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Today in Science History

The Old Timer Gives a Safety Lecture

The Old Timer Gives a Safety Lecture, December 1960 Radio-Electronics - RF CafeJack Darr authored many pieces for Radio-Electronics magazine. Most were monthly columns dealing with servicing and troubleshooting. He also published a dozen or so book on electronics, like Eliminating Man-Made Interference, Servicing Unique Electronic Apparatus, Transistor Audio Amplifiers, and How to Test Almost Everything Electronic. Release dates range from the 1960s through 2021 Mr. This article on safety "best practices" when working on electrical and electronics equipment appeared in a 1960 issue of Radio-Electronics. A lot of the danger back in the day was attributable to poor design methods that did not properly isolate the line voltage from exposed metallic surfaces. That included the chassis onto and into which components were installed, hookup wires, and shafts for potentiometers, tuning capacitors, and switches. The plugs on supply cords were not polarized...

1200 V GaN Semiconductors

1200 V High-Performance GaN Semiconductors"Scientists have developed GaN semiconductors to boost efficiency and reduce costs in electric vehicles and renewable energy, aiding the energy transition. Key technologies crucial for the energy transition - including electric vehicles, charging infrastructure converters, energy storage systems, as well as solar and wind power plants -depend heavily on electronic components that deliver both high performance and efficiency. Wide band gap semiconductors are essential in these components' development because they operate with lower losses, handle higher voltages, and tolerate greater temperatures compared to traditional silicon-based (Si) semiconductors. The Fraunhofer Institute for Applied Solid State Physics IAF uses the power semiconductor..."

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...

FCC CBRS Rules Changes

FCC CBRS Rules Changes - RF CafeA lot is happening in the world of Citizens Broadband Radio Service (CBRS). Now the FCC Chairwoman Jessica Rosenworcel wants to kick off a proceeding to consider new rules for the band. Known in FCC parlance as a Notice of Proposed Rulemaking (NPRM), the proceeding would seek comment on a range of potential rule changes to improve the CBRS band for current and future users. The 3.5 GHz CBRS band is unique to the U.S. and uses a three-tiered model to protect Navy radar while allowing commercial use of the spectrum. “Cooperation is critical for a successful spectrum future. We can preserve and enhance the Citizens Broadband Radio Service to both protect progress and look ahead...

Anatech Electronics Intros 3 New Filter Models

Anatech Electronics Intros 3 New Filter Models for Mid June 2024 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new ceramic filters have been announced for mid June 2024 - a 2595 MHz bandpass filter with a 50 MHz bandwidth and 1.5 dB insertion loss, 2535 MHz bandpass filter with a 70 MHz bandwidth and 2.2 dB insertion loss, and a 2437 MHz bandpass filter with a 14 MHz bandwidth and 3.2 dB insertion loss. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when...

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...

Tektronix 547 Oscilloscope Advertisement

Tektronix 547 Oscilloscope Advertisement, February 28, 1964 Electronics Magazine - RF CafeAs with a lot of things, when you have been around test equipment for a long time and new equipment with new features evolve over time, you might forget how things used to be as you come to take the modern stuff for granted. Displaying more than one channel's trace at a time is a good example. When Tektronix introduced the "Automated Display Switching" feature on their model 547 oscilloscope with the 1A1 time base plug-in, its ability to show two sweeps simultaneously was ground-breaking. Prior to that, the user needed to manually switch between input time base units to get the waveform displayed. Monitoring two waveforms at a time required separate oscilloscopes, which, given the massive size of their vacuum tube-based...

Conformal Coatings for Printed Circuits

Conformal Coatings for Printed Circuits, October 1969 Electronics World - RF CafeDuring my tenure in the early-to-mid 1980s as an electronics technician at Westinghouse Electric's Oceanic Division, in Annapolis, Maryland, I assembled many a Mil-Spec printed circuit board. An initial week-long soldering class and then periodic refreshers were required to get NASA-certified for the type of critical work we did there. I have written before about the rigid inspection process that each PCB, cable harness, wire-wrap board, etc., was put through. Many of the assemblies for use in underwater vehicles and ship-based controllers needed to be conformably coated for protection against the corrosive salt water environment. The first step was usually thorough cleaning in a heated ultrasonic bath of methyl chloroform (aka 1,1,1-trichloroethane, no citrus-based cleaners in those days), which not only removed...

Electronics-Themed Comics

Electronics-Themed Comics, April 1962 Radio-Electronics - RF CafeMany of these vintage electronics-theme comics would fit well into today's "meme" for the "You know you are old if you remember this" type pictures. There might be a photo of a dial phone, a car or truck with three pedals under the dashboard (accelerator, brake and clutch), a phone booth on the street corner, a bicycle with a banana seat and sissy bar, or maybe a typewriter. The April 1962 issue of Radio-Electronics magazine includes comics showing a record player (vs. Blu-ray or DVD player), a set of headphones (vs. ear buds), an electronics chassis filled with vacuum tubes and leaded components (vs. leadless ICs and passives), and a sports car having a radio installed (vs. Bluetooth connection for streaming from smartphone). Who among us remembers adjusting the tone arm on a turntable for optimum tracking and balance?...

Future G Summit at IMS 2024

Future G Summit at IMS 2024 - RF Cafe"The IEEE International Microwave Symposium (IMS) will be organizing Future G Summit this year. The summit will feature four sessions throughout the day, each focusing on a different theme: Spectrum Co-Existence and Sustainability, Non-Terrestrial Networks (NTNs), Metaverse Technologies, and 6G Technologies. Each of the themed sessions will feature speakers from industry describing some of the interdisciplinary concepts enabling these Future G systems. At the conclusion of each session, there will be an interactive panel comprising technical experts who will field questions from the audience and discuss some of the challenges for the realization of Future G networks..."

Stretching the Junk Box

Stretching the Junk Box, April 1952 QST - RF CafeWe live in days of plenty of everything. People throw away and stash away items that our parents - and particularly grandparents - could only dream of having available. Even households that have never seen a penny of earned income in decades are overflowing with stuff. Shopping carts in Walmart, K-Mart, and Target are filled to overflowing when I am there with toys, shoes and clothes, electronic gadgets, sporting goods, automotive accessories, pet food (Target has reefers with fresh meat for dogs) and accessories, lawn and garden implements, hand tools, DVDs and Blu-rays, televisions, disposable diapers (lots of disposable diapers), snack cakes and crackers, soda, bottles of - get this - water (that costs as much as soda), ice cream, frozen pizzas and microwaveable dinners, energy bars and bags of candy. You get the picture. People have so much stuff that one of the largest areas of the store is the plastic storage bin section - reserve one for each giant...

Howard W. Sams & Co. Photofact

Howard W. Sams & Co. Photofact, April 1962 Radio-Electronics - RF CafeThis Sams Photofact ad from a 1962 issue of Radio-Electronics magazine is a good example of why the company's electronics product service packets were so highly regarded. A couple other competitors came and went in the decades of the twentieth century, but Sams kept on because of their reputation. In fact, Sams Technical Publishing is still in business today! By 1962, the electronics industry was in the beginning stages of transitioning from vacuum tube amplifiers and rectifiers to solid state equivalents, and from point-to-point wiring to printed circuits. The illustrations created by Sams artists for point-to-point component hookups were very high quality, and as can be seen here, those for printed circuits were equally good. One and two sided PCBs were the rule in the day, and sweeping curvy trace lines with big round soldering pads were used - partly because they were easy to create, and because the absence of sharp points eliminated peeling points...

Hybrid Bonding Plays Starring Role in 3D Chips

Hybrid Bonding Plays Starring Role in 3D Chips - RF Cafe"Researchers at the IEEE Electronic Components and Technology Conference (ECTC) last week pushed the state of the art in a technology that is becoming critical to cutting-edge processors and memory. Called hybrid bonding, the technology stacks two or more chips atop each other in the same package, allowing chipmakers to increase the number of transistors in their processors and memories despite a general slowdown in the pace of the traditional transistor shrinking that once defined Moore's Law. Research groups from major chipmakers and universities demonstrated a variety of hard-fought improvements, with a few showing results that could lead to a record density of connections between 3D stacked chips of around 7 million links in a square millimeter of silicon. All those connections are needed because of the new nature of progress in semiconductors, Intel's Yi Shi told engineers at ECTC..."

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). 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 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...

Dilbert on Trade Shows - IMS 2024

Dilbert on Trade Shows - RF CafeBeing that the world's largest RF and microwave trade show, IMS2024 (International Microwave Symposium - see Exhibit Floor map highlighting RF Cafe sponsors) is happening beginning June 16th in Washington, D.C., I thought this Dilbert™ comic strip from May 6, 2012, would be a fitting subject for posting on RF Cafe. Having been to a couple of the IMS shows and talking to exhibitors, many seem to actually relate to Dilbert's experience. RF Cafe advertiser booth locations on IMS 2024 exhibit hall floor map. - RF CafeThe main value of having a presence there is often simply being seen in the realm of major players, which confers a certain level of industry gravitas. So, even if spending a week at the show does not directly result in new customers, at least some companies believe the cumulative effect of a persistent presence will pay off in the long run. At least one major RF/microwave manufacturer has concluded otherwise...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols"" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000+ symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing...

Anatech Electronics June 2024 Newsletter

Anatech Electronics June 2024 Newsletter - RF CafeSam Benzacar, of Anatech Electronics, an RF and microwave filter company, has published his June 2024 newsletter that, along with timely news items, features his short op-ed entitled "The Vital Role of Microwave Technology in Quantum Systems." In it, he discusses the use of microwave components in quantum computers. I have noticed in the photos of the quantum computers, suspended by fine cables giving them a golden chandelier look, that there seems to be lots of small diameter coaxial cable and connectors plugging into what appears to be standard microwave-like packages. Turns out, according to Sam, that those are coaxial cables and components like mixers, amplifiers, directional couplers, circulators and isolators, and of prime interest to him, filters. It all still seems like black magic, as does aka quantum teleportation and entanglement (or "spooky action at a distance" as Albert Einstein referred to it)...

Lord Kelvin and His Analog Computer

Lord Kelvin and His Analog Computer - RF CafeThis tide-predicting machine was one of many advances he made to maritime tech. "In 1870, William Thomson, mourning the death of his wife and flush with cash from various patents related to the laying of the first transatlantic telegraph cable, decided to buy a yacht. His schooner, the Lalla Rookh, became Thomson's summer home and his base for hosting scientific parties. It also gave him firsthand experience with the challenge of accurately predicting tides. Mariners have always been mindful of the tides lest they find themselves beached on low-lying shoals. Naval admirals guarded tide charts as top-secret information. Civilizations recognized a relationship between the tides and the moon early on, but it wasn't until 1687 that Isaac Newton explained how the gravitational forces of the sun and the moon caused them. Nine decades later, the French astronomer and mathematician Pierre-Simon Laplace..."

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks, and more. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Electronics-Themed Comics

Electronics-Themed Comics, May 1962 Radio-Electronics - RF CafeHaving been born sometime before around 1970 will make it much more likely that you will be familiar with the scenarios depicted in these three electronics-themed comics. They appeared in a 1962 issue of Radio-Electronics magazine (I colorized them). The comic from page 72 can be applied to to modern day situations where an owner calls in a repairman after he tinkers around trying to save some money on a service call, and makes things worse than they were to begin with, then trying to BS the serviceman into believing he hasn't monkeyed with it. The page 96 comic is a guy thing - which used to be allowed before tender feeling were offended by such things. The last one brings back memories of being in the local convenience store with my father as he is checking the vacuum tubes...

FM Carrier Stabilization: the Phasitron

FM Carrier Stabilization, May 1946, Radio-Craft - RF CafeHere is another instance of an article which, if it had been in an April magazine issue, you might be justified in thinking it might be a gag. "FM Carrier Stabilization," a 1946 Radio-Craft feature, centers around the use of a General Electric (GE) GL-2H21 "Phasitron" vacuum tube. Be assured that it is a real component, developed to address the difficulties in achieving frequency modulation (FM) requirements set forth by the Federal Communications Commission (FCC) at what was really the dawn of the FM commercial broadcast radio era. Only a little over a decade had passed since Major Armstrong announced his broadband FM invention, and radio stations were planning to adopt the superior (to AM) form of broadcasting at a rapid rate, following the end of World War II. The Phasitron was GE's solution to the problem of maintaining the average carrier frequency stability requirement...

Analog Computers Solve Complex Problems

Analog Computers Solve Complex Problems, November 1951 Radio & Television News - RF CafeCharles Babbage's 19th century Difference Engine might be considered the beginning of complex mechanical calculators' use in science and engineering. It really was not all that long ago. Massive single-purpose analog computers were designed and constructed in the middle of the last century for calculating, among other things, projectile trajectories, multi-body orbits, electrical circuit functions, nuclear detonations, calculation of mathematical function tables, and navigation. Eventually electrical computers joined the arsenal of tools available to significantly reduce the amount of time required to carry out complex calculations requiring multiple iterations using a range of input variables. Programmable vacuum tube and then transistorized digital computers expanded the range of applications, but recall that even by the early 1960s, during the early manned space flight projects...

Editorial: Radiobotage

Editorial: Radiobotage, May 1941 Radio-Craft - RF CafeAn incredibly glaring example of the famous admonishment* that those who ignore history are condemned to repeat it, Radio-Craft magazine editor Hugo Gernsback wrote in May of 1941, a full half year before the United States of America officially entered World War II, about how current conditions regarding domestic commercial radio broadcast stations were likely being used by German agents to send coded messages to offshore vessels (ships, submarines, and aircraft). In example, he cited, amazingly, an article he himself published in 1915 in The Electrical Experimenter magazine accusing Dr. K. G. Frank, of the German Telefunken company, of conducting spy operations from the Sayville, NY, station on Long Island. A copy of the letters that were exchanged between Mr. Gernsback and Dr. Frank were reprinted in this edition (see "Sayville Once More"). Spoiler alert in case you don't read the other article: Dr. Frank was eventually arrested for his espionage activities and interred for the duration of WWI...

"Grounds" for Confusion

"Grounds" for Confusion, January 1960 Electronics World - RF CafeRobert Gary waxes philosophical on the subject of ground in his Electronics World magazine article, "'Grounds' for Confusion." He is justified from the viewpoint of someone attempting to make sense of how something as seemingly fundamental as Earth ground is not a constant. The layman probably doesn't care. Practitioners in the electrical and electronics realms who deal only with low frequencies and short distances might occasionally be affected by differences in ground potentials, although they might not realize it is the cause of their problems. Those with more than a casual involvement (designers, installers, and maintainers as opposed to only users) in high frequencies and/or long distance signal interconnections are likely to be intimately familiar with the effects of ground potential differences...

News Briefs

News Briefs, April 1962 Radio-Electronics - RF CafeWhen this News Briefs column appeared in a 1962 issue of Radio-Electronics magazine, solid state infrared (IR) detectors were still a relatively new technology, and integrated circuits had not entered the commercial marketplace. Developing an IR orientation sensor compact enough to fit a pair of them (azimuth and altitude sensing) into an orbiting surveillance platform was quite a feat. A phased array could not be made small enough, so a rotating angled mirror was used for steering - reminiscent of the early electromechanical television scanning systems. Also reported, among other things, were a new ruby laser, fraudulent color TV tube claims, and more women entering the engineering and science fields...

Axiom Blog: Calibration Baths Fine Tune Temperature

Axiom Test Equipment Blog: Calibration Baths Fine Tune Temperature - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post that covers how temperature calibration baths provide a dependable means of calibrating temperature sensors of different shapes and sizes, with capabilities of many at one time. Often simply called calibration baths, temperature calibration baths are not just tanks for temperature-controlled fluids. They are integrated systems consisting of a stainless-steel tank, a condensing coil and cooling plate, a heater, propeller, and stirring motor. These components combine to maintain selected fluids within the tank at tightly controlled temperatures across a wide temperature range. When evaluating temperature calibration baths, parameters for comparison include the volume, size, and weight of the bath, its total temperature range, power consumption, heating and cooling times...

Curiosa in Radio

Curiosa in Radio, June 1935 Radio-Craft - RF CafeI usually try to post something a little less serious and technical on Fridays to help everyone wind down from the long week just passed. It could be a Carl & Jerry or a Mac's Radio Service Shop story, an electronics quiz, or even something I found out on the Internet. This time it is a "believe-it-or-not" type feature in a c1935 Radio-Craft magazine entitled "Curiosa in Radio," about radio manufacturing, operating, and infrastructure. One factoid claims "Only 1.1% of set manufacturers in business in 1924 are building sets today." It could due to being in the middle of the Depression Era so almost nobody was making / buying radios, but more likely it reflects the reality of the many people who jumped into the fledgling radio industry early on and then could not gain market share...

Vector-Circuit Matching Quiz

Vector-Circuit Matching Quiz, June 1970 Popular Electronics - RF CafeThis vector circuit matching quiz will hurt the brain a little more than most of the ones that were printed in Popular Electronics magazine. In order to score well, it helps to visualize the circuits relative to where they would appear on a Smith Chart. Capacitive impedances lie in the bottom half and have negative phases (-s, -jω). Inductance lie in the upper half and have positive phases (s, jω). The familiar "ELI the ICE man" mnemonic helps, too. Be sure to pay attention to the color of the vector arrow heads. Example: In a purely inductive circuit like #4, voltage leads current by 90°. Since phase rotation is CCW, you need to look for lettered phase diagram where the white arrowhead (voltage) is 90° ahead of the black arrow head (current), going in the CCW direction. Vector diagram letter "H" looks like that. Circuit #10, being purely capacitive, is just the opposite, so its vector diagram...

How Far Amplification?

How Far Amplification?, December 1960 Radio-Electronics - RF CafeRadio-Electronics magazine founder, editor, and publisher Hugo Gernsback wrote this "How Far Amplification?" article in 1960. In it, he briefly discusses the history of radio signal detection and amplification in the preceding 60 years, and then projects what the state of the art might be 60 years henceforth. Relative to 1960, that would be the year 2020, which is already four years old. In 1960, the electronics world was transitioning from vacuum tubes to solid state devices, so vast improvements in low noise and amplification factors were being made. Mr. Gernsback, the remarkable futurist that he was, foresaw generally the extremely low noise figure amplifiers of today, which enable higher levels of amplification before the signal-to-noise ratio renders further amplification useless. Interestingly, he did not mention the theoretical noise floor of -174 dBm/Hz, which except maybe for spread signal communications imposes a fairly hard limit on how much amplification is useful. At that level, an amplification factor of 10(174/10) = 1017.4 = 251 quadrillion, only gets the signal to 1 mW...

After Class: Power Transformers & Electrostatic Speakers

After Class: Power Transformers & Electrostatic Speakers, August 1955 Popular Electronics - RF CafeBasic transformer circuits have not changed in the more than sixty years since this article was published in Popular Electronics magazine. The applications have definitely changed, though, since active circuits of the day required a relatively low voltage (step-down) for vacuum tube cathode heaters, and at least one relatively high voltage (step-up) for biasing the tube plate. Most transformers for today's consumer applications perform a single step-down operation for 3.3 V, 5 V, 12 V, etc. In many applications, transformers are done away with altogether in favor of solid state rectifiers and regulators. A 5-question quiz is provided at the end. There is also a short tutorial on electrostatic speakers and some analog and digital signal info...

Taking the Guesswork out of Scatter Communications

They're Taking the Guesswork out of Scatter Communications, September 1969 Electronics Illustrated - RF CafeAs with many areas of electronics communications, much of both the initial and continued research in atmospheric scattering of electromagnetic signals was/is done by amateur radio operators. The phenomenon is routinely used for accomplishing long distance communications (DX, in Ham terms) by exploiting the reflection property of ionized layers when radio signals impinge at a certain angle. The portion of the signal that returns to the transmitter location, when monitored, can provide information to the sender about the height, distance, and frequency range of the reflecting atmospheric layer. Some of the first indications of backscattering were noticed by radar operators who would receive echo returns from "phantom" targets that were really atmospheric reflections...

What's Your EQ?

What's Your EQ?, April 1962 Radio-Electronics - RF CafeHere is another triplet of mystery circuit configurations for you to cogitate upon, if you are inclined to cogitate upon such things. The first one is not too much of a challenge, so don't over-think it. Number two: Fuggetaboutit, unless you were a television repairman back around 1962 when this "What's Your EQ?" feature appeared in Radio-Electronics magazine. Just reading the description makes my head hurt. Of course this would pose no difficulty for Mac McGregor. Last but by no means least is the dreaded "black box" problem. I usually do not fare too well on these. I have the reference Black Box No. 3 issue posted, but haven't added the images yet. My simplistic solution is to say there is a constant current source in the black box, but that is not the inventor's intention...

Tunable YIG Filters for High-Frequency Bands

Tunable YIG Filters Prevent Interference in High-Frequency Bands - RF Cafe"Engineers from the University of Pennsylvania School of Engineering and Applied Science have developed an adjustable filter that can successfully prevent interference, even in higher-frequency bands of the electromagnetic spectrum. In the early 2010s, LightSquared, a multibillion-dollar startup promising to revolutionize cellular communications, declared bankruptcy. The company couldn't figure out how to prevent its signals from interfering with those of GPS systems. The newly developed adjustable filter could prevent such problems from ever happening again. "I hope it will enable the next generation of wireless communications," says Troy Olsson, Associate Professor in Electrical and Systems Engineering (ESE) at Penn Engineering and the senior author of a new paper in Nature Communications that describes the filter. The electromagnetic spectrum itself is one of the modern world's most precious resources..."

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...

How Do We Hear?

How Do We Hear? Part II, June 1936 Radio-Craft - RF CafeA story in an electronics magazine on the physics and biology of the human ear is as relevant today as it was in 1936 when this appeared in Radio-Craft magazine. Back then, creating sound in an efficient and effective manner for consumer, commercial, and military purposes was a relatively new science. Thomas Edison introduced his phonograph in 1877. While it did not feature an electrically driven speaker, research determined the shape, size, and material composition of the mechanism that converted minute grooves etched into the surface of a cylinder into sound pressure great enough for perception. Alexander Graham Bell's telephone of the same era (1876), used an electromagnetic coil to power a speaker membrane. 40 years later, radios were appearing everywhere and the race was on to provide high fidelity sound as a means to differentiate quality models from lesser models. Much research - the first of its kind - was performed on the workings of the human in an attempt to quantify its functional parameters...

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...

9 of the Latest New Developments from G-E Research

Nine of the Latest New Developments from G-E Research, March 6, 1964 Electronics Magazine - RF CafeHalf a decade after Texas Instruments (Jack Kilby, 1958) and Fairchild Semiconductor (Robert Noyce, 1960) produced the first semiconductor integrated circuits, General Electric must not have been too confident that the newfangled technology was going to take hold. This 2-page spread from a 1964 issue of Electronics magazine, promotes their "Compactron" integrated circuit vacuum tubes. The Compactron is a building block concept where standardized stages of diodes, triodes, pentodes, etc., are encapsulated in a single vacuum tube package with necessary input and output pins for connecting external components. The incentive was smaller volume, lower parts count, lower power supply current, simpler chassis wiring or circuit board layout, and greater ruggedness. One source I found showed the availability in 1962 of 24 distinct Compactron models...

Thin Air My Foot!

Thin Air My Foot!, July 1956 Popular Electronics - RF CafeWhilst reading this Carl Kohler technodrama™ entitled "Thin Air My Foot!," I happened upon this word new to me: 'din,' as in "It was dinned into me." OK, maybe you already knew that, but surely I should have been aware of its alternate meaning other than being a loud noise ("the agitated cat made quite a din"). Fortunately, I am not subject to a household of people who refuse to put things back in their respective places when through with them, but this tale of woe tells what might be a familiar scenario to you. To be honest, this could have been written about me as a boy - before the U.S. Air Force taught me a thing or two about organization and neatness - since I continually frustrated my father by leaving his tools (and hardware and lumber and paint) scattered...

News Briefs

News Briefs, January 1961 Radio-Electronics - RF CafeTo show how far in advance of publication date magazines used to need to have their content submitted, this January 1961 issue of Radio-Electronics noted the fortieth anniversary of the country's first commercial radio broadcast by KDKA on November 2, 1920 (two months). KDKA's first daily broadcast began on September 20, 2021. Also reported was a record 100 mile underground communication record. Using a buried antenna, it used a new transmission mode that exploits the interface region between the ground surface and the atmosphere. A new international standard meter was changed to the length of 1,650,763.73 wavelengths of the orange-red line of light given out by krypton 86. Since 2019, the meter is defined as the distance light travels in a vacuum in length of the path travelled by light in vacuum in 1/299792458th of a second, based on a cesium time standard. A color TV standard...

Engineering & Tech Headlines <Archives>

ARRL Youth Rally Success at Dayton Hamvention

UK Semiconductor Institute Creation

More Spectrum to Add $27B to India's GDP

• U.S. Tariffs Prompt Supply Chain Shift

• IARC Again Asked to Review RF Cancer Risk

Electronic Crosswords

Electronic Crosswords, April 1960 Electronics World - RF CafeJohn Gill published many electronics-themed crossword puzzles in Electronics World magazine in the 1950s and 1960s. Unlike the weekly RF Cafe engineering crossword puzzles, some of the words used herein are not directly related to science, engineering, mathematics, etc. Some of the words are more particular to the era, but that shouldn't present too much difficulty. You will find the level of difficulty much less than that of a Sunday edition New York Times crossword, but there are some challenging clues, particularly given the era that it was created. Bon chance...

Many Thanks to ConductRF for Continued Support!

ConductRF coaxial cables & connectors - RF CafeConductRF is continually innovating and developing new and improved solutions for RF Interconnect needs. See the latest TESTeCON RF Test Cables for labs. ConductRF makes production and test coax cable assemblies for amplitude and phased matched VNA applications as well as standard & precision RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the iBwave component library. They also provide custom coax solutions for applications where some standard just won't do. A partnership with Newark assures fast, reliable access. Please visit ConductRF today to see how they can help your project! 

Zener Diodes Simplified

Zener Diodes Simplified, January 1961 Radio-Electronics - RF CafeZener diodes, named after their inventor, Clarence Zener, were a paradigm-changing introduction to the electronics industry. At a very low price and parts count, precise and stable voltage sources can be built for just about any voltage reference level. Zeners are designed to operate in the breakdown region of the pn junction which is normally avoided with standard rectifier diodes. That voltage level is predictable and consistent. A standard range of voltages (2.7 V, 3.0 V, 3.3 V, 3.6 V, 3.9 V...) are manufactured to satisfy most needs. Notice a familiar pattern there? Yep, they follow the standard 5% tolerance resistor value series. I don't know why that was done - there is no semiconductor physics reason for it. Just as having a standard 5x10n Ω value for resistance would be extremely handy, so it would be for a voltage reference, given the prevalence of 50 Ω for impedances and 5.0 V for digital circuits...

Vintage College Engineering Labs

Vintage College Engineering Labs - RF CafeWhen I think back at the engineering labs from my days in school, I wonder how much things have really changed from then until now. It is hard to believe that freshman and sophomore labs are not still consumed with radial lead resistors, inductors, and capacitors, solderless breadboards, and a variety of light bulbs, motors, transformers, relays, and rheostats. By the time you move into the junior year, labs have gotten a bit more intense with microprocessor controls (mine used an 8088 CPU with machine language programming for the serial port), some high voltage apparati[sic], digital logic circuits (74-series leaded ICs), and a chance to lay out/fabricate/populate a PCB. On-hand test equipment consists of 2nd or 3rd generation oscilloscopes, signal generators, and power supplies...

Radar-Tracking Accuracy Increased

Radar-Tracking Accuracy Increased, May 4, 1964 Electronics Magazine - RF CafeThe many idiosyncrasies of atmospheric phenomena that affect long distance communications are certainly more well known and understood today than they were in the early days of radio. Ionization, temperature and pressure gradients, suspended particulate contamination, and other factors have been extensively studied, measured, and modeled. Daily and seasonal patterns are somewhat predictable and exploitable for purposes of general use, but short term variability that affects long distance radar measures of distance, altitude, and speed requires near instantaneous, pulse by pulse analysis of atmospheric conditions. Research and development of methods for accommodating short term variations that skew measurements are an ongoing science. An extreme example of atmospheric variation compensation is the method used by ground-based telescopes that shine lasers into the ionosphere to create "artificial stars" whose scintillation properties can be used in both software and adaptive optics to cancel out apparent changes in position and intensity...

Many Thanks for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.

Temwell's 30% Off Sale for June!

Temwell's 30% Off Sale for June!- RF CafeTemwell is running a 30% Off sale on it's in-stock line of filters --- for the entire month of June. Temwell 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...

Empower RF High-Power S-Band Pulsed Transmitter

Empower RF Systems High-Power S-Band Pulsed Transmitter - RF CafeEmpower RF Systems, the technology leading provider of high-performance RF amplifiers, is proud to announce the launch of the Model 2254 S-Band Pulsed Transmitter. This air-cooled, high-power transmitter operates from 2900 to 3500MHz and is designed to meet the demanding requirements of radar and electronic warfare applications. The Model 2254 boasts an impressive peak power output of 15kW peak power, making it one of the most powerful S-band transmitters in its class. With a duty cycles up to 20% and pulse widths up to 500 micro seconds, this transmitter is capable of delivering sustained high-power pulses for extended periods, ensuring reliable performance in mission-critical scenarios. This transmitter combines cutting-edge technology with robust design, delivering unparalleled performance and reliability for our customers' most challenging applications in radar, electronic warfare and directed energy research.

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). 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 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...

Air Corps Radio Phraseology Training

Air Corps Radio Phraseology Training, January 1945 Radio News - RF Cafe"Say again." That phrase is heard often in telephony conversations both wired and wireless. It was coined near the end of World War II by Air Corpsman 2nd Lt. Byron A. Susan, as reported in the January 1945 edition of Radio Craft magazine. Lt. Susan was responsible for setting standards for "radio phraseology" to eliminate ambiguity between aviators and ground forces. "Say again" replaced "Repeat" because the latter is an artillery term used to order another round of assault from a gun salvo. The history of the confirmation "Roger" is murky, but many agree it comes from the older military phonetic pronunciation of the letter "R" being "Roger," and in radio the letter "R" meaning "received." Another common bit of radio phraseology is "Wilco," which is a contraction of the words "will comply..."

Forgotten History Chinese Keyboards

Forgotten History Chinese Keyboards - RF CafeToday, typing in Chinese works by converting QWERTY keystrokes into Chinese characters via a software interface, known as an input method editor. But this was not always the case. Thomas S. Mullaney's new book, The Chinese Computer: A Global History of the Information Age, published by the MIT Press, unearths the forgotten history of Chinese input in the 20th century. In this article, which was adapted from an excerpt of the book, he details the varied Chinese input systems of the 1960s and '70s that renounced QWERTY altogether. 'THIS WILL DESTROY CHINA forever,' a young Taiwanese cadet thought as he sat in rapt attention. The renowned historian Arnold J. Toynbee was on stage, delivering a lecture at Washington and Lee University..."

withwave microwave devices - RF Cafe
Werbel Microwave (power dividers, couplers)

Anatech Electronics RF Microwave Filters - RF Cafe

TotalTemp Technologies (Thermal Platforms) - RF Cafe