Women Tried To Break Into Astronaut Program In 1960s; One Just Made It

When Mary Wallace “Wally” Funk reached the boundary of space aboard the first crewed flight of Blue Origin’s New Shepard capsule earlier today, it marked the end of a journey she started 60 years ago. In 1961 she became the youngest member of what would later become known as the “Mercury 13”, a group of accomplished female aviators that volunteered to be put through the same physical and mental qualification tests that NASA’s Mercury astronauts went through. But the promising experiment was cut short by the space agency’s rigid requirements for potential astronauts, and what John Glenn referred to in his testimony to the Committee on Science and Astronautics as the “social order” of America at the time.

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End Of An Era: NTSC Finally Goes Dark In America

A significant event in the history of technology happened yesterday, and it passed so quietly that we almost missed it. The last few remaining NTSC transmitters in the USA finally came off air, marking the end of over seven decades of continuous 525-line American analogue TV broadcasts. We’ve previously reported on the output of these channels, largely the so-called “FrankenFM” stations left over after the 2009 digital switchover whose sound carrier lay at the bottom of the FM dial as radio stations, and noted their impending demise. We’ve even reported on some of the intricacies of the NTSC system, but we’ve never taken a look at what will replace these last few FrankenFM stations.

If you are an American you may have heard of ATSC 3.0, perhaps by its marketing name of NextGen TV. Just like the DVB-T2 standard found in other parts of the world, it’s an upgrade to digital TV standards to allow for more recent video compression technologies and higher definition broadcasts. It has an interesting backwards compatibility feature absent in previous ATSC versions; there is the option of narrowing the digital bandwidth from 6 MHz to 5.5 MHz, and transmitting an analogue FM subcarrier where the old NTSC sound carrier on the same channel would have sat. Thus the FrankenFM stations have the option of upgrading to ATSC 3.0 and transmitting a digital channel package alongside their existing FM radio station. It’s reported that this switchover is happening, with one example given in the Twitter thread linked above.

The inexorable march of technology has thus given better quality TV alongside the retention of the FrankenFMs. We have to admit to being sorry to see the passing of analogue TV, it was an intricate and fascinating system that provided a testbed for plenty of experimentation back in the day. Perhaps as we see it slip over the horizon it’s worth pondering whether its digital replacement will also become an anachronism in an age of on-demand streaming TV, after all it shouldn’t have escaped most people’s attention that in 2021 the good TV content no longer comes to your screen via an antenna socket. Meanwhile we’ll keep our CRTs running, just in case we ever want to relive a 1980s night in with a VHS tape of Back To The Future.

Header image: Mysid, Public domain.

Despite Uncertainty, WWII Warbirds Resume Tours

Back in September of 2019, I had the opportunity to climb aboard the restored B-17G bomber Nine-O-Nine as part of a national “Wings of Freedom” airport tour operated by the Collings Foundation. I was excited to get up close and personal with such an iconic aircraft, particularity since Hackaday gave me a platform to share the experience with a global audience. With fewer than 50 B-17s left in the world, and most of those in the United States, taking this sort of “virtual tour” was as close as most people would ever get to seeing what it was really like for the crews who operated these machines over the skies of Europe more than 75 years ago.

Tragically, just a week after the article was published, the Nine-O-Nine crashed during a visit to Bradley International Airport in Connecticut. The pilot, co-pilot, and five paying passengers were all killed in either the initial impact or the subsequent fire. When crews were finally able to extinguish the flames, the left wing and tail were all that remained of the once mighty bomber. In a twist of fate, some of the images I took for the Hackaday article ended up being included in the National Transportation Safety Board (NTSB) accident report, as they represented perhaps the most detailed photographic record of the aircraft’s condition before the crash.

Wreckage of the Nine-O-Nine.

In the weeks and months that followed, many voiced their concerns over what the Federal Aviation Administration (FAA) calls “Living History Flight Experience” aircraft such as those operated by the Collings Foundation. The main point of contention was whether or not these planes were too old to safely carry passengers, and by extension, whether continuing to fly them around the country presented a menace to the national airspace. Critics argued that whatever cultural benefit offered by the chance for the public to tour or ride these antique aircraft was not worth anyone losing their lives over; a line of logic that’s difficult to find fault in.

Then came COVID-19. By March of 2020, individual states had already started going into lockdown, and suddenly there were far more pressing matters to address than the fate of a few dozen teetering WWII aircraft. It was around this time that the FAA pulled the Collings Foundation’s license to conduct any more paid flights, but since outdoor gatherings such as airshows were being put on hold for the foreseeable future, the measure had little immediate impact. It was clear these airborne museum pieces were going to spend most of 2020 in their hangers anyway.

Now, thankfully, the pall of COVID-19 is finally beginning to lift over the United States. In response to widespread vaccine availability, most states are ending or at least reducing their restrictions on outdoor events. With major airshows like the “World War II Weekend” in Reading, Pennsylvania given the green light to proceed, these legendary aircraft are being awakened from their long slumber and making their first tentative flights of the post-pandemic era.

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You Can’t Put The Toothpaste Back In The Tube, But It Used To Be Easier

After five years of research, Colgate-Palmolive recently revealed Australia’s first recyclable toothpaste tube. Why is this exciting? They are eager to share the design with the rest of the toothpaste manufacturers and other tube-related industries in an effort to reduce the volume of plastic that ends up in landfills. It may not be as life-saving as seat belts or the Polio vaccine, but the move does bring Volvo and OG mega open-sourcer Jonas Salk to mind.

Today, toothpaste tubes are mostly plastic, but they contain a layer of aluminum that helps it stay flattened and/or rolled up. So far, multi-layer packaging like this isn’t accepted for recycling at most places, at least as far as Australia and the US are concerned. In the US, Tom’s of Maine was making their tubes entirely out of aluminum for better access to recycling, but they have since stopped due to customer backlash.

Although Colgate’s new tubes are still multi-layered, they are 100% HDPE, which makes them recyclable. The new tubes are made up of different thicknesses and grades of HDPE so they can be easily squeezed and rolled up.

Toothpaste Before Tubes

Has toothpaste always come in tubes? No it has not. It also didn’t start life as a paste. Toothpaste has been around since 5000 BC when the Egyptians made tooth powders from the ashes of ox hooves and mixed them with myrrh and a few abrasives like powdered eggshells and pumice. We’re not sure what they kept it in — maybe handmade pottery with a lid, or a satchel made from an animal’s pelt or stomach.

The ancient Chinese used ginseng, salt, and added herbal mints for flavoring. The Greeks and Romans tried crushed bones, oyster shells, tree bark, and charcoal, which happens to be back in vogue. There is evidence from the late 1700s showing that people once brushed with burnt breadcrumbs.

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Human Google: Ruth Freitag, Isaac Asimov, And Bibliographies

You don’t often turn on a light and think, “That power company is sure on the ball!” You generally only think of them when the lights go out without warning. I think the same is true of search. You don’t use Google or DuckDuckGo or any of the other search engines and think “Wow! How awesome it is to have this much information at your fingertips.” Well. Maybe a little, but it is hard to remember just how hard it was to get at information in the pre-search-engine age.

I were thinking about this the other day when I read that Ruth Freitag had died last year. Ruth had the unglamorous but very important title of reference librarian. But she wasn’t just an ordinary librarian. She worked for the Library of Congress and was famous in certain circles, counting among her admirers Isaac Asimov and Carl Sagan.

Ruth Freitag in 1985

You might wonder why a reference librarian would have fans. Turns out, high-powered librarians do more than just find books on the shelves for you. They produced bibliographies. If you wanted to know about, say, Halley’s comet today, you’d just do a Google search. Even if you wanted to find physical books, there are plenty of places to search: Google Books, online bookstores, and so on. But in the 1970s your options were much more limited.

Turns out, Ruth had an interest and expertise in astronomy, but she also had a keen knowledge of science and technology in general. By assembling comprehensive annotated bibliographies she could point people like Asimov and Sagan to the books they needed just like we would use Google, today.

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