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Sylvania High-Voltage Rectifiers

Sylvania High-Voltage Rectifiers, June 1968 Radio-Electronics - RF CafeIn much the same way as the solution to a word problem seems obvious when you look it up in the back of a textbook, Sylvania's answer to manufacturing a vacuum tube heater element that is more robust and less subject to vibration failure is illustrated in this advertisement which appeared in a 1968 issue of Radio-Electronics magazine. Eliminating the suspended element and wrapping it securely on a supporting post facilitated an "instant on" requirement for up-and-coming transistorized televisions and radios by reducing heat-up time to about a second. The heater's symmetrical shape also assured even emission of electrons from the cathode. Its captured winding around the support post also eliminated the annoying failure mode where a broken-off heater...

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.

Capacitors: A Brief History

Capacitors: A Brief History - RF CafeThe development of capacitors dates back to the 18th century when scientists were exploring the principles of static electricity. The first practical capacitor was the Leyden jar, invented in 1745 by Pieter van Musschenbroek of the University of Leiden and independently by Ewald Georg von Kleist in 1746. The Leyden jar consisted of a glass container coated with metal foil on both its inner and outer surfaces, with a conducting rod protruding from the top to connect to an external charge source. This device demonstrated the principle of storing electrical charge, laying the foundation for future capacitor technologies. Capacitors function based on the principle of electrostatic...

Engineering & Tech Headlines <Archives>

• EVs Stall, Hybrids Gain

• ARRL Launches Dream Station Sweepstakes

• FCC Spectrum Auction Pays for Huawei Rip-and-Replace

• 4G & 5G to Take off in 35 USAF Bases in 2025

• Magazine Highlights Achievements in 6G Research

After Class Feature: Crystals

After Class Feature: Crystals, April 1960 Popular Electronics - RF CafePopular Electronics magazine for years ran a monthly electronics tutorial column entitled, "After Class." Various guest authors wrote the articles. All you need to do is substitute transistors and associated biasing and interstage coupling for the tubes used in these fundamental crystal oscillator circuits to bring this article's content up to date. Or, maybe you are the owner of a vintage vacuum tube radio and would like to learn a little about how things were done in the olden days. Either way, as with so many aspects of electronic circuits, the basics haven't changed much in the last 100 years. It's all still good...

Please Welcome dB Control as a Supporter!

dB Control - RF CafeEstablished in 1990, dB Control supplies mission-critical, often sole-source, products worldwide to military organizations, as well as to major defense contractors and commercial manufacturers. dB Control designs and manufactures high-power TWT amplifiers, microwave power modules, transmitters, high- and low-voltage power supplies, and modulators for radar, ECM, and data link applications. Modularity enables rapid configuration of custom products for a variety of platforms, including ground-based and high-altitude military manned and unmanned aircraft. Custom RF sources and receivers, components and integrated microwave subsystems as well as precision electromechanical switches. dB Control also offers specialized contract manufacturing and repair depot services...

News Briefs

News Briefs, February 1964 Radio-Electronics - RF CafeLots of happenings in the tech world were reported in the February 1964 "News Briefs" section of Radio-Electronics magazine. The winner for best item has to be where a little girl bit into a TV power cord and got launched a couple feet into the air. The aftermath was gruesome. UNIVAC 1 was retired from service at the Bureau of the Census where it crunched numbers since March 1951. Awarding of engineering PhD and Master of Science degrees were on the rise, while Bachelor of science degrees were in decline. No explanation was offered. Maybe the relatively new hippie movement was causing...

Unlocking the Speed of Light

Unlocking the Speed of Light"Researchers have created a new type of optical memory called a programmable photonic latch, which is both fast and scalable. This memory unit provides a high-speed solution for temporary data storage in optical processing systems, utilizing silicon photonics to enhance performance. The programmable photonic latch is inspired by the set-reset latch, a fundamental electronic memory device that stores a single bit of data. It works by switching between two states: set (1) and reset (0), based on input signals. 'While optical communications and computing..."

Anatech Intros 3 Filters for February

Anatech Electronics Intros 3 New Filter Models for February 2025 - 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 filter models have been added to the product line in February, including a 5470-5725 MHz cavity bandpass filter, a 4960 MHz cavity bandpass filter, and a 5530 MHz cavity bandpass filter, all with low insertion loss and outstanding return loss. Custom RF power filter...

Acoustic Surface-Wave Devices

Acoustic Surface-Wave Devices, March 1971 Popular Electronics - RF Cafe"Praetersonic" - now that's a word you don't run up against very often. It is a combination of praeter (beyond) and sonic (related to sounds), or what more familiarly is called ultrasonic. If fact, praetersonics was the early term given to surface acoustic wave (SAW) piezoelectric devices. Amazingly, even as far back as the early 1970s, SAW filters were being fabricated that worked in the 40 MHz realm. This 1971 Popular Electronics article does a really nice job of introducing the basics of SAW and BAW (bulk acoustic wave) technology...

What's Your EQ?

What's Your EQ?, July 1967 Radio-Electronics - RF CafeOnly two circuit challenges were presented in the July 1969 "What's Your EQ?" feature in Radio-Electronics magazine. "EQ," or Electronics Quotient, is a play on "IQ," Intelligence Quotient. EQs are submitted by readers, although occasionally one of the magazine editors contributes. "Lamp Switching" is a classical puzzle where a mechanical switch and a handful of steering diodes are connected, and your mission, if you choose to accept it, is to figure out what is inherently wrong with the way the author constructed his circuit. He admits it didn't work as planned, and invites you to come...

Ultra-Thin Absorbers Revolutionize Energy and Stealth

Ultra-Thin Absorbers Revolutionize Energy and Stealth - RF CafeElectromagnetic absorbers are essential in energy, stealth, and communication technologies, yet current designs underperform. A research team has introduced ultra-thin absorbers nearing theoretical efficiency limits, promising transformative industrial applications. Absorbing layers are essential to advancements in technologies like energy harvesting, stealth systems, and communication networks. These layers efficiently capture electromagnetic waves across wide frequency ranges, enabling the creation of sustainable, self-powered...

Teledyne HiRel Semiconductors Releases Wideband 50 GHz RF Switch

Teledyne HiRel Semiconductors Releases Wideband 50 GHz RF Switch - RF CafeTeledyne HiRel Semiconductors announces the availability of its latest rad-tolerant wideband 50 GHz RF switch, model TDSW050A2T. This switch operates from true DC to 50 GHz, delivering excellent RF performance down to zero Hertz, making this device ideal for many of today's complex space and defense applications. It has been developed in a 150 nm pseudo orphic High Electron Mobility Transistor (pHEMT) Indium Gallium Arsenide (InGaAs) process and is available in a 1.15 mm x 1.47 mm x 0.1 mm die ideal for hybrid...

Radio Amateur Course - How the Vacuum Tube Works

Radio Amateur Course - How the Vacuum Tube Works, October 1935 Short Wave Craft - RF CafeA while back I was using the familiar analogy that relates water pressure, hose diameter, and flow rate to electrical voltage, resistance, and current, respectively, in an explanation to my daughter regarding why the water characteristics in her house changed after the well supply pipe and indoor plumbing changed. The cause, I proposed, was due to an increased distance between well and house, and the use of the plastic PEX tubing with a smaller inside diameter than the old copper pipe, respectively. The submersible pump and holding tank still supply the same 50 psi as before, but since that pressure now has to force...

everything RF Publishes Electronic Warfare eBook

everything RF Publishes Electronic Warfare eBook - RF CafeWarfare has evolved far beyond the conventional image of tanks, troops, and artillery. In today's battles, control over invisible forces often determines victory or defeat. One of the most critical of these forces is the electromagnetic spectrum - a domain where Electronic Warfare (EW) plays a pivotal role. EW involves the strategic use of electromagnetic energy to sense, disrupt, or deny an enemy's capabilities, often without a single shot being fired. Electronic Warfare has become an indispensable tool, shaping the outcome of conflicts by dominating the unseen forces that power today’s military technology. everything RF has created the "Electronic Warfare" eBook to act as a comprehensive...

More Problems - More Questions and Answers

More Problems - More Questions and Answers, February 1967 QST - RFCafeHere is a good old fashion Q&A session on Ham radio topics, with the emphasis on "old." QST magazine published a couple of these columns in the 1960s, and this is the second in the series. It is the half-century-ago equivalent of the contemporary "The Doctor Is In" column by the ARRL's Joel Hallas, W1ZR. I didn't read anything that wouldn't be applicable today, especially if you have some vintage gear. As with most such articles, there is something to be learned by just about anyone who deals with electronics, especially in the RF realm. One particularly interesting part is where the author, in response to a question about building and tuning your own radio...

Electronics-Themed Comics

Electronics-Themed Comics, February 1964 Radio-Electronics - RF CafeThe February 1964 issue of Radio-Electronics magazine contained these three electronics-themed comics. The one on page 48 reminds me of the time about a decade ago when I was moving an old freezer out of someone's garage, and found underneath it a huge skeleton of some sort of rodent or ruminant. I'm not sure what it was, but given the ferocious teeth if had I was glad it was long dead. The page 100 comic is my favorite. I didn't notice at first what was displayed on the oscilloscope. "Getting" the page 109 comic took a moment, but the gag eventually hit me. I colorized them to bring them into the 21st Century...

Rohde & Schwarz RadEsT Automotive Radar Testing Seminar

Rohde & Schwarz RadEsT Automotive Radar Testing Seminar - RF CafeJoin this Automotive Radar Testing Seminar on Wednesday, February 26, 2025. The introduction of the R&S RadEst revolutionizes automotive radar testing. It sets a new price-performance point and provides radar developers and production managers with benefits such as cost, space and time efficiency as well as assurance from accurate and reliable results. In this webinar we will talk about the latest automotive radar technology and market developments. We will dive deep into the radar lifecycle and test challenges as well as the applications of the RadEsT compact target generator...

Diamond Transistors for High-Power

Diamond Transistors for High-Power Applications - RF Cafe"Glasgow University researchers have led work that could lead to a new generation of diamond-based transistors for use in high-power electronics. Their new diamond transistor is claimed to overcome the limitations of previous developments in the technology to create a device much closer to being of practical use across a range of industries that rely on high power systems. The team has found a new way to use diamond as the basis of a transistor..."

The Iconoscope

The Iconoscope, July 1944 QST - RF CafeAn iconoscope was an early form of television image capturing tube. Some amateur radio operators were experimenting with slow scan TV even back when the technology was relatively new to the world. When this article was appeared in a 1944 of QST magazine, there were still large portions of the United States that did not have television broadcast coverage. Of course I would argue that at the time of my growing up in the 1960s and early 1970s a lot of areas - even suburbs - were still not covered by TV signals, based on how cruddy the reception...

What's Your EQ?

What's Your EQ?, December 1962 Radio-Electronics - RF CafeContinuing its long-time monthly "What's Your EQ?" feature where readers submit electronics-related challenges, Radio-Electronics magazine published these three in the December 1962 issue. I have to admit to not getting the "120-240 Switchover" problem due to thinking only "inside the box." I didn't consider that adding another component to the circuit was permissible. I thought only the presented wires and component were available for use. Don't you make the same mistake. "Voltage Quandary" was not as difficult, but took some head scratching...

Ivanpah Solar-Thermal Plant Shutting Down

Ivanpah Solar-Thermal Plant Shutting Down - RF Cafe$1.6B in government loans gone up in steam. "Maybe you've seen the unsightly, blindingly bright towers while traveling from L.A. to Las Vegas, in the Mojave Desert near the California-Nevada state line. Maybe you've read about birds getting fried to death as they fly through the sunlight directed to the tops of the towers by fields of mirrors. When state officials agreed to let Pacific Gas & Electric and Southern California Edison buy power from Ivanpah roughly 15 years ago, they saw this type of technology - known as 'concentrated solar power' - as the future of renewable energy. It was expensive...

DIY Airplane Detector

DIY Airplane Detector, May 1942 Popular Science - RF CafeDuring World War II, Americans, Britains, Frenchmen, and other civilians were seriously engaged in helping to defend their homeland. Those who were not in the military gathered bottles, tin cans, tires, and clothing to use in the war effort. Others volunteered at the Red Cross, veterans' hospitals, and USO offices. Some stood guard at their nation's seashores and land borders, both as armed sentries and as troop and aircraft spotters. As part of the civil defense effort, listening devices were built to help detect the sound of approaching airplanes. In patriotic tradition, magazines like Popular Science published many articles to assist the population contribute. Here is a plan for a "Homemade Plane Detector." It used a horn "antenna" that...

Electronics-Themed Comics

Electronics-Themed Comics, December 1962 Radio-Electronics - RF CafeIt is Friday when this is being posted, so that makes it a good day for these three new electronics-themed comics. They come from a 1967 issue of Radio-Electronics magazine, so the scenarios are a bit outdated. However, even if you didn't live during the era or have not read much about what the hottest topics and concerns of the era were, you can still appreciate the humor. As recently as the 1990s and early 2000s there were still a fair number of computer and electronics repair services around, so even Gen Z'ers might remember them, and certainly Millennials (aka Gen Y) . By 1967, vacuum tubes were disappearing from the repair scene as radio and TV owners...

Anatech Electronics January 2025 Newsletter

Anatech Electronics January 2025 Newsletter - RF CafeSam Benzacar, of Anatech Electronics, an RF and microwave filter company, has published his January 2025 newsletter that, along with timely news items, features his short op-ed entitled "Wi-Fi 8 Is Coming, and It's All About Reliability," which discusses the major improvement in data speed and reliability over all previous versions. The Wi-Fi Alliance predicts a 10x growth in wireless connectivity from now until 2028. Automatic arbitration between Wi-Fi zones for power levels, sub-channel assignments, and traffic handling, is intended to deal with an increasingly dense operational environment. Wi-Fi operations are nowadays conducted in both fixed and mobile scenarios where signal coexistence requirements are continually changing not just from dynamic multipath conditions due to reflections, but from constantly changing Wi-Fi bases station locations. Incredibly sophisticated mathematics are required to implement the schemes.

Light-Powered Memory 100x Faster

Light-Powered Memory 100x Faster - RF Cafe"A new era in computing is emerging as researchers overcome the limitations of Moore's Law through photonics. This cutting-edge approach boosts processing speeds and slashes energy use, potentially revolutionizing AI and machine learning applications. For decades, computer and smartphone circuits have steadily become smaller and more powerful, following the trend known as Moore's Law. However, this era of consistent progress is nearing its end due to physical limits, such as the maximum number of transistors..."

Tesla Roadster Misidentified as Asteroid

Tesla Roadster Misidentified as AsteroidThis news suggests that nobody has been tracking the flight trajectory of the Tesla Roadster which Elon Musk launched into solar orbit on February 6, 2018. "On Jan. 2, the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, announced the discovery of an unusual asteroid, designated 2018 CN41. It came less than 150,000 miles from Earth, closer than the orbit of the Moon. That qualified it as a near-Earth object - one worth monitoring for its potential to someday slam into Earth. But less than 17 hours later, the Minor Planet Center issued an editorial notice: It was deleting 2018 CN41 from its records because, it turned out, the object was not an asteroid. It was a car..."

Nationwide Television Is Now in the Making

Nation-Wide Television Is Now in the Making, January 1948, Radio-Craft - RF CafeDr. Allen Du Mont played a huge role in making television practical because of the improvements he made to the cathode ray tube (CRT). Prior to his work, the lifespan of a CRT was measured in tens of hours, and they were expensive, so their use was limited to special military and research applications. Du Mont's interest in "wireless" began at an early age, and he earned his commercial radio operator's license at the age of 14 (in 1915). He designed and produced oscillographs (aka oscilloscopes) that incorporated his CRTs. His involvement in the television industry was a natural evolution and extension of the work done in related industries...

News Briefs - Active Antenna

News Briefs, July 1967 Radio-Electronics - RF CafeWith as much ink as was used in reporting on this "Major Antenna Breakthrough?" item in the July 1967 issue of Radio-Electronics magazine, it could have qualified as a feature story. The breakthrough is an active antenna, dubbed a Subminiature Integrated Antenna (SIA), with amplifying transistors in series with the radial elements. This hookup makes practical, it is claimed, to reduce antenna length from 1/4 to 1/50 wavelength and still have reasonable signal pickup. A TV or FM receiver version could be 2 or 3 inches long. Half a year later the magazine had an SIA article entitled "Build a Mini-Tenna," which operated in the 88-108 MHz FM radio band. There does not seem to have been a widespread...

Today in Science History

Today in Science History - RF Cafe

TV X-Rays (Again)

TV X-Rays, April 1970 Radio-Electronics - RF CafeHere is the promised follow-up on yesterday's article, "TV X-Rays Are Back," from June 1969 issue of Radio-Electronics. This x-ray emission issue, whether legitimately a serious health problem or not, was a big deal and was hyped up by the news media the way cellphones causing brain cancer and laptop computers sterilizing men is done today. For a while it measurably affected the volume of color television sales. X-rays are a form of ionizing radiation (unlike microwaves which are not) and can thereby cause cancer by rearranging atoms and molecules. At the root of the problem was the extremely high acceleration voltage (HV) and beam current being used in the cathode ray tube (CRT). Potentials in excess of 25 kV generated the most harmful level of x-rays, so manufacturers redesigned sets to use lower voltages, and also incorporated...

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 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..."

Tech Themed Comics - May 1966 & December 1965 Popular Electronics

Comics with an Electronics Theme, December 1965 & May 1966 Popular Electronics - RF CafeTelevision (TV) and high fidelity stereo (HiFi) were a big deal from the 1950s through the 1970s as electronics technology underwent major improvements in component capabilities and research produced high-complexity circuits that featured sophisticated methods of signal processing. The industry went through the transition from vacuum tubes to transistors during that three decade period, setting the groundwork for the next generation of microprocessor-based audio-visual entertainment. Printed comics and TV and radio shows favorite themes included jokes having to do with Joe Sixpack and his family's anecdotes involving television and HiFi stereo. Here are a few more from the mid-1960s...

The Field That Stays at Home

The Field That Stays at Home, April 1942 QST - RF CafeHere is a really good introductory article on electromagnetic (EM) fields as they pertain to inductors, transformers, and antennas. It appeared in the April 1942 edition of QST magazine. The FCC had only been in existence for eight years at the time and was pretty much just figuring out how to regulate the heck out of everything. The author discusses compliance issues for these newfangled RF devices that were becoming more and more numerous. Interestingly, the first sentence says, "Every time you threw the transmitting switch in pre-war days...," bringing to mind how the Feds banned Amateur Radio during most of World War II for security reasons as well as to assure that scarce resources went toward building and servicing military gear as needed. Many Hams offered their gear either as a donation...

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...

Tip for Copying Images from Websites

Editing Image URL for Copy / Paste - RF CafeIn my daily routine of perusing the WWW (World Wide Web - remember that?) for good information to post, I need to copy images into which thumbnail versions are made. A very recent trend has evolved for the sake of mobile device displays which appends some sizing directives to the end of the otherwise normal URL, and that prevents doing a copy and paste with right-click -> Copy Image, and then paste it into a graphics editor. Instead, do a right-click -> Copy Image Location and then paste that URL into your browser. Click the thumbnail image above for an example. Note the appendage after the ".png" file extension:

?auto=format&fit=crop&h=432&w=76"

That prevents the normal Image Copy from working. Delete everything after .png and then hit enter. You should now be able to copy and paste the image into your editor.

Electronic Factor Quiz

Electronic Factor Quiz, November 1966 Popular Electronics - RF CafeRobert Balin created this Electronic Factor Quiz for the November 1966 edition of Popular Electronics magazine. Your challenge is to match the drawing of a particular electronics circuit or implement with the corresponding "factor." Examples are "current amplification factor," "damping factor," "modulation factor," "duty factor," "form factor," "quality factor," etc. There are ten in all. Of course on a quiz like this you cannot get just one answer wrong - or any odd number for that matter. I managed to reverse #5 and #10 (I and B, respectively). For some reason I couldn't remember what "form factor" was, but was sure that #10 was a scale factor of sorts... wrong - a clear case of cranial rectumitis...

His Mentor's Mentor Was Major Armstrong

Frequency Modulation Fundamentals, August 1939 QST - RFCafeRF Cafe visitor Mike M. sent this very interesting note after reading this "Frequency Modulation Fundamentals" article: Again, you hit it out of the ballpark, Kirt! Great article out of QST. Absolutely accurate to credit "The Old Man" Edwin Armstrong for the invention/development of FM and much more, plus the work of Dan Noble, who worked with the Connecticut State Police and Motorola as Director of Research. Also many, many others. Some that have never been properly credited. Guys like Bob Morris, W2LV and Frank Gunther, W2ALS. They were both interviewed by Ken Burns for "Empire of the Air". I was fortunate enough to talk to both of these guys after I got my Tech license in 1970. My immediate supervisor/mentor from 1972 until he retired in ~1990, was George. He was a superb mentor, who espoused the best engineering methods and as he would say " the price of success is constant vigilance." George had worked for Armstrong at the pioneering FM station, W2XMN in the late 40's and early 50's. George had several stories about working for "The Old Man..."

Crossnumber Puzzle

Crossnumber Puzzle, August 1958 Popular Electronics - RF CafeIn many ways a crossnumber (aka cross number or cross figure) puzzle, which is an intersecting grid of numbers, is more challenging than a standard crossword puzzle, which is an intersecting grid of letters. John Comstock created a few of these crossnumber puzzles for Popular Electronics back in the early days of the magazine. If you have never tried creating a crossword puzzle, especially one that uses only technical terms and has many interconnected squares in the grid, then you cannot appreciate the frustration it can be. The nice thing about creating a crossnumber puzzle versus a crossword puzzle is that every number is a valid "word" and it is therefore never a problem to find a clue to go with it. For example, any random number can be the answer to a clue that expresses ...

Homepage Archives for January 2024

Homepage Archives for January - RF CafeHomepage Archives for January 2024. Items on the RF Cafe homepage come and go at a pretty fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple megabytes). New items are added at the top of the content area, and within a few days they shift off the bottom. If you recall seeing something on the homepage but now it is gone, fret not because many years I have maintained Homepage Archives.

Homepage Archives for December 2022

Homepage Archives for December - RF CafeHomepage Archives for December 2022. Items on the RF Cafe homepage come and go at a pretty fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple megabytes). New items are added at the top of the content area, and within a few days they shift off the bottom. If you recall seeing something on the homepage but now it is gone, fret not because many years I have maintained Homepage Archives.

FQXi: Is Reality Digital or Analog?

FQXi: Is Reality Digital or Analog? - RF CafeEach year the Foundational Questions Institute (FQXi) holds an essay contest inviting writers to submit missives addressing the question chosen by the FQXi board as being particularly thought-provoking. In their words, "FQXi catalyzes, supports, and disseminates research on questions at the foundations of physics and cosmology, particularly new frontiers and innovative ideas integral to a deep understanding of reality, but unlikely to be supported by conventional funding sources." The 2011 question was "Is Reality Digital or Analog?" (here is The Wayback Machine's capture of the original webpage). Scientific American magazine, being one of three partners, published the runner-up entry in the December 2012 issue: University of Cambridge professor of theoretical physics...

Electronic Analogy Quiz

Electronic Analogy Quiz, August 1960 Popular Electronics - RF CafeThis electronics analogy quiz is a little easier than many of the others published in Popular Electronics magazine because all of the electrical and mechanical objects depicted here are very familiar. The concepts might seem trivial to those of us who have been immersed in the science for decades, but I for one can remember when first hearing these analogies how helpful they were. Not only that, but I also recall during physics and mechanics courses in college being amazed at the similarity of equations shared by electrical and mechanical processes. Wikipedia has a huge page describing many of the most familiar mechanical-electrical analogies...

Toxic Air: Our Other Import from China

Toxic Air: Our Other Import from China - RF Cafe SmorgasbordYay for us. Our pollution production levels are way down compared to what they were in the middle of the last century. Seriously, things were getting really bad. Pittsburgh was considered such a hopeless mess that famed architect Frank Lloyd Wright, whose landmark Fallingwater home sat nearby, when asked what to do about Pittsburg's terrible pollution responded, "Abandon it." Lake Erie had been declared officially dead. Love Canal dominated headlines. Los Angeles air was (and still is, BTW) unbreathable. After huge public awareness campaigns, cleanup efforts, and stricter enforcement of pollution laws, the trend halted and has reversed. That is unquestionably good news. The bad news is that as pollution control got better, companies found continuing manufacturing operations in the U.S. was unprofitable based on what people were willing to pay for their products. Steel, the literal and figurative backbone of industry, could not be mined, smelted, and processed into finished goods at a price that would encourage innovation and growth...

Radio Amateur Course - How the Vacuum Tube Works

Radio Amateur Course - How the Vacuum Tube Work, October 1935 Short Wave Craft - RF CafeA while back I was using the familiar analogy that relates water pressure, hose diameter, and flow rate to electrical voltage, resistance, and current, respectively, in an explanation to my daughter regarding why the water characteristics in her house changed after the well supply pipe and indoor plumbing changed. The cause, I proposed, was due to an increased distance between well and house, and the use of the plastic PEX tubing with a smaller inside diameter than the old copper pipe, respectively. The submersible pump and holding tank still supply the same 50 psi as before, but since that pressure now has to force the water through a path inside the house with more resistance to water flow, the delivery rate to fixtures is now lower. When I hold the contacts closed on the pump control relay, the most I can get is about 55 psi. Raising the pressure will require replacing...

Alaska Telephone Cable Opened for Use

Alaska Telephone Cable Opened for Use, March 1957 Radio & Television News - RF CafeAlaska and Hawaii were added to the Union as the 49th and 50th states, respectively, in 1959. Prior to that time, both were referred to as possessions or territories. This story from a 1957 edition of Radio & Television News refers to Bell Telephone Systems and the U.S. Army Signal Corps laying the first cable for opening commercial telephone service between Port Angeles (near Seattle), Washington, and Ketchikan, Territory of Alaska. The 900 mile, submarine cable carried 36 circuits, and took 2 years to install at a cost of $20 million ($192 million in 2021 money). Work conditions for crews were nowhere near as accommodating or protected against accidents as they are today. As with so many things, our forebears sacrificed life and limb, literally, to bring us to the comfortable existence we enjoy today...

Service Data Technicians and Money

Service Data Technicians and Money, November 1949 Radio-Electronics - RF CafeJohn T. Frye was an electronics service technician long before he began writing techno-dramas like "Mac's Radio Service Shop" and "Carl & Jerry." His expertise and real-world experience evidenced itself in the wide variety of situations and subjects covered in the stories. If you have never read any of them, I whole-heartedly suggest that you sample a few (or listen to one of my podcast readings of them). In this article from a 1949 issue of Radio-Electronics magazine, Mr. Frye discusses what was evidently a reluctance on the part of service men to acquire and/or use printed service data when troubleshooting and/or aligning radios, televisions, tape recorders, etc. The attitude of some elitists was that if you needed to consult documentation that it was evidence of your ineptness; you were not a worthy electronics technician. More than one episode of "Mac's Radio Service Shop" had owner Mac McGregor admonishing young Barney about wasting time during troubleshooting by not consulting the service data sheets he stocks in the shop. Even if a shop owner could not afford the elite service literature from SAMS Photofacts...

Carl & Jerry: Sonar Sleuthing

Carl & Jerry: Sonar Sleuthing, August 1963 Popular Electronics - RF CafeIn this August 1963 adventure from Popular Electronics magazine, teenage techno-investigators Carl Anderson and Jerry Bishop use their home-brew sonar device to help the local sheriff nab a couple bank robbers. The "Hydro Probe" mentioned in the article was a real product manufactured by the Raymond Development Company of Watertown, Massachusetts (no longer in business). By this time the duo were students pursuing electrical engineering degrees at Parvoo University (a play on Perdue University, located in the boys' home state of Indiana). Enjoy.

Science Theme Crossword Puzzle for March 14th

Science Theme Crossword Puzzle for March 14th, 2021 - RF CafeThis Science-Theme Crossword Puzzle for March 14th has many words and clues related to... you guessed it... RF engineering - and mathematics, chemistry, physics, and other technical words. As always, this crossword contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Homepage Archives for February 2023

Homepage Archives for February - RF CafeHomepage Archives for February 2023. Items on the RF Cafe homepage come and go at a pretty fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple megabytes). New items are added at the top of the content area, and within a few days they shift off the bottom. If you recall seeing something on the homepage but now it is gone, fret not because many years I have maintained Homepage Archives.

An Impedance-Matching Transformer Tutorial

An Impedance-Matching Transformer Tutorial, February 1943 QST - RF CafeThe word "transformer" in the title for this 1943 QST magazine article does not refer to a mutual inductance transformer, but an impedance transformer for matching transmission lines to antennas (or anything else for that matter). Author T.A. Gadwa gives examples of impedance-matching circuits both for when the antenna impedance is lower than the characteristic impedance of the transmission line and when the antenna impedance is higher than that of the feed line. "L," "pi," and a couple other circuit configurations are covered. Equations are also given...

Copper Mountain Technologies (VNA) - RF Cafe
LadyBug RF Power Sensors

Windfreak Technologies Frequency Synthesizers - RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe