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Homepage Archive - April 2023 (page 4)

See Page 1 | 2 | 3 | 4 | of the April 2023 homepage archives.

Sunday the 30th

Electronics Theme Crossword for April 30

Electronics Theme Crossword Puzzle for April 30, 2023 - RF CafeThis custom RF Cafe electronics-themed crossword puzzle for April 30th contains words and clues which pertain exclusively to the subjects of electronics, science, physics, mechanics, engineering, power distribution, astronomy, chemistry, etc. Every other row has words beginning with "R" and "F." If you do see names of people or places, they are intimately related to the aforementioned areas of study. As always, you will find no references to numbnut movie stars or fashion designers. Need more crossword RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating back to the year 2000. Enjoy.

Please Support RF Cafe

Amazon Prime - RF CafeThe RFCafe.com website exists partly on the support of its visitors by way of a small percentage earned with your Amazon.com purchases, which typically works out to less than $20 per month. That does not even cover the domain registration and secure server fees for RFCafe.com. If you plan to buy items via Amazon.com, please click on this link to begin your shopping session from here so that I get credit for it. Doing so does not cost you anything extra. Thank you for your support.

Many Thanks to Amplifier Solutions Corporation (ASC) for Continuing Support!

Amplifier Solutions Corporation (ASC) - RF CafeAmplifier Solutions Corporation (ASC) is a manufacturer of amplifiers for commercial & military markets. ASC designs and manufactures hybrid, surface mount flange, open carrier and connectorized amplifiers for low, medium and high power applications using Gallium Nitride (GaN), Gallium Arsenide (GaAs) and Silicon (Si) transistor technologies. ASC's thick film designs operate in the frequency range of 300 kHz to 6 GHz. ASC offers thin film designs that operate up to 20 GHz. ASC is located in an 8,000 sq.ft. facility in the town of Telford, PA. We offer excellent customer support and take pride in the ability to quickly react to evolving system design requirements.

Friday the 28th

Build a Mini-Tenna for FM Radio

Build a Mini-Tenna for FM Radio, February 1968 Radio-Electronics - RF CafeHere is an excellent example of how scientific evaluations performed by two independent subject experts can result in significantly different conclusions. James Gupton, Jr., reports on what previously had been considered secret military technology - an active, electrically small receiving antenna. This particular example, dubbed the Mini-Tenna, is designed for use on the FM radio band. After building and testing his antenna, Mr. Gupton offered it to two Radio-Electronics magazine editors for investigation. Each used a carefully considered method in what are generally similar environments - urban dwelling with strong signals and opportunity for multi-path, connected to a commercial FM radio receiver. The divergent results were not commented upon by the author. As a side note, I still have a 1980s vintage active FM radio antenna from Radio Shack...

Software-Defined Radio Advancing Radar Systems

Software-Defined Radio Advancing Radar Systems - RF CafeApparently SDR now also stands for Software-Defined Radar, not jut Software-Defined Radio. "Radar systems are increasingly important in many industries. However, as they carry out complex techniques, they need transceivers that can meet their needs. Software-defined radio provides a versatile and effective solution. Radar (or radio detection and ranging) systems are precise and versatile RF instruments that have become indispensable for many industries, playing a significant role in shaping the modern world. From military operations to air traffic control, these systems are now the main tools for monitoring and tracking objects in motion. Naturally, development of novel radar techniques and devices requires significant resources. However, complex techniques involving multiple channels and anti-jamming waveforms can’t be easily performed using traditional RF transceivers..."

Planning Integrated Signal Communications

Planning Integrated Signal Communications, December 1950 Radio & Television News - RF CafeThe U.S. Army's Signal Corps was set up to "exercise supervision over signal communications literally from the Pentagon to the foxhole." Created in 1860 at the suggestion of a military doctor, the Signal Corps originally used a system of flag waving for messaging dubbed "wigwag" and graduated to overseeing the nationwide telegraph network six years later. By 1870, members were tasked with establishing and operating a weather forecasting service, so in 1907 when they created an aeronautical division it was just in time for facilitating the nation's rapidly growing cadre of aircraft pioneers (recall the Wright brothers had flown four years earlier at Kitty Hawk) by providing en route weather information. Having already mastered the state of the art that was radio and telephone by 1937, the Signal Corps then undertook the challenge of a sophisticated new technology called "radar." Their motto is "Watchful for the Country." This is the first of four articles...

IPP RF Feedback Resistors for Solid State Amplifiers

Innovative Power Products RF Feedback Resistors for Solid State Amplifiers - RF CafeInnovative Power Products (IPP), with more than 30 years of experience designing & manufacturing RF & microwave passive components, introduces a line of RF Feedback Resistors for Solid-State Amplifiers. IPP's line of Feedback Resistors are designed to support wideband RF/Microwave solid-state transistor power amplifiers, which require resistive feedback. Using negative resistive feedback is a simple way to improve transistor amplifier stability and frequency gain sloping. These feedback resistors are flange mounted and designed to fit directly over the RF/microwave transistor using the same mounting holes as the transistor. This mounting configuration utilizes normally unused space above the transistor without taking up valuable PCB area adjacent to the transistor. This also decreases parasitic inductance associated with resistor leads...

How Far Can You Go in Electronics Without a Degree?

How Far Can You Go in Electronics Without a Degree?, September 1957 Popular Electronics - RF CafeThis story reads like an infomercial for IBM, which it just might be. Infomercials were still a little used marketing scheme in 1957 when this piece appeared in Popular Electronics magazine, so IBM was ahead of its time. The answer to the article's title, "How Far Can You Go in Electronics Without a Degree?" was the same 66 years ago as it is today: As far as your intellect and ambition will take you. Back then, as with today, few people could rise to the level of design engineer without a college degree. However, there are many aspects of electronics that require no formal education at all if you possess the requisite skills - with or without the title of engineer. However, I disagree with the feel-good line that "you can be anything you want to be." Some people simply cannot achieve the mastery necessary to do a particular job, regardless of how hard they try...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to Exodus Advanced Communications for Their Support

Exodus Advanced Communications - RF CafeExodus Advanced Communications is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. Power amplifiers ranging from 10 kHz to 51 GHz with various output power levels and noise figure ranges, we fully support custom designs and manufacturing requirements for both small and large volume levels. decades of combined experience in the RF field for numerous applications including military jamming, communications, radar, EMI/EMC and various commercial projects with all designing and manufacturing of our HPA, MPA, and LNA products in-house.

Thursday the 27th

Automated Electronic Newspaper

Automated Electronic Newspaper, March 1963 Radio-Electronics - RF CafeEver the enthusiastic futurist, Radio-Electronics magazine editor Hugh Gernsback laid out the need for and predicted the implementation of an electronically broadcast form of newspaper publishing. He states, "In this electronic-automation age, physical newspapers, that must be printed at a central plant, then distributed by trucks to newsstands, or mailed or transported by rail or air to distant cities, are an anachronism. They are wholly unnecessary and economically suicidal." That was in 1963, when he discussed the technology "RAFAR" (from Radio Automated Facsimile And Reproduction). Facsimile (fax) machines were already in use with signals being transferred over telephone lines. My first question was how is the entire newspaper content made available on demand by multiple users? There was no means of electronically storing that much information other than on magnetic tape. The RAFAR scheme had a miniature version of the newspaper printed on paper, then the reader scrolled through the paper while viewing a magnified image projected on a glass screen - akin to a microfiche machine. Magnetic storage could have been used...

Shape-Shifting Nano-Scale Electronic Transformer

Shape-Shifting Nano-Scale Electronic Transformer - RF Cafe"The golden parts of the device depicted in the above graphic are transformable, an ability that is 'not realizable with the current materials used in industry,' says Ian Sequeira, a Ph.D. student. UC Irvine physicists have discovered nano-scale electronic devices that can change shapes and sizes in solid states, potentially revolutionizing electronic devices and atomic-scale quantum material research. The devices, made of graphene sheets and gold wires, enable flexible and dynamic movement on van der Waals material surfaces. The nano-scale electronic parts in devices like smartphones are solid, static objects that once designed and built cannot transform into anything else. But University of California, Irvine physicists have reported the discovery of nano-scale devices that can transform into many different shapes and sizes even though they exist in solid states..."

Calculus and Its Application in Radio

Mathematics in Radio, Calculus and Its Application in Radio, July 1932 Radio News - RF CafeI challenge you to find a calculus lesson in a modern-day electronics magazine. In 1932, not all that long after Isaac Newton developed differential calculus (that's a joke), Radio News magazine ran a series of "Mathematics in Radio" articles that included, among other topics, a few lessons in calculus. Anyone who has taken college-level science or engineering courses knows how indispensible calculus is in working out many circuit, physics, and chemistry problems. My appreciation for calculus came when I realized that it actually allowed me to derive the kinds of standard equations that are commonly seen in lower level applications. For instance, if you needed to know the volume of a sphere, you could look up the familiar Volume = 4/3 π r3 formula, or you could write the equation Volume = Sphere volume equation - RF Cafe. Area, mass, center of mass, and length of a spiral line, are other examples of problems that can be solved by knowing the fundamental mathematics behind the equations...

Modelithics SELECT+ Library for MATLAB

Modelithics Launches Modelithics SELECT+ Library for MATLAB - RF CafeModelithics, the leading provider of highly accurate RF/microwave simulation models, and MathWorks, the leading developer of mathematical computing software, announced the launch of the new Modelithics SELECT+ Library for free use to MATLAB® and Simulink® customers. This product is a direct result of Modelithics joining the MathWorks Connections Program, a group of third-party organizations that develop and distribute commercially-available products that are complementary to the MathWorks product line. The Modelithics SELECT+ Library is a collection of Modelithics Microwave Global Models™ for passive devices, including capacitors, inductors, and resistors. Microwave Global models are highly scalable models that are developed using specialized measurements covering a range of test conditions. All Modelithics models contain a detailed model datasheet that lists recommended model validity parameters, measurement and test fixture details, and model-to-measurement data comparisons...

An Avocation Becomes a Vocation

An Avocation Becomes a Vocation, February 1943 QST - RF CafeDid you know that the Hallicrafters line of radios is named after founder Bill Halligan (W9WZE)? Hallicrafters, founded in 1932, was a major manufacturer of amateur radio gear. During the years of WWII they ruggedized some of their products to survive the harsh environments of battle. Hallicrafters was sold to Northrop Corporation in 1966, at which time the product line essentially ceased. Their gear is still very collectible by aficionados of vintage Ham equipment. This story from the February 1943 QST magazine provided an inside look at the production floor at Hallicrafters. Having cut my figurative electronics teeth on radar and radio equipment built with tubes and point-to-point wiring while in the USAF, and then later as an assembly/test technician at Westinghouse Electric building sonar equipment for the Navy which included wiring chassis and building large complex cable harnesses, I can personally relate to the photos accompanying the article. When, for readers in the U.S., is the last time you saw a company touting its "expert American craftsmen...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to Withwave for Long-Time Support!

Withwave RF & Microwave Components - RF CafeWithwave manufactures an extensive line of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch, board edge, panel mount), calibration kits (SOLT), a fully automated 4-port vector network analyzer (VNA) calibrator, between- and in-series connector adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes & probe positioner. Special test fixtures for calibration and multicoax cable assemblies. Frequency ranges from DC through 110 GHz. Please contact Withwave today to see how they can help your project succeed.

Wednesday the 26th

The Technician Who Knew Too Much

The Technician Who Knew Too Much, February 1968 Radio-Electronics - RF CafeElectronics industry trade magazines used to like to print what I refer to as technodramas, which were stories that had a plot centered around a technical issue. Sometimes it was circuit troubleshooting, design, customer interaction, component reliability, availability of technical information, supply chain problems, hired help troubles, finances, or any other thing involved in the operation of an electronics service business. Mac's Radio Service Shop is probably the most well-known example, but there was also Carl and Jerry and similar regular series. This "The Technician Who Knew Too Much" story from a 1968 issue of Radio-Electronics magazine is an example of a random technodrama that was not part of a series. The moral of this story involves not being too proud to concede to the possibility that someone you regard as being lesser in experience than yourself might be capable of solving a problem which evaded your first attempts...

Magnetic Quantum Leap for Ultra-Fast Computers

Magnetic Quantum Leap Unleashes Ultra-Fast Sustainable Computers - RF Cafe"The researchers have for the first time succeeded in demonstrating a device, based on a 2D magnetic material, in room temperature. The 2D magnetic crystal is shown as the blue, yellow and white balls and is a mix of Iron, Tellurium and Germanium atoms. The big turquoise arrow indicates the magnetization direction of the 2D magnet. The crystal with gray color is the carbon atoms of the graphene channel. The smaller turquoise arrows indicate the spin-polarized electrons injected from the 2D magnet into the graphene channel. Here, the 2D magnet act as a source for spin-polarized electrons and the graphene channel for spin transport and communication. The discovery of new quantum materials with magnetic properties are believed to pave the way for ultra-fast and considerably more energy efficient computers and mobile devices. So far, these types of materials have been shown to work only in extremely cold temperatures..."

The Whys and Wherefores of Watts

The Whys and Wherefores of Watts, January 1957 Popular Electronics - RF CafeMost visitors to RF Cafe are either engineers, technicians, or hobbyists who deal with watts in terms of electrical power. This article from the January 1957 edition of Popular Electronics magazine deals primarily with watts in terms of acoustic power, but it also addresses how obtaining acoustic watts relates to electrical watts. Audiophiles will appreciate the table of speaker watts needed based on your room volume as well as rules of thumb for selecting the amplifier power required to deliver that sound effectively. You will note that back in the day the common abbreviation for decibels was all lower case (db) ad opposed to how we do it today (dB). A tech-related comic was on a page in the article so I included it as well...

Wideband Microwave Materials Characterization

Artech House: Wideband Microwave Materials Characterization - RF CafeJohn W. Schultz's latest book from Artech House, "Wideband Microwave Materials Characterization," is a practical engineering guide to microwave material measurements for both laboratory and manufacturing/field environments, including nondestructive inspection (NDI) and nondestructive evaluation (NDE). The book, published by Artech House, covers topics including Electromagnetic Materials Properties, Free Space Methods, Microwave Non-Destructive Evaluation, Focused Beam Methods, and more! This book is a practical engineering guide to microwave material measurements for both laboratory and manufacturing/field environments, including nondestructive inspection (NDI) and nondestructive evaluation (NDE)...

Capacitor Circuit Quiz

Capacitor Circuit Quiz, June 1968 Popular Electronics - RF CafeHere is a good quiz on calculating total equivalent capacitance for circuits containing various combination of series, parallel, and series-parallel connections. It appeared in the June 1968 issue of Popular Electronics magazine. To help in calculation, all of the individual capacitor values are the same. Many of them you can probably solve in your head, especially if you mentally rearrange the circuit into a more readily recognizable configuration. For instance, circuit #1 can be redrawn having two parallel branches across the source. One branch has just a single capacitor while the other has two parallel capacitors in series with one capacitor. The equation is then C + (2C2/3C) = C + 2/3C = 5/3C. For C = 6 pF, Ctotal = 5/3*6 pF = 10 pF...

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 (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF CafeThe leading website for the PCB industry. PCB Directory is the largest directory of Printed Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the Internet. We have listed the leading printed circuit board manufacturers around the world and made them searchable by their capabilities - Number of laminates used, Board thicknesses supported, Number of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services (manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.

Tuesday the 25th

Looking Ahead: Pay-TV

Looking Ahead: Pay−TV, March 1969 Radio-Electronics - RF CafeIn the February 1967 issue of Radio-Electronics magazine, editor Forrest Belt wrote about the up-and-coming Pay TV scheme. At the time, nearly everyone received over-the-air (OTA) broadcast programming, and cable TV was getting its beginnings in metropolitan and nearby suburbs. As originally envisioned, Pay-TV would be delivered OTA on allocated frequencies within the UHF band. This 1969 article provides some updated information. Many people were already paying separately for cable television, so Pay-TV targeted the others. Two of the main marketing pitches were no commercials during movies, and availability of shows not presented anywhere else. History has shown that not only will people gladly pay to watch TV programming, but they'll pay for it while also being required to endure an ever-increasing amount of commercials. Access via the Internet has greatly accelerated the "cord cutting" movement not just to telephones, but for music and TV...

An Intrstng Exprmnt in Spch

An Intrstng Exprmnt in Spch, January 1957 Radio & Television News - RF CafeHere is a little insight into early speech processing research by the Bell Telephone Laboratories. 1957 was the early era of real-time digital processing where the need to cram more calls into less signal space (bandwidth) led to sampled systems - 1:6 in the case of this advertisement from Bell that appeared in Radio & Television News magazine. Engineers of the day would be amazed at how the state of the art has advanced since then, both in mathematical techniques and in miniaturized hardware. Waaaaay back in the early 1990s while working at Comsat Laboratories, in Germantown, Maryland, one of the Intelsat earth station modem transceivers I worked on used groundbreaking software algorithms to reduce call bandwidth by replacing certain parts of spoken word sounds with shorter segments of code that would then be reassembled at the receiver end. I specifically remember the software guys have a hard time getting the "s" sound, "ess," working properly. That issue and many others were conquered long ago...

Smart Capsule Monitors Dose for Radiotherapy

Smart Capsule Monitors Dose for Radiotherapy - RF Cafe"For monitoring X-ray does in patients undergoing radiotherapy for gastrointestinal cancer, a group of researcher have created a prototype swallowable dosimeter capsule that also measures gut pH and temperature. SAIT CAS xray dose capsule 'The researchers found that the dosimeter was approximately five times more accurate than standard methods for dose determination,' according to the Chinese Academy of Sciences, whose Shenzhen Institute of Advanced Technology (SIAT) worked with the National University of Singapore and Tsinghua University. NUS xray dose capsuleThe 18mm long 7mm diameter capsule has an optical fibre encapsulated with X-ray persistent lanthanide-doped nano-scintillators whose glow can be used to estimate radiation dose, and a colour-changing pH-sensitive polyaniline film..."

The Antenna Research Laboratory

The Antenna Research Laboratory, March 1950 Radio & Television News - RF CafeBy 1950, says the author of this Radio & Television News magazine story, "No longer are 'aerials' merely required to transfer electromagnetic energy into space," in reference to airborne platforms." Following great advancements in radio and radar technology during World War II, great interest lay in what would later become referred to as 'stealth' technology and in secure communications. The transition of aircraft speeds into the realm of supersonic also mandated that projections beyond the main airframe outline be either eliminated or very much minimized. The long cable aerials that stretched from the cockpit area to the tip of the vertical fin, and the round direction finding antennas hanging from below could not be accommodated at airspeeds above about 300 knots. The aerodynamic drag would be excessive and the forces would tear the antennas apart. Douglas Aircraft set up one of the first antenna measurement laboratories...

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 or so 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. Check them out!

Please Visit Empower RF's Website in Appreciation of Their Support

Empower RF Systems - RF CafeEmpower RF Systems is the technological leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers incorporate the latest semiconductor and power combining technologies and with a patented architecture we build the most sophisticated and flexible COTS system amplifiers in the world. Solutions range from tens of watts to hundreds of kilowatts and includes basic PA modules to scalable rack systems.

Monday the 24th

Imaginary Numbers Are a Cinch

Imaginary Numbers Are a Cinch, February 1968 Radio-Electronics - RF CafeMathophobes beware; I cannot be held accountable for instances of hyperventilation, fainting, intense sweating or nervousness, post traumatic stress, etc. When in high school and junior high, I suffered from the common malady. However, after setting my sights on earning an electrical engineering degree, I embraced mathematics as a necessary skill to be successful. In fact, I did very well in all my math classes even up through calculus, differential equations, and even higher levels. It soon became evident that my fellow students who struggled the most - even failed - at engineering courses were those who never had a handle on math. Since becoming comfortable with higher mathematics, my appreciation for its abilities to describe the physical world has constantly grown. It is also nice when reading technical articles to at least somewhat understand the math behind the concepts. Author Norman Crowhurst attempts in this 1960 Radio-Electronics magazine article to sooth the pain of complex numbers a bit...

Critical Metal Needs Rise While Cars, Trucks Decarbonize

Critical Metal Needs Rise While Cars, Trucks Decarbonize - RF Cafe"As automobile electrification speeds up, the world faces an overwhelming need for critical metals and minerals to make atmosphere-saving electric vehicles possible. The demand for battery-grade lithium, nickel, cobalt, manganese and platinum will climb steeply as nations work to reduce greenhouse gas emissions through mid-century, but will likely set off economic snags and supply-chain hitches, according to new Cornell research published April 11 in Nature Communications. 'Electrification and decarbonizing fuel production are critical for adequately mitigating greenhouse gas emissions from road transportation,' said Fengqi You, the Roxanne E. and Michael J. Zak Professor in Energy Systems Engineering, the senior author on 'Trade-off Between Critical Metal Requirement and Transportation Decarbonization in Automotive Electrification..."

The Hobbyist

The Hobbyist, April 1967 Popular Electronics - RF CafeHere are a few tech-themed comics from the April 1967 edition of Popular Electronics magazine depicting the perception of techies during the era. I took the liberty of colorizing them. As mentioned before, stereo equipment was a big deal in the era, back before most people listened to music through ear buds attached to smartphones. When in the USAF in the early 1980s, a sure sign of hipness was to have 19" equipment rack in your barracks room, stuffed full with a reel-to-reel tape deck, a high end AM/FM receiver ("tuner," to the audiophile), power amplifier that could deliver at least 200 W per channel, a dual cassette deck, turntable (referring to it as a "phonograph" revealed your squareness). Of course no self-respecting stereo aficionado would be caught dead with an 8-track tape deck in the rack. Things really haven't changed much when it comes to serious audiophiles, except now a CD/DVD player will be included...

China Building Cyberweapons to Hijack Enemy Satellites

China Building Cyberweapons to Hijack Enemy Satellites"China is building sophisticated cyber weapons to seize control of enemy satellites, rendering them useless for data signals or surveillance during wartime, according to a leaked US intelligence report. The U.S. assesses that China’s push to develop capabilities to 'deny, exploit or hijack' enemy satellites is a core part of its goal to control information, which Beijing considers to be a key 'war-fighting domain.' The CIA-marked document, which was issued this year and has been reviewed by the Financial Times, was one of dozens allegedly shared by a 21-year-old US Air Guardsman in the most significant American intelligence disclosures in more than a decade. A cyber capability of this nature would far exceed anything Russia has deployed in Ukraine, where electronic warfare teams have taken a brute-force approach with little effect. These attacks, first developed in the 1980s, attempt to drown out signals between low-orbit SpaceX satellites and their on-ground terminals by broadcasting on similar frequencies..."

Detector Circuits

Detector Circuits, September 1945, Radio-Craft - RF CafeThis continuation of Part I of the three-part "Detector Circuits" series covering the basics of diode detectors delved into some of the specific circuit configurations and their applications. Here in Part II, author Robert Scott touches on regenerative and superregenerative feedback "tickler" circuits that are able to detect very low level signals. You have no doubt heard of "quenching" but how about "squegging?" The nonlinear devices used in the article happen to be vacuum tubes, so stay away if you suffer from thermionophobia (a term I just created). Imagine a generic semiconductor diode in place of the tube if it makes you feel better ;-) Part I appeared in the August 1945 issue, and Part III, the final article in the series, was published in the October 1945 edition...

   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 2018 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. An intro video takes you through the main features...

Please Thank Lotus Communication Systems for Their Support!

Lotus Communication Systems Modular RF/Microwave Components - RF CafeLotus Communication Systems began in 2009, setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex Country, Massachusetts. Lotus is committed to highest quality and innovative products. Each RF/microwave module meets exceedingly high standards of quality, performance and excellent value, and are 100% Made in the USA. Lotus' RF/microwave products cover frequency band up to 67 GHz. Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production. All products are custom designed. We will find a solution and save your time and cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters. In stock, 1-day free shipping.

Sunday the 23rd

Electronics Theme Crossword for April 23

Electronics Theme Crossword Puzzle for April 23, 2023 - RF CafeAs always, this week's crossword puzzle for April 23rd sports an electronics theme. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only 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, Hedy Lamarr, or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to Anatech Electronics for Long-Time Support!

Anatech Electronics logo - RF CafeAnatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed. 

These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

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RF Cascade Workbook 2018 - RF Cafe
Crane Aerospace Electronics Microwave Solutions: Space Qualified Passive Products

LadyBug RF Power Sensors

RF Electronics Shapes, Stencils for Office, Visio by RF Cafe