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Carl & Jerry: Wrecked by a Wagon Train

Carl & Jerry: Wrecked by a Wagon Train, February 1962 Popular Electronics - RF CafeIn this adventure from a 1962 issue of Popular Electronics magazine, Carl and Jerry were once again called upon by law enforcement to apply their combined electronics expertise to help collar a perp. By this time, the boys were college students in the electrical engineering program at Parvoo U. (fabled to be a tribute to Perdue). A storied past in their high school days is well-documented in previous "Carl & Jerry" technodramas. Mr. Frye was always careful to provide a balanced mix of technical prowess and adventure into his stories. It is easy when reading these kinds of stories in today's world to ask what is so special about the feat pulled off here, but in fact access to materials and equipment...

DNA the Future of Quantum Computing

DNA the Future of Quantum Computing - RF Cafe"Researchers have uncovered a way to manipulate DNA at the atomic level using electric field gradients to control nitrogen nuclear spins. Their findings suggest that DNA could be used as both a storage and computation mechanism in future quantum computing devices. A recent study by researchers from Peking University highlights the potential of nuclear electric resonance to control the nuclear spins of nitrogen atoms in DNA using electric field gradients. This breakthrough suggests that DNA could one day be manipulated for computational purposes..."

Green Energy & Electric Vehicles: Full Life Cycle Cost

Green Energy & Electric Vehicles: Full Life Cycle Cost- RF CafeRF Cafe visitors are involved in many aspects of what has come to be known as "green energy" through direct involvement in resource, component, and end-product production, through ownership of those end products, and through paying taxes to government which allocate subsidies for all phases of the life cycle. For example, with government incentives, an EV like the Tesla Model Y may cost the buyer $46k. However, without subsidies, the real cost would be closer to $66k to $76k. The pursuit of green energy encompasses both notable achievements...

SatNow: Upcoming Satellite Launches

Upcoming Satellite Launches at SatNow - RF CafeSatNow maintains a list of upcoming satellite launches from the leading launch companies. These include NASA, Space X, Rocket, ISRO, Blue Origin and many more. Learn more about each launch, its launch date, location and launch vehicle used. We provide the latest news, interesting white papers, technical articles and an innovative product search tool. The product search tool is the first of its kind and helps engineers find products across various categories in three areas: Satellite, Ground, Launch. SatNow also provides a huge collection of online calculators for satellite communications. Examples are an anomalistic period calculator, an antenna G/T ratio calculator, an antenna polarization...

Radio Wittiquiz, November 1937 Radio-Craft

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

Engineering & Tech Headlines <Archives>

• Wireless Broadband Alliance's 10 Predictions for Wi-Fi in 2025

• Fixed Wireless Access is Preferred Next Internet Connection (I use it)

• FCC Upholds Forfeiture Order Against Ham Operator

• European Commission Updates AI Act

• 345% News Radio Listening Surge for LA Wildfires

Combinational Logic: History and Applications

Combinational Logic: History and Applications - RF CafeCombinational logic is a fundamental category of digital circuit design in which the output depends solely on the present input values, without any memory or feedback elements. Unlike sequential logic, which retains state across clock cycles, combinational logic circuits process input signals in real-time and produce immediate output. The relationship between input and output in these circuits can be described using Boolean algebra and truth tables. The history of combinational logic dates back to the early 20th century when Boolean algebra, introduced by George Boole in the mid-19th century, was first applied to electrical circuits. In the 1930s and 1940s, engineers like Claude Shannon and George Stibitz...

Basic Digital Logic Course

Basic Digital Logic Course, December 1974 Popular Electronics - RF CafeThis first of a three-part series on digital electronics run by Popular Electronics magazine begins with introducing binary (base 2), octal (base 8), and decimal (base 10) number systems, along with conversions between the types. Sure, this is probably old-hat to most RF Cafe visitors, but there is always a new cadre of electronics enthusiasts entering the field who appreciate the instruction. No matter how advanced digital electronics gets, a fundamental understanding and fluency in binary arithmetic is essential to success whether as a hobbyists or as a professional. If you cannot move effortlessly between the various number formats...

D2D Satellite Push Takes Off

D2D Satellite Push Takes Off - RF Cafe"The Federal Communications Commission (FCC) last week announced a Special Temporary Authority (STA) for AST SpaceMobile to enable its operator partners - AT&T and Verizon - to test its Bluebird direct-to-device (D2D) satellite constellation over the United States. Meanwhile, in the United Kingdom, Vodafone has used the nascent Bluebird constellation to enable a video call between Margherita Della Valle, Vodafone Group chief executive in Newbury, England, and Vodafone engineer Rowan Chesmer..."

San Andreas Fault: High Tech Corridor in Peril

San Andreas Fault: High Tech Corridor in Peril - RF CafeThe San Andreas Fault has been in the news again lately, with hundreds of small tremors being detected along its 750 mile extent. Given its proximity to many of the world's most important and valuable high technology companies, government facilities, and universities, a delve into some of the issues is relevant to RF Cafe visitors. According to some sources, the probability of a major rupture along the San Andreas Fault varies depending on the specific segment and the time frame considered. According to the Third Uniform California Earthquake Rupture Forecast (UCERF3), developed by the USGS and other institutions, there is an estimated 7% chance of a magnitude 8.0 or greater earthquake occurring...

Many Thanks to Transcat | Axiom Rental Equipment for Continued Support!

Transcat | Axiom Rental Equipment - RF CafeTranscat | Axiom Rental Equipment allows you to rent or buy test equipment, repair test equipment, or sell or trade test equipment. They are committed to providing superior customer service and high quality electronic test equipment. Transcat | Axiom offers customers several practical, efficient, and cost effective solutions for their projects' TE needs and is committed to providing superior customer service and high quality electronic test equipment. For anyone seeking a way to offload surplus or obsolete equipment, they offer a trade-in program or they will buy the equipment from you. Some vintage items are available fully calibrated. Please check out Transcat | Axiom Rental Equipment today - and don't miss the blog articles!

What's Your EQ?

What's Your EQ?, February 1964 Radio-Electronics - RF CafePut on your thinking cap again and take a shot at these trio of new circuit analysis problems that appeared in the "What's Your EQ?" feature in the February 1964 issue of Radio-Electronics magazine. These days, I'm guessing not too many people are familiar with the characteristics of neon bulbs, and even way fewer with vacuum tube circuits. Neon bulbs were one of the earlier forms of voltage references since once ignited, the voltage drop across them is fairly constant, sort of like a gaseous Zener diode - except there was zero current flow prior to ignition. Although I didn't know for sure, I figured that even with its high input impedance...

A Baffling Quiz

A Baffling Quiz, January 1968 Popular Electronics - RF CafeIt is doubtful that as many people today build their own stereo speaker enclosures as was the case back in the 1950s through about the 1970s. During those decades stereo equipment was a really big deal, as evidenced by the large number of articles in technical and hobby magazines. I have posted a couple dozen articles on the subject here on RF Cafe. Topics included equipment reviews and feature comparisons, troubleshooting and alignment, modifications to commercial units, build-it-yourself projects, optimized room layout and construction, and even advice on how to best enjoy your stereo system. Lots of comics appeared in the magazines as well poking fun at how a stereo enthusiast's family members and neighbor might not appreciate the ear drum-busting power capability of your system. There were also quizzes like this one on speaker enclosure baffle design ...

ParkerVision vs. Qualcomm Legal Battle

ParkerVision vs. Qualcomm: A Legal Battle over Wireless Technologies - RF CafeThe long-running patent litigation between ParkerVision and Qualcomm is in the news again. It has been a significant case in the wireless technology industry, focusing on radio-frequency (RF) receivers and signal down-conversion methods. Given the importance of RF technology in Bluetooth, ZigBee, Wi-Fi, and even wireless charging, the outcome of this case has broader implications for wireless communication markets. ParkerVision's patents center on RF down-conversion technology, a key process in wireless communications. RF down-conversion involves converting high-frequency signals into lower frequencies...

Ofcom Grants Amazon Satellite Broadband Licence

Ofcom Grants Amazon Satellite Broadband Licence - RF Cafe"Ofcom has given Amazon the go-ahead to launch satellite broadband services in the UK and simultaneously announced it is releasing more high-band spectrum that could be used by the satellite industry. Meanwhile, the UK government is also getting in on the act, allocating funding to a pair of projects in the satellite space. The UK telecoms regulator has granted an earth station network licence to Amazon's Kuiper. That essentially means that the company has the green light to provide satellite connectivity services, including high-speed..."

For Safety's Sake

For Safety's Sake, December 1966 QST - RFCafeThis is a story with a lesson learned by the author and thousands of others ever since electric power appliances and tools first became available. Fortunately, his Ham buddy was not permanently harmed, but even today with all the effort put into educating the public, people continue to use ungrounded (2-wire type, or with the ground prong removed) extension cords in conjunction with 3-wire power cords on tools and end up electrocuting themselves (or somebody else). I've told the story before about a friend of mine from high school who shortly after graduation was making a piece of furniture in a garage that had a damp dirt floor, and was electrocuted to death by the metal-framed circular saw that had no ground connected. Nowadays we often have power provided by a GFCI receptacle...

Thanks to Crane Aerospace & Electronics for Their Support!

Crane Aerospace & Electronics - RF CafeCrane Aerospace & Electronics' products and services are organized into six integrated solutions: Cabin Systems, Electrical Power Solutions, Fluid Management Solutions, Landing Systems, Microwave Solutions, and Sensing Components & Systems. Our Microwave Solution designs and manufactures high-performance RF, IF and millimeter-wave components, subsystems and systems for commercial aviation, defense, and space including linear & log amplifiers, fixed & variable attenuators, circulators & isolators, power combiners & dividers, couplers, mixers, switches & matrices, oscillators & synthesizers.

Bell Telephone Lab - Wire Wrapping

Bell Telephone Lab - Wire Wrapping, October 1953 Radio & Television News - RF CafeIf you believe this 1953 advertisement in Radio & Television News magazine, engineering at Bell Telephone Laboratories invented the wire-wrapping process. A little additional research shows that indeed it was a Bell Telephone engineering team led by Arthur Keller who developed the method and a wire-wrap tool to do the job. Field technician needed a fast, durable, and reliable electrical connection when making hundreds or thousands of splices at relay stations and while up on telephone poles. The key to making a good wire-wrap connection is sharp corners on the wrapping post so that the corner pushes through any oxidation or contaminant on the bare wire. NASA and the Department of Defense (DoD) have exacting workmanship standards to guarantee a rugged, durable electrical connection...

Autonomous Tools for Satellite Swarms

NASA Pioneers Autonomous Tools for Satellite Swarms - RF Cafe"Coordinate your actions, unify your approach, and collaborate to fulfill a shared objective. This 'pep talk' succinctly captures how NASA's latest swarm-based breakthrough operates. Known as Distributed Spacecraft Autonomy (DSA), it allows each satellite to make decisions independently while uniting with fellow spacecraft to pursue collective goals, all free from human oversight. Within NASA's DSA project, researchers achieved multiple unprecedented feats when testing technologies for satellite swarms. Managed at NASA's Ames Research Center in California's Silicon Valley, the project..."

Anti-Collision Systems for Autos

Anti-Collision Systems for Autos, October 1972 Popular Electronics - RF CafeThis article reporting ongoing research for auto anti-collision systems and backup warning systems appeared in a 1972 issue of Popular Electronics has only come to practical fruition within the last decade and a half. High-end cars were offering such equipment options in the early 2000s, but it has only been commonplace since around 2010. 1972 components were still pretty large and power hungry, and digital processing capacity and speed was significantly less advanced as well. Bendix, one of the early developers of anti-collision systems, estimated that the option on a new car might add about $200 to the price, which was...

The Penny: Is It Worth the Cost of Minting?

The Penny: Is It Worth the Cost of Minting? - RF CafeThe debate over whether to stop minting new pennies is rooted in economic efficiency, public convenience, and the broader impact on commerce. President Trump's directive to the Treasury Department to halt penny production is driven by the fact that each penny costs nearly three cents to produce, leading to a financial loss for the U.S. government. However, this decision raises concerns about potential shortages, changes in pricing strategies, and consumer sentiment regarding the smallest unit of U.S. currency. One major argument in favor of stopping penny production is the high cost...

Please Thank RF & Connector Technology for Their Support

RF & Connector Technology - RF CafeProviding full solution service is our motto, not just selling goods. RF & Connector Technology has persistently pursued a management policy stressing quality assurance system and technological advancement. From your very first contact, you will be supported by competent RF specialists; all of them have several years of field experience in this industry allowing them to suggest a fundamental solution and troubleshooting approach. Coaxial RF connectors, cable assemblies, antennas, terminations, attenuators, couplers, dividers, and more. Practically, we put priority on process inspection at each step of workflow as well as during final inspection in order to actualize "Zero Defects."

Electronics-Themed Comics

Electronics-Themed Comics, October 1963 & September 1966 Radio-Electronics - RF CafeHere are four more electronics-themed comics to help get your work week started on a happy note. They all appeared in Radio-Electronics magazine in the 1960s. The page 107 comic conjures up a bit of a nostalgic memory in me, remembering earlier days sitting at a workbench and troubleshooting a piece of electronics gear. I never heated a coffee pot on a chassis, but definitely remember cases with vacuum tubes operating inside that were hot enough to do so. Some of those buggers could melt flesh. I've told the tale before how whilst in the USAF tuning up our air traffic control radar system, I (and fellow techs) would open an access door on the front (not intended to admit passage of a human hand) and blindly "walking" tuning wand-carrying my fingers across the tops of piping hot tubes to get to a potentiometer...

Webinar: AI's Impact on Engineering

Webinar: AI's Impact on Engineering - RF Cafe"Join The Engineer, Dassault Systèmes, BAE Systems, Monolith AI, AMRC and others experts from across industry on Tuesday Feb 25th for this online panel session exploring what the rise of AI means for engineers. AI is currently dominating industry discussion, is at the heart of industry's accelerating digital transformation and is widely anticipated to be one of the most transformative trends in manufacturing and engineering as more and more engineering and manufacturing organizations look at how they can integrate AI capabilities within..."

Jefferson's Decimal System vs. The Metric System

Jefferson's Decimal System vs. The Metric System - RF CafeThe late 18th century was a period of intense effort to standardize measurement systems in both France and the United States. Thomas Jefferson and the French Academy of Sciences independently developed proposals for a rational system of weights and measures based on decimal principles. While Jefferson's system was designed for national use, the French metric system aimed for universal application. Despite their similarities, the two systems differed in fundamental ways, particularly in their definition of base units...

Exodus AMP20100, 2-8 GHz, 200 W, TWT Replacement

Exodus Advanced Communications AMP20100, 2.0-8.0 GHz, 200 W, TWT Replacement - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. Exodus' model AMP20100 is an elegant, quiet, broadband class A/AB solid state amplifier (SSPA) and excellent TWT replacement. Ideal for EMC/EMI testing applications including automotive pulse/radar & commercial applications. Frequency ranges from 2.0 to 8.0 GHz, 200 W minimum, 250 W typical, 53 dB minimum gain, and -20 dBc harmonics. Monitoring...

Inside Britain's Newest Jet: Gloster E.1/44

Inside Britain's Newest Jet: Gloster E.1/44, October 1948 Popular Science - Airplanes and RocketsThe Gloster E.1/44, presented in this 1948 issue of Popular Science magazine, was a British experimental jet fighter developed in the 1940s as a potential single-engine counterpart to the twin-engine Gloster Meteor. Designed by the Gloster Aircraft Company to meet Air Ministry Specification E.1/44, it was powered by a Rolls-Royce Nene turbojet and featured a sleek, straight-wing design with a tricycle landing gear. Initially conceived as a simpler and more economical jet fighter for the Royal Air Force, the project faced numerous delays due to shifting priorities...

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.

Sylvania High-Voltage Rectifiers

Sylvania High-Voltage Rectifiers, June 1968 Radio-Electronics - RF CafeIn much the same way as the solution to a word problem seems obvious when you look it up in the back of a textbook, Sylvania's answer to manufacturing a vacuum tube heater element that is more robust and less subject to vibration failure is illustrated in this advertisement which appeared in a 1968 issue of Radio-Electronics magazine. Eliminating the suspended element and wrapping it securely on a supporting post facilitated an "instant on" requirement for up-and-coming transistorized televisions and radios by reducing heat-up time to about a second. The heater's symmetrical shape also assured even emission of electrons from the cathode. Its captured winding around the support post also eliminated the annoying failure mode where a broken-off heater...

Today in Science History

Today in Science History - RF Cafe

Last Chance to Buy a New Radio - c1942

Last Chance to Buy a New Radio - c1942 (Kirt's Cogitation #308) - RF CafeIt is probably safe to say that most people, especially today, believe that the United States was suddenly and unexpectedly thrust into involvement in World War II on December 7, 1941, when the Japanese navy launched a surprise attack on Pearl Harbor. The fact is the U.S. was "unofficially" engaged for over a year beforehand by "lending" both equipment and personnel to British, Russian, Chinese, French, and other militaries as part of their effort to drive back invading German, Italian, and Japanese Axis forces. World War II actually began in the Fall of1939 with Hitler's invasion of Poland. Americans, being safely separated from the front lines by the Seven Seas, knew little of and were concerned little about the goings on "Over There." Once the call to arms was sounded with the Pearl Harbor attack, the country quickly and enthusiastically converted to full wartime mode. Manufacturing plants...

The FM Radio Boom

FM Radio Boom, August 1947 Radio-Craft - RF CafeHugo Gernsback is not necessarily a household name in 2020, but in the early to middle 20th century, he was fairly well known in both the hard science and science fiction realms. He was a prolific author of books and magazines in both areas, applying his profound knowledge of technology and his ability to foretell the futures of many aspects of communications, mechanics, electronics, and marketing and societal behavior to the aforementioned. If you are a regular RF Cafe visitor, you have seen very many articles written by Hugo Gernsback reproduced. This particular work of prognostication appeared in a 1947 issue of his Radio-Craft magazine. It presciently claimed that a post-war boom in consumer buying after half a decade of sacrifice of creature comforts for the good of the country and world would feed a significant adoption of FM radio over...

Science Theme Crossword Puzzle for May 23rd

Science Theme Crossword Puzzle for May 23rd, 2021 - RF CafeFor twenty years now, I have been creating weekly crossword puzzles for the education and enjoyment of the technically minded visitor like you. This Science Theme Crossword Puzzle for May 23rd 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!

Wireless World: Practical Hints and Tips

RF Cafe - March 9th 1932 Wireless World CoverI finally managed to get an early edition of The Wireless World magazine for a reasonable price on a eBay auction. Now I will be able to post a few of those articles from the UK to compliment those from some of the American magazines. This particular edition is from March 9th, 1932. My next target is to get a few from the World War II era which although it began on December 7, 1941 from America's perspective, it officially began on September 1, 1939 for Europe. Warning for the weak of heart - epochal words like "niggardly" and "parsimonious" are used herein, and therefore adult supervision should be employed if ignorance might cause an objection to at least one of the aforementioned...

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...

The Wavelength Factor - Part II

The Wavelength Factor - II, May 1952 QST - RF CafePart 1 of this 3-part article, titled "Influence of the Antenna of the Choice of Wavelength for Best Communications," appeared in the February 1952 issue of QST magazine. Unfortunately, I do not yet own that edition. However, I do have Part 3, which subsequently appeared in the August 1952 edition. It will eventually get posted here. QST does not have a publicly available archive, but if you happen to be an ARRL member, you can access Part 1 after signing in. In this series, author Yardley Beers discusses propagation effects, modulation systems, and receiver techniques. A particularly interesting topic included in this installment is that of using a form of pulse modulation in FM broadcasting in order to exploit the 'capture effect' whereby a signal in the presence of noise will tend to suppress the noise. I don't think modern stations use that method, possibly because of incompatibility with stereo channels and data added for digital readouts...

Electromaze Puzzle

Electromaze Puzzle, June 1966 Popular Electronics - RF CafeRobert Radford's (not to be confused with Robert Redford) "Electromaze" is a unique - and weird - sort of word puzzle that first appeared in the April 1966 issue of Popular Electronics magazine. Some people were confused about the strategy, believing that all the white spaces needed to be filled in. They do not. Just because a letter might have an empty square adjacent to it does not imply that another letter must fill it. You will probably want to print out the maze grid and find an old guy who should still have a pencil stowed away somewhere you can borrow to use for filling in the boxes...

Goddard Satellite Missions of the 1960s

NASA Goddard Satellites of the 1960 Decade - RF CafeAmerica's first successful orbiting of a satellite launch happened on February 1, 1958 with the launch of Explorer 1 atop a Juno 1 rocket. Our first attempted satellite launch was the Vanguard TV3, on December 6, 1957, but it unfortunately succumbed to a failed booster rocket (it rose only 4 feet off the launch pad). Russia had already launched its Sputnik 1 satellite on October 4, 1957, making it the very first manmade satellite to orbit the earth - to the forever chagrin of U.S. scientists. Fortunately, advances occurred rapidly for the U.S. space program after Explorer 1. In its first full decade of existence, the Goddard Space Flight Center, located in Greenbelt, Maryland, was responsible for launching more than 100 different spacecraft...

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...

After Class: Working with Thermistors

After Class: Working with Thermistors, November 1956 Popular Electronics - RF CafeA good primer on the physics behind and use of thermistors was published in the November 1956 edition of Popular Electronics. Thermistors are fundamentally substances that exhibit a large change in resistance for a given change in temperature, called temperature coefficient of resistance (TCR, or RT). Standard resistors would ideally maintain the exact same resistance regardless of temperature, but in reality most resistor types increase in resistance with an increase in temperature; i.e., a positive TCR. Most thermistors have a negative TCR, which makes them useful for cancelling out resistor temperature sensitivity. Thermistors are also used for temperature sensing and measurement, although thermocouples generally do a much better job for that application...

Reactance Chart

Reactance Chart, May 1959 Electronics World - RF CafeReactance charts were a dime a dozen (free, actually) and appeared as regular features in electronics magazines in the days before smartphone apps provided ready access to reactance versus frequency calculations. This one was in the May 1959 issue of Electronics World. Calculators are nice and indispensible in design work, but sometimes having "the big picture" of how various values of inductance and capacitance "react" with changes in applied frequency is often useful - especially if you are a newcomer to electronics. To paraphrase a popular saying, "A reactance chart is worth a thousand calculators."

New Magnetron Shifts Frequency Fast

New Magnetron Shifts Frequency Fast, April 6, 1964 Electronics Magazine - RF CafeFrequency hopping spread spectrum, first proposed and patented by Hollywood actress Hedy Lamarr, relies on both transmitters and receivers to precisely tune in a pseudorandom manner to a band of discrete frequencies in a time-synchronized manner with each other. The faster an encoded signal hops between frequencies, the more difficult it is for an unintended listener to decode the message. Same goes for the number of discrete frequencies used in the spread spectrum scheme. Modern computer programs and fast-tuning receiver systems can gather huge amounts of information spread across a broad bandwidth and re-assemble it into intelligible data, and if an unlimited amount of time was available to do so, just about any message can be decoded...

Highway Radar

November 1947 Radio Craft Cover - RF CafeRadar speed guns have been the bane of drivers - and the bounty of police department coffers - since the 1940s. The technology that helped the Allied Forces win World War II was exploited immediately thereafter by law enforcement in an effort to make the highways a safer place. Rather than relying on a police officer's learned estimation of a car or truck's speed, a certified radar unit was used by a trained operator. Prior to the advent of speed radar, a common method for determining a motorist's speed was to measure the time taken to travel between two points whose distance apart was known. The information was admissible in court, but was more vulnerable to a crafty prosecutor's interrogation. Radar removed that variable, although there probably have been cases where the accuracy of the radar unit was challenged in terms of electronics performance, false signal returns, adjustment for slant ranges, etc. The cover photo of this 1947 issues of Radio-Craft magazine shows a constable...

Build This Novice CW Transmitter

Build This Novice CW Transmitter, February 1955 Popular Electronics - RF CafeEven though this CW (continuous wave, for sending Morse code) transmitter circuit was published in 1955 in Popular Electronics magazine, it is still legal for today's Amateur radio operator. Portions of the 40-meter and 80-meter bands are still reserved exclusively for CW operation. As of 2021, the 40-meter band (7.025-7.125 MHz) and the 80-meter band (3.525-3.600 MHz) are both reserved for CW for Hams holding either Novice (no longer issued) or Technician licenses. Additionally, the 15-meter band (21.025-21.200 MHz) and the 2-meter band (144.0-144.1 MHz) have CW-only areas. That is different than the frequencies given in the article, so beware if you are tempted to throw one together for old time's sake. The value for XTAL will need...

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...

Homepage Archives for September 2022

Homepage Archives for September - RF CafeHomepage Archives for September 2022. Items on the RF Cafe homepage come and go at a pretty fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple megabytes). New items are added at the top of the content area, and within a few days they shift off the bottom. If you recall seeing something on the homepage but now it is gone, fret not because many years I have maintained Homepage Archives.

Homepage Archives for August 2024

Homepage Archives for August - RF CafeHomepage Archives for August 2024. Items on the RF Cafe homepage come and go at a pretty fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple megabytes). New items are added at the top of the content area, and within a few days they shift off the bottom. If you recall seeing something on the homepage but now it is gone, fret not because many years I have maintained Homepage Archives.

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...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

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...

Cleveland Institute of Electronics "Troubleshooters"

Cleveland Institute of Electronics "Troubleshooters", January 1968 Popular Electronics - RF CafeThe Cleveland Institute was one of many electronics training organizations that exploited the rapidly growing electronics service industry in the last century. Although this particular two-page spread appeared in a 1968 issue of Popular Electronics magazine, the trend began back in the 1930s. Earlier electronics hobby and professional electronics publications like Short Wave Craft and Radio News were pitching the unlimited opportunities for anyone with the smarts and motivation for technical subjects as employees and/or owning a business. Even in the days when there were user-serviceable parts (primarily vacuum tubes and fuses) inside many electronic products, few people were willing to risk causing harm to themselves or their hard-earned radio and television sets. Even by 1968 when most of the electronics industry had shifted to solid state circuitry, the vast majority of existing equipment still had tubes in them. The television set my parents owned ...

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Anatech Electronics RF Microwave Filters - RF Cafe

RF Cascade Workbook 2018 by RF Cafe

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