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Exodus Advanced Communications

Homepage Archive - January 2021 (page 4)

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 January 2021 homepage archives.

Friday the 29th

Thursday the 28th

Wednesday the 27th

Tuesday the 26th

New Radio Garage Door Opener

The New Radio Garage Door Opener, September 1933, Radio-Craft - RF CafeOnly a couple decades prior to when this article on a newfangled wireless automatic garage door opener appeared in Radio-Craft magazine, there would have been no demand for such a device ... although maybe an automatic horse barn door opener would have been in demand if a battery was available on the coach. Amazingly, the system employed an early, albeit crude, form of both spread spectrum and digital communications in order to trigger the receiver for opening the door. The spread spectrum characteristic of the signal was the natural consequence of using a spark transmitter. A digital 'Morse' code encryption allowed multiple openers to be installed in close proximity. The opener did not have any type of safety sensor to prevent people or things from being crushed, but then it wasn't until sometime around the 1970s that the feature became standard...

Understanding Stability Circles

Understanding Stability Circles - RF CafeIt has been a while since I saw an article discussing stability circles for amplifier design. Ain Rehman has one posted on the High Frequency Electronics website entitled, "Understanding Stability Circles." Even in the age of computer design and optimization for just about everything, it always help to have a basic understanding of what the result should look like as well as what affects the result. He begins: "Stability circles are a tool, used to examine and analyze the stability of an amplifier (in the case under discussion) using a graphical technique, with the help of a Smith Chart. This monograph presents the stability circle tool for engineers. It is understood that many CAD programs can generate these, but it is always useful to understand the stability circle on an intuitive level as a good engineering practice..."

Thanks to PCB Directory for Their Support!

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

Monday the 25th

Radio Repair in Bed

Radio Repair in Bed, July 1945 Radio & Television News - RF CafeI learned a new word from this Radio-Craft article: "chemurgic," which refers to chemurgy, the science of creating products such as soybean gear shift knobs and cellulose movie film from agricultural raw components. It has nothing to do with the story other than to describe the town in which the subject, Wesley Rushing, lived. As the title suggests, Mr. Rushing established and thrived at a radio repair business built while confined to bed with a crippling illness. He worked an average of 10 hours per day and repaired two hundred radios each month. Although not a veteran himself due to his sickness, the story was offered as a means of support to the thousands of returning World War II veterans who suffered disabilities in battle. Today's handicapped veterans need and deserve similar encouragement, so if you have a can-do story, please submit it to one of the trade or hobby magazines; it will be greatly appreciated by many...

Embedded Trends and Tech to Watch in 2021 - RF Cafe"Shawn Prestridge, Lead FAE Engineer and U.S. FAE Team Manager at IAR Systems offers his insights and predictions about embedded development - the technology, markets, and tools - in 2021. We’ve seen R&D groups at large customers dabble with RISC-V to see if they want to base a platform on it, and we've seen smaller customers start to use it. A few large companies have really committed to using it in at least some business units. While part of the RISC-V trace specification was ratified this past February, there will still be a few tweaks made in 2021. Ultimately, you'll see a good deal of high-quality debug information like live instruction trace, interrupt visibility, power usage, and other metrics that can be fed through the debug port. Amongst other things, this will truly empower embedded developers to produce..."

Gain Efficiency with Fragmented-Aperture Phased Arrays

Gain Efficiency with Fragmented-Aperture Phased Arrays - RF CafeCarl Novello has an interesting article on the Electronic Design website entitled, "Gain Efficiency with Fragmented-Aperture Phased Arrays." I've always been skeptical of repetitive, pixelated type antenna patterns like the use of fractals and the seemingly random pattern (but probably computer optimized - looks Fragmented Phased Array looks like Space Invaders characters - RF Cafelike shapes from Space Invaders) used here. Evidently, there is something to it, though. He begins: "The world's demand for broadband connectivity has created a new generation of high-throughput satellites in geosynchronous Earth orbit (GEO), medium Earth orbit (MEO), and now low Earth orbit (LEO). But technology innovation in the ground segment has struggled to catch up to the space segment, especially when it comes to developing the most elusive of all antennas: Those that are low-cost and electronically steerable to power these next-generation, lower-orbit satellite networks. Electronically steerable antennas (ESAs), often referred to as flat panels..."

Bell Telephone Laboratories Salutes 3 New Nobel Prize Winners

Bell Telephone Laboratories Salutes Three New Nobel Prize Winners, February 1957 Radio & Television News - RF CafeAnyone visiting RF Cafe (other than by accident) almost certainly knows of Drs. Bardeen, Brattain and Shockley fame for their transistor invention while jointly working at the Bell Telephone Laboratories. The trio shared The Nobel Prize in Physics in 1956. Bell was so proud of their employees' efforts that they ran full page advertisements to boast of the accomplishment. This one appeared in the February 1957 edition of Radio & Television News. Alas, Ma Bell's moment of glory was a bit diminished by needing to add a footnote admitting that Drs. Bardeen and Shockley no longer work there. Note that while the ad says the transistor was announced in 1948, the first demonstration to Bell managers was in December of 1947...

Out of Order: Of Pointy-Haired Bosses

Out of Order: Of Pointy-Haired Bosses  - RF CafeThis story, submitted by RF Cafe visitor Jerry L., of Cincinnati, OH, reminds me of a certain manager in a popular engineering comic strip. Do you have a good work-related anecdote to share in the "Out of Order" feature? Please email it to me for consideration. Jerry Writes: "I worked in the defense electronics industry for my entire career and it is hard to think of a project in more than four decades that was not made infinitely more difficult due to the 'helpful' input of project managers. One experience in particular comes to mind as a perfect topic for your Out of Order feature. In the mid 1970s I was a "fresh-out," as new engineering college graduates were called at the time. Newly minted as a Masters degreed electrical engineer, my aspirations were high and I was ready to set the mobile radio system world on fire. A synergistic combination of my own zeal and aptitude (I earned my Ham license at age 16) with that of a seasoned engineer mentor...

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.

Sunday the 24th

Science Theme Crossword Puzzle for January 24th

Science Theme Crossword Puzzle for January 24th, 2021 - RF CafeThis Science Theme crossword puzzle for January 24th contains only words and clues related to engineering, mathematics, chemistry, physics, and other technical words. 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., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Friday the 22nd

Electronics-Themed Comics

Electronics-Themed Comics, January 1951 Radio-Electronics - RF CafeThe January 1951 issue of Radio-Electronics magazine had a big collection of electronics-themed comics - five of them. All of them are pretty good, and you don't need to have been there during the early TV era to appreciate the humor. The comic from page 127 is a good first step in troubleshooting for today, and is usually at the top of the problem solving section of consumer gear throughout the electronic age. The page 126 comic is an oft-used gag for garage-related funnies. Although not directly related, it reminds me of how early wireless garage door openers had their antennas stretched underneath of the car...

RF Cafe Quiz: Gigabit μ−wave and mm−Wave Communications

RF Cafe Quiz #34: Multi-Gigabit Microwave and Millimeter-Wave Wireless Communications - RF CafeAll RF Cafe Quizzes make great fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job. This quiz is based on the information presented in Multi-Gigabit Microwave and Millimeter-Wave Wireless Communications, by Jonathan Wells.

Microstrip Circuit and Material Characterization System

Microstrip Circuit and Material Characterization System - RF Cafe"Characterizing microstrip superconducting film at millimeter-wave frequencies is difficult without undergoing a complex thin film fabrication process. This characterization includes measuring the ohmic loss at a resolution of 10100 parts per million (ppm). Typically, characterizing microstrip superconducting film utilizes antenna-coupled bolometers as part of the superconducting film structure. Bolometers are components that measure incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance; however, this process is disadvantageous as embedded detectors, such as bolometers, make the superconducting film fabrication process more difficult. This process also requires various millimeter-wave components, further complicating film fabrication. Additionally, characterizing superconducting film..."

Bandwidth Requirements for Pulse-Type Transmissions

Bandwidth Requirements for Pulse-Type Transmissions, February 1945 QST - RF CafeIn 1945, when this article was published in QST magazine, radar was still in its infancy. Engineers were already aware of the need to shape pulse waveforms from experience with CW keying and the need to mitigate the effects of "chirping." A perfectly rectangular pulse in the time domain, as we learned in our signals and systems courses, creates a sin (x)/x response in the frequency domain. The Fourier transform shows that a perfectly square pulse in the time domain is the summation of an infinite number of odd harmonics of the fundamental (1st harmonic). The first few harmonics are audible to the CW copier as higher frequency "chirps." To reduce the annoyance (and wasted transmitted energy), time constants were added to the leading and trailing edges of the waveform to remove the higher frequencies, while leaving the pulse shape sufficiently rectangular to achieve its goal. The same type issue applies to radar pulses...

Tales from the Cube

Tales from the Cube - RF CafeHere's a trip down Memory (640 kB) Lane for those of us around during the early PC days, using MS−DOS. EDN magazine has been running their column "Tales from the Cube" (a take-off of the equally long ago "Tales from the Crypt" TV show) where readers submit sagas of (usually) troubleshooting experiences. Most often the problem is the result of an intermittent event or of human error (pronounced "stupidity"). This is a case of the latter. If you fondly recall the times when 256-color VGA CRT monitors, 3½" floppy disks, 20 MB hard drives, and an i80287 math coprocessor were to die for, when you were deemed a computer expert if you could write batch files, and half your computer's CPU power was not consumed by antivirus programs (no WWW, just Kermit for local net access), then you might like this "The Mysterious MS-DOS Reboot" anecdote by Robert Yankowitz. Enjoy!

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...

Many Thanks to Axiom Test Equipment for Continued Support!

Axiom Test Equipment - RF CafeAxiom Test 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. 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 Axiom Test Equipment today!




White Paper: Cadence Software for 5G/6G Design Challenges

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 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.

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...


Next-Gen Computer Chip with 2 Heads

Next-Gen Computer Chip with 2 Heads - RF Cafe"EPFL engineers have developed a computer chip that combines two functions - logic operations and data storage - into a single architecture, paving the way to more efficient devices. Their technology is particularly promising for applications relying on artificial intelligence. It's a major breakthrough in the field of electronics. Engineers at EPFL's Laboratory of Nanoscale Electronics and Structures (LANES) have developed a next-generation circuit that allows for smaller, faster and more energy-efficient devices—which would have major benefits for artificial-intelligence systems. Their revolutionary technology is the first to use a 2-D material for what's called a logic-in-memory architecture, or a single architecture that combines logic operations with a memory function. The research team's findings appear today in Nature..."

Nanotubes Show Their True Colours

Nanotubes Show Their True Colours - RF Cafe"Why do some thin films of single-wall carbon nanotubes take on colourful hues even though as-synthesized films are usually black? A team of researchers in Finland, the US and China has now come up with a possible answer in a development that could prove useful for future display screens and solar cells. Single-wall carbon nanotubes (SWCNTs) are rolled-up sheets of carbon just one atom thick, with a diameter of about 1 nm. Atoms in these sheets are arranged in a hexagonal lattice and the direction in which the sheet is rolled - its chirality - dictates whether the tube is a metal or a semiconductor. When these SWCNTs are sorted by their diameter or chirality - two traits denoted by an '(n,m)' numbering system..."

Electric-Powered Warship

Electric-Powered Warship - RF Cafe"The first full-electric power and propulsion surface combatant, the USS Zumwalt, has been delivered to the US Navy. The electric propulsion solution delivers efficiency, survivability, cost-of-ownership reductions, and system redundancy for enhanced vessel safety. In addition, machinery layout is more flexible and configurable. GE's Power Conversion business was the designer and provider for the high-voltage system (HV), propulsion drive trains consisting of multiphase converters and Advanced Induction Motors (AIM) for the DDG 1000 class of futuristic destroyers. 'Delivery is an important milestone for the Navy, as the DDG 1000 continues more advanced at-sea testing of the Zumwalt Combat System..."

Coffee Sales 2.0

Coffee Sales - RF Cafe"Coffee is one of the most widely consumed beverages in the U.S. and worldwide. Americans consume 400 million cups per day, making the U.S. the world's leading consumer of coffee. E-commerce and coffee go hand-in-hand. As the market grows - and becomes more competitive - coffee companies are coming up with more creative ways to get their products to online consumers. The E-Commerce Times recently spoke with coffee and e-commerce experts to get their views on what's involved in successful online coffee sales. Selling coffee online was very popular even before the pandemic hit, which, of course, increased demand for all goods online..."

DoD Strategy to Counter-Small Unmanned Aircraft Systems

DoD Strategy to Counter-Small Unmanned Aircraft Systems - RF Cafe"The U.S. Department of Defense (DoD) has released a plan to counter the increased threats posed by the proliferation of small drones commercially and by militaries. In a 36-page strategy released on January 2021, strong emphasis has been placed on inter-agency cooperation in the federal government to develop a baseline of knowledge, solutions, infrastructure, and response to counter small, unmanned aircraft systems (sUAS) threats. Small drones have become increasingly affordable and portable with growing capabilities, such as the ability to swarm and carry out cyberattacks, all of which could be enhanced with the use of artificial intelligence and autonomous systems..."























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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 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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