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Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• Field Trials Start for 5G Broadcasting in Germany

Ford to Eliminate 7,000 Jobs, 10% of Workforce

• Ericsson's ConsumerLab Outlines Consumer Expectations for 5G

DOD Keeps Getting "Out Recruited" for Cyber Talent

Electric Air Racing Looking to Take Flight

• The FCC is Not Reinstating a Vanity Call Sign Fee

• UK's Disastrous 4G Emergency Services Network

• Puerto Rico Declares May 14 as "Radio Amateur Day"

Kilogram Gets New Physics-Based Definition

Sansui TA−300 Integrated Tuner Amplifier

Sansui TA-300 Integrated Tuner Amplifier - RF CafeSometime around 1980, while stationed at Robins AFB, Georgia, I finally succumbed to the peer pressure of other more sophisticated audiophiles in the barracks and bought a "real" stereo. Unlike my roommate who had a full compliment of rack-mounted gear, my meager enlisted military pay only allowed for a mid-grade instrument. The solution was a Sansui TA−300 Integrated Tuner Amplifier. It put out a whopping 30 watts per channel, but unlike my existing radio (a Readers Digest 800−XR), those 30 watts were nearly distortion free when driving good speakers. Having only the pathetic 5 W speakers that came with the 800-XR, I designed a set of speakers rated for 60 W, and built the enclosures myself in the base woodshop. Unfortunately, in preparation for a household move about 20 years ago, I sold the Sansui and the speakers ...

Today Is World Metrology Day!

Today Is World Metrology Day! - RF CafeIn case you forgot to put it on your calendar, today, May 20th, is World Metrology Day. To commemorate the occasion, this is the day that the official definition of the kilogram is being changed from a physical cylinder of metal to the equivalent mass (recall Einstein's E=mc2) derived from a photon energy-to-frequency ratio measured to its most precise value. Per the new definition, the magnitude of a kilogram would be "set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 069… × 10–34 when it is expressed in the SI unit s–1 m2 kg (J s) ..."

How Many Microhenrys in That Coil?

How Many Microhenrys in That Coil?, December 1931/January 1932 Short Wave Craft - RF CafeThis is a nice short article covering the calculation of inductances for coils wound on cores and wire sizes. It appeared in a 1932 issue of Short Wave Craft, but of course inductance has not changed since then so it is still relevant. The author recognized that standard formulas, although concise and accurate, are sometimes difficult to work with when calculations for a large number of values is needed for a particular circuit design. To address the situation, he presents a handy nomograph, chart, and a table of typical values. He also introduces a rarely seen term "Nagaoka's correction factor*" for skin effect. A smartphone app, a spreadsheet, or a desktop computer program would be used today to calculate inductance ...

Positive Threshold in GaN Transistors with P-Type AlTiO

Positive Threshold in GaN Transistors with P-Type AlTiO - RF Cafe"The Indian Institute of Science claims the first enhancement-mode (e-mode) operation of aluminum gallium nitride / gallium nitride (AlGaN/GaN) high-electron-mobility transistors (HEMTs) using p-type aluminum titanium oxide (AlTiO) gate insulation. The metal-oxide-semiconductor (MOS) gate stack combined the high-k dielectric properties of TiO2 (k greater than 60) with the p-type properties supplied by Al2O3 doping (k ~9). The Al2O3 substitutes the 2Als on Ti sites and the 3Os have a deficit of one vacancy that is doubly positively charged. The charged O vacancy can release two holes, which can subsequently be reabsorbed by uncharged O vacancies ..."

Approaching the 5G mmWave Filter Challenge

Approaching the 5G mmWave Filter Challenge - RF Cafe5G is providing plenty of challenges for filter designers. The issue is probably no so much achieving narrow bandwidths with extremely sharp rejection regions as implementation in available media. Peter Matthews, of Knowles Precision Devices, as an article entitled, "Approaching the 5G mmWave Filter Challenge," on the Microwaves & RF website that discusses some of the issues. "In the world of LTE, developers are very familiar with the available filtering technologies that work, namely surface acoustic wave (SAW) and bulk acoustic wave (BAW) filters. These filters cover a range of frequencies up to 6 GHz, come in small sizes and offer good performance-to-cost trade-offs ..."

Bittele Electronics: PCB Fabrication & Assembly

Bittele Electronics PCB Fabrication - RF CafeSince 2003, Bittele Electronics has consistently provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly services. It specializes in board level turnkey PCB assembly for design engineers needing low volume or prototype multi-layer printed circuit boards. Free Passive Components: Bittele Electronics is taking one further step in its commitment of offering the best service to clients of its PCB assembly business. Bittele is now offering common passive components to its clients FREE of Charge ...

Engineering & Science Crossword Puzzle for May 19

Engineering & Science Crossword Puzzle May 19, 2019 - RF CafeThis week's crossword puzzle will keep you busy for a while. 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 ...

For the Record: Technological Revolution

For the Record: Technological Revolution, May 1955 Radio & Television News - RF CafeThe 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?

What are the 8 Most Important Oscillator Specs? - RF CafeJim 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

Quiz on AC Circuit Theory, December 1970 Popular Electronics - RF CafeHere 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 Announces Opening of Eindhoven, Netherlands Office - RF CafeAltum 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 ..."

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

Changing the Light Bulb on a 1,500' Tower - RF CafeBack 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

Hams Help Trace "Mystery" Signal Disrupting Keyless Entry Devices - RF CafeThis 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 TechnologiesWindfreak 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 ...

How the J-K Flip-Flops

How the J-K Flip-Flops, January 1969 Radio-Electronics - RF CafeAn 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

Generating Multiple Phase Coherent Signals - RF CafeTesting 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

Acorns in Microwave Antenna - RF Cafe Video for EngineersThis 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

Glass Semiconductors Developed, January 1969 Radio-Electronics - RF CafeThe 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

Air Force Test of SHiELD Laser Weapon - RF Cafe"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 ..."

Cunningham on R/C: Edsel Murphy's Law

Cunningham on R/C: Edsel Murphy's Law, March 1972 R/C Modeler - Airplanes and RocketsOne 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 ...

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About RF Cafe
Kirt Blattenberger - RF Cafe Webmaster
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    Kirt Blattenberger,

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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