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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..."

Build a Field Strength Meter

Build a Field Strength Meter, September 1960, Popular Electronics - RFCafeThere is little incentive to build your own field strength meter these days when commercial instruments are readily available and relatively inexpensive. For instance, you can buy an MJF-801 FSM with a 100 kHz to 500 MHz spectrum coverage for just $45, brand new. More sophisticated, calibrated instruments are available for a lot more, but this basic unit is dirt cheap. However, if you want to read a little about the theory behind a field strength meter and see how one goes together, this article from a 1960 issue of Popular Electronics magazine provides that opportunity...

Antenna Reference Chart

Antenna Reference Chart, March 1953 Radio-Electronics - RF CafeSelecting the proper antenna for a particular application can mean the difference between success and failure when any combination of signal strength and/or signal interference is involved. Modern spread spectrum technologies has eased the job a bit, but there are still instances when high gain and/or directivity is necessary. You might be tempted to say that gain and directivity are essentially the same thing, and to some extent that is true. However, in the case of needing to minimize signal interference from surrounding sources, a directional antenna might be utilized not due to a need for increased desired signal strength but to reduce the power of undesired emitters. Such was often the requirement for television and FM radio reception. After years of needing to reorient the folded dipole antenna for my FM radio because...

It's a Man's Job Behind That Microphone

It's a Man's Job Behind That Microphone, April 1932 Radio News - RF CafeThe old-time radio broadcasts available on the Internet are obviously recorded version of shows made long ago. However, back in the day those shows were originally performed live in front of microphones and recorded in a broadcast studio. With a cast of two or three or even more, the actors would voice their lines with as much talent and effort as those performing for movies. The crew usually included a group of people responsible for creating background sound effects like horses running, car horns tooting, airplanes buzzing by, and dogs barking. All was done real-time with split-second timing required to pull it off and sound convincing. Radio audiences were unaware of all the work required as they sat intently listening to the Adventures of the Lone Ranger and The Shadow. Behind the scenes were dozens of engineers and technicians tending local radio broadcasting equipment and all-important telephone landlines used for synchronizing stations across the country...

Vintage Taylor Tubes Advertisement

Vintage Taylor Tubes Advertisement, February 1941 QST - RF CafeSome of us like seeing the old advertisements from vintage era magazines. This Taylor Tubes advertisement from the February 1941 edition of the ARRL's QST magazine is a prime example. Vacuum tubes had a high degree of automation for stamping out internal components, forming the glass shells and evacuation of the air, but they still required human production line operators for assembling the components prior to being encapsulated and sealed. National Instruments hadn't invented LabVIEW yet to run the testing station, so people manually placed the tubes into a board full of sockets for burn-in and testing...

Electronics-Themed Comics

Electronics-Themed Comics, April 1969 Radio-Electronics - RF CafeHere is a little technology humor to help easy you into the week ahead. Ironically, the themes of the three comics (by three separate artists) represent an evolution of the electronics realm over the past few decades, although almost certainly not planned by the editors. The first has to do with a couple TV servicemen installing an antenna, the second is of an out-of-work TV repairman, and the third is what might be considered a drone by today's norms. There is a huge list of other comics at the bottom of the page...

Nation-Wide Television is Now in the Making

Nation-Wide Television is Now in the Making, January 1948, Radio-Craft - RF CafeDr. Allen Du Mont played a huge role in making television practical because of the improvements he made to the cathode ray tube (CRT). Prior to his work, the lifespan of a CRT was measured in tens of hours, and they were expensive, so their use was limited to special military and research applications. Du Mont's interest in "wireless" began at an early age, and he earned his commercial radio operator's license at the age of 14 (in 1915). He designed and produced oscillographs (i.e., oscilloscopes) that incorporated his CRTs. His involvement in the television industry was a natural evolution and extension of the work done in related industries. The DuMont Television Network was formed in 1942, rivaling the established CBS and NBC...

Heathkit SS-9000 Deluxe Synthesized HF Transceiver

Heathkit SS-9000 Deluxe Synthesized HF Transceiver - RF CafePrior to the availability of affordable synthesized transceivers under microprocessor control, Ham radio operators needed to tune a continuously variable local oscillator (internal or external) or have a selection of crystals for specific frequencies. Even by 1982 microprocessors were relatively expensive, so equipment incorporating them was also pricey. Heathkit's model SS-9000 transceiver claimed to be designed by amateurs for amateurs, and was "so feature-conscious, it has no options." That's right, anything and everything that could be imagined was included in the base model; there we no upgrades. It used a high accuracy and stability internal 10 MHz reference oscillator for the PLL synthesizer. Also incorporated was an RS-232 serial port for control via computer (up to 9600 baud!), such as the Heathkit/Zenith personal computer (the IBM PC had hit the market in the prior year, and the the Radio Shack TRS-80 and Apple II had been around since 1977). The SS-9000 was solid state throughout (likely where the "SS" prefix originated)...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - <em>RF Cafe</em>One aspect of advertising on the RF Cafe website I have not covered is using Google AdSense. The reason is that I never took the time to explore how - or even whether it is possible - to target a specific website for displaying your banner ads. A couple display opportunities have always been provided for Google Ads to display, but the vast majority of advertising on RF Cafe is done via private advertisers. That is, companies deal with me directly and I handle inserting their banner ads into the html page code that randomly selects and displays them. My advertising scheme is what the industry refers to as a "Tenancy Campaign," whereby a flat price per month is paid regardless of number of impressions or clicks. It is the simplest format and has seemed to work well for many companies. With nearly 4 million pageviews per year for RFCafe.com, the average impression rate per banner ad is about 225,000k per year (in eight locations on each page, with >17k pages)...

Early Radar Development

Early Radar Development - RF Cafe Cool PicWe read a lot about the early radar system that was in operation at Pearl Harbor in December 1941 when the surprise attack by Japanese naval airplanes decimated the fleet with a 3-hour-long raid beginning at around 8:00 on that sleepy Sunday morning. According to "The Untold Pearl Harbor Radar Story," by C.P. West, the SCR-270B (Signal Corps radio #270, rev B) radar system had a range of 250 miles at an altitude of 50,000 feet. Westinghouse built the system in 1940 following a development contract issued by the Army Signal Corps in 1936. Historical documents report of the three systems on the island, two had been shut down and that with the remaining system, operators Joseph Lockard and George Elliot detected a formation of aircraft about 137 miles out to sea. They were told it was a squadron of B-17s and to not worry about it...

SimSmith Smith Chart Software

SimSmith Smith Chart Software - RF Cafe Cool ProductRandy Rogers*, AD7ZU, mentioned in the May 2020 issue of QST magazine the Smith Chart software called "SimSmith," by Ward Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java, it will run on any operating system that supports Java (Win64, Win32, Apple Mac OS X, Solaris, and Linux). If you are using Win64 as I am, you will want to download the "windows64-with-JRE.exe" file. Windows security will try to block it, but it is safe to run after your antivirus program scans it and gives a green light. AE6TY recommends using the installation files rather than just downloading the "SimSmith.jar" file even if you already have a version of Java installed. When launching the program, the window might not be very large, so grab a corner and stretch it out so the components are easier to see. After playing around with SimSmith for a while, you might want to click on the "SimSmith->preferences" menu selection...

Theory and Application of U.H.F.

Theory and Application of U.H.F., June 1945 Radio News - RF CafeThis is the final installment of an 11-part series in Radio News magazine entitled "Theory and Application of U.H.F.," written by Milton Kiver. It spanned from December 1943 to June 1945. Topics included basic electrical, magnetic, and electromagnetic theory, cavity resonators as tuning units of klystron and magnetron oscillators, waveguide, free space propagation, high frequency amplifiers, transmission lines, and coupling energy to/from cavity resonators. As the list suggests, there was a great concentration on field theory. Being that the Radio News readership covered a broad range of experience and education, Mr. Kiver went light on use of equations and heavy on use of diagrams, charts, and textual descriptions. Everything described throughout the series is as valid and applicable today as it was 75 years...

Do You Know Your DC Circuits?

Do You Know Your DC Circuits?, May 1973 Popular Electronics - RF CafeA series of three articles appeared in 1973 issues of Popular Electronics that conducted a high-level review - or introduction if you've never seen it before - of DC circuit analysis. In this first installment, Professor Arthur Seidman, of the Pratt Institute, covers a variety of subjects starting with direct current (DC) circuit theory. Ideal current and voltage sources, units and notations, Ohm's law, Kirchhoff's law, resistors, capacitor and inductor charge and discharge curves, series and parallel circuits, power calculations, conductance, and other good stuff is covered. There is even (gasp) a bit of calculus presented...

Rejuvenating Old Meters

Rejuvenating Old Meters, February 1943 QST - RF CafeAn article with instructions relating to subjects like overthrow, balance, friction, and cleaning could very well be about a country's revolutionary struggles. In this case, it is an article about how to rejuvenate a persnickety or inaccurate mechanical (aka analog) meter movement. W.R. Triplett, relative (I assume) of meter manufacturer Ray L. Triplett, is the author (Triplett is now owned by Jewel Instruments). There are a lot of analog meters around in labs, workshops, and garages. Unless they have been burnt out, most probably still work like new. Occasionally, however, the movements get sticky because of accumulations of dirt and dust, bug filth, or even from corrosion. This article offers some great tips for making them serviceable again...

Filter Prototype Denormalization Page Reworked

Filter Prototype Denormalization Equations Formulas - RF CafeThis entire page has been reworked to make the denormalization of prototype lowpass filter component values much easier to understand. I have received numerous questions about the process over the years, particularly regarding the swapping of capacitor and inductor values for highpass transformations. Bandpass and bandstop transformations can be equally confusing. The original page pretty much regurgitated the kind of presentation made by many textbooks, but this new format should make amply clear the transformation from normalized lowpass component values ...

FCC Proposes CB "Type Acceptance" - Manufacturers Blamed for Malpractices

FCC Proposes CB "Type Acceptance" - Manufacturers Blamed for CB Malpractices, May 1967 Popular Electronics - RF CafeIn all-too-typical style, the Federal Communications Commission (FCC) decided to look for a scapegoat it could not just blame for but strong-arm a solution for claimed problems plaguing Citizen Band (CB) radio as it was rapidly becoming a popular hobby in the 1960s. In the same manner in which bureaucrats blame gun and steak knife manufacturers for the abusive actions of a minority of their products' users, the FCC sought to curtail improper (maybe even illegal) operation of CB radios by imposing type certification and feature restrictions on equipment manufacturers. To demonstrate its magnanimity , though, the FCC offered to give companies half a year to deplete their existing inventories. At the time and through 1977, CBs had 23 channels, after which time 40 channels became the new mandate...

Friday 17

Electronic Angle Quiz

Electronic Angle Quiz, September 1967 Popular Electronics - RF CafeDang, I swapped two answers and scored an 80%. Haste makes waste, as the saying goes. Don't rush through this 1967 Popular Electronics "Electronic Angle Quiz" like I did and you'll probably ace it with the greatest of ease - especially if you have been in the electronics realm at least since the 1980s. Generation X'ers can have a two-question handicap (might never have seen real-life example of drawing "A" or "E") and Millennials (might never have seen drawing "A," "B," "D," or "H") get a four-question handicap...

Antenna Performance Key to Good Color Reception

Antenna Performance Key to Good Color Reception, May 1969 Sylvania News - RF CafeThere was a time that selecting a television antenna was as important to the quality of life as buying the right smartphone is today. There were probably as many choices in antennas then as there are phones now. You might think, especially if you are not an amateur or military radio operator, that nobody worries about antennas anymore, but as I've written before there is a slight resurgence in people installing the old fashioned multi-element antennas for receiving local television and radio stations. The market's not huge, but seems to be keeping companies like Channel Master in business. Incidentally, in contrast to my aforementioned comment, dig the opening sentence of the article: "Virtually no one in this day and age goes about discussing the reception quality of his telephone."

Radar - Secret Weapon No. 1

Radar - Secret Weapon No. 1, October 1945 Radio-Craft - RF CafeBy the beginning of 1945 when most people believed the War was all but won, the national and global attitude began to shift from a wartime footing back to a commercial and domestic mindset. For the Axis powers the prospect was one of shame and contrition, while knowing that unlike if they had been the victors, Allied nations would deal harshly only with the leaders of the aggression and destruction while showing mercy, humanity, and graciousness to the general populations. In fact we became very good friends with Germany, Italy, and Japan in the years immediately following their respective unconditional surrenders. As the end of hostilities neared, information began being released by the government about some of the previously closely guarded secrets of technical developments in the previous half decade - such as the radar systems covered in this October 1945 issue of Radio-Craft magazine...

Carl & Jerry: Stereotaped New Year

Carl & Jerry: Stereotaped New Year, January 1963 Popular Electronics - RF CafeHere for your New Year's Eve entertainment is a new-old adventure story of "Carl & Jerry" titled, "Stereotaped New Year." In the same manner that author John T. Frye's highly regarded "Mac's Radio Service Shop" technodramas had themes echoing the time of year they were published, this appeared in the January 1963 issue of Popular Electronics magazine, which would have arrived in subscribers' mailboxes in December. Carl & Jerry, if you are not familiar with the dynamic duo of the teenage electronics and Ham radio enthusiasts, routinely got themselves involved in police investigations, creature comfort inventions, and practical jokes involving tape recorders, disembodied spirits, and remote controlled models. By 1963, they were out of high school and matriculating at "Parvoo University," which many people believe is a reference to Purdue University, given the boys' Midwestern locale. Admittedly, this plot...

Free General-Purpose Scientific and Engineering Plotting Library w/Smith Chart

DISLIN Scientific and Engineering Plotting Library w/Smith Chart - RF Cafe Cool ProductDr. Scott Best, of SiberSci RF engineering services, sent information about the FREE general purpose DISLIN scientific and engineering plotting software library that includes Smith Chart support. The graphics library was initially created at the Max Planck Institute for Solar System Research beginning in 1985 by Mr. Helmut Michels. Its continual series of upgrades is as recent as May 2020. The DISLIN library is available for Unix, Linux, FreeBSD, Windows, Mac OSX, and MS-DOS systems. It supports a variety of public domain and commercial compilers for Go, Perl, Python, Java, Ruby, TCL, Julia, FreeBASIC, Free Pascal, R, C/C++, and Fortran (77, 90, and 95). If you are a software developer, you probably know that most development platforms are supplied with either no plotting components or very rudimentary versions of for-purchase products. Many cost hundreds or even thousands of dollars...

Innovative Power Products Cool Chip Thermal Dissipation


Werbel Microwave (power dividers, couplers)

Windfreak Technologies Frequency Synthesizers - RF Cafe