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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2009: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
Here is page 2 of the February 2015 homepage archive.
Glass-encapsulated bi-reed magnetic switches were a relatively recent invention that came out of Bell Labs when this Carl & Jerry episode was published in 1962. It seems like such simple and common components have been around forever, and they have for a growing portion of people in the electronics realm since that was more than half a century ago. As is often the case with John Frye's enterprising pair of teenage experimenters, the reader is treated to a tutorial on the operational theory of the switch, with its dependence on magnetization by induction. The story ends up being quite humorous, and reminds me a bit of the old All in the Family episode where a window salesman uses a photography light measuring meter to convince Archie he is actually detecting severe air drafts …
It has been quite a while since I looked through TradePub's list of white papers. For along time there had not been many relevant topics that struck me as useful enough to pitch to RF Cafe visitors. The ones listed here are a small sample of a lot of new papers, articles, and booklets available. You might want to take a couple minutes to see what's new there. They are all free downloads.
Crossword puzzles have probably lost their appeal to most people. I suspect so because up until early this year, I created a custom electronics-themed crossword puzzle every week for RF Cafe visitors, but not a single person has written to ask that they be continued. Oh well, that saves an hour every Sunday. Lots of magazines used to print crossword puzzles based on their readers' interests. Unlike the RF Cafe crosswords that use only relevant words, those puzzles used common filler words where it was too hard to find a thematic word. This crossword puzzle from a 1965 edition of Electronics World does a pretty good job of using a …
$15.1 billion is a lot of money both today and in 1963, when this story was written. That was the value of the electronics market at the time. According to the Bureau of Labor Statistics' Inflation Calculator, $15.1B in 1963 is the equivalent of $116B in 2014. The Consumer Electronics Association projects a 2015 electronics gadget market value of $223B, which does not include military, medical, and industrial electronics. The World Semiconductor Trade Statistics group predicts a $333B semi market value for 2014. Apple alone just hit the $700B market cap benchmark - that's just one electronics company. By any measure, electronics has enjoyed a continual, significant gain since the early 20th …
Unless you live with or interact regularly with someone who is blind, it is easy to forget the difficulty everyday life poses for him or her. I do not know any blind people. A lot of effort has been put forth to help facilitate those who are severely sight impaired or totally blind. Helen Keller is probably the most well-known blind person, but I think of Ray Charles when the subject arises. Melanie and I visited the Florida School for the Deaf and Blind while in St. Augustine a few years ago, where we learned Mr. Charles was fortunate to have attended as a child. His rendition of "America the Beautiful" is by far my favorite. This article from a 1935 edition of Short-Wave Craft reports on efforts to make the electronics trade accessible to blind people via, in this case, pseudo-Braille versions of schematics. Although theoretical design and analysis activities were possible, the potentially lethal voltages present in …
Empower RF Systems is once again conducting live demonstrations of broadband, high power amplifiers with compelling performance, industry leading small size, and user interface / functionality that dares to challenge legacy products offered in the market. Next appearing at EMC & SI 2015 in Santa Clara, we will be showcasing our 1 to 3 GHz, 1 kW HPA in a 5U chassis - an extraordinary design and great addition to the growing product family of next generation platforms from Empower. Please stop by Booth 711 to see us.
The Douglas DC-3 revolutionized commercial air travel with its introduction in 1935, and the military version, the C-47 Skytrain (aka Dakota), proved an invaluable workhorse for the U.S. Army Air Force during World War II. Without reliable and effective radio communications, the aircraft's success would have been much less. Companies like Bendix Radio led the way with rugged avionics that could take the harsh conditions of flight that include vibration, shock, pressure changes, and temperature variations. Replacement parts were usually not conveniently on-hand and the radio operator often needed to also be a trained electronics technician or engineer. "Necessity is the mother of …
Good, clean humor has always been a welcome addition to my day whether it come in the form of a printed comic strip, a TV show, or someone's mouth. My father's side of the family was populated with many jokesters who could be counted on to deliver an ad hoc pun or zinger at the appropriate moment. The environment instilled a great appreciation for such entertainment, so these electronics-themed comics that appeared in editions of Radio-Electronics, Popular Electronics, et al, are a refreshing distraction from the workaday world. An old saying claims "laughter is the best medicine," and while it cannot cure cancer, a good dose of humor often helps ease the pain.
RFMW, Ltd. announces design and sales support for the CT2010D from EMC Technology. The CT2010D Diamond Termination offers 300W CW power handling in a chip size (2.67 x 5.21mm), SMT package. EMC Diamond RF Resistives® offer high performance in compact packages. EMC's CVD Diamond terminations surpass BeO and AlN terminations with operation up to 30 GHz. The CT2010D VSWR is specified at 1.30:1 max for applications to 6 GHz …
'Short waves,' with their ability to support long distance communications under certain conditions, became a phenomenon in the late 1920s, and a market developed for converting commercial broadcast receivers to short wave receivers. Magazines at the time were full of advertisements for the devices. The particulars of short waves and the way they propagated in the upper atmosphere were not yet well understood early on. In fact, the government considered transmission frequencies above 1.5 MHz (≤200 meters) so useless that they assigned those bands to amateur radio operators. The presence of an electrically conductive layer, known as the ionosphere, was not verified until 1927 by Edward Appleton. Hams quickly investigated …
From GSM to LTE-Advanced: An Introduction to Mobile Networks and Mobile Broadband, by Martin Sauter, contains not only a technical description of the different wireless systems available today, but also explains the rationale behind the different mechanisms and implementations; not only the 'how' but also the 'why'. In this way, the advantages and also limitations of each technology become apparent. Offering a solid introduction to major global wireless standards and comparisons of the different wireless technologies and their applications, this edition has been updated to provide the latest directions and activities in 3GPP standardization up to Release 12, and VoLTE …
In celebration of its 500th month of print, Astronomy magazine's March 2015 edition published an extensive collection titled "500 Coolest Things About Space." If you have ever tried to assimilate a list of even 50 interesting facts on any topic, you can appreciate the effort involved to come up with 500. I have been a subscriber to Astronomy, on and off, since sometime around 1980, and generally prefer it to the only other major astronomy-related publication, Sky & Telescope. Since RF Cafe's audience members are science …
Einstein won the Nobel
Prize in physics for his
discovery of the
photoelectric effect, not for
his theory of relativity.
- A nychthemeron is a period
of 24 consecutive hours.
- Eugene Shoemaker is the
only human whose ashes are
on the Moon. <more>
In 1988, the National Bureau of Standards (NBS) was re-named National Institute of Standards and Technology (NIST) because a government bureaucrat needed to justify his/her position and the financing to change all the signs, brochures, and letterhead would be paid for with OPM (Other People's Money, pronounced like 'opium'). Regardless of its name, the NBS is charged with establishing, maintaining, and enforcing standard units of measure for the country, as well as with coordinating standard units with other countries. It is interesting to read how standards have changed over the years, and what methods have been suggested for establishing those standards; e.g., the Ohm (Ω) could have been based on a foot of copper wire weighing 100 grains, an …
The Good Life is a free publication printed in northern Michigan. Along with advertisements and stories from local interests, every edition is chock full of humorous quips and jokes. These (mostly) tech-related items are from the December 2014 and January 2015 editions.
- New Dog Breeds: Bulldog +
Shih tzu = Bullshihtz, a dog
you can never believe what
he tries to tell you
- Law of Nature: Nature abhors
a vacuum. But not as much
as dogs do.
- Performance Reviews: Quick
Thinking: Offers plausible
excuses for mistakes.
- Business Signs: On a
Scientist's door: "Gone
"But his shop is a lone outpost; in a single generation, the American who built, repaired, and tinkered with technology has evolved into an entirely new species: the American who prefers to slip that technology out of his pocket and show off its killer apps. Once, we were makers. Now most of us are users." - Andy Cohen, long-time Radio Shack store owner. Radio Shack is in its last days as it plans to shut down.
Radio was a powerful propaganda tool and strategic communications means toward the end of World War I, and certainly in the lead-up to and during the course of World War II. Many governments, including the United States and most European countries, forbade the broadcasting of signals by anything other than an entity licensed for commercial and/or military purposes. Amateur radio broadcasts were prohibited, although at least here in the U.S. possession of a receiver for listening was still allowed. Some of the regions controlled by Nazis did not even permit receivers - mainly because the government did not want citizens listening to anything that could be considered propaganda. Jamming of broadcast signals from 'Allied' countries was routinely practiced by Hitler's and Mussolini's tight-fisted controllers. Many citizens were imprisoned or executed for …
When the concept of radio-refrigerators was presented in a 1933 edition of Radio-News, it was not quite what has become reality today. At the time, the Radio Electrical Exposition had recently been held in Madison Square Garden and the world was just getting used to the miracle of radio waves - and refrigerators for that matter. Radio-refrigerators never did make their way into the consumer market. Fast-forward 80 years and now we're seeing the advent of radio-refrigerators re-emerge, only in a completely different format. This time, rather than playing shows from local commercial broadcast stations, these appliances are communicating with Wi-Fi routers to allow owners to check on status and contents from remote locations. In other news, the editors report on a scheme to use a remote-controlled airplane, signaled by a Tesla spark gap transmitter, to drop bombs inside tornados in order to break up and stop their …
Anatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Anatech has released three new cavity bandpass filter designs: a 722 MHz BPF, an 836 MHz BPF, and a 915 MHz BPF. All can be ordered directly through their AMCrf web store.
"It's Just Another Manic Monday," so went a popular song from the 1980s (ouch... that long ago?) by The Bangles. If you're tired of every Monday being like the scenario in Groundhog Day movie, then maybe it's time to finally think about moving on. You know there are plenty of people standing ready to offer their finest qualified - or unqualified - opinions on the best way to go about improving your current situation, finding a new job, or avoiding screwing up what is at this time a great job. Here are a few of the most recent articles …
88 K on a P. 27 V of H K. 24 H in a D. Do you remember those kinds of puzzles where you have to figure out what is being referred to? The first one is 88 Keys on a Piano, the second 27 Varieties of Heinz Ketchup, and the last is 24 Hours in a Day. If you like tackling such challenges as associating familiar quantities with their corresponding subjects, then you'll want to check out the list I created below that all have science and engineering themes. If this proves to be popular, I'll do another - hopefully including suggestions from y'all. Good …
Mark Johnson, president of Dicing Plus, wrote asking to be added to the Technical Consulting Services listing on RF Cafe. I'm glad to oblige. "Dicing Plus is a solutions based enterprise. Whether it's custom work requiring a design of experiments or high volume manufacturing our extensive experience will provide a path to your complete satisfaction. At Dicing Plus we specialize in difficult or niche applications requiring customized processing and out of the box thinking. Our engineers have years of experience providing solutions to the semiconductor and photonics industry. We work with major suppliers to provide custom blades and consumables to meet stringent product quality. Based in the heart of Silicon Valley we stand ready to tackle your dicing and singulating needs. No job is too small or too challenging."
Maybe it is just my imagination, but the amount of full-page advertisements in the engineering magazines seems to have reached a crescendo. People write to me and complain about the amount of banner ads on RF Cafe. Considering it is the advertisers who are the ones paying to bring the information to you at no cost to you, harboring too much resentment toward either the publishers or the advertisers is unreasonable. My question to incessant whiners is how much of their time and money is spent …
- Changing the Operating
Frequency of an RF Power
Amplifier Circuit (p22),
- Keysight Technologies:
Reborn, P. Hindle & G. Lerude
- Cut the Defense Budget? Sure,
No Worries, B. Manz
- Security Threats in LTE:
Devices, Access, Core
Elements and Services,
R. Kent <more>
Not everybody with a high temperature semiconductor application in need of heat dissipation has access to a thermal management program with a database of available commercial heat sinks and/or an ability to analyze a custom-made heat sink. This article contains simple equations, a handy chart, and instructions on how to use them to figure out what kind of heat sink you need for your project.
Metal oxide resistors have been around since the early 1960s. We take them for granted now, but prior to their appearance on the market the mainstays of electronics resistance elements were carbon composition and wirewound resistors. Carbon compound types are very inexpensive and are acceptable for a wide range of applications, but they have a bad habit of shifting value over time, particularly when subject to repeated heating and cooling cycles. Wirewounds (WW) are a good alternative when cost and physical space are not issues, but WWs can be tricky or even impossible to use when frequencies get above a few tens of megahertz because of inductance limitations. Metal film resistors exhibit much better …
This has been around for a long time, but it is timeless in its message. I personally added #13 in honor of Windows 8. : Rumor has it that one year at COMDEX, Bill Gates reportedly compared the computer industry with the auto industry and stated: "If GM had kept up with technology like the computer industry has, we would all be driving twenty-five dollar cars that got 1000 miles to the gallon." In response to Bill's comments, General Motors issued a press release stating: "If GM had developed technology like Microsoft, we would all be driving cars with the following characteristics: 1. For no reason whatsoever your car would crash twice a day …
Pasternack's latest release of hi-rel RF switches consists of 42 unique designs which include 38 connectorized models as well as 4 surface-mount devices that boast a small footprint and lower cost than traditional connectorized packages. A unique patented design of the actuator and transmission link has been optimized for magnetic efficiency and mechanical rigidity which guarantees operation up to 10 million life cycles with excellent repeatability. The rugged MIL-STD-202 qualified construction of each RF relay switch is designed to withstand exposure to sine and random vibration and mechanical shock.
The June 1945 edition of Radio-Craft published a death notice for diode electron tube inventor Sir Ambrose Fleming. The date given was April 19th, but every source I can find says he died on April 18th. With having been born on November 29, 1849, that made the good fellow 95½ years old. According to a calculator on the TimeAndDate.com website, that's a grand total of 34,900 days. Who's going to argue over a potential 0.00287% error?
My favorite character in the 1970s Prime Time TV show Barney Miller was Detective Sargent Arthur Dietrich. He was the serious intellectual with a very dry sense of humor that came out at just the right moment. One episode has always stuck out in my memory where a college student claims to have built a working model of a thermonuclear bomb as part of his Master's thesis project. All it lacks for detonation, per him, is plutonium. The on-hand bomb squad expert ridiculed the idea of it being any kind of real bomb, his decades of experience on the force being his guide (still has all his fingers as proof of it). All the guys in the office have just finished …
The geographic center of the 48 contiguous (conterminous) states in America is located about 2.6 miles northwest of the center of Lebanon, Kansas (39° 50' N, 98° 35' W). That is about 85 miles from the FCC's first central frequency monitoring station at Grand Island, Nebraska. I have driven by that spot a couple times while traveling on Interstate 80. Grand Island is probably not much bigger today than it was in 1932 when this story was published in Radio-Craft, although it boasts being the state's 4th largest city (population 48,000). "Island" must have a different definition in Nebraska than in the rest of the world ;-) Because of its remoteness - 6 miles from town to minimize electrical noise - a diesel generator (chosen to …
In the episode embedded below, titled, "Sweatwork," (a takeoff on the 1976 movie "Network"), produced from my purchased copy of the Welcome Back, Kotter DVD set, is about the Sweathogs running a radio station in the school. On the blackboard outside of the broadcast studio is a schematic for a vacuum-tube-based AM transmitter. It looks legit, and includes all the components to form a basic transmitter, including the audio input. I could not make out the manufacturer of the transmitter cabinet in …
Guerrilla RF Inc., a leading provider of high performance MMICs, today introduces the newest members to the company's family of 5 GHz ultra low noise amplifier/linear power amplifier drivers. These new devices feature best-in-class noise figure , gain and linearity. The cost-effective, small footprint, flat-gain solutions are designed for WLAN access points offering the highest levels of performance for demanding 802.11ac applications. The GRF2505 features ultra-low noise and high linearity over the 5 to 6 GHz band making it ideal as either an LNA or as a power amplifier driver for demand …
While working at RF Micro Devices (now known as Qorvo) on a project to improve the ESD ruggedness of our RFICs, I had to do a number of presentations on progress over a span of about two years. I desperately searched online for this episode of Welcome Back Kotter titled "Sweathog Clinic for the Cure of Smoking." It was not available at the time, but did show up for a short time sometime around 2008. Then, it disappeared and was not available again anywhere until a few months ago when a DVD set for the Welcome Back, Kotter television series went on sale at Amazon.com. I quickly snatched a copy and produced this clip …
One of the first things you learn in chemistry class is to never contaminate a source by dipping a spoon or other implement into the container, and not to allow an object like a cloth or your finger to touch the rim of a container. Don't breathe into it, either. Always pour or pump or use a dedicated implement to effect the transfer of a source to a receptacle vessel. The other thing you learn early on is to always - always - label your container with its contents. If you are a user of alcohol, acetone, MEK, or other chemicals and routinely need to have access to small amounts, it can be a pain in the posterior to have to keep pouring from the primary container into a medicine cup, tin, or other temporary holder. During both soldering of electronics and gluing of mechanical assemblies, I very often need to access some type of chemical for cleaning with a Q-Tip or acid brush. These kinds of chemical dispenser bottles …
As time marches inextricably forward, my appreciation for the artistic ability, craftsmanship, and creativity of others seems to be growing on an exponential (or maybe it's geometric) scale - particular pertaining to the younger subset of humanity. It probably has something to do with having crossed the half-century threshold and realizing that I don't have enough time left in this world to accomplish the multitude of activities or reach the many personal goals set. Everything seems harder these days, particularly when trying to learn something completely new; the old adage about not being able to teach an old dog new tricks is hitting closer to home all the time. Nevertheless, I persist in spite of diminishing odds. Generational pride still causes me to admonish an uppity teenager or twenty-something …
Orbel Corporation, designer and manufacturer of custom EMI/RFI shielding, photo-etched precision metal parts, and precision metal stamping will be featuring their EMI/RFI solutions at IMS 2015. Products include board level shielding, finger-stock gaskets and metalized fabric gaskets. Board level shielding is used to restrict the amount of electromagnetic energy propagating between the source and a receptor to acceptable levels. Near-field effects, layout and hole design, resonances, and thermal management are all elements Orbel takes into consideration in relation to shielding effectiveness. Finger-stock …
Since deciding to discontinue the hosting of private advertising on RF Cafe, I have had many requests to resume the program. Serving between 7,000 and 9,000 pages each weekday provides a valuable amount of exposure to people like you - serious engineers, technicians, students, and hobbyists. While I do not plan to reconstitute private advertising anytime soon, there remains a very easy - and FREE - way for you to get your company's products and services in front of RF Cafe visitors: Press Releases. If your company makes products that I deem relevant to my readership, I will gladly post your press release, company news, product announcements, etc. Please send the information, along with …
The "Sherlock Ohms" series published on occasion by Design News, in case you have forgotten because of how long it has been since I highlighted an episode (not many good ones lately, IMHO), is a feature where engineers and technicians tell their stories of troubleshooting intrigue based situations experienced in on-the-job or other venues. "A Revealing Quiet," by Jason W. Evan, describes one of those oh-too-familiar "aw crap" moments that has a nasty habit of appearing just when all the world seems right with your project. Enjoy.
"Engineers are artists. These are people with visions that no one else sees or hears, and the only other domain like that is art." Steve Blank, retired serial entrepreneur and Silicon Valley historian, in Entrepreneur magazine's "Inside the Mind of Silicon Valley's Tech Innovators."
If you're a Seahawks fan and you are looking for a new job, then all things might look a little bleak at the moment for you. On the other hand if you're a Patriots fan and you are looking for a new job, then you probably feel pretty invincible this morning. Either way, many 'experts' believe that now is a pretty good time to be in the job market because there is reportedly a severe talent shortage worldwide. I actually read one article today where the author claims the announced planned massive layoff by IBM is a great opportunity for those in the crosshairs - of course …
Achieving Success in Life
- Career Tips from World's
- Ways Employers Discourage
You from Negotiating Salary
- Contract or Part-Time Work
as a Stopgap? <more>
As is frequently the case, John T. Frye's intrepid teenage technophile experimenters, Carl Anderson and Jerry Bishop, find themselves in an unplanned adventure. Often times they end up applying their electronics knowledge to bail themselves out of trouble, but this time the pair - and a friend - ended up helping the police catch some bad guys (an oft-occurring theme). As you will see after reading "All's Fair --," the device used would some day (today) be used by automobile manufacturers, at the behest of law enforcement agencies, to enable remote control of somebody else's …
Jules Antoine Lissajous was a French mathematician who in the days before oscilloscopes concerned himself with patterns (waveforms) that would be generated as the result of two separate functions (signals) driving both the x- and y-axes. Lissajous used mechanical vibration devices connected to mirrors to bounce light beams onto a projection surface, so his results were not merely hand-drawn plots on graph paper. He was probably as mesmerized with them as we are today when they appear. Sci-fi movies have used Lissajous patterns in the background to 'wow' the audience into thinking it is witnessing futuristic, cutting-edge technology. When troubleshooting analog circuits …
It is the opinion of historians that in order to understand the present, you need to know the past. Searching for one's roots in this world is big business. Online family tree type websites are used by thousands of people to research their family histories, and some services don't come cheap. You can even pay someone to dig into your past to assimilate all available information and put it in a bound, printed volume. Here on RF Cafe, I research and post a lot of our profession's past. While the individual topics themselves might no bear significantly on the present, having an insight into the people's mindsets and progression of technology is …