Today in Science History

3D Magnetic Recording for Ultra Storage HDDs

3D Magnetic Recording: Unprecedented Hard Drive Storage Density - RF Cafe"Research groups from NIMS, Seagate Technology, and Tohoku University have made a breakthrough in the field of hard disk drives (HDD) by demonstrating the feasibility of multi-level recording using a three-dimensional magnetic recording medium to store digital information. The research groups have shown that this technology can be used to increase the storage capacity of HDDs, which could lead to more efficient and cost-effective data storage solutions in the future. Enhancing Data Storage Capacity Data centers are increasingly storing vast amounts of data on hard disk drives (HDDs) that use perpendicular magnetic recording (PMR) to store information at areal densities of around 1.5 Tbit/in². However, to transition to higher areal densities, a high anisotropy magnetic recording medium consisting of FePt grains combined with heat-assisted laser writing is required. This method, known as heat-assisted magnetic recording (HAMR), is capable of sustaining areal recording densities of up to 10 Tbit/in². Furthermore, densities of larger than 10 Tbit/in² are possible based on a new principle demonstrated by storing multiple recording levels of 3 or 4 compared..."

Help Needed with Capacitor Markings

RF Cafe visitor James G. sent me photos of some paper capacitors he plans to replace in a 1950s vintage radio set. It is a foreign job, most likely from France, based on the schematic. Some markings on the capacitors are not familiar; maybe you have seen them. The photos show things like "ESSAI 1.500 V.C.C." which I assume means 1,500 V (1.5 kV) working voltage, based on the European swapping of dots and commas for decimal points. "Essai" in French means "test," or "trial." "V.C.C." is probably a French marking for voltage similar to WVDC (DC working voltage). Another marking shows "100/1000 deF," which could be μμF, but unlikely given it is a paper capacitor. Maybe millifarad? Any insight will be appreciated.

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing...

Rare Metals, Once Forgotten, Now in Production

Rare Metals, Once Forgotten, Now in Production, October 1949 Popular Science - RF CafeHere is a really good synopsis of "rare earth" elements that explains how they came to be known in that way. Hint: It is not that they are so rare, in fact per Wikipedia, Cerium is the 25th most abundant element on Earth. The issue is they are not in concentrated lodes, but spread out as components of other mineral compounds, so extensive processing is needed to isolate and purify them. One of the first post-war commercial level extraction processes was the result of experimentations during nuclear bomb research. As you might know, "holes" existed in the Periodic Table of the Elements when it was first constructed in 1869 by Dmitri Mendeleev, because not all predicted naturally occurring elements had been found. Helium, atomic number 2, was not found on Earth until 1895, after first having been observed in the sun's spectrum a few years earlier (hence its name, from Helios). Author Alden Armagnac provides a primer in the original 15 rare earths (now 17) in this 1949 Popular Science magazine article... 

Electronics: Washington Newsletter

Washington Newsletter, October 18, 1965 Electronics Magazine - RF Cafe1965 was the beginning of America's involvement in Vietnam. A mere decade had passed since the end of the Korean War (or "conflict" if you prefer), and the Department of Defense had not done much to modernize the military since then. Unlike with World War II when U.S. factories were turning out military aircraft, ships, and ground vehicles ahead of formal involvement, Congress was not interested in making headlines with news of war machines. When the first U.S. troops were sent in March of that year, things kicked into high gear. Lyndon Johnson was said to have tried to direct the war from the White House, but it was his Secretary of Defense, Robert McNamara, whose actions caused the Vietnam efforts to be nicknamed "McNamara's War." The "Washington Newsletter" feature of this October 1965 issue of Electronics magazine reported on, among other military-related items, the U.S. Air Force's plans to phase out the venerated (now, not then) B−52 Stratofortress bomber by sometime in the 1970s...

RCA Institutes Ad - A Prophecy

RCA Institutes Ad - A Prophecy, October 1961 Electronics World - RF CafeIn the original radio broadcast of Jean Shepherd's "A Christmas Story," which was set in the Great Depression era, he spoke of magazine advertisements promising rewarding careers in electronics for men of adventure. Over the last few years I have posted many such advertisements from vintage electronics magazines, but they were also commonly seen in women's magazines, Life, The Saturday Evening Post, and many others. This ad pitching the Radio Corporation of America's (RCA) home study courses for electronics technology ran in a 1961 edition of Electronics World. Chairman of the Board, David Sarnoff, sends the message to readers. Sarnoff was commissioned as a Brigadier General in the Army Air Corps during World War II. He orchestrated radio broadcasts for the D−Day invasion (June 6, 1944), and also the Radio Free Europe system for post-war years... 

Transistor Takes Advantage of Quantum Interference

Transistor Takes Advantage of Quantum Interference - RF Cafe"As transistors are made ever tinier to fit more computing power into a smaller footprint, they bump up against a big problem: quantum mechanics. Electrons get jumpy in small devices and leak out, which wastes energy while degrading performance. Now a team of researchers is showing that it doesn't have to be that way. With careful engineering, it's possible to turn electrons' quantum behavior into an advantage. A team of English, Canadian, and Italian researchers have developed a single-molecule transistor that harnesses quantum effects. At low temperatures, the single-molecule device shows a strong change in current with only a small change in gate voltage, nearing a physical limit known as the sub-threshold swing. Getting near or beyond this limit will allow transistors to be switched with lower voltages, making them more efficient and generating less waste heat. The research team, including physicists at Queen Mary University of London, achieved this by taking advantage of how quantum interference alters the flow of current in single molecules..."

Electronic Devices in TO- Packages

Silanna UV Devices (April 2024 Photonics) - RF CafeWhen's the last time you saw a magazine advertisement showing electronic devices in TO- type metal packages? "TO," by the way, stands for "transistor outline." It's been a long time for me. I did a double-take upon spotting this full-page ad by Silanna UV appeared in the April issue of Photonics. The products encased in the those vintage metal cans are ultraviolet light emitting diodes (UV LED), which are used primarily in sterilization processes for killing bacteria and viruses. Per the company website, 'Our best-in-class UV LED technologies can address everything from reducing healthcare-acquired infections and food contamination to minimizing the transmission of diseases and removing micro pollutants from drinking water. And in creating these products, Silanna focuses on minimizing its own use of natural resources and energy through innovative approaches to 'designing for manufacture' and investing in the latest, optimized production processes.'" That's it; I thought you might enjoy a trip back in time, a la the old Watkins Johnson, M/A-COM, and Avantek RF amps and mixers.

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

The Radio That Was Shot from a Gun

Coming - The Radio That Was Shot from a Gun, March 1948 Popular Science - RF CafeThis article is a good indicator of how prevalent cigarettes were back in 1948 when it appeared in Popular Science magazine. Transmitter, receiver, and hearing air amplifiers were referenced to be "about the size of a pack of cigarettes." The peanut vacuum tubes used within are said to be "smaller than a half-smoked cigarette." Those of us who lived back in the days when smoke-filled restaurants, buses, grocery stores, and houses was the norm easily compare the sizes to such a familiar entity. We even know what it means to be "smaller than a bread box." Nowadays, references to the size of electronic components would be to something like a grain of sand, which is a form of irony since that's what the chip is made from (essentially). The article's title, "The Radio That Was Shot from a Gun," derives from the miniaturization technology developed for anti-aircraft shell proximity fuses...

Electromaze Puzzle

Electromaze Puzzle, June 1966 Popular Electronics - RF CafeRobert Radford's (not to be confused with Robert Redford) "Electromaze" is a unique - and weird - sort of word puzzle format which first appeared in the April 1966 issue of Popular Electronics magazine. Some people were confused about the strategy, believing that all the white spaces needed to be filled in. They do not. Just because a letter might have an empty square adjacent to it does not imply that another letter must fill it. You will probably want to print out the maze grid and find an old guy who should still have a pencil stowed away somewhere you can borrow to use for filling in the boxes...

Electronics-Themed Comics

Electronics-Themed Comics, January 1951 Radio-Electronics - RF CafeThe January 1951 issue of Radio-Electronics magazine had a big collection of electronics-themed comics - five of them. All of them are pretty good, and you don't need to have been there during the early TV era to appreciate the humor. The comic from page 127 is a good first step in troubleshooting for today, and is usually at the top of the problem solving section of consumer gear throughout the electronic age. The page 126 comic is an oft-used gag for garage-related funnies. Although not directly related, it reminds me of how early wireless garage door openers had their antennas stretched underneath of the car, as mentioned in other articles, including "The New Radio Garage Door Opener."  I colorized them all...

Thanks to TotalTemp Technologies for Continued Support!

TotalTemp Technologies - RF CafeTotalTemp Technologies has more than 40 years of combined experience providing thermal platforms. Thermal Platforms are available to provide temperatures between −100°C and +200°C for cryogenic cooling, recirculating & circulating coolers, temperature chambers and temperature controllers, thermal range safety controllers, space simulation chambers, hybrid benchtop chambers, custom systems and platforms. Manual and automated configurations for laboratory and production environments. Please contact TotalTemp Technologies today to learn how they can help your project.

Here's One of the Dumbest Statements Ever

Life Without a Smartphone - RF CfeAn article on the TechExplore website entitled, "Why won't some people use a smartphone? And is that difficult?," states, "In a world where more and more services and social interaction are based on mobile apps, a smartphone has become close to a necessity. Despite this, some people avoid smartphones and instead use a dumbphone - a traditional mobile phone or a reduced-feature designer phone." One contributor remarked: "We found that in many societies, all sorts of tricks had to be invented to make life without a smartphone work." Um, does the university prof not realize that life "worked" just fine for the preceding many millennia without a smartphone? Evidently now if you don't feel the need to be "connected" 24/7, you're considered a weirdo. Well, count me in that group. I rarely carry a phone - dumb or smart. I read from and write (even cursive) on paper. I look up definitions and spellings in a printed Webster dictionary. My landline phone sits on the desk and has a handset on a curly cord. I eat meals and do household tasks without checking a phone ...been managing to eek out a survival that way for 65 years now. Other than by tracking purchases on credit cards around town, nobody has a record of my whereabouts or schedule. I pity the phone slaves.

Exodus AMP2070A, 1−6 GHz, 150 W, SSPA

Exodus AMP2070A, 1−6 GHz, 150 W, 100 W P1dB SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to present the new Exodus AMP2070A solid state high power amplifier, ideal for broadband EMI−Lab, Communication and EW applications. Class A/AB linear design for all modulations & industry standards. Covers 1.0 to 6.0 GHz, producing 150 W minimum Psat, 100 W minimum P1dB, and 52 dB minimum gain, with 20 dB gain adjustment. Excellent flatness, optional monitoring parameters for Forward/Reflected power, VSWR, voltage, current & temperature sensing for superb reliability and ruggedness. Integrated in our compact 3U chassis weighing approximately 25 kg...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your Banner Ads are displayed on average 280,000 times per year! New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be...

MIT's Dance of Protons

MIT's Dance of Protons - RF Cafe"New insights into how proton-coupled electron transfers occur at an electrode could help researchers design more efficient fuel cells and electrolyzers. A key chemical reaction - in which the movement of protons between the surface of an electrode and an electrolyte drives an electric current - is a critical step in many energy technologies, including fuel cells and the electrolyzers used to produce hydrogen gas. For the first time, MIT chemists have mapped out in detail how these proton-coupled electron transfers happen at an electrode surface. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies. 'Our advance in this paper was studying and understanding the nature of how these electrons and protons couple at a surface site, which is relevant for catalytic reactions that are important in the context of energy conversion devices or catalytic reactions..."

The Longitude Problem

The Longitude Problem - RF CafeKnowing that I am an avid consumer of literature pertaining to time and astronomy, Melanie picked up a book at the library for me entitled, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, by Dava Sobel. When Christopher Columbus discovered America, his intended target was, if you recall, the Indies. His original charter was to find a direct westerly pathway from the Atlantic coast of Europe to the immensely profitable trade production region of the Indies as an alternative to to sailing around the treacherous Cape of Good Hope at the southern tip of Africa. How could such an experienced navigator have missed his mark by so far, you might reasonably ask? Didn't Columbus know how to use a sextant, or at least have a navigator who could? The answer to the second question is, "no." The answer to the first question is complicated. Recall your elementary school poem titled In 1942, which began "In fourteen hundred ninety-two, Columbus sailed the ocean blue." John Hadley's and Thomas Godfrey's sextant - originally called an octant - was not invented and refined until the middle of the 18th century. The answer to the first question is that prior to the advent of the sextant and accurate sea-going clocks, determining latitude was easy, but determining longitude was mostly guesswork and dead reckoning...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

Many Thanks to Amplifier Solutions Corporation for Continued Support!

Amplifier Solutions Corporation (ASC) - RF CafeAmplifier Solutions Corporation (ASC) is a manufacturer of amplifiers for commercial & military markets. ASC designs and manufactures hybrid, surface mount flange, open carrier and connectorized amplifiers for low, medium and high power applications using Gallium Nitride (GaN), Gallium Arsenide (GaAs) and Silicon (Si) transistor technologies. ASC's thick film designs operate in the frequency range of 300 kHz to 6 GHz. ASC offers thin film designs that operate up to 20 GHz. ASC is located in an 8,000 sq.ft. facility in the town of Telford, PA. We offer excellent customer support and take pride in the ability to quickly react to evolving system design requirements.

Upheaval in Electronics 

Upheaval in Electronics, February 1961 Radio-Electronics - RF Cafe More than half a century has passed since Radio-Electronics magazine editor Hugo Gernsback wrote this piece entitled, "Upheaval in Electronics." In it, he compares the state of the art in electronics since half a century earlier, which would have been 1911 - a couple years before World War I began. He stated the obvious, "Just as electronics of today bears no resemblance to electronics of 50 years ago, the present art cannot be compared to electronics 50 years hence." Of course he was correct. Present day communications routinely goes beyond radio frequencies, into microwave, millimeterwave, nanometerwave (aka light) and onward. As of recent, add to that instantaneous quantum communications over great distances via "entangled" media. Semiconductor technology was relatively new in 1961, with the first monolithic integrated circuit having been developed the year before. As of this writing, Micron has a 5.3 trillion MOSFET memory chip on the market. An entire FM radio receiver, GPS receiver, and radar receiver fits on a single die, sans antenna and power supply - Mr. Gernsback's predicted "diminutive radios." The depth and breadth of modern electronics is impossible to document in a single printed volume. Even the collective works of Wikipedia does not comprise a panoptic resource...

The Rise and Fall of 3M's Floppy Disk

The Rise and Fall of 3M's Floppy Disk - RF CafeRaise your hand if you used 5¼" floppy disks (360 kB). Raise your other hand if you used 3½" floppy disks (720 kB). Take a bow if you used a cassette tape deck for storing and retrieving programs. I've got both hands raised, and am bowing over. My first external computer storage consisted of a Sears cassette recorder/player connected to a Sinclair ZX80 machine with a membrane keyboard and a 13" color TV for a monitor. That would have been sometime around 1983. According to Wikipedia, in 1976, Shugart Associates introduced the 5¼-inch FDD, and IBM the 3½" in 1986. This IEEE Spectrum article delves into 3M's (Minnesota Mining and Manufacturing) role in the removable storage realm..

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing...

Mac's Service Shop: Customer Cues

Mac's Service Shop: Customer Cues, October 1958 Radio & TV News Article - RF CafeIn 1958 when this "Customer Cues" installment of John T. Frye's "Mac's Service Shop" series of technodramas in Radio & TV News magazine, color television was a relatively new phenomenon. The first commercially sold color TV set - the Admiral C1617A - went on sale at the very end of 1953. The NTSC approved the first standardized specification for a composite color television composite signal (color, gray scale, audio, brightness, synchronization) earlier that year. It allowed the same signal to work with both black and white (B&W) and color receivers. A lot of research went into making sure the viewing public was happy with their sets, using polls, hands-on instruction and publications on how to properly adjust tuning and picture controls, plus tips on installing outdoor antennas and running the twin lead transmission cable down to the set. Of course the proper way to fiddle with the built-in "rabbit ears" antenna was covered as well. I don't think any official pamphlets included mashing tinfoil onto the rabbit ears in complex patterns as many people did - truth is, it must have worked in some cases. In the story, Mac schools Barney on the situation.

Clairvoyant Dr. Fox

Clairvoyant Dr. Fox, May 1937 Radio-Craft - RF CafeMystery stories were broadcast on radio stations in the days before television - and for quite a while after TV was available for that matter. Families gathered around the living room radio set in excited anticipation of the next adventure of shows like "The Shadow," "Amos 'n' Andy," "Tales of the Texas Rangers," "Dragnet," and "The Green Hornet." During that era, it was common also for electronics magazines, which focused largely on radio communications, to experiment with printed dramas that had a radio-centric theme. Here is the first of a series tried by Radio-Craft magazine in the late 1930s. A couple decades later the "Carl & Jerry" adventures were run in Popular Electronics, but other than that I don't recall seeing a lot of these things. If you're a mystery fan, then here you go. A great collection of old time radio broadcasts can be heard on the Old Radio World and Old Radio Programs websites...

Quiescent Autonomous Magnification Superintendence

Quiescent Autonomous Magnification Superintendence, April 1933 QST - RF CafeMoral standards seem to rigidly obey the second law of thermodynamics, which states that entropy (disorder) increases in a closed system. Most people would say society is more rude and corrupt today than in days gone by - count me among them. However, believing so does not obviate or excuse acts of deviance in the past. Indeed, even esteemed organizations like the American Radio Relay League (ARRL) seems to have been guilty of promoting dishonest acts. To wit, consider this offer appearing in the "Strayed" column of the April 1933 issue of QST magazine, "For Sale: QSL Cards of any country. Win your WAC without delay. Name your spot. We'll send the card." It also describes a scheme for ripping off electronics supplies stores. Shameful!

Please Welcome Temwell as an RF Cafe Sponsor!

Temwell (filters) - RF CafeTemwell is a manufacturer of 5G wireless communications filters for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000 completed spec sheets online for all kinds of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete coil & inductor solutions.

Tiny Chip Generates High-Quality Microwave Signals

Tiny Chip Generates High-Quality Microwave Signals - RF Cafe"Columbia Engineering researchers have built a photonic chip that can produce high-quality, ultra-low-noise microwave signals using only a single laser. The compact device - a chip so small, it could fit on a sharp pencil point - results in the lowest microwave noise ever observed in an integrated photonics platform. The achievement provides a promising pathway towards small-footprint ultra-low-noise microwave generation for applications such as high-speed communication, atomic clocks, and autonomous vehicles. Electronic devices for global navigation, wireless communications, radar, and precision timing need stable microwave sources to serve as clocks and information carriers. A key aspect to increasing the performance of these devices is reducing the noise, or random fluctuations in phase, that is present on the microwave. 'In the past decade, a technique known as optical frequency division has resulted in the lowest noise microwave signals that have been generated to date,' said Alexander Gaeta, David M. Rickey Professor of Applied Physics and Materials Science and professor of electrical engineering at Columbia Engineering..."

Testing RF Amplifiers

Testing RF Amplifiers by Rhode & Schwarz - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Testing RF Amplifier Designs," "...offers an overview from electronic design automation to real RF devices while focusing on verification, characterization, repeatability, and throughput. It explains the important characteristics and how they can be verified. In addition, it sheds light on the specialties along the value chain from development, validation and characterization to production." Here is a link to Testing RF Amplifier Designs that doesn't require registration...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your Banner Ads are displayed on average 280,000 times per year! New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be...

Army/Air Force Rotary Beam Parasitic Array Antenna

U.S. Army and U.S. Air Force Rotary Beam Parasitic Array Antenna, March 1948 Popular Science - RF CafeThe U.S. Air Force became a separate branch of the armed forces on September 18th, 1947, almost exactly two years after Japan unconditionally surrendered to Allied Forces (Germany had unconditionally surrendered back in May). This recruitment advertisement appeared in the March 1948 issue of Popular Science magazine, a year after the Selective Training and Service Act of 1940 expired on March 31st, 1947. It was a joint appeal by the Army and the Air Force for men seeking careers in communications - particularly targeting, it seems, amateur radio operators, by touting a steerable beam antenna. I could not find numbers on how many conscripted and volunteer troops left the service immediately after the war. Many articles reported a big force drawdown in personnel, which combined with massive layoffs in war equipment industries, led to employment problems. It did not last for long, as the Military Selective Service Act of 1948 reinstated draft registration again. After all, the Military Industrial Complex, as 5-star General/President Eisenhower would eventually call it, needed work.

Calculation of Potentiometer Linearity and Power Dissipation

Calculation of Potentiometer Linearity and Power Dissipation, August 1967 Electronics World - RF CafeHere in this 1967 issue of Electronics World magazine is yet another example of where the basics in electronics never changes. There are always new people entering into the realm, so even if the subject has been covered countless times already, there is always a need to print it again. Remember that at one time you were a newbie and appreciated seeing beginners' concepts explained. The old-timers of the day probably complained about being tired of seeing the simple stuff re-hashed over and over. Most standard potentiometers (pots) are linear in operation, that is, the resistance between the moveable wiper contact and the overall resistance between the two ends is directly proportional to the percentage of travel along the length of the resistive element (printed or wirewound). One of more popular specialty pots is the logarithmically tapered type that is used in audio circuits in order to effect an audible linear sound volume change relative to the percentage of travel of the wiper arm. Analog stereo systems are major users of tapered potentiometers. The more things change, the more they remain the same...

Stage Set for U.S.-Soviet Space Tests

Stage Set for U.S.-Soviet Space Tests, January 17, 1964 Electronics Magazine - RF CafeA love-hate relationship between major nations competing for leadership and dominance in the military and aerospace technology realms has existed in earnest at least since the space race began. Often, the pilots, astronauts, scientists and engineers are much more willing to set aside political differences in order to more effectively and efficiently advance the state of the art and/or basic knowledge. Maybe archeologists, biologists, endocrinologists, climatologists, zoologists, pathologists, and you-name-it-ologists feel the same way, but those types, dealing with squishy living things, are probably more altruistic than your typical physical sciences guy (or gal). It is the government management sides of the equation agonizing over the need to solicit or accept foreign assistance. There is (or was at the time) no better example than the U.S.A. (United States of America) and the U.S.S.R. (Union of Soviet Socialist Republics), particularly for space-based communications. Satellites were a very new entry into the radio world and both sides needed each other's help in testing and assessing the few "birds" being launched. In particular, high gain earth-based receiver systems were required...

SmallSat GEO Solution for Satellite Communications

SmallSat GEO Solution for Satellite Communications - RF CafeI wonder if this this is an actually representative of the SmallSat mentioned in the article. It looks like someone Photoshopped a set of PV panels on a standard subsystem module package. "Terran Orbital Corporation has made a significant move into the geosynchronous orbit (GEO) small satellite market with its unveiling of the SmallSat GEO solution, designed for satellites weighing over 500kg. This cutting-edge solution will be showcased at the upcoming SATELLITE 2024 trade show from March 18-21 at the Walter E. Washington Convention Center, Washington D.C., featuring an immersive augmented reality experience. The SmallSat GEO solution is specifically crafted for the communications sector, capable of operating in geosynchronous orbit to deliver unprecedented power and performance, a demand that has surged in the GEO sector's gradual shift towards smaller satellites. Leveraging a state-of-the-art 94,000 sq. ft. manufacturing facility equipped with advanced automation in both construction and testing, along with the experience gained from three prior GEO missions..."

Werbel Teams with Global Electromarketing

Werbel Microwave Teams with Canada's Global Electromarketing - RF CafeWerbel Microwave, located in Whippany, New Jersey, is a producer of high quality passive power RF and microwave components across a worldwide customer base. A partnership has recently been established with Canada's Global Electromarketing, a sales representative agency which focuses on market research, competitive analysis, and brand positioning. Werbel's founder and president Ernest Werbel says, "We are looking forward to growth and success together." Werbel Microwave designs and manufactures RF directional and bidirectional couplers (6 dB to 50 dB) and RF power dividers / combiners (2− to 16−way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available.

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing...

Bell Telephone Labs - The Future Holds Great Promise

Bell Telephone Laboratories - The Future Holds Great Promise, August 1949 Popular Science - RF CafeIf you remember watching movies and television shows up through the 1970s or so, you have probably seen scenes (see what I did there?) where someone struggled desperately to place and keep connected telephone calls to, from, or within foreign countries (outside the U.S., that is). Our Bell Telephone Company was well known and respected for the widespread, reliable, and quality network it built out across the land. A continual effort to improve the system while containing costs to make telephony affordable to most people is what did the job. Beginning with manually (or more accurately, womanually) operated switchboards, then graduating to automated electromechanical circuit switching centers, it eventually evolved to the computer controlled and optimized solid state networking circuits of today. Unlike the multitude of telecommunications companies today, Bell really had no competition, so government oversight combined with the company's desire to invoke good will amongst its customers helped keep things in check. Self-promotions like this full-page 1949 Popular Science magazine appearance were common.

How the Cathode-Ray Tube Works

How the Cathode-Ray Tube Works, February 1955 Popular Electronics - RF CafeEven with the domination of LED, plasma, and LCD displays, there are still cathode ray tubes (CRTs) on the job. Hobbyists workbenches are filled with them for sure, but design and manufacturing facilities still have huge inventories of test equipment with CRTs, and a lot of computer equipment on the production line with CRTs sitting in racks. LED, LCD, and plasma displays all have their own claims to genius on the part of their designers, but cathode ray tube designers - and the designers of the driver circuits - deserve special recognition. Consider the physics and materials involved: glass, phosphor, magnetics, thermonics, electrostatics and electrodynamics, relativity (electrons traveling at relativistic speeds gain mass, requiring stronger deflection fields). This article from the February 1955 edition of Popular Electronics provides a look into the CRT from a layman's perspective...

How to Use Radio Propagation Predictions

How to Use Radio Propagation Predictions, December 1947 Radio-Craft - RF CafeShort wave radio was a boon to both professional and amateur radio operators because of its ability to be received over longer distances using significantly lower transmitter power. In 1947 when this article appeared in Radio-Craft magazine, the problem was (and still is) that short wave bands typically suffer from atmospheric ionization effects that vary depending on time of day, local weather, solar activity, pollution, and other phenomena. Long wave's advantage was that although it required higher power and longer antennas, it was (and is) extremely reliable. For other than the most critical applications, idiosyncrasies of short wave communications were accepted as the price of more convenient and lower cost operation. Widespread adoption of short wave communications brought extensive studies and characterization of atmospheric influences in particular frequency bands. Discovery of distinct "F" layers (regions) in the ionosphere and their effects on radio transmission has allowed radio operations to predict and accommodate the affected propagation paths. What does the "F" in F-Layer mean? According to my sources the "F" refers not to frequency, but to "free" electrons in the ionosphere...

U.S. Lights New Atomic Pile for Peace

U.S. Lights New Atomic Pile for Peace, April 1949 Popular Science - RF CafeA Wikipedia on the history of nuclear power shows a photo of the first light bulbs ever lit by electricity generated by nuclear power, at EBR-1 at Argonne National Laboratory-West, December 20, 1951. That was two years after this "U.S. Lights New Atomic Pile for Peace" article in Popular Science magazine, which discusses progress at the Brookhaven National Laboratory, located in New York state. It opened in 1947. Much public excitement - and fear - was fomented over the use of nuclear energy, which had just four years earlier been used to bring an end to World War II through its awesome level of concentrated destructiveness, for peaceful uses like generating electrical power and for medicine. During the postwar era, many such articles, which some considered propaganda, were published, television shows aired, and movies produced in attempts to turn the public into pro- or anti- nuclear power activists. The "anti's" have done a pretty good scaring everyone to the point where rather than benefitting from the very "green" aspects of nuclear power (which would have been continually improving in technology), they instead are accepting monstrous installations of solar arrays, wind turbine farms, and other impractical technologies. Their cost to society, economies, and the environment are rarely reported honestly.

Moonbats Running Our Lives

Moon is mostly gas - Shiela Jackson Lee - RF CafeMembers of Congress - both the House and the Senate - are not necessarily there because they are exceptionally smart and/or wise. An argument can be made that they are there because their constituents are exceptionally stupid and/or unwise. In an address to students at the Booker T. Washington High School in Houston, Texas, Rep. Sheila Jackson Lee stated, among other dumb things, "the full moon is a complete, rounded circle, which is made up mostly of gasses." She previously claimed the Constitution is more than 400 years old, and that astronauts planted an American flag on Mars (look it up). BTW, she was a member of the House Science, Space and Technology Committee.  Rep. Hank Johnson worried back in 2011 that the island of Guam might tip over under the weight of excessive military gear. Many other examples of idiocy amongst our "leaders" can be found.

RCA "Freedom to Listen"

RCA "Freedom to Listen" Ad, January 1948 Radio-Craft - RF CafeThis RCA (Radio Corporation of America) advertisement from a 1948 issue of Radio−Craft magazine packed a lot of meaning to American citizens who had recently experienced the trials, tribulations, and ultimately victories of World War II. Company president David Sarnoff, a well-known electronic communications industry titan before the war, served under a special commission as a Brigadier General in the U.S. Army during WWII to oversee radio communications. He was very familiar with the tragedy of Communism and Socialism, having experienced its ruinous philosophy. Hitler and his minions forbade citizens, under threat of imprisonment or worse, from listening to radios lest they learn of the war's progress or of the freedoms experienced in other parts of the world. Propaganda via radio was a daunting weapon for and against all engaged nations, and even some Allied governments outlawed both transmitters and receivers for the duration. This advertisement represents the appreciation Mr. Sarnoff and his countrymen had for the simple ability to listen to radio broadcasts without fear of retribution. The scenario depicted in the picture is similar to the famous "Four Freedoms" paintings done by American artist Norman Rockwell in 1943. RCA added "Freedom to Listen" to Rockwell's list for a total of Five Freedoms...

Solar Eclipse from Greensboro, NC, April 8, 2024

Solar Eclipse from Greensboro, NC, April 8, 2024 - RF CafeOn April 8, 2024, one of the best total solar eclipses of the last century crossed the United States from Texas to Maine. Because the moon was near its closest orbital point to the Earth, and the Earth was about midway between its orbital apogee and perigee, the sun appeared relatively small and the moon appeared relatively large. That combination caused the moon's shadow to be very wide across the face of the Earth. Note in the NASA eclipse map at the right how much narrower the path of totality was for the August 17, 2017 eclipse. Maximum eclipse for this location was just shy of 81%. That was enough to cause an eerie feel in the sky, but it was nowhere near dark. Let me state that when I first became aware of this solar eclipse, it was sometime around 2016, when I was living in Erie, Pennsylvania. Due to scheduling issues, Melanie and I decided to not travel to South Carolina to view the August 21, 2017 eclipse, figuring we would have a front-row seat to it on April 8, 2024, from our house, which was only a few miles from the center of the path of totality. Life happened, and we ended up moving back to North Carolina in 2022. Because hotel rooms just about anywhere in the path of totality were in the $300+ per night range, we stayed here and missed totality...

Radio Waves, Sunspots, and Planets

Radio Waves, Sunspots, and Planets, June 1959 Popular Electronics - RF CafeI did a little research on this 1959 Popular Electronics magazine article about John H. Nelson's work on how the positions of planets affect magnetic storms on Earth. It looked a little more like astrology than science, but as it turns out, Nelson's findings gained support in both the astronomical and meteorological fields. Naturally, the astrology crowd claimed him as part of their goofiness, but that wasn't Nelson's fault. He published a book in 1974 titled ,"Cosmic Connections." Yeah, even that sounds like an astrology title - poor choice (or maybe he was trying to fool the contemporary Pharisees in to buying his book). The book is out of print now, and I could not find any contemporary work that leverages Nelson's work. My guess is that due to the relatively short time that observations were made, the sun had not even gone through a full sunspot cycle. Each sunspot cycle, while occurring on average every eleven years or so, can vary widely both in intensity and duration from one period to the next. What might have produced the claimed 85% accuracy for that particular sunspot cycle likely never provided enough correlation in subsequent cycles to solidify the theory...

Diode Function Quiz

Diode Function Quiz, August 1965 Popular Electronics - RF CafeIt's time for another pop quiz (does that line give you a fearsome flashback to your school days?). Whenever I have one available, I like to post quizzes from vintage electronics magazines, like this one on diode circuit functions which appeared in the August 1965 issue of Popular Electronics. Many from that era include vacuum tubes, but this one has the solid state symbols so the under-40 folks won't be uncomfortable. Your job is to look at the diode circuits and match them with the names of the functions. A couple of them will probably cause some head scratching, but you should do well. Don't jump to a quick conclusion with circuit "E" without noticing the two signal generators attached to it...