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World's 1st Quantum Entanglement Communications Service

World's First Quantum Entanglement Communications Service Offered by QentComm - RF CafeIn a groundbreaking announcement that will forever transform global communications, QentComm®©™ (Quantum Entanglement Communications) has unveiled the world's first commercially viable quantum entanglement communication system. Dubbed QeG®©™ (Quantum entanglement Generation, pronounced kwee-gee), supplementing the traditional 4G, 5G, and 6G nomenclature, this revolutionary technology eliminates the limitations of traditional radio-based systems, delivering instantaneous, unlimited connectivity across any distance without reliance on satellites, cell towers, or fiber optics. Under the leadership of Kirt Blattenberger, QentComm (pronounced kwent-kōm) has created a system that defies conventional physics by utilizing quantum entanglement for real-time, secure communication between devices anywhere in the universe - including here on Earth...

Carl & Jerry: Secret of Round Island

Carl & Jerry: Secret of Round Island, March 1957 Popular Electronics - RF CafeIn this "Carl & Jerry" technodrama from a 1957 issue of Popular Electronics magazine, the two boys start out enjoy a casual day of kite flying, using a homebrew radio-controlled camera attached to the kite to capture an aerial view of Round Island in a lake. After successfully taking a picture, they develop the film and discover two men and an odd setup on the island. Curious, they return the next day, find a hidden tunnel, and stumble upon an illegal liquor still. As you might expect, the teens run into a heap of trouble when the moonshiners nab them. Using their combined ingenuity and knowledge of communications methods common to Ham radio operators of the era, contact was made and help was on the way. Read about Carl and Jerry's exploit and exactly what it was that saved the day - and their hides!

Ham Radio Students at DSES Radio Telescope

Amateur Radio Students Visit DSES Radio Telescope - RF Cafe"In late January 2025, 17 students and staff members from Las Animas High School (LAHS) in Colorado visited the Deep Space Exploration Society Radio Telescope (DSES) located at the Plishner Radio Astronomy and Space Sciences Center near Haswell, Colorado. They also got an introduction to amateur radio. 'This first field trip visit of high school students reflected the dreams of Michael Lowe, former DSES board president, who sought to create a center for radio astronomy and space science education in southeast Colorado,' said DSES President Myron Babcock, KL7YY..."

Old World Standards Breaking Through

Old World Standards Breaking Through, April 1966 Popular Electronics - RF CafeMaking format changes to magazines after many years of an established standard always ruffles the figurative feathers of a significant portion of regular readers. Two magazines I read monthly, Model Aviation and QST, recently underwent a format change - both of which I considered very nice. However, reader comments in the aftermath showed a few who were not impressed. Popular Electronics magazine in 1966 made announcements regarding plans to adopt some of the newer base units for physical measurements, including this one for beginning to use "Hertz" (Hz), along various numerical prefix forms, instead of "cycles per second" (cps). The editors give sound reason...

Harold Beverage of the Eponymously Named Antenna Type

Harold Beverage of Eponymously Named Antenna Type, August 1944, Radio-Craft - RF CafeThe Beverage Antenna, very familiar to amateur radio operators, is a simple but efficient, highly directional, non-resonant antenna that consists of a single straight wire of one or more wavelengths that is suspended above the ground. It is orientated parallel to the direction of intended reception. One end is terminated to ground through a resistor, and the other is connected to the receiver. The following quote comes from the patent (US1,81,089) text: "In accordance with theoretical considerations, if an antenna were to be freely suspended and if the surface of the earth constituted a perfectly conducting parallel plane, current waves would travel through...

Dear Mr. Fips: 30-Day Record Response

Dear Mr. Fips: 30-Day Record Response, June 1961 Radio-Electronics - RF CafeThis letter was sent to Hugo Gernsback, publisher of Radio-Electronics magazine, in response to the "30-Day Record Response" article penned by noted scientist and inventor Mohammed Ulysses Fips. In it, Stephen A. Kallis, Jr. heaped laud upon the "Most Revered and Esteemed Fips" for his long-term recording device (remember, 1961 was many decades before microminiature terabyte memory and microprocessors) were available, and chastises Mr. Gernsback for evidently calling into question the authenticity of the recorder. Kallis, a self-proclaimed stereo enthusiast, bolsters Fips' case by citing "A Proposed Listening Area," by the Institute of Synergistic Statics Proceedings...

Ulano Masking Films - Rubylith

Ulano Masking Films, December 27, 1965 Electronics Magazine - RF CafeRaise your hand if you're old enough to remember doing printed circuit board layout using Rubylith tape. My hand is up. Back in the early 1980s, I did prototype PCB designs in an engineering development lab at Westinghouse Electric's Oceanic Division. Most of it was for analog and RF substrates that would be photographically reduced in size for use with bare integrated circuit die and surface mount passive components (Rs, Ls, and Cs), upon which I would later epoxy-mount those components and wire-bond everything using 1-mil gold wire. However, there were projects where full-size leaded components were used on a through-hole PCB that used not only the Rubylith tapes but also sheets with special electronics shapes for solder pads around the holes for components leads, ground and power planes, board-edge connectors...

Mind-Bending Quantum Phase Flip

Mind-Bending Quantum Phase Flip - RF Cafe"Quantum systems don't just transition between phases - they do so in ways that defy classical intuition. A new experiment has directly observed these dissipative phase transitions (DPTs), revealing how quantum states shift under carefully controlled conditions. This breakthrough could unlock powerful new techniques for stabilizing quantum computers and sensors, making them more resilient and precise than ever before. A new frontier phase transitions, like water freezing into ice, are a familiar part of everyday life. In quantum systems, however, these transitions can be far more extreme, governed by principles like Heisenberg's uncertainty..."

DX Hams Do Get Around

DX Hams Do Get Around (November 1940 Boys' Life Article) - Airplanes and RocketsIn this November 1940 issue of the Boy Scouts Boys' Life magazine, amateur radio operators, or "hams," are described as having the ability to communicate across vast distances, connecting far-flung locations such as Goulds, Florida, Cali, Colombia, Cairo, Kenilworth, England, Bombay, and Brisbane. These operators, licensed by the Federal Communications Commission, engage in various activities such as talking to distant stations, participating in contests, and providing emergency communication during natural disasters. With call letters assigned by international treaty, these stations use a combination of code and phone to make contact, exchanging reports and QSL cards. The Radio merit badge was first offered in 1918 and has been...

Thanks Again 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! 

Electronic Razor

Electronic Razor, April 1962 Radio-Electronics - RF CafeThe date approacheth when, according to Western customs, every body needs to stand a vigil against the attempt of another body to make him or her a fool. That date is of course April 1st, aka, April Fools' Day. Many of the technical magazine we grew up with - and some still today - engage in the ruse. Innovator and publisher Hugo Gernsback, who's long list of accomplishments includes this Radio-Electronics magazine, often contributed his own wit to the April editions. The usual scheme is to make the article just authentic enough to be possibly real, while including features outrageous enough to clue the read that he is being "had." Experienced subscribers knew that the Mohammed Ulysses Fips byline was sure to deliver an April Fools delight. Here, Mr. Fips expounds on the newfangled "Electronics Razor..."

Photon Entanglement Miniaturizes Quantum Computers

Photon Entanglement Miniaturizes Quantum Computers - RF Cafe"Quantum computing has long struggled with creating entangled photons efficiently, but a team of researchers has discovered a game-changing method using metasurfaces - flat, engineered structures that control light. By leveraging these metasurfaces, they can generate and manipulate entangled photons more easily and compactly than ever before. This breakthrough could open the door to smaller, more powerful quantum computers and even pave the way for quantum networks that deliver entangled photons to multiple users..."

Waveguide Temperature Rise

Temperature Rise in Rigid Waveguide, January 17, 1964 Electronics Magazine - RF CafeHere is a chart you don't see every day - "Temperature Rise in Rigid Waveguide." The company, Engineering Antenna Systems, of Manchester, New Hampshire, that published the chart in a 1965 edition of Engineering magazine, does not exist anymore. They were probably bought by someone else, but I could not even find an honorable mention of them in a Google search. Given the very low attenuation of properly sized and installed waveguide, it is hard to imagine a temperature rise of 500°F; however, when megawatts are pumped into it even a couple tenths of a decibel of attenuation per 100 feet results in a lot of power loss. Noted is how attenuation - and therefore temperature rise - is greater for frequencies at the lower end of the waveguide's operational range. Temperature rise numbers are for natural convection in free air...

everything RF Interviews Ernest Werbel

everything RF's Interview with Ernest Werbel from Werbel Microwave - RF CafeHere is an inspiring interview of Werbel Microwave's Ernest Werbel - a case of pulling oneself up by one's own bootstraps --- everything RF recently interviewed Ernest Werbel, the Chief Design Engineer of Werbel Microwave. He is from Livingston, NJ, and got his associates in EE Technology, at County College of Morris. Ernest completed his Bachelors in Electronics and Computer Engineering Technology from NJ Institute of Technology. He founded Werbel Microwave in 2014. Q. Can you tell us about Werbel Microwave? When did you start the company and how has it evolved over the years? Ernest Werbel: Firstly, thank you for the opportunity to participate in the everything RF community. I appreciate everything that Raghav and his team have done for us since the beginning, getting our products listed on everything RF and featuring our products in the email blasts... As a child and teen in the 90s, I was always interested in electronics. When I was very young, a radio was a magical box with a voice. Later, when my grandparents passed in '97, my parents and I were cleaning out their home in Brooklyn. Among other things were many old and broken consumer electronic items...

Have You Seen Him?

Have You Seen Him?, April 1935 Short Wave Craft - RF CafeToday we have missing persons notices printed on milk cartons and computer-aged pictures of missing kids on bulletin boards at Walmart, and of course the Internet with all its various forms of publicity. In 1935, evidently, an electronics magazine was a proper venue for placing a missing person ad. At the time there was no convenient and accessible way for family members to reach out to a nationwide audience other than to place ads in magazines and/or newspapers in remote locations. I thought it odd to see such a placement in this edition of Short Wave Craft magazine, but considering the aforementioned, doing so is entirely reasonable for a worried family. I wonder how much it cost to place the notice? It's heartbreaking, really...

Engineering & Tech Headlines <Archives>

• 2025 Tech Jobs Expected to Take Off

• Semiconductor Industry Faces a Seismic Shift

• 76% of News Consumers Still Use AM/FM

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• Radio Attracts High Purchasing Power Consumers

Turn Your Vertical Antenna into a Rotatable Beam

Turn Your Vertical Antenna into a Rotatable Beam (QST) - RF CafeI'm always aware of the old saying that it is better to remain silent and thought a fool, than to open your mouth and remove all doubt, but I'll take the risk here. The ARRL's QST magazine has for decades in the April issue published at least one unannounced "April Fool" item. I think I found at least two for 2025. While enthusiastically reading "Turn Your Vertical Antenna into a Rotatable Beam," (p60), it didn't occur to me that this was the April issue, and I was in awe of Jay Kolinsky's (NE2Q) intuition and creativity in devising a scheme to get directivity from his standard vertical whip antenna. By sliding a carbon fiber tube with a narrow slit along the length over top of the antenna, a 14 dB increase was realized in the direction of the slit. NE2Q has named his invention the Loof Lirpa Slot (LLS). What's in a name - Juliet?. Is a patent in the works?
CW Corporation of America's "Snappy Training Key" - RF CafeThe other suspect is the CW Corp. of America's "Snappy Training Key," reported on page 95 by Ellwood Brem (K3YV). You need to log in to read the articles, or borrow a hard copy from a Ham friend.

Unbreakable 13,000 km Quantum Link Beam

Unbreakable 13,000 km Quantum Link Beam - RF Cafe"A major scientific leap has been made with the creation of the longest ultra-secure quantum satellite link between China and South Africa, spanning nearly 13,000 km. This unprecedented achievement, marking the first quantum satellite link in the Southern Hemisphere, relied on real-time quantum key distribution to transmit encrypted images between continents. World’s Longest Quantum Satellite Link Established Scientists from South Africa and China have successfully created the world’s longest intercontinental quantum satellite link, spanning 12,900 kilometers (~8,000 miles). This ultra-secure connection was made possible using China's Jinan-1..."

Radiocarbon Nuclear Battery Lasts a Lifetime

Radiocarbon Nuclear Battery - RF CafeAccording to the science and mechanics magazine I read during the 1960s through 1980s, we should all have personal nuclear power generators powering our houses, watches, cars, and just about anything that runs on electricity. Like with flying cars and robotic domestic servants, were not even close to that a quarter of the way through the next century (2025). This news item appears to be a good start on the promise. "Imagine never charging your phone again or having a pacemaker that lasts a lifetime. Scientists are developing tiny nuclear batteries powered by radiocarbon, a safe and abundant by-product of nuclear plants. Unlike lithium-ion batteries, which degrade over time and harm the environment, these new designs use beta radiation to trigger an electron avalanche and generate electricity. The technology could one day make nuclear power as accessible as your pocket device..."

FM Radio Quiz

FM Radio Quiz, April 1950 Radio & Televsion News - RF CafeFM (frequency modulation) radio certainly was a hot topic beginning in the middle to late 1940s. With the war out of the way, energies and resources were being redirected back to peacetime production. Major Edwin Armstrong announced his FM scheme in 1935, and as with many new inventions, it was met with skepticism by many who doubted his claim of static interference immunity. For many, it was a lack of understanding that caused the negative reaction, caused primarily by the increased level of sophistication of the transmitter and receiver circuitry. Amplitude modulation (AM) was so easy even a caveman could understand it, but adding phase relationships into the equation (literally) left many in the dust. This FM Radio Quiz from a 1950 issue of Radio & Television News magazine tests your grasp of frequency modulation principles...

Archie's Ham Radio Adventure

Archie's Ham Radio Adventure - RF CafeStan Goldberg is a familiar name to comic book aficionados for his artistry in Spider Man, the Incredible Hulk, and the Archie series. QST magazine had him listed in the "Silent Keys" column in the November 2014 issue because he passed away in August. A Silent Key, in Hamdom, is usually a title reserved for a deceased licensed operator (the 'key' reference being a Morse code key), but a search of the Internet and the FCC license database web page did not turn up a call sign for him. Unless his record has been dropped from the database, Mr. Goldberg might never have actually been a Ham, but earned the Silent Key acknowledgement because of his involvement in a 1986 special edition comic book titled "Archie's Ham Radio Adventure." It was quite an extensive story...

Storage Battery Could Bring Back Electric Autos

Tech Notes: New Storage Battery Could Bring Back Electric Autos, December 1966 Radio-Electronics - RF CafeIn a 1966 issue of Radio-Electronics magazine, a revolutionary sodium-sulfur storage battery was demonstrated at a Detroit press conference, suggesting that Ford could enter the electric car market within the next ten years, and in the process "bring back electric autos." That suggests there were EVs before, and in fact, there were, at the turn of the 20th Century. The new battery, operating at 800° Fahrenheit, was completely sealed and produced 15 times more power than a lead-acid battery of the same weight, without the need to vent charging gases. The battery's design featured sodium and sulfur separated by a ceramic partition, with sodium ions moving through the ceramic to form sodium sulfide during discharge and reversing the process during charging, producing no gases or byproducts...

Electronic Current Quiz

Electronic Current Quiz, October 1963 Popular Electronics - RF CafeThis Electronics Current Quiz from the October 1963 edition of Popular Electronics magazine is recent enough (if you consider more than half a century ago to be recent) that it uses both transistors as well as vacuum tubes in the example circuits. I have to admit to only scoring 60% on the quiz, which is pretty lame. You will probably do better, especially if you are my age or older. I thought the names of the current type would make the challenge a breeze, but not so in my case. Just as back in school days when looking up the solution to problems in the back of the textbook and the answers seem obvious (well, not always), so, too, do these...

Photonic Chip Transforms Radar and Comms

Photonic Chip Transforms Radar and Comms Systems - RF Cafe"Researchers at the University of Twente, in collaboration with the City University of Hong Kong, have designed a cutting-edge programmable photonic chip in a thin-film lithium niobate platform, an important material in photonics. Published in Nature Communications, this work paves the way for next-generation high-performance radar and communication applications. An important material is changing the way optical chips work, making them smaller, faster, and more efficient: thin-film lithium niobate (TFLN). It offers exceptional properties for how light and electrical signals can interact..."

Alexander Graham Bell: A Short Bio

Alexander Graham Bell: A Short Biography - RF Cafe - RF CafeAlexander Graham Bell was born on March 3, 1847, in Edinburgh, Scotland, to Alexander Melville Bell and Eliza Grace Symonds. His father was a professor of elocution and the inventor of Visible Speech, a system designed to help deaf people communicate. His mother, Eliza, was an accomplished pianist who lost her hearing later in life. Bell was the second of three children; his brothers, Melville James and Edward Charles, both died of tuberculosis. Bell's early education was influenced by his father's work in speech and elocution. He attended the Royal High School in Edinburgh and later studied at the University of Edinburgh, though he did not complete a degree. His family moved to London in 1865, where Bell continued his studies at University College London, focusing...

$5.00 for Best Short Wave Kink

$5.00 for Best Short Wave Kink, November 1935 Short Wave Craft - RF CafeHere is a handy-dandy baker's dozen of "kinks," otherwise known as tricks of the trade, shortcuts, or clever ideas, that could prove useful while working in the lab at work or in your shop at home. They appeared in a 1935 issue of Hugo Gernsback's Short Wave Craft magazine. One suggestion is to place a sheet of tracing paper over your schematic while wiring a circuit and draw each connection as it is completed, rather than mark up the original drawing. That was definitely good for a time when making a spare copy of a magazine page or assembly instruction from a kit was not as simple a matter as it is today. Whether it be a schematic or a set of plans for a model airplane, I always make a copy to work and draw notes on rather than defacing the original...

Do You Know the Law?

Do You Know the Law?, November 1963 Radio-Electronics - RF CafeThis quiz from a 1963 issue of Radio-Electronics magazine tests readers' familiarity with key electrical laws beyond the well-known Ohm's Law, including Kirchhoff's voltage and current laws for circuit analysis, Joule's law for heat in resistors, Poynting's theorem for energy flow, Lenz's law for induced forces, Neumann's formula for transformers, Wien's displacement law impacting infrared electronics, Helmholtz's theorem for vector fields, the Wiedemann-Franz-Lorentz law connecting conductivity types, and Faraday's law of induction, challenging engineers to recall these foundational principles and their discoverers. Well, it is not exactly a quiz as much...

Today in Science History

Today in Science History - RF Cafe

Electronics-Themed Comics from May 1947 Radio-Craft

Electronics-Themed Comics, May 1947 Radio-Craft - RF CafeMany topics of the electronics-themed comics which appeared in Radio-Craft were suggested by the magazine's readers. Staff artists like Frank Beaven turned those suggestions into cartoons. For a while there was a special feature called "Radio Term Illustrated" where, as the name suggests, terms like "Signal Generator" and "High Potential" are rendered in farcical form. These four comics, two of each type, appeared in a May 1947 issue of Radio-Craft. I have to admit that even with my familiarity with vintage electronics memes I do not get the Television "Organ" comic (yes, I understand the organ grinder, but not how it applies to TV).

Mathematics in Radio - Differential Calculus

Mathematics in Radio - Differential Calculus, September 1932 Radio News - RF CafeThis entry level introduction of differential calculus as it applies to electronic circuit analysis appeared way back in a 1932 edition of Radio News magazine. It was written by none other than Sir Isaac Newton himself (just kidding, of course). Author J.E. Smith created an extensive series of lessons that began with simple component and voltage supply descriptions and worked up through algebraic manipulations and on finally to calculus. I remember not being the best math student in high school (OK, one of the worst), but once I got an appreciation for the power of mathematics for analyzing electronics, mechanics, physics, and even economics, my motivation level soared to where I craved more of it and ended up receiving "As" in all my college math courses. That is truly an indication that while not everyone can excel at math, the proper environment can make a world of difference...

Kluge Electronics Advertisement

Kluge Electronics Advertisement, January 1946 Radio News - RF CafeHaving an unusual last name like "Blattenberger" in the U.S. has caused me some abuse over the years as many people have felt the need to either purposely mispronounce it or make make snide comments about its length and number of syllables. Even school teachers joined in the fray, especially on the first day of class when attendance was being taken. My drill sergeant in USAF basic training (circa 1978), TSgt. Ramerez, felt the need to needle me about it. People in America with surnames of German origin were often the victims of physical abuse, alienation, and derision during both World War I and World War II. You hear a lot about the government's internment of Japanese Americans during WWII, but some Germans were also rounded up merely because of their names...

Radio Lands the Plane

Radio Lands the Plane, August 1938 Radio News - RF CafeConsidering that only three-and-a-half decades had passed since the brothers Wright first flew their eponymous "Flyer" off the sands of Kitty Hawk, North Carolina, it is pretty impressive to think that by 1938 the majority of commercial air transport planes were under the able control of electromechanical apparatus(es?). Rudder, elevator, aileron, and throttle, driven by electrical servomechanisms rather than human hands and feet, responded to the signals to analog computers fed data from onboard barometer, accelerometer, level, and compass sensors, and from ground-based radio directional beams. That was for mostly straight and level flight from one fixed waypoint to another. An ability to program vectored flight paths came later. This "Radio Lands the Plane" article discusses progress being made in the realm of completely automated landings. As can be seen, the framework for modern instrument landings systems was being laid...

What Does Your Daily Commute Cost You?

What Does Your Daily Commute Cost You? - RF Cafe SmorgasbordHow far do you commute each day for the privilege of doing your part to push back the frontiers of technical ignorance and to boldly go where no engineer - or technician - has gone before. Do you know what the cost equates for you each year? This handy-dandy infographic lays out some gruesome numbers. Those with a weak stomach probably should pass on viewing this one. Here's a hint at what you will see: See that big $795 in the thumbnail image? That's the average cost per year for commuting -- per mile! Yessiree, if you live just 10 miles from work, you're losing nearly $8,000 per year, depending on you automobile type, on gas, tires, maintenance, devaluation, and loss of your personal time (which is valuable, after all). Back in the early 1990s I drove about 45 miles each way to Comsat, which took about 65 minutes due to miserable traffic, which is 130 minutes round-trip, or 2 hours and 10 minutes (about the run time of an average movie) each day. Figuring two weeks vacation and 10 holidays, that leave 48 weeks x 5 days/week = 240 days per year of commuting. 240 days x 130 minutes = 31,200 minutes = 520 hours per year. That's a fourth of a man-year (2,080 hours) on the road. It was a great job, but combined with working 60-70 hours per week...

Glowing Trees a Problem for Astronomy

Glowing Trees a Problem for Astronomy - RF CafeA controversy brews over the merits of breeding plants that glow like a lightning bug. Proponents say glowing trees could eventually replace electric street lights, thereby reducing pollution created by generating stations. Opponents say messing around with tree genes is dangerous and should be disallowed since it could lead to unanticipated environmental ramifications on both plant and animal species. The unique aspect of this effort is that it is being pursued primarily by genetic hobbyists rather than corporations - at least for now. There is bound to be a huge financial potential for such a copyrighted line of plants. My opposition to the concept is primarily a concern for light pollution projected skyward. Astronomers have a difficult enough time with ever-encroaching sources of ambient light...

Comics with an Electronics Theme

Comics with an Electronics Theme, May 1967 Popular Electronics - RF CafeWalt Miller drew a lot of comics for electronics magazines like Popular Electronics, and he did the cover art for Astounding Science Fiction magazine. No doubt there were others. I could not find any detailed information about Mr. Miller's personal background, such as whether he was a Ham radio operator, but clearly he enjoyed electronics and science topics. This group of comics, which appeared in the May 1967 issue of Popular Electronics, touches on many scenarios that would have been familiar to hobbyists of the day. I like the one where the guy sneezes and scatters carefully counted and sorted resistors all over the floor. Another refers to installment plans for purchasing equipment. That was from a time when credit cards were not handed out like candy and only people with provable credit-worthiness could get them...

Electronics-Themed Comics

Vintage Electronics-Themed Comics September 1968 and March 1969 Radio-Electronics - RF CafeIt is Thanksgiving Day in the United States, so a lot of people will be off work, sitting at home waiting for the turkey, mashed potatoes and gravy, hot rolls, assorted vegetables, and of course pumpkin pie for the grand finale. If that describes you, or you are visiting from elsewhere, here are a couple of electronics-themed comics from vintage Radio-Electronics magazines to bide the time. For anyone not old enough to remember when reel-to-reel magnetic tape players (see example to the left) were the prized possession of every true audiophile, the comic on the bottom might be a bit confusing. Recorded music quality was better than other formats, and the machines had much finer control over play speed accuracy. Buying factory-recorded song reels was very expensive...

FM Radio in Canada

FM Radio in Canada, January 1946 Radio News - RF CafeDepending on which news story you believe, both AM and FM (and television for that matter) over-the-air broadcasting is dying out at an increasingly rapid rate. Between recordable podcasts, wired Internet connections, and the growing ubiquity of Wi-Fi connectivity, a large majority of people in the civilized world are getting their broadcasts via the Web. If you "follow the money" in broadcast advertising, the lion's share of dollars have shifted to online venues, simultaneously draining revenue from local stations. When this story was written in 1946, OTA radio was king for real-time and free reception of information - particularly in a mobile environment. A dilemma arose in the form of RF spectrum allocation in border regions between the U.S. and Canada, both of which were scrambling to stake a claim on channels. AM was old-hat and sharing issues had largely been worked out, but the advent of FM (frequency modulation) and an entirely new band of frequencies opened a real can of worms for national and international regulators...

Great Britain Interference Survey

Great Britain Interference Survey, November 1976 QST - RF CafeWhen I began reading this piece I wasn't sure whether it was reporting on interference caused to amateur radio operation or interference caused by amateur radio operation. It turns out to be the latter. Ever since radio operation began in the days of Marconi, unintentional interference has been a problem. The problem has always been a combination of improper transmitter and/or receiver filtering. Electromagnetic spectrum regulatory agencies attempt to assess and address interference through operational band assignments for particular segments of the spectrum, including how much residual (unintentional) power can be emitted outside of band or within a defined power mask. Amateur radio operators are often the first group to be suspected of causing interference, no doubt due to the "amateur" part of their moniker. In truth, many amateurs are some of the most knowledgeable and responsible users of the airwaves...

Radio-Electronics Monthly Review

Radio-Electronics Monthly Review, April 1946, Radio-Craft - RF CafeBelieve it or not, many countries did - and some still do - charge people wanting to receive over-the-air (not cable or satellite) commercial radio and/or television programming a wireless license fee for the privilege. Yes, this is for receiving, not transmitting, signals. If you dared to tune in a BBC program without a license, a fee could be expected upon detection (pun intended). The Monthly Review feature in this 1946 issue of Radio-Craft magazine reported an increase in cost to the equivalent of $29 in 2021 money (per the BLS Inflation Calculator). Also highlighted was a method for printing radio circuits made with conductive inks on ceramic sheets - known today as thick-film printing. An announcement of the U.S. War Department's 18,000-tube ENIAC electronic calculating device was made as well. The electronics field was moving quickly...

Patent Infringers Beware

Patent Infringers Beware, July 1966 Popular Electronics - RF CafeAre you violating patent laws in your basement? Patent laws have changed since this article was published in 1966, but the tenets are basically the same - do your due diligence on prior work assignment before publishing any publicly accessible product (print or physical). Since part of Popular Electronics' raison d'être is to provide circuits for hobbyists to build and benefit from, the lawyer who wrote this piece focuses on such applications. He claims, at least according to 1960 patent law, "There are court decisions which hold that experimental use of a patented invention for the sole purpose of gratifying curiosity or a philosophical taste, or for mere amusement, is not an infringement." HOWEVER, before you conclude that this must still be the case, read this synopsis from the Ius Mentis website...

Flying Radiomen (and Radiowomen) of the Ferrying Division

Flying Radiomen [and Radiowomen] of the Ferrying Division, June 1944 QST - RF Cafe"Necessity is the mother of invention" is an oft-heard phrase that never rang truer than during World War II. Both the Axis and the Allied powers had extremely brilliant and capable people working to defeat each other, driving advances in technology and methods at a break-neck pace for nearly a decade (remember WWII began before the U.S. entered the fray in 1941). Aircraft and radio were powerful new weapons for all sides at that point since both were still in their fledgling modes in WWI. Efficient and effective execution of aircraft ferrying, troop movement, and supply delivery was absolutely dependent on radio equipment and operators that could adapt to new strategic situations and endure all sorts of weather and geographic stresses. While the Army Signal Corps had a good cadre of radio operators available, few were experienced with operating in their gear while airborne...

Understanding Wave Physics

Understanding Wave Physics - RF CafeHere is the electromagnetic wave section of the "Wireless Networking in the Developing World," book (open source). "Wireless communications make use of electromagnetic waves to send signals across long distances. From a user's perspective, wireless connections are not particularly different from any other network connection: your web browser, email, and other applications all work as you would expect. But radio waves have some unexpected properties compared to Ethernet cable. For example, it's very easy to see the path that an Ethernet cable takes: locate the plug sticking out of your computer, follow the cable to the other end, and you've found it! You can also be confident that running many Ethernet cables alongside each other won't cause problems, since the cables effectively keep their signals contained within the wire itself. But how do you know where the waves emanating from your wireless device are going..."

Television and FM Antennas

Television and FM Antennas, January 1948 Radio-Craft - RF CafeThis article on the design and use of antennas for television and FM radio was printed in a 1948 issue of Radio-Craft magazine. Equations and charts are provided for calculating element lengths for half-wave antennas, including directors and reflectors. Many types of antennas - dipole, stacked dipole, folded dipole, conical, adjustable "V," cross-element - are discussed regarding siting issues (location and height above the ground), and radiation patterns. It is a pretty good primer for someone new to antennas, and makes a great supplement to the data furnished in study guides for obtaining a Ham radio license...

Radio Wittiquiz, November 1937 Radio-Craft

Radio Wittiquiz, November 1937 Radio-Craft - RF CafeMixing a little fun with learning has always been a good motivation for students. I have written in the past about a particular electronic circuits professor I had that liked to play practical jokes during lessons and exams. Including gag options on a multiple choice test is a great way to inject a bit of tension-easing levity while at the same time eliminating one or more opportunities to guess at a wrong answer (although no relief for the truly clueless). I sometimes do that on the RF Cafe Quizzes that I generate. Radio-Craft printed a large bunch of such quiz questions under the title "Radio WittiQuiz," where the questions and answers were provided by readers. Here is one from November 1937...

Pendulum-Driven Mechanical Clock Escapement

Pendulum-Driven Mechanical Clock Escapement - RF CafeAlways wanting to have a pendulum-driven clock with a good old-fashioned mechanical escapement movement, I resorted to eBay to find what I wanted. I'm sure there is a local clock store somewhere around here that would sell me a clock, but I figured a better deal might be had bidding against somebody online than trying to talk a shop owner down in price. Besides, I was really looking for a clock that I could strip down and refinish without worrying about reducing any collector value that it might have. There is a video of it in action at the bottom of the page. After a couple weeks of watching the auctions, I settled on two clocks - one that can sit on a mantel or hang on the wall, and another - the one shown here - that is purely a wall-mounted regulator type. This clock was made in China in 1899, according to a paper that was glued to the back plate. Since this type of clock typically has no real value (they were all cheap imports for working-class people), I performed the stripping and refinishing without...

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...

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 225,000 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...

CBS Tubes Advertisement

CBS Tubes Advertisement, August 1958 Radio News - RF CafeThis full-page advertisement by CBS Tubes caught my eye because of the vast array of vacuum tube shapes and sizes. Most people, even back in the era of tube-based electronic equipment, think of the standard 12AX7 type rounded top, cylindrical glass package with a plastic or phenolic base and some metal pins sticking out of the bottom. Television and radio sets were full of them, and those are what you or your parents or grandparents would yank from the chassis and take to the local drug store or electronics shop to plug into the big tube tester that was commonplace back then. However, as this photo shows there was a great variety of special glass and inner electrode configurations. If you have ever attended the MTTS (IMS) show, you might have seen the equipment display provided by the National Electronics Museum ...

Changji-Guquan UHV DC Transmission Link in Anhui, China

Changji-Guquan UHV DC Transmission Link in Anhui Province, China - RF Cafe Cool PicWhen up in a small airplane or helicopter, I have never had any sense of fear of heights, but when at the top edge of a really tall building or at the precipice of a high cliff, the need to control the panic sensation is required. It is not strong enough to prevent me from going there, but I'm definitely not one of those fearless types that will go anywhere with reckless abandon. Even seeing a photo like this one on the IEEE Spectrum website invokes the fight or flight emotion. You need to click on the thumbnail to see the larger version to really get a sense of the height at which the technicians are working. The story is about China's Changji-Guquan ultrahigh-voltage direct-current transmission link along the Yangtze River, in Anhui province. Arguments abound over whether DC or AC is better overall for electrical distribution, but the main reason for this DC line is to accommodate energy storage at locations throughout the country...

Electronic Noise Quiz

Electronic Noise Quiz, August 1962 Popular Electronics - RF CafeOK, class, put your books away and take out a pencil. Spread your chairs out because we're going to have a short test today. A collective sigh permeates the room. Remember those days? I still have nightmares over those moments, and they were decades ago for me. At least this "Electronic Noise Quiz" from the August 1962 edition of Popular Electronics won't affect your GPA. Sometimes PE's quiz illustrations are kind of hard to interpret, but this one does a pretty good job (except item 'E', but I'm not telling what it is since nobody helped me). You will need a fairly diverse background in consumer type electronics to do well, and having a few gray hairs will probably help as well. Good luck. BTW, my score was a somewhat embarrassing 80%...

Anatech Electronics RF Microwave Filters - RF Cafe
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Copper Mountain Technologies (VNA) - RF Cafe

Werbel Microwave (power dividers, couplers)