1996 - 2016
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 Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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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.
Homepage Archive Pages
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Here is page 2 of the December 2014 homepage archive
"Sally, the Service Maid" was a relatively short-lived feature in Radio Craft magazine. It began in early 1944 to bring deserved attention to the women who were left to run their husband's or brother's or son's electronics service shops while they were overseas securing the blessings of liberty for mankind. The sagas involved our heroine, Sally, confidently and impressively attacking malfunctioning electronic equipment in the stead of her father Gus Mason, who had volunteered his services as an instructor of electronics for the military. Unlike in past episodes where she tackled complex radio circuits for dashing military emissaries bringing equipment to her shop, this …
By 1945 everyone of importance in the electronics industry was blowing the figurative horn of television. The country would transform from "a chicken in every pot" to "a TV in every living room" (OK, I just made that up). The NTSC had set the standards for transmission, but hardware implementation was by no means agreed upon. If my memory is correct, there were still some manufacturers clinging to the mechanical spinning disc with a projection screen rather than using electronic circuits and a CRT. Entire industries - not only electronics - were bursting at the seams in anticipation of the war ending and being allowed …
Empower is pleased to be releasing additional, industry leading power amplifier models that compliment the frequency coverage and power level "footprint" of our next generation, high power PA product family. Model 2170, covering 1 to 3 GHz and delivering 1 kW of broadband output power in a 5U, air cooled chassis is our latest market release. Offering unrivaled size / power advantages and building on a design architecture that has been a catalyst for technology upgrades from customers with diverse requirements from multiple markets, Model 2170 provides excellent performance for …
While photographing the General Electric 7-4305c clock radio that I posted last week, it occurred to me that I had never posted anything on my Reader's Digest 800-XR stereo system. It is another of my had-since-a-teenager electronic items that still works as well as the day I bought mine in fall of 1975. Self-respecting audiophiles would never admit to having ever owned such a low-end system, but at least at the time it was the best I could afford. The price escapes me, but it was somewhere in the $100 neighborhood. A turntable came with it, but that is long gone now. Since I much prefer listening to over-the-air broadcasts rather than on the Internet, both the AM and FM tuners get a daily workout. A whopping 10 watts per channel stressed the limits of what my parents would tolerate, and …
111 years ago this week (December 17, 1903), Orville and Wilbur Wright made their historic first flight whereby a human and aircraft took off and flew under its own power. The Wright Flyer, piloted by Orville, took off from rails on a dune at Kill Devil Hills, NC, and remained airborne for 120 feet before landing on the beach below. The location was chosen for the orographic lift generated by the ocean winds blowing up the sandy slopes. This week's crossword commemorates the event by incorporating many relevant terms and clues. Enjoy!
RF Wizard creator Gordon Hockey wrote to let me know about his new software for RF amplifier design. "RF Wizard has been created for RF designers, educators, and students to greatly simplify the normally complex tasks associated with RF and microwave amplifier design for specific gain and bandwidth. It also simplifies the design of matching interconnection networks between RF subsystems such as antennas, transmission lines, amplifiers, mixers, etc." Only $39.99!
New directional coupler from Werbel Microwave covers 2-18 GHz continuously at 10 ±1.00 dB. Made in the USA from domestic materials. Return loss is specified at -14 dB or better, directivity specified at 15 dB min (up to 12.4 GHz, -12 dB above 12.4 GHz). Ready for immediate production. Order now!
This week's collection of career-related articles starts out with on that cites reasons why overly - and overtly - nice people might not be the most trustworthy amongst your employees / co-workers. It will probably come as no surprise to anyone that "New research suggests habitually pleasant people may not be as deserving of your trust as their more curmudgeonly counterparts." Then again, research papers tend to have the nasty habit of producing results sought after by their authors, particularly if a 'shock factor' can be generated. You'll also be treated to some …
This quiz is based on the information presented in Space-Time Adaptive Processing for Radar, by J. R. Guerci. Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway "Space-time adaptive processing (STAP) is an exciting technology for advanced radar systems that allows for significant performance enhancements over conventional approaches. Based on a time-tested course taught in industry, government and academia, this second edition reviews basic STAP concepts and methods, placing emphasis on implementation in real-world systems. It addresses the needs of radar engineers who are …
Here I go again saying how Germany missed an opportunity - twice - to be the world's technical superpower by starting wars that numerically proved it could never win. Scientists and engineers of Deutschland designed and implemented what would be the first wirelessly guided missile for correcting the flight path of the V-2 rocket (the 'V' stood for Vergeltungswaffe, or vengeance weapon). This article from a 1945 edition of Radio News describes how a radio 'cone' was formed by a ground-based transmitter array that caused an airborne guidance system to keep the rocket on course during the boost phase of its flight. Embarrassingly, I don't recall …
RF Cafe visitor Adam V. wrote to let me know about OnRecycle's services for disposing of your electronic gadgets in an environmentally - and possibly profitable - manner. OnRecycle is located in the United Kingdom, and is basically a clearing house for finding the best price offered for your used device, be it a smartphone, dumbphone, tablet, PC, e-reader, GPS unit, camera, or whatever. In the same manner that a service like Priceline shops around for the best airline rates, OnRecycle searches its database of buyers to find the one that offers the best price. Per their website, "OnRecycle is a recycling comparison site …
The probability-based quantum mechanical model of atoms has been in existence since around 1932 when Robert Mulliken coined the term 'electron orbital.' It superseded the Bohr model that modeled the atom as a proton / neutron nucleus that was surrounded by electrons orbiting like planets around a star. For many decades thereafter, text books - particularly those used in beginner level courses - continued to present the Bohr model and only gave passing reference, if at all, to the quantum model. The Bohr model was and still is easier for most people to envision, although as time goes on the percentage of people who even recognize a planetary model is probably rapidly decreasing …
You know by now if you have visited RF Cafe a few times that I like to collect and restore vintage electronics and mechanical items that can be put to use - as opposed to just accumulating stuff and never using it for anything (although, admittedly, I do a bit of that as well). Since I don't do it for the collector's value, most items, if they are not already in good condition, get reworked until they look as new as possible - and work. Some 'experts' would admonish me to leave the items with their original paint, varnish, metal and wood parts, etc., and never do anything that would destroy its authenticity. If I ever happen to acquire a Rembrandt or a Stradivarius, I'll be sure …
The ARRL Handbook is widely used by radio amateurs as a reliable and highly-respected guide to station design, construction, modification, and repair. Introduced in 1926 as the Radio Amateur s Handbook, each edition has remained true to this publishing legacy: a concise source of reference and information for applied radio electronics and experimentation. Chapter by chapter, you will discover the theory, practical information and construction details to expand your knowledge and skill as an Amateur Radio operator and experimenter.
Wouldn't it be nice if you could get a free subscription to your favorite cycling, fishing, or camping magazine merely by demonstrating that you have a vested interest in the subject that advertisers can exploit? Don't be looking for a year's worth of Sports Illustrated, Field & Stream, or Handyman to arrive in your mailbox anytime soon (unless some kind soul gives you a subscription), but you can, if you are qualified, received complimentary subscriptions to many of the big-time engineering magazines. Here are just a few of what is available …
Innogia Technologies announces the availability of APIs which allow for its ATmate software to quickly and seamlessly integrate with Marvin Test Solutions' ATEasy test executive software. As a result, ATEasy users can now benefit from ATmate's data mining, analysis, charting and reporting capabilities, creating a complete solution from test execution to data storage, analysis and reporting. "We are very excited to provide these APIs to the ATEasy user base and believe that this integration will help engineers accelerate their design cycles. Now with
- Sorting through Balun
Confusion, D. Jorgesen
- Optimizing a Coaxial
Connector to Microstrip
Transition (p.22), NI AWR
- Möbius Strips and
U.L. Rohde, & A.K. Poddar
- Recent Market Driven Filter
Advances, D. Howett,
M. Busse, D. Rawlinson,
J. Burkett, T. Dolan,
R. Hershtig, D. King
- GaN-on-Diamond Wafers: A
Tutorial, B. Bolliger, F. Faili,
F. Ejeckam, D. Francis,
F. Lowe, and D. Twitchen
"...it is once and for all clear from the very appearances the earth is in the middle of the world and all weights move towards it." - Ptolemy, The Immobility of the Earth in the Centre of the World. Of course today we know that line of reasoning to be ridiculous since obviously the center of the world is Washington, D.C., or London, or Buenos Aires, or Canberra, or Beijing, or Seoul, or Brussels, or Riyadh, or Moscow, or … - just ask any politician.
Imagine if you wanted to transmit from your car with a 400 kHz radio and had to trail a 600-foot-long ¼-wave wire antenna behind to do it. Of course nobody ever did that, but it was common practice with airplanes in the days before VHF and UHF communications became the norm. It wasn't because nobody knew that it would be more advantageous to operate at higher frequencies in order to reduce antenna size requirements, it was that electronic equipment capable of withstanding the rigorous environment of airborne conditions was not ready for prime time, as the saying goes. Come to think of it, the term 'prime time' had probably not even been coined yet when this article was written in 1946 because it derives from the …
Narda Safety Test Solutions has announced a new generation of RF analyzers: NRA RX. These 19” rack mount devices analyze RF signals up to 6 GHz in the frequency and time domains, and exhibit receiver characteristics at the same time, thanks to a new high frequency receiver section. They are therefore ideal for radio monitoring applications. The new RX version of the NRA Remote Analyzer has been equipped with an RF module that has been specially developed for low phase noise and low
Non-standard fonts are highly discouraged in web pages because having them render properly requires that the user either have the fonts installed locally or fonts must be on the web server to be downloaded and used. The former relies on change, the latter on the willingness of the user to wait for the fonts to download and install just to see what is usually an unnecessary embellishment. These two fonts, on the other hand, might justify the trouble. The nice thing about carrelec.tff and elecsym1.tff is that they present often used electronics symbols in a scalable format. Building an actual schematic …
Hugo Gernsback, ever the prolific author on futuristic technology of the wireless nature, proposes here a new form of sea-faring weapon that would project an practically unstoppable assault on enemy ships: a high speed, remote controlled torpedo. After being launched from the safety of a location far out of range of enemy fire, a human controller in an airborne platform would, using navigation advice provided by spotter aircraft, steer the explosive craft over potentially long distances to direct hits on battleships, destroyers, landing craft, patrol boats, etc. Fortunately for all involved, the war would only …
63 years ago today marked the United States' entrance into World War II. Axis and Allied powers delineated foes and friends, respectively. This week's engineering crossword has as its theme Axis and Allied powers - all of whom are global trading partners nowadays. The 'Allied' powers term is clear enough, but where does the 'Axis' powers term originate? Merriam-Webster answers that in its 9th - and last, therefore least used - definition: "a point or continuum on which something centers <an axis of social power>."
Pasternack Enterprises has significantly expanded their portfolio of connectorized RF amplifiers including high power, high-rel, broadband, limiting, low noise, log amplifiers, and gain blocks. Pasternack’s broad lines of coaxial amplifiers are employed across the entire spectrum of commercial and military applications including use in radar, electronic warfare, satcom, wireless communications, test lab
'7' seems to be the magic number of this week's collection of career-related articles and news tidbits. I don't know whether it is by coincidence that so many titles include the same number or whether a memo goes out to career advice gurus suggesting a common theme (aka 'talking points,' as it were). There are some good unnumbered pieces as well.
7 Things You Can Learn from
a Company's Website
- 7 Signs of a Toxic Culture
- 7 Easy Steps for Ruining Your
- 7 Tips for Job Seekers That
Hiring Managers Secretly
Want You to Know <more>
Nothing is the subject of a lot of research by mathematicians. If you, like me, have read books on the origin of number systems (A History of Pi, et al), you know that no original counting systems had a symbol representing nothingness. Don't believe me? What is the Roman numeral for zero? Most religions forbade the concept because it was an affront to a Creator. Crazy? Galileo was "vehemently suspect of heresy" and required to "abjure, curse and detest" his belief that the Earth was not the center of the universe. Mathematical archeologist Amir Aczel thinks he has located the earliest example of the number '0' in a temple (of all places) in Cambodia. Does this finally prove that 'nothing' is sacred?
Did you know work is about to begin on a new canal system linking the Atlantic with the Pacific? Aside from being a bottleneck, the Panama Canal is too small to permit passage of some of China's largest supertankers which are as long as the Empire State Building is tall and hold 18,000 shipping containers. Aside from running through the country's main inland drinking water reservoir, destroying untold acres of 'rain forest,' and being in a hurricane region, its a great idea. Fortunately, 'developing countries' like Nicaragua (and China, if you can believe that) get to ignore all kinds of environmental regulations that strangle the rest of us (see map).
Do you know these men, or any of the many others that appear in the articles I post from vintage magazines? They might be your father or grandfather, brother or uncle. Once in a great while I will receive an e-mail from somebody telling me he or she recognized a person whose photo was posted with the article. I always try to include the names and, if available, cities of people in picture captions in hopes that the search engines will pick them up. Tracing family roots is a big hobby today and being able to find such an obscure source for a relative's past is a thrill to many such Internet sleuths …
Keysight Technologies today announced the latest release of Electromagnetic Professional (EMPro) software, its 3-D electromagnetic simulation software. EMPro 2015.01 offers a number of new capabilities to reduce simulation time and increase design efficiency. The most notable enhancement in EMPro 2015.01 is a speed improvement to its Finite Element Method (FEM) simulator that reduces by half, on average, the time it takes for simulations that exceed two
It would be more than a decade after the publishing of this article before the first direct-to-home satellite television broadcasts would be a reality, so it shows how long plans were being made for such systems. Rural landscapes are still peppered with the large vestigial C-band (~4 GHz) satellite dishes, many with faded eyeballs and other clever (and ugly) artwork on them. Before coaxial cable was strung beyond suburbs, country dwellers who either could not pull in over-the-air broadcasts from downtown locations or just wanted more viewing options paid dearly for satellite service. Equipment and installation costs on early systems could run into the $30k realm. Today's satellite TV systems use much smaller antennas operating in the Ku …
NuWaves Engineering introduced today the next generation of its NuPower™ small, lightweight and high-efficiency RF PA family of products with the NuPower 13G05A. The NuPower 13G05A provides saturated RF power of at least 35 Watts from 800 to 2000 MHz with greater than 40% module efficiency across the frequency band. With a nominal input drive level of 0 dBm, the NuPower 13G05A offers an impressive 45 dB of RF gain. Further, the PA's aluminum chassis features improved
I was going to wait until a couple days before Christmas before posting this poem that appeared in the December 1958 (my 1st Christmas) edition of Radio Electronics magazine, but doing it now will give you time to integrate it into a report or presentation if desired. It is a take-off of the famous children's story 'Twas the Night Before Christmas, by Clement Clarke Moore, originally titled A Visit from St. Nicholas. The Day Before Christmas, by Jack Darr, might contain some terms not familiar to a more contemporary crowd. For instance, how many even know what "Gunsmoke" is, other than a forbidden word in …
Did you know that Amazon has a program whereby you can sell your book on their website and get up to 80% back? If your book is eligible, Amazon even pays the shipping cost for you to send it to them. Here are the details on the Amazon Book Trade-In program.
Melanie and I drove 300 miles from Erie to Harrisburg, Pennsylvania, back in June of 2013 to pick up this circa 1941, Crosley 03CB floor console model radio. As can be seen in the 'before' photos, it was in pretty rough condition. The wooden console was dinged and the walnut veneer was separated and missing in places. A severe overheating condition must have occurred the last time it was plugged in because the plastic front panel knobs were partially melted and distorted. Both concentric tuning, band switching, volume, and on/off switch shafts were rusted together. It was definitely a diamond in the rough. After a year and a half of wood, metal, and electronics work, it is now what I believe is one of the fine examples of a restored Crosley 03CB radios in existence …
Z-Communications announces a new RoHS compliant VCO model CLV1625B-LF. The CLV1625B-LF operates at 1445 to 1820 MHz with a tuning voltage range of 2 to 25 Vdc. This high performance VCO features a spectrally clean signal of -105 dBc/Hz @ 10 kHz offset and a typical tuning sensitivity of 23 MHz/V. The CLV1625B-LF is well suited for test equipment and satellite communication applications that require low phase noise performance.
November 2014 Book Drawing winner Dean M., of Buford, Georgia, decided on Behavioral Modeling and Linearization of RF Power Amplifiers, by John Wood. Each month I randomly choose one or two names from my electronic hat (an Excel spreadsheet) to offer a free book selection. I pay shipping, even on overseas addresses, when the cost is under $25 - which it has always been thus far. This book was Graciously provided by Artech House.
There was a time when we did not take the availability and abundance of everything for granted. Most of us have parents or grandparents who were around during World War II that can tell stories of ration stamps for certain food and clothing items, fuel, tires, and other things. I have a few given to me by my grandfather. Many industries, including electronics manufacturing, were strongly encouraged or required to dedicate all efforts toward war production. Crosley Corporation, based in Cincinnati, OH, was no exception. A notice of Crosley abandoning their 1943 line of commercial radios to make …
ET Industries specializes in the design, development and manufacture of the state-of-the-art radio and microwave frequency, narrowband and wideband subsystems and components. The model C-140-10 is a broadband directional coupler operating over a frequency range of 1-40 GHz. The frequency sensitivity is 0.9 dB maximum and the directivity is specified at 10 dB minimum. The insertion loss is 2.5 dB maximum and VSWR
"No rocket will reach the moon save by a miraculous discovery of an explosive far more energetic than any known. And even if the requisite fuel were produced, it would still have to be shown that the rocket machine would operate at four hundred and fifty-nine degrees below zero - the temperature of interplanetary space." Nikola Tesla, from A Prophet of Science Looks into the Future, November 1928 Popular Science.
Does your company make products that RF Cafe visitors use, like RF and microwave filters, amplifiers, couplers, mixers, etc., simulation software, test equipment, or provide design services, educational material, etc? If so and you are in the habit of publishing Press Releases (aka Product Update, Product Announcement, etc.), you are welcome to send them to me for consideration for posting on RF Cafe. With typically 6,000 to 9,000 website visitors each weekday, the exposure can be pretty good. A quick scan of the current RF Cafe homepage will likely turn up a couple examples of the abbreviated versions that go on the homepage and link to the main page. I will create a separate page for your …
Images, harmonics of the intermediate frequency (IF), harmonics of the local oscillator (LO), multiple station IF mixing, inductive and capacitive coupling, other types of RF noise can find a way into circuits if sufficient shielding and judicious component placement is not implemented. It is as true today as it was sixty years ago when this article appeared in Radio Craft magazine. An interesting interference generator discussed is that of heterodyned signals generated external to the receiver by means of random nonlinear junctions reacting to multiple high power broadcasting stations in a local area, as was fairly common when AM stations were the norm. Rusty bolted joints in buildings, towers, even …
Engineers designed Kiva Systems' robotic warehouse vehicle fleet and support infrastructure, but creating the traffic pattern algorithm that optimizes locomotion, navigation, and servicing (charging, repair, etc.), was almost certainly the work of mathematicians. This is the ultimate automated storage and retrieval system, although Kiva is loathe to call it that. As you watch the video, be sure to note the way the robots lift pallets, run through aisle ways with clearances of only a few inches, affect the stop-and-go and right-of-way procedures to avoid collisions and flow bottlenecks, and finally deliver products to their intended 'pickers' at the packing stations. I'm guessing there are also sensors onboard that detect and correct …
Anatech Electronics has released four new RF SAW filter designs with center frequencies at 1542, 1542.5, 1642, and 1643 MHz. All can be ordered directly through their AMCrf web store.
Wharfdale is a brand well known to stereo hobbyists and professionals for more than half a century. Wharfdale Wireless Works was founded by British entrepreneur Gilbert Briggs in 1933, and still sells speakers under the name 'Wharfdale.' As a pioneer in high fidelity sound reproduction, Mr. Briggs was highly sought as an author by electronics and audio media. In May 1957, he wrote this article for Radio & TV News magazine. Studies of the audio response of the human ear and the physics of the space where speakers and listeners would be were undertaken as the electronics age progressed in the post-war years and consumers began …