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Homepage Archive - March 2021 (page 1)

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

Homepage Archive Pages

2021:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2018:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2017:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2016:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2015:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2014:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2013:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2012:  1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13

See Page 1 | 2 | 3 | 4 | 5 of the March 2021 homepage archives.

Friday the 5th

Thursday the 4th

Wednesday the 3rd

U.H.F. Transmission Lines and Converters

U.H.F. Transmission Lines and Converters, June 1954 Radio-Electronics - RF CafeAbout the only kind of transmission line homeowners use today is 75 Ω coaxial cable for television and Internet connections. Up until the turn of this new century (two decades old by now - ugh!), a fair percentage of TV owners still had an antenna mounted on the roof or maybe rabbit ears sitting atop the set. Twin lead transmission line was still a common sight as at least the "last mile" (last few inches, actually) connection via an impedance converter to the pair of screws on the back of a TV or FM radio. By then, most TVs also had an "F" coaxial connector for direct attachment without a converter. Internet connections at the time were telephone cords connected to the modem board inside your computer. It's hard to believe that was just a relatively few years ago that we early WWW users got to cross our fingers when dialing up a local phone number for AOL, Earthlink, Compuserve, Prodigy, Mindspring...

Speed Limit Also Applies in Quantum World

A speed limit also applies in the quantum world - RF Cafe"Even in the world of the smallest particles with their own special rules, things cannot proceed infinitely fast. Physicists at the University of Bonn have now shown what the speed limit is for complex quantum operations. The study also involved scientists from MIT, the universities of Hamburg, Cologne and Padua, and the Jülich Research Center. The results are important for the realization of quantum computers, among other things. They are published in the prestigious journal Physical Review X, and covered by the Physics Magazine of the American Physical Society. Suppose you observe a waiter (the lockdown is already history) who on New Year's Eve has to serve an entire tray of champagne glasses just a few minutes before midnight. He rushes from guest to guest at top speed..."

RF Test Technician / Associate Engineer Needed by Safe-Com Wireless

RF Test Technician / Associate Engineer Needed by Safe-Com Wireless - RF CafeSafe-Com Wireless designs and manufactures wireless communications equipment for first responders. The equipment comprises boosters and fiber optic distributed antenna systems. The equipment is used inside buildings to permit the first responder to communicate during emergence incidents. The Radio Frequency Test Technician / Associate Engineer position requires minimum 5 - 15 years direct experience in RF board level testing using a spectrum analyzer, radio frequency signal generators and similar radio frequency equipment. The successful candidate will be experienced in reading circuit schematics, troubleshooting circuits and documenting test results. Also hand soldering and modification of surface and through-hole printed circuit boards (PCBs) is required. Direct experience in a production work environment required...

RCA Numitron Readout

RCA Numitron Readout, March 1970 Popular Electronics - RF CafeRCA's Numitron was their answer to the Nixie tube (manufactured by Burroughs Corporation). It was a simpler 7-segment incandescent display (DR2010) that, with all lines energized, formed the number 8. It worked off of +3.5 to +5 volts, with each element requiring 24 mA of current. The number 8 drew 192 mA of current and dissipated 0.672 W at 3.5 volts and a whopping 0.96 W at 5 volts! RCA marketed a BCD*-to-7-segment display driver (the CD2501E). The Numitron was pitched as a sensible alternative to the 7-segment LED display, but with an element size of 0.35" wide by 0.6" high, there was no real advantage over the LEDs, which were just entering the electronics market in 1970. Numitrons do have a certain nostalgic 'cool' factor, though. It is interesting to note that the author's last name, Wood, is the same as that of Frank Wood, who was issued...

Teledyne e2v HiRel and Integra Partner on High Voltage GaN Devices

Teledyne e2v HiRel and Integra Technologies Partner on High Voltage GaN Devices - RF CafeTeledyne e2v HiRel Electronics, a leading provider of high reliability semiconductor solutions, today announced a new high reliability partnership with California-based Integra Technologies, Inc. (Integra). Under the new agreement, Teledyne will leverage Integra's portfolio of GaN on SiC RF power transistor products to deliver optimized power solutions for the space market. With Integra, Teledyne e2v HiRel will specialize in providing high power RF devices for emerging space applications in the LEO and GEO payload market. Teledyne will also offer high reliability options for Integra's popular GaN on SiC power devices and pallets targeted at the defense market. "Our space customers are requesting RF power devices at higher power density levels and operating at higher frequencies," said Brad Little, VP and General Manager of Teledyne e2v HiRel. "The combination of our expertise in providing space...

Thanks to NextPCB for Continued Support!

NextPCB - RF CafeNextPCB is one of the most experienced PCB manufacturers in China, has specialized in the PCB and assembly industry for over 15 years. NextPCB provides the most innovative printed circuit boards and assembly technologies in the highest quality standards, turnaround time as fast as 24 hours, the lowest manufacturer direct prices, and the most dedicated customer service in the industry. Turnkey service without a broker including components sourcing, PCB prototyping, manufacturing, assembly, quality testing, and final shipment. Certified by IATF16949, ISO9001, ISO14001, UL, CQC, RoHS and REACH.

Tuesday the 2nd

War Bonds Promotion

War Bonds, January 1945, Radio-Craft - RF Cafe"The more things change, the more they remain the same." That old saw has held true throughout the ages, but there seems to be cycles within cycles that causes, to mix in a metaphor, the pendulum to swing back and forth in greater and lesser peak amplitudes, and over long periods of time a bias sets in that causes a perceivable change from the symmetric tick-tock-tick-tock-tick-tock, to tick----tock-tick----tock-tick----tock-tick. Without an outside-of-the-system input, the bias grows. If you have a "real" gravity-driven pendulum clock, you probably know what I mean. Bringing the system back to symmetry requires adjusting the clockworks movement or "righting" the physical orientation by rotating the clock on the wall or shimming up one side on the shelf until the preferred tick-tock-tick-tock is restored. Economic cycles are much the same, as alluded to in this World War II, War Bonds promotion. There are long periods of overall ups and overall downs, and in-between there are lesser rises and falls. Eventually, those who learn to control the cycles tend to insert a bias into the works...

3-D Diamond Valleytronic Transistor

3-D Diamond Valleytronic Transistor - RF Cafe"Researchers have, for the first time ever, demonstrated electrical control of valley transport in 3-D dual-gate diamond field-effect transistors. Not many people are aware of it, but the diamond is actually a wide-bandgap semiconductor with many extremely good properties, such as high thermal conductivity, high breakdown field, high carrier mobilities, and chemical inertness. These properties, together with the possibility to synthesize high-purity, single-crystalline diamond make it a very interesting material and a candidate for use4 in power electronics. The low impurity concentration achieved when fabricating diamond, together with its rigid lattice, causes it to exhibit a uniquely low scattering rate, especially at low temperatures..."

Behind the U.L. Label

Behind the U.L. Label, August 1955 Popular Electronics - RF CafeThe Underwriter's Laboratory (UL) is an entity that seems to have been around forever. A lot of people - maybe most people - assume that it is a government entity. In fact, it is a non-profit organization sponsored by the National Board of Fire Underwriters (later changed to American Insurance Association, then to APCIA). Its roots are traceable back to the Chicago World's Fair in 1893. Concern over the potential fire hazard of Edison's light bulbs was the impetus for the effort. Another aspect of the UL that a lot of people don't know is that the UL label of approval is no guarantee that the device works properly, only that is passes standards of safety as it relates to fire hazards. This article in the August 1955 edition of Popular Electronics magazine gives a brief history.

17 Best RTL-SDR Software Defined Radio Dongles

17 Best RTL-SDR Software Defined Radio Dongles - RF CafeRF Cafe visitor Tommy Reed sent me this link to a blog he recently posted on FromDCtoDaylight.com (great name) website entitled, "17 Best RTL-SDR Software Defined Radio Dongles." About six months ago I bought the Nooelec NESDR Smart v4 bundle to use with a modification I'm making to a couple vintage 72/75 MHz radio control systems. The 3rd-party interface and processing software is OK, but could be better. Otherwise, it works quite well. Says Tommy: "Software Defined Radios (SDRs) are become more and more popular. This is partially due to the wide availability of low cost USB dongle SDR radios based on RTL2832U demodulator chipset. This is where the 'RTL' in RTL-SDR comes from. While these low cost SDRs are not as capable as some of the higher performance SDR radios, they do offer a good bang for the buck. In this post we'll take a look at 17 great RTL-SDR dongles..."

Modelithics® Reaches Milestone of 20 Years!

Modelithics® Reaches Milestone of 20 Years in Establishment! - RF Cafe - RF CafeModelithics is honored to announce that it has crossed another milestone in the history of the company. As of March 1, 2021 Modelithics,, will be celebrating 20 years of establishment. What began as a small spinout startup from the University of South Florida has risen to stand tall as the industry leader in RF, microwave and millimeter-wave measurements and measurement-based modeling of RF and microwave components and semiconductor devices. We are proud of our company's many innovative products, custom service projects, designer focused application notes and other accomplishments that have proven to be exceptionally productive for our customers...

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...

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments.

Monday the 1st

Special Tubes by Sylvania

Special Tubes by Sylvania, January 1945, Radio-Craft - RF CafeWith most solid state devices, be they discrete elements or integrated circuits, discerning their functions by visual inspection is nearly always impossible. A trained observer can use a microscope on a bare die to get a good idea of what the various parts do. Memory banks, transistors, resistors, capacitors, etc., are usually pretty obvious even to someone relatively new at the job. Opaque overmolded packages and/or extremely small features complicate the task. In the vacuum tube days, anyone accustomed to working with them could fairly easily look at the the arrangement of heaters, cathodes, grids, and plates - sometimes singular but often multiple - and figure out the function. Experts could even make a fair guess at the key electrical specifications. Of course that only applied to those with clear glass envelopes. Tubes with special shapes might have been a bit more difficult to guess the application. To wit, the long, skinny R-1110 "Pirani Tube" shown here is an example. It is designed to measure ambient pressure...

Many Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

NASA Helicopter Will Soon Fly on Mars

NASA Helicopter Will Soon Fly on Mars - RF Cafe"The Perseverance rover's Mars Helicopter (Ingenuity) will take off, navigate, and land on Mars without human intervention. Tucked under the belly of the Perseverance rover that will be landing on Mars in just a few days is a little helicopter called Ingenuity. Its body is the size of a box of tissues, slung underneath a pair of 1.2m carbon fiber rotors on top of four spindly legs. It weighs just 1.8kg, but the importance of its mission is massive. If everything goes according to plan, Ingenuity will become the first aircraft to fly on Mars. In order for this to work, Ingenuity has to survive frigid temperatures, manage merciless power constraints, and attempt a series of 90 second flights while separated from Earth by 10 light minutes. Which means that real-time communication..."

Understanding Transistor Circuits

Understanding Transistor Circuits, August 1959 Popular Electronics - RF CafeIt had been only a little over a decade since the transistor was invented when this article appeared in the August 1959 edition of Popular Electronics. Transistors were still a mystery to most people, including engineers, technicians, and hobbyists. Author James Butterfield takes a unique approach in presenting the material by writing it as a dialog between an instructor and a student. If you are also new to transistors, this will be worth your while to read. The basics will never change. As an aside (and mentioned in the article), while still a technician I had a manager one time who actually told an engineer working for him that a transistor could be made by soldering two diodes together and using the center node as the base connection...

KR Electronics Intros 1000 MHz Bandpass Filter

KR Electronics Intros 1000 MHz Connectorized Bandpass Filter - RF CafeKR Electronics, a designer and manufacturer of high quality filters for the commercial and military markets for more than 45 years, introduces the model 3450 lumped element bandpass filter with a 1,000 MHz center frequency and a 1 dB bandwidth of 50 MHz (~975 - 1025 MHz). The filter is a highly selective elliptic type filter. The filter is supplied either with SMA connectors (0.60" x 0.60" x 2.25" not including connectors) or in a surface mount package. Other frequencies and bandwidths are available...

Many Thanks to Atenlab for Their Continued Support!

Atenlab microwave components - RF CafeAtenlab has been operating in Taiwan for more than a decade, and has sold and installed hundreds chambers around the world. Holistic, affordable Over-the-Air (OTA) measurement systems perform comprehensive measurement and test in a controlled environment. Compact Antenna Test Range (CATR) with one-touch operation supports multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA measurement systems offer reduced time measurements over single-probe systems.



























 Electronics-Themed Comics June 1951 Radio-Electronics  

Engineering Job Opening

Promote Your Company on RF Cafe for as Little as $40/mo.

Sponsor RF Cafe for as Little as $40 per Month - RF CafeRF Cafe typically receives 8,000-15,000 website visits each weekday and about half that on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 13,000 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. Advertising begins at $40/month.

New for 2021! RF & Electronics Schematic & Block Diagram Symbols for Office™ r2

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000 or so symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing. Check them out!

RF Cascade Workbook 2018

RF Cascade Workbook 2018 Is Available Now! - RF CafeRF Cascade Workbook 2018 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...

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...

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...

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...


Reconfigurable Electronics Based on Multiferroics and Nanomagnetism

Reconfigurable Electronics Based on Multiferroics and Nanomagnetism - RF Cafe "Research could lead to the development of new materials with large magnetoelectric (ME) coupling for next-generation multifunctional devices, including, multi-state (neuromorphic-like) circuits and memories, and E-field tunable microwave resonators for secure communications. Multifunctional magnetoelectric materials with high exchange represent a missing 'holy grail' of materials physics. To combine polarization and magnetization in the same solid is nothing short of actually controlling the fundamental nature of electromagnetism in matter. Although magneto-electricity (ME) is an intrinsic phenomenon in some natural materials at low temperature, such single-phase materials suffer from an extremely weak ME exchange..."

Heavy Rain Hinders LiDAR Sensors

Heavy Rain Hinders LiDAR Sensors - RF Cafe"The team from the Intelligent Vehicles Group at Warwick University published its study in the IEEE Sensors Journal, which details how the researchers specifically simulated and evaluated the performance of LiDAR sensors in the rain. High-level autonomous vehicles (AVs) are promised by Original Equipment Manufacturers (OEMs) and technology companies to improve road safety as well as bringing economical and societal benefits. All high-level AVs rely heavily on sensors to operate. Using the WMG 3xD simulator, researchers tested an autonomous vehicle's LiDAR sensors in different intensities of rain..."

Addressing the World's E-Waste Issues

Addressing the World's E-Waste Issues - RF Cafe"Electrical and Electronic Equipment (EEE) has become indispensable in modern societies and is enhancing living standards, but its production and usage can be resource-demanding. After its use, EEE is disposed of, generating an e-waste stream that contains hazardous and valuable materials. EEE includes a wide range of products with circuitry or electrical components with a power or battery supply, according to The Global E-Waste Monitor, a report produced annually by United Nations University and other international organizations..."



















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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 typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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