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Homepage Archive - April 2023 (page 1)

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

Friday the 7th

Circuit Quiz

Circuit Quiz, June 1966 Radio-Electronics - RF CafeBeing that this Circuit Quiz appeared in a 1966 issue of Radio-Electronics magazine, the amplifier components shown are transistors, rather than vacuum tubes. I have to admit to not doing very well on it. One of the challenges is first determining what the intended function of the circuit is supposed to be, then you figure out what is wrong with it. Spoiler alert: I'm going to use circuit A as an example. It is declared to be a voltage regulator circuit, and the deficiency is the lack of a stable voltage reference. The architecture is typical of a voltage regulator with the common base setup used to increase the current supply. However, there is no reason to necessarily assume the DC IN is not itself already regulated, and the function if merely to increase the current supply capacity. If that is the case, then the circuit seems sufficient as shown. Maybe the fact that there is no problem otherwise should tell you make an assumption about the designer's intention and look for something that would be suspect under that condition. Anyway, that's my excuse and I'm sticking with it ;-)

Ultramicro Supercapacitor with Ultrahigh Charge Storage

Ultramicro Supercapacitor with Ultrahigh Charge Storage - RF Cafe"Researchers at the Department of Instrumentation and Applied Physics (IAP)have designed a novel ultramicro supercapacitor, a tiny device capable of storing an enormous amount of electric charge. It is also much smaller and more compact than existing supercapacitors and can potentially be used in many devices ranging from streetlights to consumer electronics, electric cars and medical devices. Most of these devices are currently powered by batteries. However, over time, these batteries lose their ability to store charge and therefore have a limited shelf-life. Capacitors, on the other hand, can store electric charge for much longer, by virtue of their design. For example, a capacitor operating at 5 volts will continue to operate at the same voltage even after a decade. But unlike batteries, they cannot discharge energy constantly - to power a mobile phone, for example. Supercapacitors, on the other hand, combine the best of both batteries and capacitors - they can store as well as release large amounts of energy, and are therefore highly sought-after for next-generation electronic devices..."

Saturable Reactors

Saturable Reactors, March 1952 Radio & Television News - RF CafePrior to the advent of thyristors and semiconductor lamp and motor control circuits, a relatively simple and safe - although heavy and bulky - method for controlling AC voltage was with the use of saturable core transformer arrangements. By using a DC winding to control the saturation level of the transformer core material, the inductance, and therefore inductive reactance, of secondary windings can be controlled. Doing so has the same effect as using a Variac that uses mechanical control of the coupling and transformer voltage input/out ratio. The method shown here has a potentiometer for adjusting the DC current level, but, as the author mentions, electronic control circuits were/are also widely used...

See How Modelithics Is Making Waves Lately

See How Modelithics Is Making Waves Lately, April 2023 - RF CafeModelithics will be at WAMICON on April 17th and 18th. Modelithics is pleased to announce the release of version 23.0 of the Modelithics COMPLETE+3D Library for use with Ansys HFSS. This version includes Modelithics' collection of over 500 3D electromagnetic (EM) geometry models for inductors, capacitors, filters, packages, and connectors. Also included are nearly 400 highly scalable Microwave Global Models™ for components from many popular vendors. With both circuit and 3D EM models, the Modelithics COMPLETE+3D Library together represent over 26,000 individual components. Version 23.5.1 of the Modelithics Qorvo GaN Library is now available for use with Keysight Technologies' PathWave Advanced Design System (ADS) and Cadence AWR Design Environment®. This latest version offers new models for Qorvo's QPD1025, QPD1028, QPD1425, and QPD1425L discrete GaN-on-SiC HEMTs. Version 23.5.1 also offers 2 new embedding models for the T2G6000528-Q3 and T2G6003028-FL devices...

The Selenium Rectifier

Selenium Rectifier - RF CafeBefore silicon and germanium semiconductors came online for use as diode rectifiers, selenium was the material du jour. Selenium devices were widely adopted for use as bridge rectifiers in power supplies and as detectors in AM radios, where applicable, in place of vacuum tubes. At the time, they were not particularly cheaper to implement, but there was an advantage in greater ruggedness, longer lifetime, and lower power consumption (no heater element or high bias voltage required). Electronics magazines of the era published many articles about selenium rectifiers, including After Class: Working with Selenium Rectifiers, The Semiconductor Diode, New Selenium Rectifiers for Home Receivers, Selenium Rectifiers, Applications of Small High-Voltage Selenium Rectifiers, and Using Selenium Rectifiers.

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.

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.

Thursday the 6th

Bell Telephone Company - Airlines Communications

Bell Telephone Company - Airlines Communications (December 1961 Boys' Life) - Airplanes and RocketsBell Telephone Company played an important role in the development of the aviation industry by providing communications systems for airlines. As intimated in this promotion in Boys' Life magazine, in 1961, Bell introduced the "air-ground-air" radio system, which allowed pilots to communicate directly with air traffic controllers on the ground, improving safety and efficiency in air travel. This system was a major technological advancement, as it replaced the earlier system of communicating via Morse code, which was slow and prone to errors. The air-ground-air system allowed pilots to communicate in real-time with controllers, enabling faster and more accurate instructions for takeoff, landing, and navigating airspace. Bell Telephone Company continued to innovate in the aviation industry, introducing new technologies such as satellite-based navigation systems and weather radar systems, which have greatly improved air travel safety and efficiency...

Do-or-Die Moments Determined Fate of Internet

Do-or-Die Moments Determined Fate of Internet - RF Cafe"New technologies often are introduced through spectacle: Think of the historic demonstrations carried out by Faraday, Edison, Morse, and Bell, or, more recently, by Steve Jobs onstage in his black turtleneck at Macworld 2007, holding the first iPhone. Indeed, hyped-up product announcements at industry events like the Consumer Electronics Show (now CES) and the Game Developers Conference have become regular features of the digital world. There's also a parallel tradition - less flashy but no less important - of industry events that focus attention on digital infrastructure. Several of these events, such as the first public demo of the ARPANET in 1972, or the mid-1980s conferences now known as Interop, alerted experts to new technologies, and, in some cases, altered the balance between competing approaches. Here we describe a few of these do-or-die moments..."

Hotel Directory of the Radio Trade

Hotel Directory of the Radio Trade, October 1930 Radio-Craft - RF CafeIf you think paying $80-$100 per night for a relatively low end chain hotel/motel is outrageous, then this advertisement in a 1930 issue of Radio-Craft magazine will help justify your indignation. While in California for the IMS 2016 show, a convention-goer likely paid $200 or more per night for a room within walking distance of the Moscone Center in downtown San Francisco. Compare that rate to, say, the Eastgate Hotel or St. Clair Hotel in Chicago in 1930. Room prices started at $2.50 - including free garage parking. The Madison Hotel in Atlantic City had rooms starting at $4 per night that even included "Showers and Baths Throughout." According to the CPI Inflation Calculator published by the U.S. Bureau of Labor Statistics, $2.50 in 1930 is the equivalent of $45.58 in 2023 currency, and $4.00 equals $72.93. Those were prices for downtown medium grade hotels in downtown areas of major cities. Yeah, you're being shaken down, alright...

Axiom Blog: Measure Efficiency of Renewable Energy Grids

Axiom Blog: Measure the Efficiency of Renewable Energy Grids - RF CafeAxiom Test Equipment, Inc., an electronic test equipment rental and sales company has published a new blog post entitled "Measure the Efficiency of Renewable Energy Grids," that that covers how the latest power analyzers and grid simulators can keep the power flowing efficiently and without fail on energy grids. Developing and maintaining these power grids requires regular voltage and current measurements on AC and DC power lines and junctions. Fortunately, the latest power analyzers and grid simulators combine the test speed and accuracy needed to ensure the highest-quality power from renewable energy sources and the power grids they support. Basic measurements of AC and DC electric power in power grids include voltage, current, efficiency, power, and total harmonic distortion (THD), with accuracy within a fraction of one percent...

Electronics Themed Comics

Comics with an Electronics Theme in Popular Electronics and Radio & Television News - RF CafeUnashamedly I offer up these vintage yet timeless electronics-themed comics for your enjoyment. I freely admit to reaching for the comics page(s) of the newspaper to read the latest antics of Beetle Bailey, Dilbert, Hagar the Horrible, Garfield, Dennis the Menace, Peanuts, Blondie, and many others. As if that was not bad enough in some people's opinion, what would really keep me from getting invited to any more high class dinner parties if the word got out is the fact that I actually try to spot the 6 differences in Bob Weber, Jr.'s drawings. Melanie and I also like to work the crossword puzzles together; supposedly that helps keep ageing gray matter from undergoing atrophy...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

/jobs.htm">Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable /jobs.htm">job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products has been designing and manufacturing RF and Microwave passive components since 2005. We use the latest design tools available to build our baluns, 90-degree couplers, directional couplers, combiners/dividers, single-ended transformers, resistors, terminations, and custom products. Applications in military, medical, industrial, and commercial markets are serviced around the world. Products listed on the website link to detailed mechanical drawings, electrical specifications, and performance data. If you cannot find a product that meets your requirements on our website, contact us to speak with one of our experienced design engineers about your project.

Wednesday the 5th

Evolution of an Integrated Circuit

Evolution of an Integrated Circuit, June 1966 Radio-Electronics - RF CafeThe first time I ever saw a silicon boule was in my semiconductor physics course at the University of Vermont, circa 1989. For some reason that class gave me trouble. I got a B+ grade, but that was after spending an inordinate amount of time with it. Energy level diagrams, doping, and the equations behind them never quite found a good home in my gray matter. Fortunately, the world has not missed my participation in semiconductor development. When this "Evolution of an Integrated Circuit" article appeared in Radio-Electronics magazine in 1966, germanium was still a fairly large player in the semiconductor world. Silicon began to overtake germanium as the primary semiconductor material in the late 1950s and early 1960s. Germanium was the first material used to create transistors in the 1940s, but it had some limitations, such as its high sensitivity to temperature and its low ability to amplify signals. Silicon, on the other hand, had better electrical properties and was more stable, making it a more practical material for creating electronic devices...

Radio Seeks Black Gold

Radio Seeks Black Gold, July 1948 Radio News - RF CafeDiscovering new oil reserves usually takes more than the good fortune of being out shoot'n at some food, when up from the ground come a bubbl'n crude - oil that is, black gold, Texas tea. Over the decades, chance has been replaced by high tech prospecting methods including ground-penetrating radar, radio and acoustic wave sounding, ultrasonic transponders, and even satellite sensors that discern telltale variations in gravitational pull, and magnetic fields. This article from a 1948 issue of Radio News describes the use of radio for coordinating activities between the point of explosions and where recording equipment is located, all of which required the transmission of precise timing signals...

76 Years of the Transistor

76 Years of the Transistor - RF Cafe"Transistor advances have gone through several stages over the years, each driven by the need to meet new demands in terms of size, performance, and power consumption. Explore the historical journey of the transistor and the race to meet new apps. When John Bardeen, Walter Brattain, and William Shockley built the first successful working model of a transistor in 1947, little did they know that it would go on to become the most important invention for modern-day electronics. What started off as an ambition to solve longstanding issues of power and size caused by vacuum tubes, laid the foundation for the impact that electronic devices would have on people's lives today. No doubt, 76 years is a long period of time for one to reflect on, long enough that most of us can't imagine a world without transistors. Over the years, engineers have devoted their careers to understanding the transistor’s use and applications while reinventing the humble transistor several times..."

Engineering & Science Humor

Engineering & Science Humor - RF CafeThese engineering and science tech-centric jokes, song parodies, anecdotes and assorted humor have been collected from friends and websites across the Internet. I check back occasionally for new fodder, but it seems all the old content is reappearing all over (like this is). The humor is light-hearted and clean and sometimes slightly assaultive to the easily-offended, so you are forewarned. All three pages are workplace-safe.

Withwave Intros DC-145 GHz Connector Adapters

Withwave Intros DC-145 GHz Connector Adapters - RF CafeWithwave is a leading designer and developer of a broad range of RF, microwave, and millimeter−wave test solutions and subsystems with a focus on electromagnetic field analysis and signal processing. As available bandwidth gets increasingly crowded, technology must advance to facilitate higher and higher frequencies of operation. Companies such as Withwave work hard to design and manufacture components enabling engineers and technicians to create and maintain cutting edge building blocks and systems. Two new sets of between−series and in−series connector adapters have been introduced by Withwave. New 0.8 mm Adapter Series (DC to 145 GHz) Withwave's 0.8 mm to 0.8 mm Adapter Series are manufactured to precise microwave specification and constructed with male and female gender on both side. The precision microwave connector interfaces ensure an excellent microwave performance up to 145 GHz...

Choosing a TV Antenna

Choosing a TV Antenna, March 1972 Popular Electronics - RF CafeUnless you happened to live close to a television broadcasting tower, receiving an acceptable signal has always been largely a matter of luck. Obstructions such as buildings and terrain can greatly attenuate signal strength and multipath can generate telltale ghost images and confuse the synchronization portions of signals. It was bad enough with black and white (B&W) broadcasts, but the advent of color made the situation notably worse because more information needed to be received properly in order to display a good picture. Color TV adoption really began to take off in the late 1960s, and that is about the same time when electronics and technology magazines started publishing articles like this one about how to select a roof-mounted TV antenna. A follow-up article appeared in the April 1973 issue of Popular Electronics. The December 1958 issue had an antenna selection article as well, obviously for B&W TVs...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

Thanks Again for Windfreak Technologies' Continued Support!

Windfreak TechnologiesWindfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project.

Tuesday the 4th

Radio-Electronics Puzzler

R-E Puzzler, January 1967 Radio-Electronics - RF CafeHere is a different kind of crossword puzzle. Called the "R-E Puzzler," it has only Across words and clues - no Downs. Its sort of a crossword puzzle with training wheels, or a crossword puzzle for the vertical word challenged. Actually, not having cross-linking Down words can make solving it a bit more difficult since only the one or two provided letters are available to assist in figuring out the correct word. Other variations of this sort of word grid has the provided letters spell out a word or phrase, but this one doesn't. Every word is related to electronics or electrical principles. Bon chance...

CubeSat Operators Launch IoT Space Race

CubeSat Operators Launch IoT Space Race - RF Cafe"A rocket carrying CubeSats launched into Earth orbit two years ago, on 22 March 2021. Two of those CubeSats represented competing approaches to bringing the Internet of Things (IoT) to space. One, operated by Lacuna Space, uses a protocol called LoRaWAN, a long-range, low-power protocol owned by Semtech. The other, owned by Sateliot, uses the narrowband IoT protocol, following in the footsteps of OQ Technology, which launched a similar IoT satellite demonstration in 2019. And separately, in late 2022, the cellular industry standard-setter 3GPP incorporated satellite-based 5G into standard cellular service with its release 17. In other words, there is now an IoT space race. In addition to Lacuna and Sateliot, OQ Technology is also nipping at the heels of satellite telecom incumbents such as Iridium, Orbcomm, and Inmarsat for a share of the growing satellite-IoT subscriber market. OQ Technology has three satellites in low Earth orbit and plans to launch seven more this year, says OQ Technology's chief innovation officer, Prasanna Nagarajan..."

Safety Technique in TX Operation and Construction

Safety Technique in Transmitter Operation and Construction, March 1939 QST - RF CafeSpecial Snowflake alert on this article from a 1939 edition of QST magazine! Do not read the first paragraph if you are easily offended or easily induced to self-flagellation over misplaced guilt for statements made by people you had no relation to or control over. If you are brave and decide to continue, author George Grammer provides a very good guide regarding how to be safe around high voltage, high power electronics equipment. A lot of the opportunity for harm has been removed with modern transistorized circuits and improved chassis design, but there are still plenty of people who work with vintage and/or homebuilt equipment and are thereby exposed to potentially (pun intended) dangerous levels. This note on the voltage present at the ends of a λ/2 dipole fed with a 1,500 W full limit power (Ham radio) has 4,397 Vrms or ±6,200 Vpeak - that'll leave an RF burn mark on 'ya...

ChatGPT: Inaccuracies in Technical Responses

ChatGPT: Inaccuracies in Technical Responses, Kirt's Cogitations #351 - RF CafeSince January, I have used ChatGPT to generate many mini essays on various technical topics such as company histories, biographies on notable engineers and scientists, physics principles, and industry standards. My goal is to reduce the amount of references to off-site information like Wikipedia. A careful reading of ChatGPTs replies is always performed because inaccuracies appear fairly often. Overall, I find it very useful, but caution is needed. In example, today I queried ChatGPT for an equation of the voltage distribution along a half-wave dipole antenna. It took three rounds of correcting its response to finally get an accurate answer...

India's New Network of Radio Broadcasting

India's New Network of Radio Broadcasting, April 1938 Radio-Craft - RF CafeWhen this story was published in 1938 in Radio−Craft magazine, India was a country of roughly 2 million square miles, while the 48 U.S. had about 3.1 million square miles. Radio station growth in the U.S. already had a 3-decade head start in establishing a nationwide network of broadcast and receiving stations. Manufacturing of the required equipment was well established within our borders. India, by contrast, relied heavily on outside sources for equipment and the training of operators and servicemen. The U.S. never has had and still does not have an official "state radio" as was All-India Radio. A nice feature of the system was inclusion of a time-keeping signal that would allow anyone within the reception of a clear signal to synchronize clocks. The included map shows where the first four 10 kW main shortwave transmitters were installed in key population areas. The terms "direct-ray" and "indirect-ray" were used at the time to describe non-skip and atmospheric skip, respectively, propagation...

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.

Thanks to Anritsu for Their Support!

Anritsu (electronics test equipment) - RF CafeAnritsu has been a global provider of innovative communications test and measurement solutions for more than 120 years. Anritsu manufactures a full line of innovative components and accessories for RF and Microwave Test and Measurement Equipment including attenuators & terminations; coaxial cables, connectors & adapters; o-scopes; power meters & sensors; signal generators; antenna, signal, spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth & WLAN testers; PIM testers; amplifiers; power dividers; antennas. "We've Got You Covered."

Monday the 3rd

What's Your EQ?

What's Your EQ?, June 1966 Radio-Electronics - RF CafeThe electrical circuit entitled "Resistors Galore," which was part of the collection of posers in the June 1966 issue of Radio-Electronics magazine's "What's Your EQ" (EQ = Electronics Quotient, a la IQ = Intelligence Quotient) feature, resulted in an interesting response from a reader. Mr. Milton Badt submitted the bit shown to the left ("Ladder Lingo") in the following January edition of the magazine. Interestingly, while he pointed out the significance to the relation to phi (φ), defined as (1+√5)/2, he did not also note that the fraction is commonly referred to as the Golden Ratio, and its result, 1.618034... is called the Golden Number. A rectangle with side lengths who's proportions are according to a/b = φ is called a Golden Rectangle. There is also a resistor | capacitor voltage divider, and a mystery power source challenge...

Meminductor: New Type Circuit Element

Meminductor: New Type Circuit Element - RF CafeQ: Why, if we call a memory resistor a "memristor" (not memresistor), don't we call this memory inductor a "memductor" and the memory capacitor a "mempacitor?" "Dr. H. Rusty Harris, associate professor in the Department of Electrical and Computer Engineering at Texas A&M University, has identified a new circuit element known as a meminductor. A circuit element is an electrical component used to help direct and control the flow of electricity through an electrical circuit. The classical three are known as the resistor, capacitor and inductor. Two additional circuit elements, the memristor and the memcapacitor, were only discovered in the past 15 years. These newer circuit elements are known as the mem- versions of their classical counterparts, and their current and voltage properties are dependent on previous values of current or voltage in time, like a memory. 'Those two discoveries set the world a little bit on its head as far as electrical engineering,' Harris said. 'All of the sudden, we thought we had three, but now we found these two others. And so that led us to think, 'OK, there's got to be more then, but how do we understand what they are? How do we map all of these things relative to each other?' And it turns out, there is a relationship between each of the resistors and its family and each of the capacitors and its family..."

Mac's Service Shop: Electronics in Automobiles

Mac's Service Shop: Electronics in Automobiles, September 1973 Popular Electronics - RF CafeElectronic ignition, computer-controlled fuel injection and air intake, alarm systems, radar, rear back-up cameras, GPS, stereo sound systems, Bluetooth tire pressure monitors, hands-free telephones, automatic headlight directors, drowsy driver detectors, collision avoidance, anti-lock brakes, fuel efficiency management, air bag deployment, self-parking and even self-driving features are now or soon will be standard features in automobiles. Mac McGregor and Barney hit upon a lot of these items - some explicitly, some implicitly - in this 1973 installment of "Mac's Service Shop" found in Popular Electronics magazine. Amazingly impressive devices and systems are fermenting in the minds of engineers and scientists today that will begin appearing in new car models a decade or decades from now. While I am duly impressed, I would gladly trade my 2011 Jeep Patriot for a nicely restored 1960s or 1970s pick'em-up truck. I'll add the desired newfangled gizmos myself...

Anatech Electronics Filter Announcement

Anatech Electronics Intros 3 Filter Models for Early April 2023 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new filter models have been introduced - a cavity bandpass filter with a bandwidth of 5 MHz and a minimum return loss of 20 dB, a 1920-1980 / 2110-2170 MHz cavity duplexer with 90 dB of isolation, and a 240-320 MHz LC bandpass filter with a 1.5 dB insertion loss. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found, or the requirements are such that a custom approach is necessary...

Log All Continents on Broadcast Band

Log All Continents on the Broadcast Band, June 1959 Popular Electronics - RF Cafe"DXing," or long distance communications, has been a goal of amateur radio operators since the inception of radio. The sport is as popular today as it was in 1959 when this article appeared in Popular Electronics magazine. As you might expect, achieving success at making contacts with  like-minded hobbyists half-way around the world has been made quite a bit easier both by vastly improved transmitters, receivers, and antennas and by a much greater knowledge of propagation paths and accommodating atmospheric conditions. In 1959, you relied on monthly publication of reported conditions that was itself a few months old. Nowadays a DXer simply visits one of many websites with real-time status on meteorological status and current operator reports on contact conditions, equipment being used, frequency and power levels, etc. Still, though, it takes a special kind of dedication to earn the coveted "Worked All Continents" certificate...

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...

Many Thanks to San Francisco Circuits for Continued Support!

San Francisco CircuitsSF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

Sunday the 2nd

Electronics Theme Crossword for April 2nd

Electronics Theme Crossword Puzzle for April 2, 2023 - RF CafeThis custom RF Cafe electronics-themed crossword puzzle for April 2nd contains words and clues which pertain exclusively to the subjects of electronics, science, physics, mechanics, engineering, power distribution, astronomy, chemistry, etc. 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...

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 for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.

Coronet Model C-2 Schematic & Parts List

Coronet Model C-2 Schematic & Parts List, February 1947 Radio News - RF CafeYou wouldn't know it from the schematic, but this Coronet Model C−2 tabletop radio has a very unique feature: The tuning scale/pointer, and volume and tuning knobs are on the top of the case, that is, the face of the radio points upward when properly displayed. When searching for photos of the Coronet C2, I found a few examples where the radio was sitting on a surface with the face situated vertically like a standard model, but the feet are clearly on the side opposite the face. The schematic and parts list for the Coronet C2 radio appeared in the February 1947 issue of Radio News magazine. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. I keep a running list of all data sheets to facilitate a search...

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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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