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Homepage Archive - May 2019 (page 3)
See Page 1 | 2 | 3 | 4 | 5 of the May 2019 homepage archives.

Friday 17

For the Record: Technological Revolution

The problem of and concern about our country's youngsters seemingly not being overly interested in pursuing technical career paths is a theme often heard in the tech news media and workplaces. As our world grows increasingly automated and everything from light bulbs to telephones and automobiles are so packed with "no user serviceable parts inside," there seems to be little motivation for an otherwise potential budding tinkerer to take stuff apart to discover what makes it work. In the "old days" like, say, 1955, products were much more accessible to kids' curious nature and explains why fostering the next crop of engineers, scientists, and technicians took care of itself. You might think so, but alas, the dilemma evidently persists with each succeeding generation...

What are the 8 Most Important Oscillator Specs?

Jim Holbrook has a useful guide on the Microwaves &  RF website entitled, "What Are the 8 Most Important Oscillator Specs?" It begins: "What's the first thing you think of when selecting electronic components? Chances are it's the processor or something else central to the system. The timing component may be the last thing on your mind, even though the clock provides the heartbeat that all signals in the system depend on. Selecting these essential timing components may appear to be a straightforward process, but one must consider a number of factors that affect system performance. So, what are the most important specifications and considerations? Here's a short rundown of the top oscillator parameters..."

Quiz on AC Circuit Theory

Here is a fairly simple quiz on AC circuit analysis. If you are not already comfortable with adding series and parallel circuits containing resistors, capacitors, and inductors, you will appreciate the simple formula presented that will keep the sweat level down ;-) . An even simpler form that solves explicitly for the four variables are as follows:

VTotal = √ [(VL - VC)2 + VR2]

VR = √ [(VT)2 - (VL - VC)2]

VL = VC + √ [VT2 - VR2]

VC = VL - √ [VT2 - VR2]

OK, pick up your pencils... now...

Altum RF Announces Opening of Eindhoven, Netherlands Office

Altum RF, a supplier of high-performance millimeter-wave to digital semiconductor solutions for next generation markets and applications, announces the opening of its Eindhoven, Netherlands office located on the campus of Eindhoven University of Technology. "Opening an office on this university campus gives us the strategic advantages of access to top engineering talent and to leading-edge electrical engineering research and development," stated Greg Baker, Altum RF CEO. "We work closely with electrical engineering research groups and collaborate with other start-ups to develop ground-breaking technology, so this location is ideal for our company. There is also an excellent source of high-tech talent in this region, which is important for our expansion plans in the future..."

Changing the Light Bulb on a 1,500' Tower - A Drone's-Eye View

Back in 2012, I posted a video of the PBS "Frontline" show (Cell Tower Deaths) that highlighted the dangers cell tower climber technicians face while working for very low wages. Other news stories since then have reported on new regulations from OSHA and other agencies that have helped make the safety issue better, but I haven't seen anything on whether the pay has gotten any better. There are lots of videos and photos online of tower climbers all over the world, but this one showing tower climber Kevin Schmidt making the ascension to the very top of the now inactive KDLT TV analog broadcast antenna near Salem, SD, is unique in that the recording was made from a drone platform. It has more than 12 million views. Capturing this kind of video requires a drone with a wireless live feed so the pilot...

Hams Help Trace "Mystery" Signal Disrupting Keyless Entry Devices

This is pretty amazing: "A recent article in The New York Times reported that many garage door openers and keyless vehicle entry fobs in an Ohio town near Cleveland mysteriously stopped working. While the article invoked The X-Files and hinted initially that a NASA research center somehow could be involved, the cause was not so much mystifying as arcane. 'Garage door repair people, local ham radio enthusiasts, and other volunteer investigators descended on the neighborhood with various meters,' the May 4 article by Heather Murphy recounted. 'Everyone agreed that something powerful was interfering with the radio frequency that many fobs rely on, but no one could identify the source..."

Windfreak Technologies: USB-Powered RF Synthesizers, Mixers

Windfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project...

Thursday 16

How the J-K Flip-Flops

An alternate title for this article that appeared in a 1969 issue of Radio-Electronics magazine could have been, "How to Build a J-K Flip-Flop." Author Leonard Geisler takes the reader through a step-by-step assembly of a functional J-K flip-flop using a collection of 1- 2- and 3-input NAND gates. The 1-input NAND, in case you are wondering, is used as an inverter. The piece reads like an in-depth first-semester electrical engineering technician course textbook. In the process of building the J-K, an R-S (reset/set) flip-flop is described. Nowhere does Geisler offer an explanation of from where the "J" and the "K" input labels come. According to electrical engineer Sourav Bhattacharya blog, it was Dr. Eldred Nelson of Hughes Aircraft who first coined the term J-K flip-flop...

Generating Multiple Phase Coherent Signals – Aligned in Phase and Time

Testing multi-antenna systems such as phased array or beamforming antennas requires a test system capable of providing multiple signals with constant phase relationships between them. The coherent test signals must have a specific or definable phase difference (relative phase) and definable amplitude. Some of the challenges for such a test system include compactness, phase control capability and simplicity in handling. In particular, phase stability between the channels is of importance. This Generating Multiple Phase Coherent Signals–Aligned in Phase and Time application note explains how to generate phase coherent signals. It details what to consider and how to configure the test setup...

Acorns in Microwave Antenna

This you need to see. The full story behind this video is unknown, but supposedly customers were complaining about poor reception associated with the Bear Creek Road microwave station somewhere in northern California. Upon inspection, the technicians discovered a small hole in the radome. When the cover was pulled away, according to the video somewhere between 35 to 50 gallons of acorns spilled out. You can see the bulge in the radome before emptying. The tech probably thought the water drain hole was clogged and it was full of water. From a National Geographic story: "Walter Koenig, a senior scientist with the Cornell Laboratory of Ornithology, says he's pretty sure the the acorn woodpecker..."

Glass Semiconductors Developed

The term "ovonic" - a fairly unfamiliar word these days - appeared in the May edition of Radio-Electronics, in an article entitled, "All About Ovonics," just a few months after this news item ran in the January issue (which I posted last month). Ovonics is a portmanteau of "Ovshinsky" (from Stanford R. Ovshinsky, the inventor) and "electronics." Read the "All About Ovonics" article for a deeper dive into the subject. The big deal, which turned out to be not a big enough deal, was the use of amorphous "glassy" compounds as semiconductors rather than the standard crystalline silicon structures. Maybe someday an enterprising genius inventor type will give a rebirth to the concept...

USAF Test of SHiELD Laser Weapon

"The Air Force said it successfully shot missiles out of the sky with a ground-based laser system that it plans to make small enough to fit on its aircraft. The Self-Protect High Energy Laser Demonstrator Advanced Technology Demonstration Program, or SHiELD , conducted the tests on April 23, an Air Force Research Laboratory statement said Friday. 'The successful test is a big step ahead for directed energy systems and protection against adversarial threats,' said Maj. Gen. William Cooley, AFRL commander. 'The ability to shoot down missiles with speed-of-light technology will enable air operation in denied environments.' During the tests at White Sands Missile Range, N.M., the laser system engaged and shot down multiple air-launched missiles in flight. It was not immediately clear whether the laser..."

San Francisco Circuits: PCB Fabrications & Assembly Service

SF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today...

Wednesday 15

Cunningham on R/C: Edsel Murphy's Law

One of the monthly columns in R/C Modeler magazine, written by Chuck Cunningham, entitled "Cunningham on R/C," that reported on the current state of radio control, which had only fairly recently evolved into fully solid state, proportional control systems. Anyone involved in electronics is painfully familiar with the weird kinds of issues that crop up in complex circuits that operate in hostile environments. The March 1970 issue contained part of an article authored by D. L. Klipstein, Director of Engineering, Measurement Control Devices, entitled, "Murphy's Law: The Contributions of Edsel Murphy to the Understanding of the Behaviour of Inanimate Objects.*" Only a few of the items were printed in Cunningham's column, but I managed to locate a copy of the full article...

For Safety's Sake

This is a story with a lesson learned by the author and thousands of others ever since electric power appliances and tools first became available. Fortunately, his Ham buddy was not permanently harmed, but even today with all the effort put into educating the public, people continue to use ungrounded (2-wire type, or with the ground prong removed) extension cords in conjunction with 3-wire power cords on tools and end up electrocuting themselves (or somebody else). I've told the story before about a friend of mine from high school who shortly after graduation was making a piece of furniture in a garage that had a damp dirt floor, and was electrocuted to death by the metal-framed circular saw that had no ground connected. Nowadays we often have power provided by a GFCI receptacle...

Axiom Test Equipment Blog: Keeping Self-Driving Vehicles on the Road

Axiom Test Equipment, an electronic test equipment rentals and sales company, has published a blog post entitled, "Keeping Self-Driving Vehicles on the Road," which discusses the technical and test requirements for the mm-wave radars and optical wavelength Lidar systems used for precise, fast-acting sensing and processing. Sophisticated test equipment is required for development, all of which Axiom Test Equipment can provide on a sale or lease basis. Self-driving cars, also known as autonomous vehicles, are literally right down the road. These electronically guided vehicles of the future will be built with advanced driver assistance system (ADAS) hardware and software, using several different technologies to detect and track other cars, pedestrians, and objects on the road and steer the vehicle...

A Real-Life RoboCop Is in Your Future

I assume the "real" RoboCop won't be sporting a hokey helmet and will handle inclement weather interfaces. This concept is actually a good idea based on how dangerous traffic stops have become for police officers. "The new cop robot was created to make police stops and arrests safer for everyone. We have all been stopped by a cop a few times and it is never a pleasant experience. However, according to Reuben Brewer, a Senior Robotics Research Engineer in SRI International's Applied Technologies and Science Department (ATSD), it can even be a downright dangerous one. According to the video's description...

Slingshot Flying Pig Accelerometer

My daughter, Sally, in addition to owning and operating a very successful horse riding school named Equine Kingdom Riding Academy, has a rather large eBay store she uses as a venue for selling items purchased at the local Goodwill "Bins" store. She often buys vintage toys with electronics features - sometimes working and sometimes not. A properly functioning vintage toy, be it a stuffed animal or a game of some sort, can make a huge difference in the resale price. When that is the case, she sends them home with me to attempt a repair. Many times the problem is corroded contacts from leaky batteries. A dental pick and some isopropyl alcohol usually solves the problem. When that doesn't work, it's time to open 'er up for a deeper look. Over the years I have found problems ranging...

Alliance Test Equipment: Used & Refurbished, Purchase & Rental

Alliance Test sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Please visit Allied Test Equipment today to see how they can help your project...

Tuesday 14

All About Dolby

This photo of Ray Dolby holding one of his prototype noise reduction circuits is probably the most widely published of him and therefore the most iconic of the Dolby noise reduction system. Audiophiles of the era (and today for that matter) immediately recognize the man who took the hisses and pops out of their beloved music. I always like to keep in mind when reading article like this one in a 1971 issue of Radio-Electronics magazine is that when it was originally published, Dolby had not yet become a household word and news of his accomplishment was just getting out. Many articles, books, and research papers have been written on how the Dolby system works. At least five of them from the groundbreaking era have been posted here on RF Cafe, so you can get some insight into the excitement. The technical term "companding" (compressing and expanding) was being seen in print for the first time...

Microwave Journal Releases Comprehensive Microwave Basics Library

Microwave Journal has developed and published an enhanced Microwaves Basics section online. This comprehensive library is based on content from the books "Microwaves and Wireless Simplified," by Thomas S. Laverghetta and "Handbook of RF, Microwave, and Millimeter-Wave Components," by Leonid A. Belov, Sergey M. Smolskiy and Victor N. Kochemasov, both published by Artech House, plus "Mixer Basics Primer: A Tutorial for RF & Microwave Mixers," by Ferenc Marki & Christopher Marki of Marki Microwave. If your work involves microwave or wireless communications technology or you just want to brush up on your technology basics, the Microwave Basics Library provides a good understanding of key concepts...

Rediscovery of FM Broadcasting

"Rediscovery of FM Broadcasting" could be a contemporary headline. The decline of broadcast radio has been a major concern of station owners for well over a decade since Internet and satellite radio has dominated the venue through which listeners access radio stations. Local broadcasters have long aired syndicated programs that include national advertising, but the money to pay for those segments came from revenue supplied largely by local companies. FM broadcasting began commercially around 1945 in the familiar 88-108 MHz band yielded by the military following World War II, and grew in number of stations very rapidly in the first few years. Then, it began a decline for a few more years until finally leveling off after about a decade. Even though FM had a clear advantage (literally) over AM because of electrical noise immunity...

Many Thanks to Centric RF for Their Continued Support!

Centric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. Order today, ship today! Centric RF is currently looking for vendors to partner with them. Please visit Centric RF today...

Korea's New 5G Futuristic Hospital

"Hologram visitors, indoor navigation, facial recognition security, and voice-controlled rooms are coming to a hospital in South Korea. When Yonsei University Health System opens its newest hospital next year, in Yongin, about 25 miles outside of Seoul, it will be decked out with some of tech's hottest gadgets. Very sick patients in isolation rooms can visit with holograms of their loved ones. Visitors will find their way around the hospital using an augmented reality (AR)-based indoor navigation system. Authorized medical workers will use facial recognition to enter secure areas. Patients can call a nurse and control their bed, lights, and TV with an Alexa-style voice assistant..."

The New R&S® FSVA3000 Signal & Spectrum Analyzer

The new R&S®FSVA3000 signal and spectrum analyzer has everything needed to keep up with demanding measurement applications. An analysis bandwidth of 400 MHz, an outstanding phase noise of -120 dBc/Hz and a high dynamic range. Capabilities that used to be only available for performance instruments have now become accessible to everyone. Key Facts Frequency range of 10 Hz to 4 GHz, 7.5 GHz, 13.6 GHz, 30 GHz or 44 GHz (up to 500 GHz with external harmonic mixers from Rohde & Schwarz) Analysis bandwidth up to 400 MHz SSB phase noise at 10 kHz offset (1 GHz): -120 dBc (1 Hz) Third-order intercept (TOI) at 1 GHz: +20 dBm (typ.) DANL at 1 GHz: -153 dBm DANL at 1 GHZ with optional preamp: -167 dBm Ready for cloud based test...

VidaRF: Passive RF & Microwave Components

At VidaRF, the phrase 'Providing Simple Solutions for Complex Connections' is more than just a slogan – it's a mindset, a mission, and a driving force behind everything we do. Their pledge is to design and distribute high performance, cost effective RF Microwave products to fit each customer's unique applications. Please visit VidaRF today to see how their lines of attenuators & terminations, directional couplers, power dividers, coaxial connectors, and circulator & isolators can be of use to your project. "When the standard just will not do, VidaRF has the solution for you!"...

Monday 13

Resistors Improve Performance While Their Size Decreases

When the electronics product world consisted of vacuum tube based circuits, the physical sizes of standard fixed-value passive resistors, inductors, and capacitors were not of much concern in terms of how much volume they consumed. R's, L's, and C's, had wire leads protruding from their molded bodies, or in the case of larger power supply filtering capacitors had solderable tabs. Point-to-point wiring consisted of components and hookup wire suspended in the air between solder terminal strips and tube base tabs. Even with miniature (peanut) tubes, all but the largest passives had no significant impact on overall unit size. Once semiconductors came onto the scene, everything changed. Suddenly, even the standard 1/4 W carbon resistor and tantalum capacitor became a significant factor when attempting to reduce size...

Why IP2 Matters for Wideband Amplifiers

In the days before wideband and single-conversion radio systems, few system designers worried much about 2nd-order intercept point (IP2) power levels because the likelihood of two or more signals generating significant inband spurious products was small. Today's systems are fundamentally different. This article by Chris DeMartino comments on Custom MMIC's application note #106 entitled "IP2 Measurements of Wideband Amplifiers." He begins, "Amplifier distortion exists in several forms. One form occurs when an amplifier is driven by a signal with a sufficiently large amplitude, thus causing the amplifier to approach its P1dB. Another type of distortion involves the scenario in which two signals - with frequencies that are different but still close to one another in value - are driving an amplifier, resulting in second- and third-order distortion..."

The Electronics Hobbyist

Here are a few tech-themed comics from the April 1967 edition of Popular Electronics magazine depicting the perception of techies during the era. As mentioned before, stereo equipment was a big deal in the era, back before most people listened to music through ear buds attached to smartphones. When in the USAF in the early 1980s, a sure sign of hipness was to have 19" equipment rack in your barracks room, stuffed full with a reel-to-reel tape deck, a high end AM/FM receiver ("tuner," to the audiophile), power amplifier that could deliver at least 200 W per channel, a dual cassette deck, turntable (referring to it as a "phonograph" revealed your squareness). Of course no self-respecting stereo aficionado would be caught dead with an 8-track tape deck in the rack...

Thanks to Transient Specialists for Continued Support!

Transient Specialists specializes in EMC test equipment rentals and carries a complete line of ESD guns, surge immunity test equipment, and EFT generators. Rentals available for military (Mil-Std 461), automotive (ISO 7637), and commercial (IEC 61000-4) EMC testing. Flexible terms, accredited calibrations and technical support on EMC testing equipment offered. Equipment consists of top EMC Test System manufacturers, including Teseq, Thermo Keytek, EM Test and EMC Partner...

Solution to Test GPS Spoofing Vulnerabilities in Automated Vehicles

"Southwest Research Institute (SwRI) has developed a cybersecurity system to test for vulnerabilities in automated vehicles and other technologies that use GPS receivers for positioning, navigation, and timing. GPS spoofing is a malicious attack that broadcasts incorrect signals to GPS receivers, while GPS manipulation modifies a real GPS signal. GPS satellites orbiting the Earth pinpoint physical locations of GPS receivers embedded in everything from smartphones to ground vehicles and aircraft. SwRI designed the new tool to meet United States federal regulations. Testing for GPS vulnerabilities in a mobile environment had previously been difficult because federal law prohibits over-the-air re-transmission of GPS signals without prior authorization..."

RF Superstore: Supplier of RF & Microwave Components

RF Superstore launched in 2017, marking the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and microwave Industry. Pasternack fundamentally changed the way RF components were sold. Partner Jason Wright manages day-to-day operations, while working closely with Mr. Pasternack to develop RF Superstore into a world class RF and microwave component supplier. RF coaxial connectors & adapters, coaxial cable & cable assemblies, surge protectors, attenuators. Items added daily. Free shipping on orders over \$99. We're leading the way again!

Sunday 12

Engineering & Science Crossword Puzzle for May 12

Since 2000, I have been creating custom engineering- and science-themed crossword puzzles for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or not this type of mental challenge helps keep your gray matter from atrophying in old age, but it certainly helps maintain your vocabulary and cognitive skills at all ages. A database of thousands of words has been built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

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