Today in Science History -
 This RF Cafe Engineering & Technical Headlines Crossword Puzzle contains at least 10 words from headlines posted on the homepage during the week of September 16 through September 20, 2019 (marked with an asterisk*). These custom-made engineering and science-themed crossword puzzles are done weekly for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. Every word and clue - without exception - in these RF Cafe puzzles has been personally entered into a very large database that encompasses engineering, science, physical, astronomy, mathematics, chemistry, etc. Let me know if you would like a custom crossword puzzle built for your company, school, club, etc. (no charge).
 Here is the final installment in the "Basic Digital Electronic Course" series that ran in three issues of Popular Electronics magazine. The first two parts laid the groundwork with an introduction to binary, octal, and hexadecimal arithmetic, Boolean logic, AND, OR and NOT gates, and some truth tables. Armed with those fundamentals, the authors now dive into flip-flops, encoders and decoders, debouncing circuits for switch inputs, integrated circuit (IC) types, and interconnect methods to design and build a simple digital computer with a 7-segment LED display. Don't expect too much from the computer since it was only three years earlier, in 1971, that Intel introduced the world's first integrated microprocessor - the 4-bit model 4004 central processing unit (CPU) ...
 "It was made clear that I was not to touch this sacred totem, especially the threaded rods..." - Steve Ford, WB8IMY, in an article entitled, "Duplexers & Diplexers," in the October 2019 issue of QST magazine. That statement was made in regard to a cavity-tuned duplexer that was part of a Ham radio repeater installation. Mr. Ford, a monthly columnist, discusses the difference between a duplexer and a diplexer. A pull quote from the piece is, "If you're about to pay less than $100 for the device in question, it is a diplexer. If the price tag has four digits to the left of the decimal, it is a duplexer." Do you agree with that generalization? Unfortunately, the ARRL does not make the magazine articles available to non-subscribers.
 Planar Monolithic Industries (PMI) recently introduced six new products in their extensive line of RF and microwave components. Included are a successive detection log video amplifier (SDLVA) for 0.1 to 2.0 GHz; a 18 GHz, 12-BIT, vector phase shifter; a digital frequency discriminator (DFD) for 20 to 18.0 GHz, a 100 MHz amplified 8-way power divider, a 7-bit programmable attenuator for 1.0 to 18.0 GHz, a 0.1 to 50.0 GHz SP16T absorptive switch, and a Frequency Discriminator for 0.5 to 1.5 GHz. Contact PMI today for more information ...
 As a long-time Paul Harvey fan, I used to listen to his radio news broadcasts and especially looked forward to his "The Rest of the Story" pieces. It was a challenge to listen and try to figure out who or what the alluded-to person, place, or thing at the end of the the story would be. In honor of Mr. Harvey, who left this Earth in 2009, the following Smorgasbord about featured celebrity "Sam" is fashioned after his trademarked style. As is often the case with people of accomplishment, this subject's talents extended beyond the skill for which he is most known. An article in the September 2011 Smithsonian magazine inspired the research ...
 "A research team developed VLF antennas using piezoelectric material and principles, resulting in an antenna that's far smaller than metal antennas, thus overcoming a major impediment to VLF links. While everyone is focused on RF signals in the gigahertz-plus range, it's important to remember that the other end of the electromagnetic spectrum also has its uses. However, signals in very-low-frequency (VLF) RF band present a technical dilemma: On one hand, you can't easily live with them; on the other, you can't live without them for some applications cases. The former assessment is due to their need for extremely large antennas (on the order of kilometers). The latter assessment is a result of their propagation characteristics, including Earth-hugging signals and low atmospheric attenuation, as well as their ability to penetrate seawater ... "
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 On the heels of searching for the first mention of Nikola Tesla in U.S. newspapers, I performed a similar search on Albert Einstein, again using editions available in the NewspaperArchive.com database. I was utterly surprised to find it in a 1919 issue of the The New York Times. His theory of Special Relativity was published in 1905 and his theory of General Relativity was published in 1915, so it took The NY Times four years to mention it. There is a reference to Dr. Einstein's' work on relativity in a 1915 edition of The Manitoban*, from Winnipeg, Canada. The New York Times article is an actual interview with Albert Einstein, wherein at one point it is stated that there were perhaps only a dozen people in the world at that time who understood general relativity. Interestingly, Einstein uses the term "difform motion" to describe what we now call "non-uniform motion ..."
 When I saw this photo of a man holding a fluorescent light bulb in the beam of a radar antenna, it reminded me of how we used to do the same thing on our AN/MPN-14 radar system in the USAF. The unit in the photo is a General Electric's FPS-6 height-finding radar, which operates in the S-band 2,700-2,900 MHz region. The AN/MPN-14 is a mobile ground control approach (GCA) with both an S-band airport surveillance radar (ASR) and an X-band precision approach radar (PAR). Our S-band radar had a 600 kW peak power whereas the FPS-6 put out a couple megawatts, but 600 kW was enough to light the bulb. Of course these days you would never see a company-sponsored photo of a man standing in front of a high power radar antenna with a fluorescent light bulb in his hand ...
 Here is a really interesting animation of the world's top 20 country ranked by the number of Internet users in those countries. It runs (as of this posting date) from 1990 through 2019. I have not verified the numbers used by the Animate Stats producers, but the results do not seem unreasonable. Given the the U.S. Department of Defense's research arm, Defense Advanced Research Projects Agency (DARPA), created the Advanced Research Projects Agency Network (ARPANET) that eventually became the Internet, showing the U.S. as the run-away leader in the beginning is not surprising. Around 1996, things begin to change quickly as Japan advances, but it is in 2000 when the Internet user landscape really becomes dynamic ...
 Apologies to Chrysler aficionados for not having similar articles for your classic automobiles, but this article from a 1957 edition of Radio & TV News only covers Chevrolet radios. Maybe someday I will acquire editions with other models. Transistors were fairly recent newcomers on the portable radio scene (on any radio scene for that matter), so you will please excuse the absence of them in most radios of the era. In fact, as evidenced by a companion article in this same edition titled "Delco's All-Transistor Auto Radio," such newfangled devices like transistors were reserved for top-of-the-line models like Cadillac's Eldorado Brougham. A move toward printed circuit boards, rather than the time-honored point-to-point wiring, was well underway, and push-button tuning ...
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 "To hear technologists describe it, Wi-Fi 6 is about to transform connectivity. The next-generation Wi-Fi connectivity technology - along with the emerging 5G cellular generation - will shake up the way we connect with each other. The ability of Wi-Fi 6, or 802.11ax, to instantly route traffic - even to devices on the far reaches of very crowded networks - will also change the way we interact with our smart devices. It will even rework the way smart devices communicate with each other. But from what we've seen thus far, Wi-Fi 6 is emerging on the scene in much the same manner as previous generations of wireless technology: integrated inside the latest smartphones and laptops. And in new routers and access points that promise faster ..."
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 On a whim, I did a search for the earliest appearance of Nikola Tesla's name in U.S. newspapers included in the NewspaperArchive.com database. This story from Mr. George Grantham Bain appeared in multiple newspapers within a few days of this March 5, 1896 edition of The Warren Times in Warren, Pennsylvania, which coincidentally is only a few miles from me here in Erie. The article reports on the role that Tesla's high voltage generators played in the development of x-ray images on fluorescent displays and on film (which Tesla termed "cathode photography"). It mentions how the term "cathode" is relatively new to the general public even though it had been around since 1832 when Michael Faraday introduced it in his work. Wilhelm Röentgen made the world's first x-ray image ...
 1957 was part of the heyday of the newfound radio-in-your-car craze, and the public was voraciously consuming all the high tech equipment it could afford. Rock and Roll music was on every teenager's mind and many guys for the first time were able to have their own wheels and were outfitting them with sound systems that could blast the latest works of Buddy Holley, Chuck Berry, Elvis Presley, and Fats Domino. Those machines were the first babe magnets used for cruising the strip on Saturday nights. Radio stations were popping up all over the country, enabling cross-country travel with non-stop music, news, and variety show entertainment. Ford and Chevrolet were not going to miss an opportunity, so they delved into the high end mobile radio manufacturing business ...
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 It took me a couple passes of the explanation to comprehend the advantage of a Thomson-Varley (aka Kelvin-Varley, since Thomson and Lord Kelvin are one and the same person) switchable voltage divider compared to a standard type. At first I thought the author, Edwin Bohr, was implying that the source and load impedances would not have as great of an effect on the accuracy of the divider (and to some extent it is less sensitive), but the main advantage is that the configuration permits simple cascading stages of decade dividers to achieve essentially any degree of resolution. Both a standard series-wired type voltage divider and the Thomson-Varley need ten resistors ...
 Ruh-roh. "Switzerland was among the first countries to begin deploying 5G, but health fears over radiation from the antennas that carry the next-generation mobile technology have sparked a nationwide revolt. Demonstrators against the technology are due to fill the streets of Bern later this month, but already a number of cantons have been pressured to put planned constructions of 5G-compatible antennae on ice. The technology has been swept up in the deepening trade war between China and the United States, which has tried to rein in Chinese giant Huawei - the world's leader in superfast 5G equipment - over fears it will allow Beijing to spy on communications from countries that use its products and services ..."
 English mathematician George Boole published his "Formal Logic" syllogism system of deductive reasoning in 1847. Fellow countryman Augustus De Morgan followed on Boole's work to develop the basic combinational logic rules the AND gates, OR gates, and NOT (negation) operators. What has become known as Boolean algebra and De Morgan's theorem forms the fundamental foundation of everything related to digital logic. This second in a three-part series from a 1974 issue of Popular Electronics introduces both concepts at a beginner's level. Part 3 will present flip-flops and an overview of how all the parts come together to build a simple computer.
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