RF Cafe Software
About RF Cafe
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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NIST-4 Watt Balance Weighs in on Planck's Constant
"The latest version of the watt balance at the U.S. National Institute of Standards and Technology (NIST) has made its first measurement of Planck's constant (h) with an uncertainty of 34 parts per billion, demonstrating that the institute's device – dubbed NIST-4 – is accurate enough to be used to redefine the kilogram. The data from this latest measurement values the h at 6.62606983 x 10e-34 J·s, with an uncertainty of ±22 in the last two digits. For almost 130 years, the international definition of the kilogram has been based on a lump of platinum-iridium metal housed at the International Bureau of Weights and Measures (BIPM) in Paris ..."
Triad RF Systems Bi-Directional SSPA for Dual MIMO Applications
Triad RF Systems has introduced the TTRM1078D, a Bi-Directional SSPA for Dual MIMO Applications The TTRM1078D is a 2.2- 2.5 GHz SSPA for UAS radio links utilizing MIMO technology. It is capable of high 20 W output per channel for QPSK operation and 4 W / channel for higher data rate applications such as 64QAM OFDM. This class AB LDMOS module is designed for both military and commercial applications. It is capable of supporting any signal type and modulation ...
Qualcomm Files 17 Complaints Against China Smartphone Maker Meizu
"Qualcomm Inc has filed 17 fresh complaints in China against Meizu Technology, stepping up its battle with the Chinese smartphone maker after the two were unable to reach a licensing accord in the U.S. tech giant's biggest market. The patent infringement complaints by Qualcomm, submitted to intellectual property courts in Beijing and Shanghai on Thursday, mark the second time in a week it has taken legal action against Meizu, one of China's top 10 handset suppliers ..."
Directed Energy Weapons Making Great Leap Forward
"Paul Shattuck is director and chief engineer for Directed Energy Systems at Lockheed Martin Space Systems Co. He's been with Lockheed since 1974, with a focus area of the development of beam control technologies for High Power Laser Directed Energy Systems. He spent most of the 1980s developing and testing beam control technologies for the Strategic Defense Initiative, culminating in a simulated ground demonstration of a pace-based laser engagement of enemy ballistic missiles for President Reagan in November 1987. For 15 years he held various leadership roles on the Airborne Laser (ABL) ..."
Here is a story - probably not too far from being true - about a Ham operator (emphasis on 'operator') who parlayed a short spat of poor health into an opportunity to get in a little rag-chewing time. The whole scenario turned out so well that he pondered afterward whether he could indulge in a bit of malingering for a repeat opportunity. So did some of the contacts he told about it while laid up ...
The Phil Gildersleeve 'Gil' Cartoon Book
RF Cafe visitor Kevin A. sent me a link to this book offered by the ARRL with a collection of comics contributed by the great Philip Gildersleeve ('Gil'). I recently posted a couple QST articles featuring his artistry. If you enjoy the unique look and humor of vintage cartoons, then you will probably enjoy this book. It only costs $15.95 directly from the ARRL.
Canada Day Contest is Friday, July 1
"Each year on July 1 - the anniversary of Canada's Confederation - Radio Amateurs of Canada (RAC) sponsors the Canada Day Contest. Amateurs everywhere are welcome to join Canada's birthday party on the air. The event gets under way at 0000 UTC on Friday, July 1, and concludes at 2359 UTC. Available bands include 160, 80, 40, 20, 15, 10, 6, and 2 meters, CW and phone. There are nine possible entry categories. You may work any station once on each mode ..."
"The Navy is looking to hunt bigger game with its laser weapons by increasing their power fivefold. National Defense reports that the service is preparing to test a 150-kilowatt laser, which would be considerably more powerful than the 30-kilowatt weapon i deployed on the USS Ponce in the Persian Gulf in 2014. The 30-kiliwatt system aboard the Ponce, known as LaWS (laser-mounted weapon system), has been shown to take out small drones ..."
Take a break from the Hump Day doldrums and enjoy a few vintage Ham-themed comics. Artist Phil Glidersleeve (aka 'Gil'), W1CJD, crated hundreds - if not thousands - of such comics for QST and other technical magazines during his multi-decade career. Most of these particular comics accompanied monthly columns and have a theme related to something within the text. However, I don't want to bore you with reading since it is not necessary to enjoy the humor ...
Huge Helium Discovery 'A Life-Saving Find'
"A new approach to gas exploration has discovered a huge helium gas field, which could address the increasingly critical shortage of this vital yet rare element. Helium doesn't just make your voice squeaky - it is critical to many things we take for granted, including MRI scanners in medicine, welding, industrial leak detection and nuclear energy. However, known reserves are quickly running out. Until now helium has never been found intentionally - being accidentally discovered in small quantities ..."
What Is This Thing Called Decibel?
There is no such thing as too many good articles about the decibel. Newcomers and mathaphobes are the most likely to find the concept to have an "aroma of mystery," per author James McLaughlin. Tell the latter that the decibel is based on logarithms and he/she will likely need to take a pill and lie down. However, once explained that dBs permit the relatively simple process of addition and subtraction rather than multiplication and division, respectively, some initial fear is assuaged. In delving into some of the history of the usage of the decibel, McLaughlin mentions the "R" system of describing signal strength, as opposed to the modern "S" units - an interesting bit of trivia. Keeping in mind ...
4 New Elements Added to Periodic Table
"Following earlier reports that the claims for discovery of these elements have been fulfilled, the discoverers have been invited to propose names and the following are now disclosed for public review: Nihonium and symbol Nh, for the element 113, Moscovium and symbol Mc, for the element 115, Tennessine and symbol Ts, for the element 117, and Oganesson and symbol Og, for the element 118. The guidelines for the naming the elements were recently revised and shared with the discoverers ..."
Coilcraft Offers Free RF Magnetics Lab Kits + Filter Design Software
Coilcraft has been around as long as I can recall since beginning my electronics career in the 1970s. In fact, Coilcraft was founded in 1945 near Chicago to make custom coils for television sets. They began manufacturing a line of standard products in the 1970s - no doubt with supporting my budding career in mind ;-) Inductors and magnetics are their primary focus. Coilcraft has been an industry leader in surface mount components, and was one of the first to provide packaging that could be used by pick-and-place automatic PCB assembly. Recognizing the value of introducing the company brand and products early in the lives of people who will spend the next many decades specifying ...
Evidence Humans Still Have 'Lost' Ability to Discern Magnetic Fields
"Evidence of humanity's lost 'sixth sense' may have been found. Joe Kirschvink, a researcher from the California Institute of Technology, claims to have confirmation that humans can subconsciously detect Earth's magnetic field. Using a Faraday cage and EEG monitor, Kirschvink observed reproducible changes in human alpha brain waves when adjustments were made to the magnetic field around them ..."
World's Smallest Lens Revealed
"The world's smallest lens has been created using 3D printing, and it's just twice the width of a human hair. Its makers claim the lens could lead to cameras the size of a grain of salt, revolutionising surgery, surveillance, robotics and drone technology. Researchers in Germany created a triplet lens device by combining three of the lenses into a 'pinhead' device. It is capable of razor sharp images and can attach to the end of an optical fibre, and is thin enough to fit in the hollow of a ..."
Notable Tech Quote: Corey S. Powell
"Often in science it takes a long time to understand exactly how confused you are." - Corey S. Powell, writing in "A Cosmos, Darkly," April 2016 Discover magazine. A maxim in all fields of science is that all theories, no matter how firmly established - or in modern political parlance "settled" - needs to be continually tested through empirical experimentation. Einstein's relativity theory an example of an area that is vehemently challenged, and continues to hod up. Other fields like cosmological evolution, is routinely found to be previously misunderstood, thus Mr. Powell's statement.
Who Killed That Component?
"James Bryant, an applications manager with Analog Devices for more than 30 years, answers a question about component failure. Q: Why do unstressed components sometimes fail for no obvious reason? A: Sometimes they die of old age, sometimes the stress is there, but, as you say, it is not obvious. 'Old age' in a component is cumulative degradation due to physical or chemical changes. It is well-known that electrolytic capacitors and some types of film capacitor eventually die as a result of chemical reactions in their dielectric caused by ..."
National Company Advertisement
As the opening sentence indicates, National Company ran a very long series of advertisements in QST magazine that were in a format more reminiscent of a short essay than a company promotion. This installment for the December 1952 edition was number 224. Subjects ran the gamut from technical innovations from the company's research and development laboratory to social and political issues relevant to electronics technicians, hobbyists, students, and engineers. Being that it was a presidential election year in the U.S., National Company felt compelled to remind readers of their patriotic duty to vote. Although this was the December issue, it would reach readers' mailboxes prior to the ...
Steve's Antique Radio Website
Mr. Steve Geary sent me a note of thanks for posting the Radio Service Data Sheet for the Zenith model 430 and 440 radio sets - a validation of my effort to make these available. He is a prolific collector and restorer of vintage tube radio - both tabletop and floor (console) models. If you are interested in radio and electronics communications history, you will want to spend a few minutes perusing all the great photos and information he has posted. Steve's collection represents 35 years of yard and estate sales, and making deals with antique dealers. He got his start in electronics repair and servicing as a technician in a hometown Ohio shop, where he worked until it closed its doors at the end of the last century ...
Physics Professor Makes Nanomagnetism Discovery
"Dr. Karine Chesnel has always been fascinated with understanding how things work, particularly the secrets of magnetism. 'There are still a lot of unknown mysteries in magnetism,' Chesnel said. 'Scientists are still trying to understand the nature of magnetism, the origin of magnetism and what's causing it.' Chesnel is one of those scientists. Her specific area of study includes magnetic behaviors occurring on a microscopic scale, also known as nanomagnetism. To study nanomagnetism, Chesnel uses synchrotron radiation facilities ..."
Prior to the advent of thyristors and semiconductor lamp and motor control circuits, a relatively simple and safe - although heavy and bulky - method for controlling AC voltage was with the use of saturable core transformer arrangements. By using a DC winding to control the saturation level of the transformer core material, the inductance, and therefore inductive reactance, of secondary windings can be controlled. Doing so has the same effect as using a Variac that uses mechanical control of the coupling and transformer voltage input/out ratio. The method shown here has a potentiometer for adjusting the DC current level, but, as the author ...
Modelithics® AVX Library for High Accuracy Electronic Simulation
The Modelithics AVX Component Library is a comprehensive collection of simulation models that offer many advanced features capable of significantly increasing accuracy during the design phase. Many AVX components are available as Modelithics Microwave Global Models™, including capacitors, inductors, resistors, diplexers, couplers and attenuators. Each model represents an AVX component series (or individual part in some cases), and offers scalable or selectable ...
FCC Dismisses Petition for Experimental Operation on Amateur Radio Bands
"The Federal Communications Commission (FCC) has denied two petitions from James E. Whedbee, an amateur radio operator from Missouri. In a June 2016 letter, Scot Stone, Deputy Chief of the Mobility Division explained that the Commission concluded that Whedbee’s petitions did not present enough evidence to merit a rule change. In November 2015, Whedbee requested that the FCC amend Part 97 of its rules to permit amateur radio operators to conduct low-power experiments on amateur frequencies without having to obtain an experimental license ..."
RF Cafe Crossword Puzzle for June 26
This week's RF Cafe Crossword Puzzle is another custom creation (they all are, actually) which contains only words and clues pertaining specifically to engineering, science, mechanics, physics, mathematics, chemistry, and other technical fields of study. If you want to exploit your knowledge of numbnut movie starts, world leaders, and remote villages in BFE, then try the New York Times. Cruciverbalist engineers, technicians, students ...
Southern California Amateurs Rise to Earthquake Emergency
This could be a headline for today, tomorrow, or from 83 years ago. It was the latter, following the magnitude 6.4 earthquake that hit the Long Beach, California region. Per Wikipedia, "An estimated $40M worth of property damage resulted, and between 115 and 120 people died. Many of these fatalities occurred as people ran out of buildings and were hit by falling debris." That paled, though, in comparison to the magnitude 7.8 San Francisco earthquake in 1906, where massive destruction occurred and upwards of 3,000 people died. As usual, radio amateurs were some of the first emergency responders ...
1 in 15 New Cars to Use Infineon SiGe 77 GHz Radar Chips by End-2016
"By the end of 2016, more than half of all new automotive 77 GHz radar systems worldwide will be equipped with chips from Munich-based Infineon Technologies, meaning that about one in 15 new cars will use a driver assistance system using its 77 GHz radar chips, says the firm. Infineon's market leadership in the rapidly growing market for radar chips for driver assistance systems was recently confirmed by market research firm IHS Technology. While Infineon has sold a total of 20 million radar chips in the past few years ..."
Mac's Radio Service Shop: Barney and the Boosters
As one who recently installed an outdoor antenna with a signal booster on it, I definitely considered whether my exercise and investment would be worthwhile because all the preamplification in the world wouldn't help if the signal-to-noise ratio was lousy to begin with. This statement from Mac McGregor sums it up well, "One thing you have to remember is that the booster has to have something to boost. Unless the antenna can deliver some sort of signal to it, it has nothing to work on. The results are about the same as when a small boy reaches the bottom of his soda. He keeps on trying, but about all his straw delivers is noise ..."
Morsecorp Develops Unmanned Aircraft That Melt
"U.S. military researchers have chosen a third company to develop small unpowered and unmanned aircraft to air-drop small packages for forward-deployed forces. After delivery, the unmanned aircraft melt without any detectable trace to keep them out of enemy hands. Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., added MORSECORP Inc. in Cambridge, Mass., to the Inbound, Controlled, Air-Releasable, Unrecoverable Systems (ICARUS) ..."
VidaRF Offers Wide Selection of Power Dividers/Combiners
VidaRF offers a wide selection of 2-way through 16-way power divider / combiners, designed to cover 100 MHz to 20 GHz with average power handling of 30 watts for narrow, octave, dual and multi-octave band applications. Standard Connector type: SMA female, other connectors available upon request. VidaRF is a North Carolina based company that is focused on being a solutions provider by building to customer specs and offering zero days lead time for custom parts through their stock ...
Revolution in the Pythagoras Theorem?
"The Pythagoras theorem has changed. Better yet, our understanding of it has changed from two dimensions to three dimensions. For the past 2500 years, the Pythagoras theorem, arguably the most well-known theorem in the world, has greatly helped mankind to evolve. Its useful right angles are everywhere, whether it is a building, a table, a graph with axes, or the atomic structure of a crystal. What does it look like in 3D? Until now, this ..."
Tips on Technology for Experts in the Courtroom
Wendy Pearson, writing for IMS ExpertServices, offers this article summarizing an expert witness' use of presentation technology in the courtroom - 3D printers, computer simulations, animated graphics, etc. It is hard to believe that in the year 2016 there are still judges that restrict use of high tech methods in the courtroom, but evidently it is so. Anyone old enough to remember when design reviews, seminar speeches, and other presentations to customers and peers consisted of overhead projectors, hard copy handouts, and occasionally a physical sample to pass around to the audience was stand operating procedure, can testify to the vast improvement realized by ...
The Reception of Single-Sideband Signals
Even though the concept could easily be demonstrated to be viable mathematically, single sideband operation was early on widely regarded as an unrealizable laboratory curiosity, especially with a suppressed carrier. More circuitry is of course needed to accomplish single sideband communications both on the transmit and receive sides, but other than stricter stabilities and precision for frequency sources, single sideband operation is easily obtainable. There still remains a debate over whether voice quality is as good versus ...
EU to Spend €1B to Turn Quantum Physics Into Quantum Technology
"A 10-year-long megaproject will go beyond quantum computing and cryptography to advance other emerging technologies This dilution refrigerator can cool quantum dots to less than 5 millikelvins for experiments in quantum computing. European quantum physicists have done some amazing things over the past few decades: sent single photons to Earth orbit and back ..."
Under a Telephone Pole, by Carl Sandburg
"There is no new thing under the sun." "Everything old is new again." Many such idioms exist regarding how often things tend to run in cycles; it's just that often times people who think they are witnessing a new phenomenon are not aware of the previous occurrences. I have written of examples where 'old timers' lament the attitudes of a fledgling work force when writings show the previous generation of 'old timers' who worked with the current 'old timers' in their youth expressed the same type concern. An article titled "OMG! We've Been Here B4," appeared in the March 2016 issue of Smithsonian magazine ...
FCC Proposes 200-MHz Blocks of High-Band Spectrum for 5G
"Federal Communications Commission (FCC) chairman Tom Wheeler this week talked up the role of the U.S. in the development of the fifth generation of mobile technology and proposed new rules designed to free up more spectrum for 5G. FCC commissioners will vote on the proposal on 14 July, Wheeler said in a speech delivered to the National Press Club on Monday, and reproduced on the U.S. regulator's Website. '5G is a national priority,' Wheeler said, having waxed lyrical about the possible applications ..."
LBA Technology Debuts New AM Tower Isocoupler Hardware
LBA Technology (LBA), a unit of LBA Group, Inc. announced the next generation of economical AM isocoupler hardware for collocating low power broadcast facilities on AM towers. The LBA research and development team has improved upon the long trusted CAMI™ and CAMIMAX™ with the release of the new CAMI500™, CAMI1800™, and CAMI5000™. While the three new models replace the CAMI™ and CAMIMAX™, LBA will still support the legacy models which are in use around the world. This new line of AM isolation solutions creates more options and opportunities for AM broadcasters to use or offer ...
The Mechanics of Modulation
Paul Huntsinger wrote a nice introductory article on amplitude modulation (AM) in a 1931 edition of QST magazine. At the time, frequency modulation (FM) was still a laboratory curiosity, and many 'experts' believed that FM would not provide any advantage over AM broadcasting. You might be tempted to think that sources of electrical noise that would interfere with AM were less at the time, thus negating the need for noise-immune FM, but the fact is by 1931 there was a lot of static caused by brushed motors, lousy automobile ignition systems, and arcing transmission lines, along with natural sources like lightning. Figures 6, 7, and 8 were missing in the original article, but fortunately I was able ...
China's BeiDou Navigation Satellite System to Have 35-Satellites by 2020
"China's homegrown navigation system, the BeiDou Navigation Satellite System (BDS), will cover the whole globe with a constellation of 35 satellites by 2020, said a government report on Thursday. By 2018, the system is expected to provide basic services to the nations along the Belt and Road, as well as neighboring countries, said a white paper on the BDS issued by the State Council Information Office. China aims to build ..."
Ford-Philco Car-Radio Models F-1440 and F-1442
Most of the earliest automobile radios had the electronics mounted in a metal box separate from the dashboard tuning dial. The bulk and weight prevented colocation. This 1937-vintage Ford-Philco F-1442 radio one for which I was able to locate a couple examples for sale on eBay. One claims to be fully functional and the other is in pretty rough shape. If your era car or truck came without a radio and you would like to finally upgrade, this is your opportunity ;-) Here are the 3 other Radio Service Data Sheets from the August 1937 Radio-Craft: General Electric FA-60 and FA-61, Howard Model B-5 (715), and Remler Model 46 "Scottie."
DARPA MMIC-Scale EM Components for Military RF & Microwave
"U.S. military researchers are trying to do for magnetic components what they've done for MMICs - develop them on semiconductor substrates to reduce their size and enable new functionality for military RF and microwave systems. Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) issued a broad agency announcement on Thursday (DARPA-BAA-16-36) for the Magnetic Miniaturized and Monolithically Integrated Components (M3IC) project ..."
The Truth About the Vertical Antenna
Whenever you see an article with "The Truth About..." in the title, the expectation is the author is going to reveal some aspect about the subject that has been kept from public knowledge by nefarious schemers, or a common misconception is going to be cleared up for the unwitting majority. This article comes closest to the later category, although it is not really clear to me after reading it what the newly revealed 'truth' is - maybe just that the effort required for using a vertical antenna at fairly long wavelengths is worth it because of low radiation angles that facilitate local area and relatively nearby communications. A lot of really good information is presented regarding vertical antenna field patterns, antenna installation, and feedline ...
EM Research White Paper: Ruggedization
EM Research just released a white paper titled, Survival Skills: Ruggedization - How to Ensure Performance Under the Toughest Conditions in 5 Steps. "It contains Extreme heat, extreme cold, the pervasive moisture of being at sea, the constant vibration of revving engines – these are all factors that can destroy complex communications components. Unless, of course, they've been ruggedized to endure the toughest conditions ...
EDI CON USA Announces 4 Courses on RF, Microwave, HS Digital Design
EDI CON USA 2016, a conference that brings together engineers working on high-frequency analog and high-speed digital designs, taking place September 20-22 in Boston, Mass. at the Hynes Convention Center, is pleased to announce a full line up of short courses available to conference attendees. The short courses will take place in the afternoon on the third day of the conference, Thursday September 22, 2016. They are included in the conference pass type for attendees and no additional registration is required. Intuitive Microwave Filter Design With EM Simulation presented ...
Space Command Readies for War with 'Space Enterprise Vision'
"Air Force Space Command has created a blueprint for fighting and winning wars in space, known by the innocuous title of the Space Enterprise Vision. The existence of the plan is not classified but many of its working elements are. The SEV is 'an all-encompassing look at all the things we need to do to create more resilience in our space forces, enhance them, and respond to threats,' Air Force Space Command spokesman Col. John Dorrian says. It includes current weapon systems and those planned for the near ..."
Notable Tech Quote: Kevin Mitnick
"You can go to conferences. Go to the memory stick bowls and swap out the free ones with weaponized sticks." - Kevin Mitnick, famous FBI "Most Wanted" hacker at the 2016 Atlantic Design and Manufacturing show in New York City ...
FCC Office of Engineering & Technology TAC Noise Floor Technical Inquiry
RF Cafe visitor Dennis C. sent a link to a public notice document published by the FCC (June 15, 2016) titled, "Office of Engineering and Technology Announces Technological Advisory Council (TAC) Noise Floor Technical Inquiry," that is an invitation for public input regarding what, if any, changes are needed in codified radio spectrum regulations to accommodate the rapidly changing RF noise environment. Comment deadline is August 11, 2016, so that does not leave much time to submit your opinion. The FCC's Technological Advisory Council (TAC), an advisory group to the FCC operating under the Federal Advisory Committee Act, is investigating ...
Fined for Off-Frequency Operation
Since its inception in 1934, the Federal Communications Commission's (FCC) Enforcement Bureau has taken seriously its charter to monitor and protect designated frequency bands against both intentional and unintentional interference. Except for malicious attacks on legitimate operations, most instances of interference are the result of utter ignorance or accidental broadcasting due to inattention to detail (wrong frequency dialed in) or equipment malfunction. Standard practice is to issue an immediate cease and desist order to the offending party, and then go forward with prosecution if compliance does not follow. News stories appear fairly often about pirate broadcasters and idiots exacting revenge on someone else who allegedly offended said idiot. The $500 fine ...
World's First 1,000-Processor Chip
"A microchip containing 1,000 independent programmable processors has been designed by a team at the University of California, Davis, Department of Electrical and Computer Engineering. The energy-efficient 'KiloCore' chip has a maximum computation rate of 1.78 trillion instructions per second and contains 621 million transistors. The KiloCore was presented at the 2016 Symposium on VLSI Technology and Circuits in Honolulu ..."
Vintage Test Equipment at Recycled Goods Website
When looking for a piece of vintage test equipment, the first place that comes to mind is eBay. However, there are other sources worth exploring. I recently ran across the Recycled Goods website that has many cool items available, ranging from spectrum analyzers to chart recorders and test probes. They feature not just electronics TE, but also industrial, optical, scientific, and other specialties. A lot of the pieces are marked as sold, but you can be put on a watch list for notification when something becomes available. It's worth a quick look ...
Harmonized Standards for new EU Radio Equipment Directive
"On June 12, 2016 the new Radio Equipment Directive (RED), 2014/53/EU replaced the previous Radio and Telecommunication Terminal (R&TTE) Directive. This update of Europe’s single market rules for radio equipment was published in May 2014. ETSI has developed Harmonized European Standards to support the Directive. The Commission will reference the Harmonized Standards in the Official Journal of the European Union, and equipment that complies with the Harmonized Standards will be presumed to comply with the requirements ..."
Reserved for YL's and YF's
"By all that is holy in ham radio, I was able to copy several CQ's de their calls and a few words!" That sentence in Mrs. Wayland M. Groves' story caused me to do some searching because I do not recall having seen 'de' used like that. As it turns out, according to AC6V's Origin of Ham Speak webpage, 'de' is borrowed from the preposition 'de' in the French language for its connotation of ownership, as in 'un ami de ma mère,' meaning 'my mother's friend' (my interpretation, subject to correction). Topics dealing with women in Ham radio typically deal either with attracting them to the hobby through participation or appeal ...
Antennas Crossword Puzzle
This week's custom crossword puzzle contains many words and clues specific to antennas (marked with an asterisk*). All the other words and clues pertain strictly to the subjects of engineering, science, physics, astronomy, chemistry, etc. As always, you will find no references to numbnut movie stars or fashion designers. Enjoy ...
Are Women Exiting Engineering Because Men Have All the Fun?
"Where are all the women engineers? That's a question that engineering educators and recruiters have been asking themselves for years now. 20% of engineering graduates are women—but only 13% of the engineering workforce is female. It's not a pipeline issue; engineering schools have been graduating women for a long time now. It's been easy to blame women leaving the engineering workforce to balance the demands of family, but is that really it? Many have said there's a culture problem, but what exactly does that mean? It turns out, according to a recent study ..."
Note on S.W.R. Measurement
Have you ever made a power or noise figure measurement and had to scratch your head over why the reported value made absolutely no sense? How about measuring a positive gain value through a passive device? I have experienced this sort of nonsensical phenomenon on more than one occasion, and to my recollection every time the cause was stray frequencies - often oscillations - mixed in with the intended signal. This app note addresses the issue in regard to impedance matching networks that are wideband enough to support RF energy that is outside the band being tuned - or even unexpected inband signals - with a simple method ...
Wireless EM Propagation Software Gets Better with 64-Bit GUI
"Remcom announced an updated version of Wireless InSite, its site-specific radio propagation software for the analysis of wireless communication systems. This update, Release 2.8.1, includes performance enhancements such as XStream GPU Acceleration support for NVIDIA Maxwell architecture-based GPUs for the X3D model and a 64-bit graphical user interface (GUI). This release updates Wireless InSite’s X3D model with support for version 7 ..."
Another Inductive Coupling System for Rotary Beams
Complete with all the nitty-gritty details and necessary formulas for designing an inductive loop coupler for a rotating antenna is this article by Mr. Robert Mumma. Such a device is useful when you desire a steerable antenna that prefers not to or cannot accommodate a section of coaxial cable interfacing the fixed mast to the rotating antenna. It is rare that such a requirement is found, since installing a set of limit switches to prevent the cable from wrapping itself around the mast is relatively simple to implement. However, if you want a system that continually rotates while searching for or broadcasting signals, then something like this is needed. A radar antenna is a prime example, as would a search and rescue operation ...
Finland, Home to Nokia and Jobless Engineers, Struggles to Fill Tech Jobs
"Finland, whose once-renowned technology sector shed 15,000 jobs with the demise of Nokia's mobile phone business, is struggling to fill thousands of vacancies for software developers because it lacks people with the right skills. At the same time, technology firms say immigration policies hamper recruiting trained workers from abroad, adding to the factors weighing on growth prospects for an industry considered key to the stagnant economy's recovery ..."
Behind the Scenes with Next Year's Model
The expectation of manufacturers to constantly come up with new and better models that outperform last years' models and compel buyers to upgrade is as old as markets themselves. This tongue-in-cheek tale of developers of the "The Dual-Ratio Knee-Action Triple-Hemispheric Multi-Tube Many-Wave Looperdyne" could easily be adopted to describe the prototype lab at Apple, Chevrolet, Panasonic, Microsoft (well, maybe no so much), Hasbro, Lockheed Martin, or Craftsman. Anyone who has worked in the pressure cooker environment of a research, development, and production qualification phases ...
Free Webinar: 802.11ax High Efficiency Throughput in Dense User Environs
NI / AWR and MW Journal are presenting a free webinar today, June 16, titled, "802.11ax – High Efficiency Wireless Improving User Throughput in Dense User Environments." "The world has benefited from the evolution of the IEEE 802.11 wireless networking standard to accommodate more and more users and their ever-increasing data consumption. At its early inception in the late 1990s, wireless networks ran at around 11 Mbps using Direct Sequence Spread Spectrum technology. Later on, the wireless standard multiplied ...
Negative Resistance: What It Is & How It's Used
My first experience with negative resistance was when an engineer I worked for at Westinghouse Electric, in Annapolis, Maryland, used a tunnel diode to design a simple oscillator circuit. The project we were working on required an absolute minimum number of parts, with everything implemented using bare die on a custom polyimide substrate printed circuit board. I did the assembly, wire bonding, and encapsulation, and often initial test. Mr. Rufus Turner does a nice job of briefly covering the history and application of negative resistance devices; tunnel diodes were not the first ...
Anyone Else Remember Calling
WE6-1212 and TI4-1212?
Long before there was a World Wide Web for getting the latest weather report and the local time for setting your clocks, there were phone numbers that were set up with recordings of the sought after information. As a kid in the 1960s and 1970s, I called the weather forecast number, WE6-1212 ('WE' for weather), multiple times daily during the winter in hopes of hearing a forecast for snow, and during the summer in hopes of favorable conditions for flying model airplanes and launching Estes rockets. An obsession with time and watches and clocks had me calling the time phone number, TI4-1212 ('TI' for time), so often that my father used to refer to the lady on the recording that ...