 Friday 24 Thursday 23 Wednesday 22  Anatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed.
 One day in late spring of 1973 I found myself walking around the gymnasium of Annapolis Junior High School (AJHS) trying to decide which courses I would prefer upon beginning tenth grade the following fall. It was one of the final days of ninth grade, which had been by far my least happy year in school. Living in Mayo, Maryland, I and my fellow neighborhood ninth graders should have attended Southern Senior High School (SSHS) in Harwood, Maryland, where our predecessors had gone for ninth grade, but overcrowding caused the Anne Arundel School Board wizards to decide that for at least that year, we would remain at AJHS for another term. Historically, kids from my area went to AJHS only for seventh and eighth grades and then switched to SSHS. Annapolis, being the capital city of Maryland, was significantly more urban than the rural areas to which SSHS type people were accustomed. The clientele was much more aggressive in the big city. Sure, we had our "red neck greaser" rowdies in the southern part of the county, but at least their parents would whip them if they got caught getting into trouble...
 "Researchers at Imec have demonstrated what they believe to be the first functional GaAs-based heterojunction bipolar transistor (HBT) devices on 300 mm Si, and CMOS-compatible GaN-based devices on 200 mm Si for mm-wave applications, showing cut off frequencies in the 40/50 GHz region. In wireless communication, with 5G as the next generation, there is a push towards higher operating frequencies, moving from the congested sub-6GHz bands towards mm-wave bands (and beyond). The introduction of these mm-wave bands has a significant impact on the overall 5G network infrastructure and the mobile devices. For mobile services and Fixed Wireless Access (FWA), this translates into increasingly complex front-end modules..."
 Copper Mountain Technologies (CMT) has produced a series of videos to help users of its diverse line of vector network analyzers (VNAs) get the most out of their extensive capabilities. Proprietary features in both hardware and software supplies VNAs designed by CMT with capabilities far beyond similar equipment by other companies. This video entitled, "Automatic Calibration Module Confidence Check," is one of a series of videos that can be found on the Copper Mountain Technologies website. "How many times have you completed a series of measurements to find them tainted by a bad cable...
 RF Cascade Workbook 2018 is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...
 At VidaRF, the phrase 'Providing Simple Solutions for Complex Connections' is more than just a slogan – it's a mindset, a mission, and a driving force behind everything we do. Their pledge is to design and distribute high performance, cost effective RF Microwave products to fit each customer's unique applications. Please visit VidaRF today to see how their lines of attenuators & terminations, directional couplers, power dividers, coaxial connectors, and circulator & isolators can be of use to your project. "When the standard just will not do, VidaRF has the solution for you!"
Tuesday 21  Imagine reading an article from a 1958 magazine that references the schematic for a specific radio manufactured in Germany, and then being able to download a copy of it for free on the Internet. Such is the case with this Mac's Radio Service Shop story entitled, "Was Ist Los?" Mac is describing to his sidekick Barney the difficulty in troubleshooting and repairing a Metz Transformatoren: Babyphon 56 that a serviceman had purchased while stationed overseas. The diagram is of course in German, which requires Mac to pull out a language translation dictionary. The problem was that many words unique to technical jargon were not in it. Additionally, units of measure for the capacitors and inductors were not like U.S. units. Mac noted that many capacitor values were labeled with units of "u," "n," and "p," for "micro," nano," and "pico." He mentions the "micro" prefix for the letter "u," but never calls the "n" and "p" by the now-standard terms...
 QST reader George P. Orphan, KG4DXJ, wrote in the February 2020 issue's "Letters from Our Members" column about an episode of the old "Hazel" television show entitled, "Stop Rockin' Our Reception," where interference on the Baxters' TV set was blamed on the "shortwave set" operated by a teenager, Bruce, who had recently moved in down the street. George Baxter, the household's impulsive lawyer father, was convinced enough that Bruce, a friend of his son, Harold, was responsible that he paid a visit to the boy's house and spoke to his father about it. Bruce politely informs Mr. B that unless his television was was manufactured before 1950, it was unlikely that his operations on the 10−meter band would be causing the interference, but it fell on deaf ears. Shortly thereafter, a power company investigator was seen walking around the front yard with a box bearing a loop antenna on the top of it. At the request of Bruce's father...
 RF Cafe typically receives 8,000-15,000 website visits each weekday and about half that on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 7,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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. I also re-broadcast homepage items on LinkedIn, Facebook, and Twitter. If you need your company news to be seen, RF Cafe is the place to be. Banner advertising begins at $175/month...
 Nova Microwave is a leader in technically differentiated electronic and radio frequency Ferrite Circulators and Isolators that connect, protect and control critical commercial and military wireless telecommunications systems. Our staff is dedicated to research and development of standard and custom design quality Ferrite Circulators and Isolators from 380 MHz to 26.5 GHz. Available in single or multi-junction topographies, the Nova Microwave product line of is specifically designed for use in varied environmental and temperature extremes.
 "In sailing, rock climbing, construction, and any activity requiring the securing of ropes, certain knots are known to be stronger than others. Any seasoned sailor knows, for instance, that one type of knot will secure a sheet to a headsail, while another is better for hitching a boat to a piling. But what exactly makes one knot more stable than another has not been well-understood, until now. MIT mathematicians and engineers have developed a mathematical model that predicts how stable a knot is, based on several key properties, including the number of crossings involved and the direction in which the rope segments twist as the knot is pulled tight. 'These subtle differences between knots critically determine whether a knot is strong or not,' says Jörn Dunkel, associate professor of mathematics at MIT..."
 Sam wrote from his One SDR website to request I post a note about the resources he is providing on Software Defined Radios. It is in its start-up phase and already has many articles introducing the concepts of SDR. Topics include low noise amplifiers, filters, bias tees, and how to shop for equipment. Says Sam, "I hope to demystify RF technology and make it more accessible to the growing community of SDR enthusiasts." The amateur radio community is adopting SDR in a major way in order to make existence in the crowded electromagnetic environment more successful.
 RF Superstore launched in 2017, marking the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and microwave Industry. Pasternack fundamentally changed the way RF components were sold. Partner Jason Wright manages day-to-day operations, while working closely with Mr. Pasternack to develop RF Superstore into a world class RF and microwave component supplier. RF coaxial connectors & adapters, coaxial cable & cable assemblies, surge protectors, attenuators. Items added daily. Free shipping on orders over $99. We're leading the way again!
Monday 20  If you are a radio guy (or gal) who likes international sleuthing, mystery, and intrigue, then you will probably want to read an article entitled, "Decoding Numbers Stations," from the November 2019 issue of the ARRL's QST magazine. Author Allison McLellan, who is interested in communications history but apparently not a Ham herself, writes, "Scanning through the bands on AM, you stumble upon something odd. It might be the last few notes of a folk song, a sound clip from an old cartoon, or phrases in a different language. A voice cuts through the static, methodically calling out, 'Mike, India, Whiskey, One, Four...' But this isn't a fellow ham announcing their call sign. These are numbers stations, an eerie subset of radio stations that has intrigued hams and non-hams alike for decades. Numbers stations are shortwave AM radio stations that transmit messages via voice or Morse code, believed to be coded in one-time pad (OTP) cryptography. In OTPs, the message is comprised of strings of numbers..."
 I'm guessing most RF Cafe visitors who are more than 50 years old are familiar with, and even have seen, the Sams Photofacts packages of documentation for consumer electronics appliances that include televisions, radios, phonographs, clock-radios, tape recorders/player, amplifiers, etc. Most electronics service shops couldn't have existed with them since many manufacturers did not distribute technical and service data to anyone who was not a certified, sanctioned dealer. Howard Sams, the company's founder, did the equivalent for electronics of what Chilton did for cars and trucks. They basically reverse engineered models bought off a showroom floor. This advertisement from a 1958 issue of Radio & TV News magazine features the man himself, Howard Sams, so now you'll recognize him if you pass him on the street...
 This excerpt from SpaceWeather.com reads like the plot from an episode of Star Trek: "Earth may have crossed through a fold in the heliospheric current sheet, described as 'a giant, wavy membrane of electrical current rippling through the solar system'." It comes from a story on the ARRL news webpage entitled, "Norway Experiences Unexpected Ground Current 'Shockwave'." On January 6, "unexpected electrical currents were detected in the soil of northern Norway starting at around 1930 UTC. 'It seemed to be some kind of shockwave,' said Rob Stammes, who monitors ground currents at the Polarlightcenter geophysical observatory in Lofoten. 'My instruments detected a sudden, strong variation in both ground currents and our local magnetic field. It really was a surprise'..."
 The American Radio Relay League (ARRL) includes a free online sample article from their monthly QST magazine - definitely a good policy to help sell the publication (and membership in the ARRL). The February 2020 edition offers "An SWR-Shifting 'T'," written by Mr. Bill Conwell, K2PO. It includes some useful Smith chart techniques. "Any feed-line mismatch can be brought to a 1:1 SWR with a single shunt capacitor, provided its value and the location where it bridges the coaxial center and shield conductors is chosen correctly. This is because there are two locations at every half-wave along a mismatched feed line where the impedance is exactly 50 Ω in parallel with a reactive component. By extending or shortening the coax so that one of these locations is at the transmitter-end of the coax, a counter-reactive shunt component can be applied using a coaxial T connector..."
Particle Accelerator in a Silicon Chip  "Researchers in the U.S. are designing a silicon chip that can accelerate electrons to over 94% of the speed of light. The team at Stanford University and the SLAC particle accelerator, backed by the Gordon and Betty Moore Foundation set up by one of the founders of Intel, and the European Union's Horizon 2020 Research and Innovation Programme, used infrared lasers and a nanoscale silicon channel to build the accelerator. The infrared pulses are synchrnised to boost the energy of the electrons. Details of the prototype accelerator-on-a-chip were published in today's issue of Science. The key is the design and fabrication techniques can be scaled up to deliver particle beams..."
Reactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project. Sunday 19  As with my hundreds of previous engineering and science-themed crossword puzzles, this one for January 19, 2020, contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades. Many new words and company names have been added that had not even been created when I started in the year 2002. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you.
|  Mya Rae Nelson has an excellent article in the current issue of Fine Woodworking magazine entitled, "The Science Behind Epoxies." I was surprised to read that epoxy has only been around since the 1940s, so when I first used it in the early 1970s, it was only a three decade old technology. As with cellphones, now that we have epoxy, how did we ever get along without it? Ms. Nelson uses layman terms to describe the molecular makeup of both the epoxy resin and the hardener, and describes how the bonds between the resin atoms are broken then reestablished with the insertion of hardener atoms into the matrix. If you attended classes for and understood the basics of chemistry, that will help with understanding the technical side of epoxy curing and strength, but even without the nerd knowledge you will still gain a better understanding of how this indispensible modeler's brew works.
 Paul Rako has a useful article over at Electronic Design entitled, "How to Select a Fuse." Not all fuses are created equal however, to paraphrase Thomas Jefferson in the Declaration of Independence. "Fuses for Electronics" and "Selecting the Proper Fuse"" are a couple articles I've posted on the topic from vintage magazines. Paul begins, "It's easy to trivialize the need for a fuse and how to select one. We have all been annoyed or exasperated by a blown fuse. Sometimes we wish there was no such component needed for our circuits. With the advent of electrical distribution in the 1800s, fuses became an essential device in preventing fires. Electrical systems need them for the same reason. Electronic systems have the same fire concerns and they need fuses as well..."
 Analog Devices engineers Travis Collins, Robin Getz, Di Pu, and Alexander Wyglinski have published a 341-page book entitled "Software-Defined Radio for Engineers," which is being made available for free in e−book format. Released in 2018, this book is about as up-to-date as you will find on SDR. They begin, "Every sector of today's society is entirely dependent on connectivity. As a result, communication systems engineering has evolved into an essential profession where practitioners are required to master a diverse set of skills and tools into order to solve the latest technical challenges. This was not the case several decades ago, where individuals on a design team each possessed complementary yet different backgrounds..."
 Keysight Technologies' Matt Ozalas and Thomas Winslow will present a free webinar entitled, "Designing for Stability in High Frequency Circuits," on January 29th at 1:00 pm ET. "High-frequency circuit designers often struggle with stability. Learn techniques to identify and solve stability problems in the design phase before they become headaches in the lab. Classical techniques will be discussed, and a new technique will be introduced using a bidirectional impedance probe in PathWave Advanced Design System (ADS) called the 'Winslow Probe.' Techniques to identify and solve stability problems in the design phase Basic design examples to compare various stability techniques Realistic examples of a successful high frequency power amplifier design..."
 Before there was the annual International Microwave Symposium (IMS) trade show, the Institute of Electrical and Electronics Engineers' (IEEE) Microwave Theory and Techniques Society (MTT-S) hosted the show, which was widely known as the MTT-S show. Before that, the event went by a variety of names, including "Intercon," (International Convention and Exposition) as reported in this 1972 issue of Popular Electronics magazine. For the first few decades since its inception in the 1950s, New York City was the venue, often in a hotel. As with tides and solar cycles, enthusiasm and attendance waned and ebbed over the years. 1972 was one of the low years. Per the story, about half the number of people were there compared to two years prior. I could not locate a chart of attendance numbers over the years, nor the numbers to generate my own chart...
 Mr. Mark Misfud, chairman of the Asia Pacific Electromagnetic Compatibility Symposium 2020 (APEMC 2020) wrote asking to have the event announced. It will be held May 19-22 at the Hilton Hotel, in Sydney, Australia. Per the website, "Modern Society is increasingly becoming more connected and the technology that is enabling this to happen is operating in a complex and hostile electromagnetic environment. As such knowledge and practical experience in EMC design, mitigation and testing is increasingly in demand. Developing technology such as 5G and autonomous vehicles present exciting possibilities but also provide challenges to those in the field due to the dynamic nature of the electromagnetic environment that the technology operates in. For the uninitiated EMC is black magic but those in the industry know it is application of common sense principles based on established electromagnetic theory and implementation of good design..."
Very unusual types 
RF Cafe typically receives 8,000-15,000 website visits each weekday and about half that on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 7,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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. I also re-broadcast homepage items on LinkedIn, Facebook, and Twitter. If you need your company news to be seen, RF Cafe is the place to be. Banner advertising begins at $175/month... RF Cascade Workbook 2018 is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...  With more than 780 custom-built symbols, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every object has been built from scratch to fit proportionally on the provided A- and B-size drawing page templates (you can use your own page if preferred). Components are provided for equipment racks (EIA and ETSI) and test equipment, system block diagrams and conceptual drawings, and for schematics...
 This assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...
 RF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge (of course a gratuity will be graciously accepted). 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...
|  "2-D semiconductors could have very useful applications, particularly as channel materials for low-power transistors. These materials display very high mobility at extreme thicknesses, which makes them particularly promising alternatives to silicon in the fabrication of electronics. Despite their advantages, implementing these materials in transistors has so far proved to be challenging. In fact, 2-D semiconductors are of a dangling-bond-free nature; thus, it is notoriously difficult to deposit ultrathin high-κ gate dielectrics (i.e., substances with dielectric properties or insulators) on the materials via atomic layer deposition (ALD), often resulting in discontinuous films..."
 "Engineers from the ESA and Sweden’s Royal Institute of Technology (KTH), have designed a novel 'water drop' antenna lens for directing radio wave signals. In the same way that optical lenses focus light, waveguide lenses serve to direct electromagnetic radio wave energy in a given direction. This can be used to minimize energy loss when sending out a radar or a communication signal. Traditional waveguide lenses have complex electrically-sensitive dielectric material to restrict electromagnetic signals as desired. But once the top plate of this water drop waveguide lens has been added on, it comes down purely to its curved shape for directing signals through it. The inventors of this new lens design, which received an ESA Technical Improvement award in February 2017, likes to call it..."
 "A team of researchers affiliated with several institutions in France and one in the U.S. has found that objects of different mass dropped in space fall at a rate within 2E-12% of each other. In their paper published in the journal Physical Review Letters, the group describes their satellite-based physics study and what they learned from it. Most everyone has heard the story of Galileo dropping two different sized cannon balls from the Tower of Pisa in the 17th century to demonstrate his theory that in the absence of air resistance, two objects will fall at the same rate. Einstein later refined the theory and added it to his Theory of General Relativity. Since that time, many people have tested the theory, and it has always been confirmed. Still, some physicists believe that there are bound to be exceptions to the theory because of the disconnect between general relativity and quantum mechanics..."
 "Analog machine learning hardware offers a promising alternative to digital counterparts as a more energy efficient and faster platform. Wave physics based on acoustics and optics is a natural candidate to build analog processors for time-varying signals. In a new report on Science AdvancesTyler W. Hughes and a research team in the departments of Applied Physics and Electrical Engineering at Stanford University, California, identified mapping between the dynamics of wave physics and computation in recurrent neural networks. The map indicated the possibility of training physical wave systems to learn complex features in temporal data using standard training techniques used for neural networks. As proof of principle, they demonstrated an inverse-designed..."
 That's a mighty familiar-looking Yagi antenna configuration with reflector and director elements - implemented with gold deposited on a glass substrate. "Physicists from the University of Würzburg have developed a low-footprint optical nano antenna that measures only 800 nanometres in size. The physicists used the antenna to convert electrical signals into photons and radiated them in specific directions. Directional antennas convert electrical signals to radio waves and emit them in a particular direction, allowing increased performance and reduced interference. This principle, which is useful in radio wave technology, could also be interesting for miniaturized light sources. After all, almost all internet-based communication utilizes optical light communication..."
 "Medical implants of the future may feature reconfigurable electronic platforms that can morph in shape and size dynamically as bodies change or transform to relocate from one area to monitor another within our bodies. Researchers from King Abdullah University of Science and Technology and the University of California, Berkeley report a silicon honeycomb-serpentine reconfigurable electronic platform that can dynamically morph into three different shapes: quatrefoils (four lobes), stars, and irregular ones. 'Quatrefoils can be used for rectangular object-based operation, while stars are for more intricate architectures, and irregular-shaped ones are specifically for implanted bioelectronics..."
 "MIRAIT Corporation, a leading information & communication engineering solutions provider and Metawave Corporation, developer of data communication antenna and in-vehicle millimeter-wave radar, have conducted radio wave propagation experiments in the quasi-millimeter wave band (20 to 30 GHz) using metamaterial reflectors. They confirmed that the result reached the expected performance level. MIRAIT is working to accelerate the technological development of the next-generation 5G mobile communication system, and emerging enterprise local 5G, which will start in earnest in the spring of 2020. Metawave has state-of-the-art technology in this field. Since last December, MIRAIT has been evaluating to confirm the practicality of Metawave's metamaterial reflectors..."
 "What makes a job nearly perfect? It’s a combination of salary, demand (the number empty posts waiting to be filled), and job satisfaction, according to job search firm Glassdoor, which this week released a list of the best jobs in America for 2020. Using median base salaries reported on Glassdoor in 2019, the number of U.S. job openings as of 18 December 2019, and the overall job satisfaction rating (on a scale of 1 to 5) reported by employees in those jobs, the company put front-end engineer in the number one spot, followed by Java developer and data scientist. That’s a switch previous trends; data scientist held the number one spot on Glassdoor's top jobs list for the four previous years. In fact, you don’t hit a non-tech job until the 8th ranking, where speech language pathologist claims the spot, boosted by astronomical demand..."
 Not sure how I missed this, but on July 21th,
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