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Today in Science History

The Bridged-T

"The Bridged-T Filter, February 1964 Radio-Electronics - RF CafeThe bridged-T filter is a quick-and-dirty construct used to notch out a specific frequency that is interfering with a desirable frequency or band of frequencies. It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor "bridging" a pair of series capacitors having a resistor to ground between them, or, if preferred, a capacitor bridging one or two inductors. A convenient nomogram (aka nomograph) is provided by the author in this 1964 Radio-Electronics magazine article for quickly selecting values, which was a very popular design aid in the pre-calculator era. A slide rule could be used to calculate a range of values when only a single variable was in play, but juggling more than one variable (component value) was greatly aided by a multivariable nomograph. Truth is nomographs can still...

Carl & Jerry: TV Picture

Carl & Jerry: TV Picture, June 1955 Popular Electronics - RF CafeTelevision, in 1955, was still a relatively new phenomenon to many - maybe even most - people. According to multiple sources, the portion of American households with a TV set went from under 20% in 1950 to nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering the expense of even a minimal TV. The technology was not even available commercially when most people were born, so the rush to join in on the craze was akin to the mass adoption of cellphones in the 1990s. "Carl & Jerry" creator John Frye used his pair of electronics-savvy teenagers to help make the "magic" behind recreating a moving picture on a CRT miles away from where it was created. Water flowing through a garden hose has often been employed as an analogy for current flowing through a wire to explain electricity to laymen and beginning students of the craft. Here, it is not water flowing through the hose but water leaving the hose and flowing through the air that serves to represent an electron stream travelling from the electron gun to the phosphor-coated glass front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms are i

RF Front-End Tech Drives Automotive Innovation

RF Front-End Tech Drives Automotive Innovation - RF Cafe"The RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its traditional focus on mobile and infrastructure to drive innovation in the automotive sector. Each segment within the industry presents unique dynamics and growth opportunities. After a difficult 2022, the smartphone market is showing signs of recovery, with expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024. The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though it may face stagnation due to market saturation and pricing pressures. This market is expected to expand, with the 2027 launch of RedCap..."

Magnetoresistance: Better Than Hall-Effect Multipliers

Magnetoresistance: Better than Hall-Effect Multipliers, April 6, 1964 Electronics Magazine - RF CafeI'm having a hard time writing this with my eyes rolled back in my head. The last time I experienced this level of overwhelmedness was probably the third or fourth week of my feedback and control class at UVM. Even though electricity and magnetism shares many complimentary and parallel concepts, for some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators, etc., has always caused brain freeze. Maybe it has to do with an ingrained bias due to my earliest dealings with circuits being from a technician background before earning an engineering degree. The equations of electric fields and magnetic fields are very similar so that helps lower...

Thanks to Temwell for Their Support!

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

What's Your EQ?

What's Your EQ?, February 1962 Radio-Electronics - RF Cafe Here we are with another set of three "What's Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics magazine. As usual, those challenges provided by Jack Darr are the purview of television servicemen of the era. The photo shown of the problematic CRT display looks like a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently the artifacts are readily identifiable to an initiated few. The Forbidden Current Path circuit answer is not what I thought it would be. I maintain that whether my answer or the designer's answer is correct depends on the physical...

New Wireless Data Rate Record Set

New Wireless Data Rate Record Set - RF Cafe"A new world record in wireless transmission, promising faster and more reliable wireless communications, has been set by researchers from UCL. The team successfully sent data over the air at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed is up to 9,380 times faster than the best average 5G download speed in the UK, which is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more than five times higher than the previous wireless transmission world record. Typically, wireless networks transmit information using radio waves over a narrow range of frequencies..."

Sputnik: A Brief History

Sputnik: A Brief History - RF CafeSputnik refers to the first series of satellites launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history, heralding the dawn of the Space Age and sparking a fierce technological competition known as the Space Race between the United States and the Soviet Union. This satellite, the world's first artificial one, orbited Earth at an altitude of roughly 215 to 939 kilometers and broadcast a radio signal that astonished the world, particularly in the United States, where it spurred rapid advancements in aerospace and scientific research. The successful launch of Sputnik was an achievement that was years in the making, involving a combination of visionary planning, political motives, and intensive engineering by some of the Soviet Union's top scientists.

Blog: Air Quality Measurements with Particle Counters

Axiom Test Equipment Blog: Provide Essential Air Quality Measurements with These Particle Counters - RF CafeTranscat | Axiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post entitled "Provide Essential Air Quality Measurements with These Particle Counters" that covers how particle counters can provide essential measurement capabilities that can help avoid contamination and support high manufacturing yields. These measurement tools can detect and measure microscopic particles suspended in air that can contaminate the most carefully planned manufacturing lines. Air particle counters can be designed for various...

Receiving U.S. Satellite Signals

Receiving U.S. Satellite Signals, March 1958 Radio News - RF CafeIn 1958, most people were not accustomed to seeing the now-familiar maps plotting sinusoidal courses of satellites across the face of the earth. It had only been in October of the previous year that any object other than the moon was in orbit around our home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright Brothers flew their fragile craft at Kitty Hawk, electronics communications and scientists worldwide hopped aboard the satellite train. This article from a 1958 issue of Radio & TV News magazine provided insight into the construction and flight characteristics...

Thanks Again to LadyBug Technologies for Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Radio and Television News - Predictions

Radio and Television News, January 1969 Electronics World - RF CafeWhat were some of the top issues of the radio and television industry half a century ago? In a lot of respects, the same things that concern it today. A ready supply of service technicians was a concern that was taken seriously by the Electronics Industry Association (EIA). While there are not many local repair shops for electronics products nowadays, there is still a huge demand to techs who are willing and able to do the hard work of keeping the world's communication infrastructure operational - climbing towers, repairing cell equipment. Now, as then, good pay, job security, benefits, and respect for the job being done were at the top of...

RIGOL Introduces Oscilloscope & Generator Lines

Impressive Performance at an Impressive Price: RIGOL Introduces Oscilloscope & Generator Lines - RF CafeIn a parallel to the traditional test setup of signal generation and signal acquisition, RIGOL Technologies announced today the latest additions to its portfolio of performance measurement equipment with the introduction of the DG5000 Pro Series Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level performance to RIGOL's respected line of high-resolution oscilloscopes, while the DG5000 Pro generators do the same for the company's capable Pro Series arbitrary waveform generators...

Basic Electronic Counting

Basic Electronic Counting, March 1958 Radio News - RF CafeWhen selecting articles for posting here on RF Cafe, I like to include ones that are directed toward newcomers to the field of electronics as well as for seasoned veterans. This piece from a 1958 issue of Radio & TV News magazine entitled "Basic Electronic Counting," is a prime example in that it introduces the concept of binary numbers. We've all been there at some point in our careers. A big difference between now and when this article appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout [sic] octal and hexadecimal. Only those relatively few people designing and working with multimillion dollar, vacuum tube-based digital computers installed in universities, megacorporations, and government research facilities had ever dealt with digital numbers. The earliest example of powers of two I remember was back in junior high school. It had to do with a

Art of Invention Constantly Reinvented

Art of Invention Constantly Reinvented - RF cafe"Every invention begins with a problem - and the creative act of seeing a problem where others might just see unchangeable reality. For one 5-year-old, the problem was simple: She liked to have her tummy rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy bear that would rub her belly for her,' explains Stephanie Couch, executive director of the Lemelson MIT Program. Its mission is to nurture the next generation of inventors and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right resources and encouragement. 'Invention doesn't come from some innate genius, it's not something that only really..."

Mechanical Filters

Mechanical Filters, April 1969 Electronics World - RF CafeMechanical filters of the type described in this 1969 Electronics World magazine article are yet another example of the genius of some people. They are actually a form of electromechanical device in that the applied electrical signals are first converted into mechanical signals, followed by resonant mechanical elements that discriminate according to frequency, and finally a conversion back to an electrical signal is made. It is fundamentally the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents the basics of mechanical filters in this brief write-up...

Thanks Again to LadyBug Technologies for Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Electronic Test Paper

Electronic Test Paper, July 1963 Radio-Electronics - RF CafeAttempts at making an electronically printed facsimile (fax) of an original document at a location distant from the source have been around for quite a while. As mentioned by Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse had a crude working device for printing messages on paper even before his eponymously named code of dots and dashes became famous in 1837. A couple decades earlier, a fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of electronically printing images and text on paper using a conductive solution and a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known figure in the electronics world, but in his day...

"Edge of Chaos" High-Performance Microchips

"Edge of Chaos" High-Performance Microchips - RF Cafe"Researchers have discovered how the 'edge of chaos' can help electronic chips overcome signal losses, making chips simpler and more efficient. By using a metallic wire on a semi-stable material, this method allows for long metal lines to act like superconductors and amplify signals, potentially transforming chip design by eliminating the need for transistor amplifiers and reducing power usage. A stubbed toe immediately sends pain signals to the brain through several meters of axons, which are composed of highly resistive fleshy material. These axons operate using a principle known as the 'edge of chaos,' or semi-stability, enabling the swift and precise transmission of information..."

Japanese Trade-Name Directory

Japanese Trade-Name Directory, August 1969 Electronics World - RF CafeThe January 1969 issue of Electronics World magazine published an extensive list of Japanese company trade names and their addresses. Many of them went out of business or were bought by other corporations long ago, as occurs in all countries. "Aiwa" is listed twice, but that might have been a legitimate duplication due to separate locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and my first "real" stereo receiver was made by Sansui. I remember the line in "Back to the Future 3" where Doc Brown, having time-travelled from 1955, makes a disparaging remark about a circuit in the DeLorean failing because of it being labeled "Made in Japan." Marty counters...

Engineering & Tech Headlines <Archives>

• ARRL Defends 902-928 MHz Amateur Radio Band

• FCC's Auto Safety Spectrum Rules

• $5M in U.S. Chips Act Money to Metrology Projects

• U.S. State Department Approves Surveillance Radar System Sale to Romania

5G Americas ITU IMT-2030 Vision for 6G White Paper

John Redman Coxe: A Short Biography

John Redman Coxe: A Short Biography - RF Cafe - RF CafeJohn Redman Coxe was a prominent American physician, scientist, and innovator born on September 20, 1773, in Philadelphia. Coxe's intellect and curiosity drove him toward an illustrious career in both medicine and early scientific exploration, which included experimentation in electrochemistry. He graduated with a degree in medicine in 1794, setting the course for his lifelong journey into medicine and early scientific innovation. Coxe broadened his approach to medicine and science, inspiring him to explore the convergence of scientific methods and practical applications. John Redman Coxe is most remembered not only for his contributions to medicine but also for his interest in experimental physics, particularly in the field of electrochemistry...

Thanks to TotalTemp Technologies for Continued Support!

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

Vibration and Shock - Nature's Wrecking Crew

Vibration and Shock - Nature's Wrecking Crew, August 1966 Radio-Electronics - RF CafeWhen I saw this 1966 Radio-Electronics magazine article entitled, "Vibration and Shock - Nature's Wrecking Crew," for some reason the first thing I thought of was "The Wrecking Crew," that anonymously played the music for a huge number of popular singers - mostly those without prominent bands of their own during the 1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential deleterious effects of vibration on electronics was in the 1970s, with airborne receivers and servos in my radio controlled model airplanes. Even though they were transistorized, vibration from glow fuel engines could wreak havoc with potentiometers in servos and solder joints everywhere, including battery packs. I remember seeing the control surfaces jitter...

Raytheon Needs Tube Design Engineers

Raytheon Manufacturing Company Needs Vacuum Tube Engineers, July 1944 QST - RF CafeYou don't see jobs advertisements like this anymore. Here is an ad that appeared in the the July 1944 edition of QST (the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon Manufacturing Company (now just Raytheon Company), looking for vacuum tube design, test, and processing engineers. Licensed amateur radio operators were in high demand during the war years because of their knowledge and enthusiasm for electronics and wireless communications. I hope you didn't come to this page hoping to really find a tube designer job available. Of course, there are still vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...

The Carborundum Signal Detector

The Carborundum Signal Detector - RF CafeThe "carborundum" signal detector, an innovative device developed by engineer General H. H. C. Dunwoody in the early 20th century, represents a significant advancement in radio technology, particularly in the context of crystal detectors used for receiving radio signals. This device utilized the unique properties of silicon carbide, also known as carborundum, which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection between Dunwoody and the material lies in the application of carborundum as a semiconductor in radio signal detection. The operational theory of the carborundum signal detector is rooted in its ability to rectify alternating current (AC) signals. When radio waves, which are essentially electromagnetic waves...

Lossless Electronics with Innovative Quantum Sandwich

Lossless Electronics with Innovative Quantum Sandwich - RF Cafe"Researchers have created a cutting-edge structure by placing a very thin layer of a special insulating material between two magnetic layers. This new combination acts as a quantum anomalous Hall insulator, significantly broadening its potential use in developing ultra-efficient electronics and innovative solar technology. A Monash University-led research team has found that a structure featuring an ultra-thin topological insulator, sandwiched between two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous Hall insulator. This heterostructure opens the door to ultra-low energy electronics and even topological photovoltaics..."

POPULAR ELEComics with an Electronics Theme

Popular EleComics with an Electronics Theme, December 1967 Popular Electronics - RF CafeIt's Election Day 2018, and depending on how the voting goes, some of us (hopefully not me) are going to need some cheering up when it's all over. If that includes you, then here is a dose of high tech POPULAR ELEComics levity to help ease your "My Side Lost and the World Is Going to End" blues. The first of this set of comics from a 1967 issue of Popular Electronics magazine could serve as an ironic tribute to the day. On the other hand, if your side wins and you're on cloud nine, then I suggest you exercise caution when seeing these comics because the added joviality might cause you to swoon from overstimulation. Of course if you are not an American or do not care about elections or happen upon this page after the 2018 mid-term elections, please enjoy these comics in the usual manner...

Electrical Engineering Crossword Puzzle for August 16th

Electrical Engineering Crossword Puzzle for August 16, 2020 - RF CafeAugust 16th's custom Electrical Engineering themed crossword puzzle contains only only words (1,000s of them) from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.

Unknown Frequency Quiz

Unknown Frequency Quiz, September 1965 Popular Electronics - RF CafeLots of old-time sci-fi movies and TV shows liked to display Lissajous patterns on oscilloscopes when an authentic high tech look was needed in a scene. Every engineer, technician, and physicist in the world - me included - roll his or her eyes at the sight of such a lame attempt to impress the public. Of course the truth is the first time I saw a Lissajous pattern gyrating on an o-scope screen, I was mesmerized. The need to crank on the signal generator knobs and take control of the electroluminescent object d'art was overwhelming. Now, in the same manner that watching the first couple Space Shuttle launches was a thrill not to be missed and then became just another launch, so, too, is watching a live Lissajous pattern on a scope - it's just another Lissajous. Except, well, that's not quite so - at least for me. I always eagerly viewed Shuttle launches...

De Forest the Inventor

De Forest the Inventor, January 1947 Radio-Craft - RF CafeWhen most people are asked to name prolific inventors, people like Thomas Edison and George Westinghouse, with 1084 and 361 each, respectively, come to mind - at least for the United States. As of this writing, Kangguo Cheng of IBM holds the record with 2039 U.S. patents assigned. Nikola Tesla had about 300 patents. Lee de Forest, the subject of this 1937 Radio-Craft article, had a little over 180 patents. That still qualifies as prolific by my estimation. However, there is more to ranking a person's inventive worth than the number of patents awarded - like how profoundly his or her invention(s) impacted the world. For instance, Alexander Graham Bell had a mere 18 patents awarded in only his name, with 12 more shared patents. If you look through Wikipedia's "List of Prolific Inventors," you will see a lot of names with a lot of patents assigned, but most of those names are probably unfamiliar. Have you noticed how many of the old patent art looks like..." 

After Class: Working with Phase-Shift Oscillators

After Class: Working with Phase-Shift Oscillators, December 1958 Popular Electronics - RFCafeThere is an old adage that goes thusly: "If you want to build an oscillator, design an amplifier. If you want to build an amplifier, design an oscillator." Its basis is the difficulty that can be experienced in obtaining the right combination of feedback phase and amplitude. Of course experience, use of simulators, and careful circuit construction minimize the opportunity for validating that saying. The basic requirement for an oscillator is feedback from the output to the input that is in-phase and great enough in amplitude to maintain, via the amplifier's gain factor, a constant output level. Tuned L-C (inductor-capacitor) tank circuits are often used as simple frequency-determining elements because of their combined resonance characteristics. Phase shift oscillators are a type of oscillator that can be built without inductors...

Satellite TV c.1965

Satellite TV, May 1956 Radio & Television News - RF CafeWhen you hear or read "satellite television," you naturally think of a service like DISH Network or DIRECTV. When encountered in a 1956 Radio & TV News article, you know "satellite" must mean "(3) someone or something attendant, subordinate, or dependent." Such was the case for satellite TV locations in areas where, without a network of microwave relay towers, communities situated where geography inhibited standard VHF and UHF broadcast signals from reaching sets with sufficient power were left with no or frustratingly poor reception. Home-based satellite TV as we know it today began in the mid 1970s with Pat Robertson's Christian Broadcasting Network broadcast. Artifacts of that ancient time can still be spotted in rural areas: 10-foot-diameter dishes with eyeballs, smiley faces, or camouflage patterns painted...

Novel Semiconductor Devices

Novel Semiconductor Devices, October 1959 Electronics World - RF CafeGermanium was "the" semiconductor of choice in 1959 even though advances were being made with silicon. Most of the newer semiconductor devices were being fabricated with germanium as the central transducer element. Temperature sensors, strain gauges, "sensistor" variable resistance units, Hall effect sensors and gyrators and circulators, torsional (twist) transducers, displacement sensors, and even neutron detectors were done in germanium. Even though silicon is referenced as being applicable to all the devices, it was not until the 1960s that silicon began to dominate semiconductor fabrication. This paper titled ,"From Germanium to Silicon, A History of Change in the Technology of the Semiconductors...

POPULAR ELEComics - Comics with an Electronics Theme

POPULAR ELEComics - Comics with an Electronics Theme, January 1968 Popular Electronics - RF CafeAlways a good way to end a busy week, here is a collection of electronics-themed comics that appeared in a 1967 issue of Popular Electronics magazine. A few of the artists you will recognize if you are a regular reader. Some drawing styles are immediately identifiable, such as those by Dave Harbaugh (of "Hobnobbing with Harbaugh" fame). Others, at least to me, are not quite so familiar. Frank Tabor, George White, Stan Fine, and JAS (I'm sure I know those initials, but can't place them) are amongst the others. I have to admit to not really knowing what the gag is in the comic with the guy in his pajamas. The party guy is cutting a wire to his ear buds ...

New York Taxing Out-of-State Healthcare Workers

New York Taxing Out-of-State Healthcare Workers"On the way back to your home state, don't let the door hit ya' where the good Lord split ya'. Oh, and we'll be sending you a tax bill in appreciation for your selfless sacrifice in caring for our citizens." That is basically the sentiment of New York's governor, who after literally begging out-of-state healthcare workers to come to NY City amongst the Chinese COVID-19 breakout, has declared that his financially mismanaged and cash-strapped state is going to collect income tax from the aforementioned good Samaritans.

Daylight Saving(s) Time - Again!

Graphical Look at Daylight Saving(s) Time - RF CafeCall me obsessive, but the switch to and from DST has bugged me not so much for its existence, but for butthead politicians that won't keep their hands off of it. A few years ago I wrote a piece titled, "A Graphical Look at Daylight Saving(s) Time," to deal with it, and then again last year with, "Daylight Saving(s) Time vs. Standard Time." Research the history of DST and you will see how often Congress has changed the days - always for good reasons, don't you know. In 1958, the year of my birth, DST began on April 27th 1958 Old Farmer's Almanac Daylight Savings Time - RF Cafe(vs. March 10th this year), and ended on September 28th (November 3rd this year) - See 1958 Old Farmer's Almanac pages. What else can I say on the matter?

Hiram Percy Maxim's Gravesite in Hagerstown, MD

Hiram Percy Maxim's Gravesite in Hagerstown, Maryland - RF CafeIsaac Newton famously said, "If I have seen farther it is from standing on the shoulders of giants." His statement was figurative, of course, but I can now say literally that I have stood on the shoulders of a giant. Somewhere recently, I don't recall where, I read that although American Radio Relay League (ARRL) founder Hiram Percy Maxim was born in New York and spent most of his adult life in Connecticut, he was buried in Rose Hill Cemetery located in Hagerstown, Maryland. That just happens to be where Melanie and I stop a couple times each year to visit her mother. We lived there ourselves for about three years in the early 1990s. That day, I surely stood if not exactly atop Mr. Maxim's shoulders, then very nearly so as I maneuvered to take this picture of his grave marker. Why is he buried in Maryland, you might ask? That is where his wife's family's burial plot is located. Mrs. Maxim was the daughter of former Maryland senator and governor William T. Hamilton. Hamilton, in fact, helped establish the Rose Hill Cemetery in the mid 1880s...

Ham Comics: There's One in Every Crowd 

Comics: There's One in Every Crowd, February 1966 Popular Electronics - RF CafeIt's the Friday before Christmas vacation and nobody is thinking about work. If you are stopping by RF Cafe to kill time until the boss lets you go home (early, preferably), thanks for thinking of us. Not that you really need something to get you in a festive mood, but here are a few funny amateur radio-themed comics from a 1966 issue of Popular Electronics magazine, compliments of artist Buz Holland. When I saw the comic with the parrot squawking CQ while including his call sign - WA4YKK - my first thought was to check the FCC's Universal License System (ULS) to see to whom it belongs, and then I realized it was the artist's...

Messages by Meteor

Messages by Meteor, October 18, 1965 Electronics Magazine - RF CafeMeteor scatter (aka meteor burst) communications is today largely the domain of amateur radio operators in their ongoing attempts to set records for making long distance (DX) contacts with a minimum amount of transmit power. When this article was written by U. California's Victor Latorre, transcontinental fiber optic cables did not interconnect the world with high speed, phase stable media that meets the exacting needs of precise time synchronization. Radio astronomy, quantum physics experiments, and even stock market trading depends on microsecond or finer timing. Mr. Latorre mentions here about using meteor scatter communications' unique phase-stable characteristic to send synchronization signals between scientific and navigation facilities. Of course meteor scatter has the severe disadvantages...

Wireless Engineering Crossword Puzzle for April 30, 2017

Wireless Engineering Crossword Puzzle for April 30, 2017 - RF CafeThis week's wireless engineering-themed crossword puzzle, as is the case every week, contains only words pertaining to science, engineering, amateur radio, physics, mechanics, mathematics, etc. Making a special appearance is the name of the most recent company to support RF Cafe through advertising. You will see their banner graphical ad appearing in the right page border sometime this week ...

Japan Stresses Research

Japan Stresses Research, October 18, 1965 Electronics Magazine - RF CafeElectronics magazine editor Lewis H. Young dedicated a series of issues in 1965 to reporting on the state of electronics research and production in Japan. The December 13 edition had many articles on the subject. The world was still in the early phase of a major transition from vacuum tubes and discrete components to transistors and integrated circuits. Japan was at the leading edge of that effort - and it was very successful. Ample evidence of the not-quite-there-yet status of the transition is all the advertisements in this edition of the magazine. Products showcased by manufacturers were discrete, not integrated - that applies to both electronic and mechanical subjects. When you look at those components and assemblies, you get feel for what made them work because the individual parts are in view. Many modern products are integrated into packaged and tested subassemblies that are ready to be integrated...

RF Cafe Engineering & Science Crossword Puzzle for February 10

RF Cafe Engineering & Science Crossword Puzzle February 10, 2019Beginning in 2000, I have created hundreds of custom technology-themed crossword puzzles for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or not this type of mental challenge helps keep your gray matter from atrophying in old age, but it certainly helps maintain your vocabulary and cognitive skills at all ages. A database of thousands of words has been built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie start like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Mac's Radio Service Shop: New Uses

Mac's Radio Service Shop: New Uses, June 1958 Radio & TV News - RF CafeIf there was another episode of Mac's Radio Service Shop where Barney was the primary teacher and Mac was the student, I don't remember what it was. In fact, this is about as total of a role reversal as there can be. First, Mac admits to having chased a presumed oscilloscope issue down the proverbial rabbit hole only to realize the cause of the problem was totally unrelated. Then, Barney produces a nifty device meant for recording telephone conversations and demonstrates to Mac a couple ingenious applications he discovered that were handy for troubleshooting television sets. When reading Mac's description of using a magnet to alter the electron beam in a CRT, it reminded me of how cool it was on the CRT displays to run a magnet ...

Finding Relay Operate and Release Times

Finding Relay Operate and Release Times, April 1967 Electronics World - RF CafeSometimes, component datasheets can be pathetically lacking in detail for parameters that you might think would be a minimum amount of information needed in order to integrate the device into a circuit or system. Or, it may be that you found a part in a spare parts box and can't find a datasheet for it. When those times come, it is necessary to characterize the part yourself. Relay control really isn't rocket science when it comes to electrical circuits, but there are a few rules of thumb that should always be observed, the most important of which (other than not exceeding voltage and current maximums) is to wire a diode reverse biased across the coil terminals so that the voltage/current induced due to the field collapse during de-energizing does not smoke the driver circuit...

Radio WittiQuiz

Radio Wittiquiz, December 1937 Radio-Craft - RF CafeRadio-Craft magazine solicited inputs from its readers for a series of 'WittiQuiz' questions and answers related to radio and electronics, with a stipulation being that there had to be some aspect of humor included. That meant that some of the multiple choice answer options needed to be inane. For most of the questions, the process of elimination is pretty easy, but a couple could cause some head scratching - especially if you are not really sure of the answer. This group starts at number 28, so obviously preceding issues had questions 1 through 27. At some point I will probably acquire them and post other WittiQuizzes.

Air Adventures Magazine Promo in Radio News

Air Adventures Magazine Promo, December 1939 and January 1940 Radio News - RF CafeUntil the last couple decades, people of the world recognized and called out evil by name when it reared its ugly head. Except for subversive imbedded agents, media outlets - radio, television, print, speeches, etc. - openly and vigorously condemned and attacked the enemy of its country's traditional way of life. The theme ran deep and wide in news reports and in magazine features. This advertisement for Air Adventures magazine which appeared in early 1940s Radio News magazine is an example. In the place of politically correct speech that doesn't dare to offend an entity which openly and maniacally seeks to kill you we had the vast majority of media promoting nationalism and patriotism in order to defeat the enemy. As with just about everything, eBay is a good source of these vintage Air Adventures magazines. This particular publication only ran for three editions. However, there were plenty of other titles that featured stories of heroic adventures against the Nazi scum ;-) Flying Aces magazine...

LadyBug LB5954L Power Sensor with LAN Option - RF Cafe
PCB Directory (Manufacturers)

Windfreak Technologies Frequency Synthesizers - RF Cafe

Amplifier Solutions Corporation (ASC) - RF Cafe