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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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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"Consider that typewriters had ¢ keys. Computers have $ keys. There's inflation for you." - Kirt Blattenberger

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe - Archive -

• Belgian Spectrum Auction Raises €1.2B

• China to Build Space Solar Power Station

• Retail's Future Amid Supply Chain Challenges

• U.S. House Proposes $10B in NG911 Auction Funding

• Gallium Oxide Power Switching

• North American 5G Penetration to reach 90% by 2027

• Radar Breakthrough for Drones

• Dealing with High-Integrity Electrical Components

• Dish Loses $3.4B Spectrum Bid Credit Appeal

Bell Telephone Labs: Battle of Atoms

Bell Telephone Laboratories: Battle of Atoms, April 1948 Radio News - RF CafeLife is a constant battle on all fronts, be it in health, personal relationships, business, medicine, careers, education, technology, or any other realm. Scientists, engineers, and technicians at the former Bell Telephone Laboratories are affected by that maxim as well as any group of people. The company, known to many as Bell Labs, invested a huge amount of funds and personnel effort into fighting the problems which constantly cropped up both during research and development and while servicing their massive installed base of equipment and transmission lines. Bell Labs regularly ran full-page ads in magazines (including technical and others like Life, The Saturday Evening Post, Woman's Day, etc.) informing the paying public of the extents they went to in order to bring new products to market and to keep existing systems providing excellent quality communications (the best in the world). This example for a 1948 issue of Radio News magazine tells of the unexpected chemistry issues solved by their crack teams of employees...

"Indoor RadioPlanner" v1.0 Software Introduced

Indoor RadioPlanner Software Introduced - RF CafeCenter of Telecommunication Technologies (CTT) is proud to announce immediate availability of its Indoor RadioPlanner v1.0 software. Indoor RadioPlanner is a planning tool for Wi-Fi and other indoor wireless networks. Release 1.0 is mainly intended for planning Wi-Fi networks in the 2.4 GHz, 5 GHz, and 6 GHz bands, but it can be used for planning indoor GSM/ 3G / LTE / 5G networks in the frequency range 300 MHz – 7.5 GHz. With Indoor RadioPlanner, you can design Wi-Fi networks of any scale - from a small office to a large multi-story building...

Berkeley Nucleonics Adds Quantum Computing Courses

Berkeley Nucleonics Adds Quantum Computing Courses - RF CafeBerkeley Nucleonics recently added a couple of courses on Quantum Computing in the Berkeley Nucleonics Academy. Because you have taken previous RF courses with 100% completion, you are entitled to those QC courses at no charge. Would you like a passcode? You may also share this code with any colleagues or students who may have an interest. Completion of the course takes approximately 4 hours and includes CEU units, a Completion Certificate and a BNC "60 Years" Commemorative Tee-Shirt. The Nuts and Bolts (and Qubits) of Quantum Computing: This exclusive course will dive into the immersive world of quantum computing. Take quizzes, watch videos and get current knowledge of quantum computing from experts in the industry. QC 02 - Quantum Computing Instrumentation in Use Today" A cursory look at some of the research and development tools...

New Selenium Rectifiers for Home Receivers

New Selenium Rectifiers for Home Receivers, November 1946 Radio News - RF CafeSelenium rectifiers were the first widely used replacements for vacuum tubes in commercial electronic equipment. Since amplification was not possible - that came in late 1948 with the invention of the transistor, compliments of Shockley, Brattain and Bardeen - diode action in AC-DC power supplies was its primary application. Typical reverse breakdown voltage is in the neighborhood of 20 volts and current handling capability depends on the interface surface area. Cost kept the selenium rectifiers from being widely adapted early in their history (1933), but by 1946 when this article was published in Radio-News magazine it had dropped enough to make their use economical. Eliminating one or two vacuum tubes in a radio or television power supply made the sets more efficient and increased reliability since the selenium rectifiers rarely suffered failures if designed into the circuit correctly...

Jr. RF Engineer Needed by Amentum

Jr. RF Engineer Needed by Amentum - RF CafeAmentum is seeking a motivated Junior RF Engineer in Hanover, MD, willing to dive into the world of satellite communication coordination. Job Summary: We are looking for an engineer with the curiosity to work problems until truly understood and then the drive to identify and implement efficiencies in the problem-solving process. You have a foundation in radio frequency (RF) engineer principles to apply that knowledge in the RF analysis of new and existing satellite systems being proposed. Responsibilities will include analysis and certification for emerging spectrum dependent technologies, review of new satellite network submissions, and evaluation of RF related interactions between satellites. Beyond the analytical, you'll also need to communicate highly technical findings to a large international stake holder community. You will be part of a team evaluating the risk to Department of Defense (DoD) assets...

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin, October 1949 Radio & Television News - RF CafeWell I'll be darned, old Mac the master radio repairman taught me something else new in this October 1949 issue of Radio & Television News magazine. Along with giving sidekick and trusted technician Barney a lesson on business ethics and how honest dealing can pay dividends as societal conditions change, he also put on his Sherlock Holmes cap and deduced a surprising cause for circuit failure based on the physical location of a lady's radio; read on to learn the details. As usual, the exact scenarios of the stories do not apply to today's environment and/or equipment, but the troubleshooting logic certainly does. And, as usual, the time of year wherein the technodrama takes place aligns with the edition's month of publication...

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 12,000 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. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

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.

Antenova Low-Power GNSS Rx Module Extends Runtime by 500%

Antenova Compact Low-Power GNSS Receiver Module Extends Runtime by 500% - RF CafeAntenova Ltd, the UK-based manufacturer of antennas and RF modules for M2M and the IoT, is launching GNSSNOVA M20071, a brand new GNSS receiver module, with power consumption reduced five-fold to enable smaller tracker designs, and trackers that run for five times longer. The M20071 module is for small tracking devices that operate from Li-ion batteries, where a lower power requirement is a clear advantage. These are typically small mobile trackers, pet trackers, personal fitness devices, and location trackers for bikes and e-scooters. The M20071 tracks the GPS, Galileo, GLONASS and BeiDou constellations simultaneously, this improves position accuracy particularly in urban environments. Based on the latest generation chip from Mediatek, it draws 17 mW of power when receiving GPS only, and 21 mW receiving all constellations. GNSSNOVA M20071 measures 9.0 mm x 9.0 x 1.8 mm. Pairing this with one of Antenova's compact SMD antennas makes a compact RF solution and a way to realise slimmed down tracker...

Feedback Tone Control

Feedback Tone Control, December 1958 Radio-Electronics - RF CafeI have to admit to not being real certain why I selected this article on feedback tone control for posting. It appeared in the December 1958 issue of Hugo Gernsback's Radio−Electronics magazine. Although it is a good write-up on some simple audio frequency filtering circuits, and the principles can be applied to any frequency, it is most likely this page was marked because it contained an electronic-themed comic on it. Oh well, Melanie already scanned and OCRed it for me, so you might as well go ahead and read it...

Transceiver Receives Power and Data Simultaneously

Transceiver Receives Power and Data Simultaneously - RF Cafe"The quest to transmit electric power wirelessly and over distance has been a goal of electrical engineers since the end of the 19th century, when Nikola Tesla tried his hand at it, to no avail. In the 1970s, NASA and the U.S. Department of Energy engineers achieved some notable successes in wireless power transfer (WPT) in the kilowatt-kilometer range, their efforts spurred on by the energy crises of the time. Interest waned, however, as energy became plentiful again. Now, with the advent of 5G and its ability to transmit at high frequencies in the millimeter-wave-band range, new opportunities and approaches are opening up for WPT. Researchers at the Tokyo Institute of Technology have developed a prototype 64-element millimeter-wave-band phased-array transceiver that can send and receive data while simultaneously receiving power. The aim is to employ the transceiver initially as a 5G relay, and later to integrate into Internet of Things (IoT) devices..."

TotalTemp Technologies in the Cloud

TotalTemp Technologies in the Cloud - RF CafeTotalTemp Technologies offers two new ways to elevate your testing with our thermal testing products. Beyond the normal ways that our Thermal Platforms and Chambers help you get the job done expeditiously, TotalTemp is offering: Thermal test equipment with Cloud Storage technology and also Outer Space Simulation chambers. Supporting the effort to get product testing done correctly, repeatedly with consistently reported results, Synergy Server and available cloud storage technologies let you have your test data quickly and easily organized, with traceability. The days of circle-chart recorders and hand plots are long gone, your test results can be reliably automatically stored. The efficient advantages of thermal platforms are a natural for conductive heat transfer in high vacuum applications. With all the new hardware going into space, where service calls are rare, thermal vacuum testing is important part of testing high altitude and satellite equipment...

Power Supply Filters

Power Supply Filters, December 1952 QST - RF CafeHere's a topic - power supply filter design - that never goes out of style. It was originally published in a 1952 issue of QST magazine. Without bothering to worry about source and load impedances, this brief tutorial on the fundamentals of power supply filter design using series inductors and parallel capacitor combinations. Author Gabriel Rumble offers a rule-of-thumb type formula for guessing at a good inductor value based on peak-to-average expected current. This is by no means a comprehensive primer on power supply filter design and is directed more toward someone new to the concept of removing or reducing noise and AC ripple from the output of a DC power supply...

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

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 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 RF Superstore for Their Continued Support

RF Superstore coaxial cable, connectors, adapters - RF CafeRF Superstore launched in 2017, marking the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and microwave Industry. Pasternack fundamentally changed the way RF components were sold. Partner Jason Wright manages day-to-day operations, while working closely with Mr. Pasternack to develop RF Superstore into a world class RF and microwave component supplier. RF coaxial connectors & adapters, coaxial cable & cable assemblies, surge protectors, attenuators. Items added daily. Free shipping on orders over $25. We're leading the way again!

Electronics-Themed Comics

Electronics-Themed Comics, June 1952 Radio-Electronics - RF CafeI really like the electronics themed comic that appeared on page 36 of the June 1952 issue of Radio-Electronics magazine. Like with this one, many of the ideas for the comics are provided by readers, and then are incorporated by artists such as Frank Beaven, a frequent contributor. Note in that comic the name of the repair shop is the first name of the guy who submitted it - a sort of hat-tip to the guy. As with many of the comics, I have taken the liberty of colorizing them in order to spice them up a bit. The page 78 comic represents the frustration (and annoyance) a lot of in-home electronics servicemen had to endure from customers who desperately want their help, but then wouldn't leave them alone to do their jobs - and then often tried to cheat them out of the pay they earned...

More About "Man-Made" Static

More About "Man-Made" Static, May 1930 Radio-Craft - RF CafeManmade electrical noise (QRM) and natural electrical noise (QRN) has been the nemesis of communications - both wired and wireless - since the first signals were sent. While it is true that over the last century the amount of "background" noise has increased significantly, the ability of modern circuits to deal with (reject) it and/or accommodate (error correction) it has pretty much kept up with the advancement. You might be tempted to think that "back in the good old days" such problems did not exist, but operators were plagued by poorly designed and inadequately filtered transmitters as well as really deficient electrical service installation that spewed noise from transformers, inadequately grounded transmission lines, lousy connections, and arcing motor brushes. This 1930 article from Radio-Craft magazine was written by a serviceman who troubleshot and solved many of the issues prevalent in his day - a very interesting read...

Transparency on Demand

Transparency on Demand - RF Cafe"Scientists at the University of Rostock, in close collaboration with partners from the Vienna University of Technology, have developed a novel process that can render artificial materials transparent or even entirely invisible, on demand. Their discovery was recently published in the renowned journal Science Advances. Turning something invisible is a common trope in science fiction, such as the Cloak of Invisibility in Harry Potter. Certainly, it sounds cool, but the reason it is so common in stories is that it would be incredibly useful technology. The uses for espionage and the military are obvious, but there are far more applications. Given its immense usefulness, it may not come as a surprise that this is something scientists and engineers have been actively working on. They've had quite a bit of progress too, using molybdenum trioxide, metamaterials, metascreens, and dielectric materials to fashion invisibility cloaks. It all comes down to manipulating light in the proper way, and what is especially marvelous is that innovation in this

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

Empower RF Systems - RF CafeEmpower RF Systems is a global leader in power amplifier solutions. Empower RF Systems is an established and technologically superior supplier of high power solid state RF & microwave amplifiers. Our offerings include modules, intelligent rack-mount amplifiers, and multi-function RF Power Amplifier solutions to 6 GHz in broadband and band specific designs. Output power combinations range from tens of watts to multi-kilowatts. Unprecedented size, weight and power reduction of our amplifiers is superior to anything in the market at similar frequencies and power levels.

Antenna Pattern Editor 2.0 Software Introduced

Antenna Pattern Editor 2.0 Software Introduced - RF CafeCenter of Telecommunication Technologies (CTT) is proud to announce immediate availability of version 2.0 of their popular Antenna Pattern Editor. Antenna Pattern Editor 2.0 is a universal tool to view, create, edit and convert antenna patterns. See the New Features in Antenna Pattern Editor 2.0 list at the left. The main idea embedded in the program is to provide the user with the opportunity to quickly create an antenna pattern file using various methods. Antenna pattern file is a simple text or xml file that describes the main characteristics of the antennas - radiation patterns, gain, frequency range, name, manufacturer and other data. These files are used in various radio planning tools including our RadioPlanner, Indoor Radio Planner, and MLinkPlanner. There are a large number of antenna pattern file formats, but it often happens that there is no file in the required format. In this case, using the Antenna Pattern Editor, you can easily convert the file to the format you need. Sometimes the antenna information is just a picture of the antenna pattern...

Measuring Inductance and Capacity

Measuring Inductance and Capacity, June 1931 Radio-Craft - RF CafeThis reactance measuring bridge circuit which appeared in a 1931 issue of Radio−Craft magazine employs a very unique element for generating an alternating current: an electromechanical buzzer which doubles as an audio source. Sure, it doesn't produce a pure sinewave, but for the method used here to determine inductance and capacitance it does not matter. Rather than attempting to measure an absolute value of inductance or capacitance, a known reactance is used as part of a balanced bridge. This is by no means a precision instrument since accuracy depends on the user's interpretation of the presence or absence of an audible "buzz" in a pair of headphones, but in an era when "real" test equipment was beyond the budgets of many (maybe most) hobbyists, the scheme was better than nothing at all...

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...

Many Thanks to Reactel for Their Long-Time Support!

Reactel Filters - RF Cafe

Reactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project.

Making Modern Tubes

Making Modern Tubes, June 1932 Radio-Craft - RF CafeIn no way do I advocate going back to the "old ways" for manufacturing electronic components, but I do admire and like to give credit to the people who used to perform the tedious procedure of building vacuum tubes, hand-wire chassis assemblies, circuit boards, etc. This 1932 issue of Radio−Craft magazine article is good example. The process required being able to sit or stand at the same work station and perform the same range of operations day after day, often for years on end. Of course at the time, automation processes were not what they are today and machinery needed to be driven by mechanical means using motors, solenoids, and limit switches. That made employing people more financially rewarding than using a machine. You can find details on the algorithms and methodology for designing those contraptions in older engineering handbooks. It is an amazing sight to to tour a WWII vintage battleship and look at the hardware that stabilized and steered the cannons without an electronic computer in sight...

Smart Molecules Act as Computer Transistors

Smart Molecules Act as Computer Transistors - RF Cafe"Researchers have discovered a single-molecule switch that can act like a transistor and store binary information such as the 1s and 0s used in classical computing. The molecule is around five square nanometers in size - more than one billion of them would fit onto the cross-section of a human hair. The researchers believe that molecules like the ones they have discovered could offer information density of around 250 terabits per square inch, which is around 100 times the storage density of current hard drives. The smart molecular switches as seen with a scanning tunneling microscope. In the study, molecules of an organic salt can be switched using a small electrical input to appear either bright or dark, providing binary information. This information can be written, read, and erased at room temperature and in normal air pressures. These are important characteristics for practical application of the molecules in computing storage devices..."

Raytheon Bonded Electronic Technician

Raytheon Bonded Electronic Technician Ad, January 1946 Radio News - RF CafeThere was a time when having a career in any field of electricity or electronics related work was an enviable mark of a person's technical prowess that conveyed a degree of respect. The whole controlling of electrons thing boggled the minds of most people, whether it meant wiring homes and buildings for lights, receptacles, and motors, or designing "all wave" radio sets for listening to the evening broadcast of "The Lone Ranger." Today, with nearly everyone alive having grown up with such conveniences, the "wow factor" is pretty much gone, except maybe with those of us who still chose to engage. If an electronics appliance or device stops working nowadays, it is discarded rather than repaired. This 2-page advertisement from a 1946 edition of Radio News magazine inviting men to become a "bonded electronic technician" is typical of those found in the era, and even in the 1920s and 1930s...

Please see the RF Cafe Homepage Archives for previous items of interest...

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