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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..."

Japan Short-Wave Phone to America Open

Japan Short-Wave Phone to America Open, March 1935 Short Wave Craft - RF Cafe"Tokyo is now a next-door neighbor-thanks to the magic of short-waves." That statement was made in a 1935 edition of Short Wave Craft magazine after the American Telephone and Telegraph (AT&T) company completed its wireless phone (voice) link between the U.S. and Japan; which is the first 'T' in AT&T. Most people today would probably have a hard time guessing that the second 'T' in AT&T stands for 'telegraph.' Its surprising that the name has not been changed to reflect the outdated-ness. Western Union sent its final telegraph in 2006. Another news headline a couple years ago reported on India sending its final official telegraph message...

RF & Electronics Symbols for Office™

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

Printed Radio Components

Printed Radios, September 1947 Radio-Craft - RF CafeAs I have written often, Hugo Gernsback was one of the electronics industry's most prolific authors, inventors, and innovators. In this 1947 article in his Radio-Craft magazine, he proposes using printed components in place of leaded resistors. In fact, he sold printed resistive cards through his Radio Specialty Company (Rasco) that could be cut into whatever size was needed to achieve the required amount resistance based on a certain ohms/square value. He also mentions creating printed inductors on Bakelite and even fashioning variable-coupling transformers with a pair of inductor plates sliding relative to each other, similar to capacitive "variometers" used for tuning RF circuits. Not to neglect the possibility of capacitors, Gernsback suggests possibly spraying a thin conductive coating on paper and then rolling multiple layers into a tubular form, achieving a smaller form factor per unit capacitance that what was currently being achieved. Single- and double-sided printed circuit boards were already being used for some high volume, compact portions of assemblies, and he proposes improving methods to eventually...

Entertaining Uncle Oscar

Entertaining Uncle Oscar, August 1939 QST - RFCafePopular comic strips (aka 'funnies') in the 1930s and 1940s featured numbskulls, ne'er-do-wells, and simpletons. There was usually one character in the strip's cast that was smart - at least in a relative way if not absolute. Being familiar with some of the old comics like Blondie, Barney Google, Krazy Kat, Beetle Bailey, Gasoline Alley, etc., I can see a definite relationship between the story line of "Entertaining Uncle Oscar" and the comics of the era in this short story that appeared in a 1939 edition of the ARRL's QST magazine. As you might guess, the feller named 'Ham' is the smart one. Q: Is it irony, coincidence, or premonition on the author's part that the uncle's name is the same as the ARRL's OSCAR series of Orbiting Satellite Carrying Amateur Radio(s)?

Chart of Radio Schematic Symbols

Chart of Radio Schematic Symbols, December 1942 Radio-Craft - RF CafeThis is a really nice electronic schematic symbols chart that will come in handy for hobbyists who work with vintage electronic equipment. Not only does it have component symbols that a modern chart (this appeared in a 1942 issue of Radio-Craft magazine) would not likely contain, but it has three-dimensional sketches of each device. For example, vacuum tube symbols show the tube outline, its socket configuration, and the pinout. If you get nostalgic for some of these old parts, some of them like the knife blade switch and ceramic light socket can be bought a many hardware stores or online. It's too bad the chart is not in color because it would make a nice picture to frame for a decoration. If anyone with an artistic bent feels compelled to colorize it and send it to me, I'll be glad to make it available to visitors...

The "Univac"

The Univac, January 1957 Radio & Television News - RF CafeThe Remington Rand "Univac" (UNIVersal Automatic Computer) computer was delivered on March 31, 1951. Its main memory consisted of liquid mercury delay lines arranged in 1000 words of 12 alphanumeric characters each. A Univac famously calculated the first presidential race forecast - Eisenhower vs. Stevenson - and was correct! This 1957 report in Radio & Television News magazine mentions how "giant electronic computers no longer rank as laboratory curiosities or frightening science-fiction robots." The Unisys company is today's descendant of Remington Rand...

Microwave Principles: Directional Couplers

Microwave Principles: Directional Couplers (NEETS) - RF CafeThe discussion of waveguides, up to this point, has been concerned only with the transfer of energy from one point to another. Many waveguide devices have been developed, however, that modify the energy in some fashion during transit. Some devices do nothing more than change the direction of the energy. Others have been designed to change the basic characteristics or power level of the electromagnetic energy. This section will explain the basic operating principles of some of the more common waveguide devices, such as Directional Couplers, Cavity Resonators, and Hybrid Junctions. The directional coupler is a device that provides a method of sampling energy from within a waveguide for measurement or use in another circuit. Most couplers sample energy traveling in one direction only. However, directional couplers can be constructed that sample energy in both directions...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed...

Mac's Radio Service Shop: The TVI Sleuth

Mac's Radio Service Shop: The TVI Sleuth, August 1954 Radio & Television News - RF CafeTracking down the source of TVI (television interference) or any kind of RFI (radio frequency interference) can be a challenge. In the days when most people received their audio and visual entertainment (radio and TV) via over-the-air broadcasts, any form of interference was usually picked up by multiple people, who promptly reported the issue to the power company or the FCC. Arcing power lines, transformers, and switches were prime generators of RFI, particularly during wet and high wind conditions. However, much more prevalent was interference from industrial and domestic equipment. Neon and fluorescent light, heating pads (see Hazel: Stop Rockin' Our Reception episode), ignition systems (automotive and oil burners), diathermy (heat therapy popular in the day), industrial RF heating, kitchen appliances, and tool motors were among the likeliest offenders. Of course amateur radio operators were guilty of spewing out interfering EM crap...

Westinghouse Directional Equipment

Westinghouse Directional Equipment, June 1945 Radio News - RF CafeWestinghouse is yet another of the original stalwart titans of companies that helped build America to her state of greatness, but is now mostly a footnote in the historical notes of the many companies which over the past few decades have bought out portions of the business. Founded in the late 1800s by George Westinghouse as a locomotive air brake manufacturer, the company added other markets including, notably, electric power generation and distribution. Emerging as the winner in the famous "War of the Currents" fought between Westinghouse and Thomas Edison secured George's place in history. Westinghouse also got into the commercial, military, and domestic electronics and appliance markets. I worked at the Westinghouse Oceanic Division in Annapolis, MD, from 1982 through 1986 and though it was a great company to work for. This advertisement for "Westinghouse Directional Equipment;" i.e., antennas, appeared in a 1945 issue of Radio News magazine.

Of Zerts, Plenches and Spunfits

Of Zerts, Plenches and Spunfits - RF CafeThe manned space program has unarguably provided mankind with many new and innovative tools, medicines, electronics, materials, physics, materials, appliances, and mathematics. Known officially as "spinoffs," products include items like the portable heart defibrillator unit, the portable vacuum cleaner, freeze-drying food processors, powdered lubricants, memory foam, quartz clocks and battery-powered tools. Many NASA inventions have not found an application in your basement or garage, however, because their purpose is too specialized. Take, for instance, the ZeRT, or Zero Reaction Tool...

Voltage-Multiplying Circuits

Voltage-Multiplying Circuits, January 1953 QST - RF CafeVoltage multipliers were found in nearly every form of battery-powered electronics in the days of vacuum tubes, because of the 100-volt or more requirement for plate voltages. Primary batteries in 30, 45, and 67½ volt sizes were produced by Eveready, Burgess, and a few other companies in order to help simplify biasing circuits. They were bulky and heavy, often comprising a significant portion of the assembly's volume. Heavy transformers contributed mightily to the weight and size as well. Exell still manufactures 30, 45, and 67½ V batteries both for the few products that are still designed to use them, and for vintage radio owners. Most circuits that need higher DC voltages these days use DC-DC converters, many of which are ICs...

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%...

Technology Theme Crossword Puzzle for June 27th

Technology Theme Crossword Puzzle for June 27th, 2021 - RF CafeThis Technology Theme Crossword Puzzle for June 27th has many words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. 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., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

National Electronics Museum Display at IMS2011 (MTT-S 2011)

National Electronics Museum Display at IMS2011 (MTT-S 2011) - RF Cafe

One of the perks of attending the International Microwave Symposium (IMS), hosted by the Institute of Electrical and Electronics Engineers (IEEE), is that you are given the opportunity to see a part of the history of microwave engineering. At the two IMS shows that Melanie and I have been to (2009 and 2011), a portion of the contents of the National Electronics Museum, headquartered in Linthicum, Maryland, (only a few miles from the Baltimore Convention Center) was on display. Safely locked behind protective glass and guarded by a paid sentinel are relics of our profession's past. Prototypes of magnetrons, circulators, filters, phased array antennas, traveling wave tubes, waveguide, oscillators, and a host of other devices dreamed up ...

The Operational Amplifier

The Operational Amplifier, August 1967 Electronics World - RF CafeThere is no such thing as too many introductory articles on operational amplifiers (opamps). Of course, when this story was written for Electronics World back in 1967, opamps were relatively new to the scene. Prior to the advent of opamps, circuit design for controllers, filter, comparators, isolators, and just plain old amplification was much more involved. Opamps suddenly allowed designers to not worry as much about biasing, variations in power supply voltages, and other annoyances, and instead focus on function. Even from the very beginning with the μa741 operational amplifier, the parameters came close to those of an ideal device: infinite input impedance, zero output impedance, perfect isolation between ports, and infinite bandwidth. OK, the bandwidth spec was more constrained compared to the other three, but still, with frequencies...

Science Celebrity Theme Crossword Puzzle for December 12th

Science Celebrity Theme Crossword Puzzle for December 12th, 2021 - RF CafeThis Science Celebrity themed crossword puzzle for December 12th contains no fewer than 18 names of notable scientists and engineers (marked with an asterisk *) known famously to folks like you who visit RF Cafe. It took quite a while to design. Elsewise, only clues and words which are directly to RF, microwave, and wireless engineering, optics, mathematics, chemistry, physics, and other science subjects. 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., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort...

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...

Delco's All-Transistor Auto Radio

Delco's All-Transistor Auto Radio, August 1957 Radio & TV News - RF CafeIn 1957, only a top-of-the-line automobile deserved a radio containing 13 discrete transistors and four crystal diodes. Only buyers of such a top-of-the-line vehicle could afford the luxury offered by an electronic marvel that promised instant-on music with superior sensitivity and selectivity over the vacuum tube models that lesser humans endured. As shown in this 1957 issue of Radio & TV News magazine, Delco's Model 7268085 was up to the task as it populated the dashboards of Cadillac's Eldorado Brougham. Modern day radios use a single IC for performing all reception, filtering, amplification, and tuning functions, with superior performance compared to the Delco without all the interstage tuning transformers, Rs, Ls, and Cs. Most of the rest of the circuitry in your car radio is for microprocessor control...

A 12,000 Tube Electron Brain

A 12,000 Tube Electron Brain, May 1948 Radio-Craft - RF CafeThis Radio-Craft magazine article starts out stating, "A skilled mathematician with a desk calculator requires four years to do what the IBM Calculator does in eight hours." That was in 1948. Just last month a headline read, "Given the task of finding a pattern in a seemingly random series of numbers, Google's quantum computer produced an answer in 3 minutes and 20 seconds. It estimates that the Summit supercomputer here at the Oak Ridge National Laboratory in Tennessee would take 10,000 years to complete the task. The IBM 12,000 vacuum tube computer performed its calculation for an improvement factor of [(3 yr • 8760 hr/yr) + (1 yr • 8784 hr/yr)] ÷ 8 hr = 4383 (4.383 thousand). The Google quantum computer performed its calculation for an improvement factor of (10,000 yr • 31557600 s/yr) ÷ 200 s = 3.15776E11 s ÷ 200 s = 1.57788E9 (1.57788 billion -- or milliard)...

PCB Directory (Manufacturers)
Axiom Test Equipment - RF Cafe

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Anritsu Test Equipment - RF Cafe