 Friday the 29th
Thursday the 28th
Wednesday the 27th
Tuesday the 26th
 Only a couple decades prior to when
this article on a newfangled
wireless automatic garage door opener
appeared in Radio-Craft magazine, there would have been no demand
for such a device ... although maybe an automatic horse barn door opener
would have been in demand if a battery was available on the coach.
Amazingly, the system employed an early, albeit crude, form of both spread
spectrum and digital communications in order to trigger the receiver for
opening the door. The spread spectrum characteristic of the signal was the
natural consequence of using a spark transmitter. A digital 'Morse' code
encryption allowed multiple openers to be installed in close proximity.
The opener did not have any type of safety sensor to prevent people or
things from being crushed, but then it wasn't until sometime around the
1970s that the feature became standard...
 It has been a while since I saw an
article discussing stability circles for amplifier design. Ain Rehman has
one posted on the High Frequency Electronics website entitled, "Understanding
Stability Circles." Even in the age of computer design and
optimization for just about everything, it always help to have a basic
understanding of what the result should look like as well as what affects
the result. He begins: "Stability circles are a tool, used to examine and
analyze the stability of an amplifier (in the case under discussion) using
a graphical technique, with the help of a Smith Chart. This monograph presents the stability circle tool for
engineers. It is understood that many CAD programs can generate these, but
it is always useful to understand the stability circle on an intuitive
level as a good engineering practice..."
 PCB
Directory is the largest directory of Printed
Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the
Internet. We have listed the leading printed circuit board manufacturers around
the world and made them searchable by their capabilities - Number of laminates used,
Board thicknesses supported, Number of layers supported, Types of substrates (FR-4,
Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services
(manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on
quotations for PCB fabrication and assembly.
Monday the 25th
 I learned a
new word from this Radio-Craft article: "chemurgic," which refers
to chemurgy, the science of creating products such as soybean gear shift
knobs and cellulose movie film from agricultural raw components. It has
nothing to do with the story other than to describe the town in which the
subject, Wesley Rushing, lived. As the title suggests, Mr. Rushing
established and thrived at a
radio repair business built while confined to bed with a crippling
illness. He worked an average of 10 hours per day and repaired two hundred
radios each month. Although not a veteran himself due to his sickness, the
story was offered as a means of support to the thousands of returning
World War II veterans who suffered disabilities in battle. Today's
handicapped veterans need and deserve similar encouragement, so if you
have a can-do story, please submit it to one of the trade or hobby
magazines; it will be greatly appreciated by many...
 "Shawn Prestridge, Lead FAE Engineer
and U.S. FAE Team Manager at IAR Systems offers his insights and predictions
about
embedded development - the technology, markets, and tools - in 2021. We’ve
seen R&D groups at large customers dabble with RISC-V to see if they want
to base a platform on it, and we've seen smaller customers start to use it.
A few large companies have really committed to using it in at least some business
units. While part of the RISC-V trace specification was ratified this past
February, there will still be a few tweaks made in 2021. Ultimately, you'll
see a good deal of high-quality debug information like live instruction trace,
interrupt visibility, power usage, and other metrics that can be fed through
the debug port. Amongst other things, this will truly empower embedded developers
to produce..."
 Carl Novello has an interesting article
on the Electronic Design website entitled, "Gain
Efficiency with Fragmented-Aperture Phased Arrays." I've always been skeptical
of repetitive, pixelated type antenna patterns like the use of fractals and
the seemingly random pattern (but probably computer optimized - looks
 like
shapes from
Space
Invaders) used here.
Evidently, there is something to it, though. He begins: "The world's demand
for broadband connectivity has created a new generation of high-throughput
satellites in geosynchronous Earth orbit (GEO), medium Earth orbit (MEO),
and now low Earth orbit (LEO). But technology innovation in the ground segment
has struggled to catch up to the space segment, especially when it comes to
developing the most elusive of all antennas: Those that are low-cost and electronically
steerable to power these next-generation, lower-orbit satellite networks.
Electronically steerable antennas (ESAs), often referred to as flat panels..."
 Anyone visiting RF Cafe (other than
by accident) almost certainly knows of Drs. Bardeen, Brattain and Shockley
fame for their
transistor invention while jointly working at the Bell Telephone Laboratories.
The trio shared The Nobel Prize in Physics in 1956. Bell was so proud of their
employees' efforts that they ran full page advertisements to boast of the
accomplishment. This one appeared in the February 1957 edition of Radio &
Television News. Alas, Ma Bell's moment of glory was a bit diminished
by needing to add a footnote admitting that Drs. Bardeen and Shockley no longer
work there. Note that while the ad says the transistor was announced in 1948,
the first demonstration to Bell managers was in December of 1947...
 This story, submitted by RF Cafe visitor
Jerry L., of Cincinnati, OH, reminds me of a certain manager in a popular
engineering comic strip. Do you have a good work-related anecdote to share
in the "Out of Order"
feature? Please email it to me for consideration. Jerry Writes: "I worked
in the defense electronics industry for my entire career and it is hard to
think of a project in more than four decades that was not made infinitely
more difficult due to the 'helpful' input of project managers. One experience
in particular comes to mind as a perfect topic for your Out of Order feature.
In the mid 1970s I was a "fresh-out," as new engineering college graduates
were called at the time. Newly minted as a Masters degreed electrical engineer,
my aspirations were high and I was ready to set the mobile radio system world
on fire. A synergistic combination of my own zeal and aptitude (I earned my
Ham license at age 16) with that of a seasoned engineer mentor...
 Empower RF Systems is a global leader
in power amplifier solutions. Empower RF Systems is an established and technologically
superior supplier of high power solid state RF & microwave amplifiers.
Our offerings include modules, intelligent rack-mount amplifiers, and multi-function
RF Power Amplifier solutions to 6 GHz in broadband and band specific
designs. Output power combinations range from tens of watts to multi-kilowatts.
Unprecedented size, weight and power reduction of our amplifiers is superior
to anything in the market at similar frequencies and power levels.
Sunday the 24th
 This Science Theme crossword puzzle
for January 24th contains only words and clues related to engineering, mathematics,
chemistry, physics, and other technical words. As always, this crossword contains
no names of politicians, mountain ranges, exotic foods or plants, movie stars,
or anything of the sort unless it/he/she is related to this puzzle's technology
theme (e.g., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
Friday the 22nd
 The January 1951 issue of Radio-Electronics
magazine had a big collection of
electronics-themed comics - five of them. All of them are pretty good,
and you don't need to have been there during the early TV era to appreciate
the humor. The comic from page 127 is a good first step in troubleshooting
for today, and is usually at the top of the problem solving section of consumer
gear throughout the electronic age. The page 126 comic is an oft-used gag
for garage-related funnies. Although not directly related, it reminds me of
how early wireless garage door openers had their antennas stretched underneath
of the car...
 All
RF Cafe Quizzes make great fodder
for employment interviews for technicians or engineers - particularly those
who are fresh out of school or are relatively new to the work world. Come
to think of it, they would make equally excellent study material for the same
persons who are going to be interviewed for a job. This quiz is based on the
information presented in Multi-Gigabit
Microwave and Millimeter-Wave Wireless Communications, by Jonathan Wells.
 "Characterizing
microstrip superconducting film at millimeter-wave frequencies is difficult
without undergoing a complex thin film fabrication process. This characterization
includes measuring the ohmic loss at a resolution of 10100 parts per million
(ppm). Typically, characterizing microstrip superconducting film utilizes
antenna-coupled bolometers as part of the superconducting film structure.
Bolometers are components that measure incident electromagnetic radiation
via the heating of a material with a temperature-dependent electrical resistance;
however, this process is disadvantageous as embedded detectors, such as bolometers,
make the superconducting film fabrication process more difficult. This process
also requires various millimeter-wave components, further complicating film
fabrication. Additionally, characterizing superconducting film..."
 In 1945, when this article was published
in QST magazine, radar was still in its infancy. Engineers were already
aware of the need to shape pulse waveforms from experience with CW keying
and the need to mitigate the effects of "chirping." A perfectly rectangular
pulse in the time domain, as we learned in our signals and systems courses,
creates a
sin (x)/x response in the frequency domain. The Fourier transform shows
that a perfectly square pulse in the time domain is the summation of an infinite
number of odd harmonics of the fundamental (1st harmonic). The first few harmonics
are audible to the CW copier as higher frequency "chirps." To reduce the annoyance
(and wasted transmitted energy), time constants were added to the leading
and trailing edges of the waveform to remove the higher frequencies, while
leaving the pulse shape sufficiently rectangular to achieve its goal. The
same type issue applies to radar pulses...
 Here's a trip down Memory (640 kB)
Lane for those of us around during the early PC days, using MS−DOS. EDN
magazine has been running their column "Tales from the Cube"
(a take-off of the equally long ago "Tales from the Crypt" TV show) where
readers submit sagas of (usually) troubleshooting experiences. Most often
the problem is the result of an intermittent event or of human error (pronounced
"stupidity"). This is a case of the latter. If you fondly recall the times
when 256-color
VGA
CRT monitors,
3½" floppy disks, 20 MB hard drives, and an
i80287 math coprocessor
were to die for, when you were deemed a computer expert if you could write
batch files, and half your computer's CPU power was not consumed by antivirus
programs (no WWW,
just Kermit
for local net access), then you might like this "The Mysterious
MS-DOS Reboot" anecdote by Robert Yankowitz. Enjoy!
 RF
Cafe's raison d'être is and always has been to provide useful, quality content
for engineers, technicians, engineering managers, students, and hobbyists.
Part of that mission is offering to post applicable
job openings. HR department
employees and/or managers of hiring companies are welcome to submit opportunities
for posting at no charge. 3rd party recruiters and temp agencies are not included
so as to assure a high quality of listings. Please read through the easy procedure
to benefit from RF Cafe's high quality visitors...
 Axiom Test Equipment allows you to
rent
or
buy test equipment, repair test equipment, or
sell or trade
test equipment. They are committed to providing superior customer service
and high quality electronic test equipment. Axiom offers customers several
practical, efficient, and cost effective solutions for their projects' TE
needs and is committed to providing superior customer service and high quality
electronic test equipment. For anyone seeking a way to offload surplus or
obsolete equipment, they offer a trade-in program or they will buy the equipment
from you. Some vintage items are available fully calibrated. Please check
out Axiom Test Equipment today!
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White Paper Showcases Capabilities in Cadence Software for 5G/6G Design
Challenges
RfCaFe
autodidacts
Electronics-Themed
Comics June 1951 Radio-Electronics
 RF Cafe typically receives 8,000-15,000
website visits each weekday and about half that
on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists,
and students all over the world. With more than 13,000 pages in the Google
search index, RF Cafe
returns in favorable positions on many types of key searches, both for
text and images. New content is added on a daily basis, which keeps the major
search engines interested enough to spider it multiple times each day. Items
added on the homepage often can be found in a Google search within a few hours
of being posted. I also re-broadcast homepage items on LinkedIn. If you need
your company news to be seen, RF Cafe is the place to be.
Advertising begins at $40/month.
 RF Cascade Workbook 2018 is the next phase in the evolution
of RF Cafe's long-running series, RF Cascade Workbook. Chances are
you have never used a spreadsheet quite like this (click
here for screen capture). It is a full-featured RF system cascade parameter
and frequency planner that includes filters and mixers for a mere $45. Built
in MS Excel, using RF Cascade Workbook 2018 is a cinch and
the format is entirely customizable. It is significantly easier and faster
than using a multi-thousand dollar simulator when a high level system analysis
is all that is needed. An intro video takes you through the main features...
 With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and
schematic drawings! Every object has been built to fit proportionally
on the provided A-, B- and C-size drawing page templates (or can use your
own). Symbols are provided for equipment racks and test equipment, system
block diagrams, conceptual drawings, and schematics. Unlike previous versions,
these are NOT Stencils, but instead are all contained on tabbed pages within
a single Visio document. That puts everything in front of you in its full
glory. Just copy and paste what you need on your drawing. The file format
is XML so everything plays nicely with Visio 2013 and later...
 This assortment of custom-designed
themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee
Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly
clever "We Are the World's
Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow
Chart." My "Matchmaker's" design has been ripped off by other people and used
on their products, so please be sure to purchase only official RF Cafe gear.
My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your
purchase price. These would make excellent gifts for husbands, wives, kids,
significant others, and for handing out at company events or as rewards for
excellent service. It's a great way to help support RF Cafe. Thanks...
RF
Cafe's raison d'être is and always has been to provide useful, quality content
for engineers, technicians, engineering managers, students, and hobbyists.
Part of that mission is offering to post applicable
job openings. HR department
employees and/or managers of hiring companies are welcome to submit opportunities
for posting at no charge. 3rd party recruiters and temp agencies are not included
so as to assure a high quality of listings. Please read through the easy procedure
to benefit from RF Cafe's high quality visitors...
|
 "EPFL engineers have developed a computer
chip that
combines
two functions - logic operations and data storage - into a single architecture,
paving the way to more efficient devices. Their technology is particularly
promising for applications relying on artificial intelligence. It's a major
breakthrough in the field of electronics. Engineers at EPFL's Laboratory of
Nanoscale Electronics and Structures (LANES) have developed a next-generation
circuit that allows for smaller, faster and more energy-efficient devices—which
would have major benefits for artificial-intelligence systems. Their revolutionary
technology is the first to use a 2-D material for what's called a logic-in-memory
architecture, or a single architecture that combines logic operations with
a memory function. The research team's findings appear today in Nature..."
 "Why do some thin films of single-wall
carbon
nanotubes
take on colourful hues even though as-synthesized films are usually black?
A team of researchers in Finland, the US and China has now come up with a
possible answer in a development that could prove useful for future display
screens and solar cells. Single-wall carbon nanotubes (SWCNTs) are rolled-up
sheets of carbon just one atom thick, with a diameter of about 1 nm. Atoms
in these sheets are arranged in a hexagonal lattice and the direction in which
the sheet is rolled - its chirality - dictates whether the tube is a metal
or a semiconductor. When these SWCNTs are sorted by their diameter or chirality
- two traits denoted by an '(n,m)' numbering system..."
 "The first full-electric power and
propulsion surface combatant, the USS Zumwalt, has been delivered to the US
Navy. The
electric propulsion solution delivers efficiency, survivability, cost-of-ownership
reductions, and system redundancy for enhanced vessel safety. In addition,
machinery layout is more flexible and configurable. GE's Power Conversion
business was the designer and provider for the high-voltage system (HV), propulsion
drive trains consisting of multiphase converters and Advanced Induction Motors
(AIM) for the DDG 1000 class of futuristic destroyers. 'Delivery is an important
milestone for the Navy, as the DDG 1000 continues more advanced at-sea testing
of the Zumwalt Combat System..."
 "Coffee
is one of the most widely consumed beverages in the U.S. and worldwide. Americans
consume
400 million cups per day, making the U.S. the world's leading consumer
of coffee. E-commerce and coffee go hand-in-hand. As the market grows - and
becomes more competitive - coffee companies are coming up with more creative
ways to get their products to online consumers. The E-Commerce Times recently
spoke with coffee and e-commerce experts to get their views on what's involved
in successful online coffee sales. Selling coffee online was very popular
even before the pandemic hit, which, of course, increased demand for all goods
online..."
 "The U.S.
Department of Defense (DoD) has released a plan to counter the increased
threats posed by the proliferation of
small drones commercially and by militaries. In a 36-page strategy
released on January 2021, strong emphasis has been placed on inter-agency
cooperation in the federal government to develop a baseline of knowledge,
solutions, infrastructure, and response to counter small, unmanned
aircraft systems (sUAS) threats. Small drones have become increasingly
affordable and portable with growing capabilities, such as the ability to
swarm and carry out cyberattacks, all of which could be enhanced with the
use of artificial intelligence and autonomous systems..."
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