Today in Science History -
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
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
"Shawn Prestridge, Lead FAE Engineer
and U.S. FAE Team Manager at IAR Systems offers his insights and predictions
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
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
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
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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!
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...
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.
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,
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
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,
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
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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
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practical, efficient, and cost effective solutions for their projects' TE
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Considering that only three-and-a-half
decades had passed since the brothers Wright first flew their eponymous "Flyer"
off the sands of Kitty Hawk, North Carolina, it is pretty impressive to think
that by 1938 the majority of commercial air transport planes were under the
able control of electromechanical apparatus(es?). Rudder, elevator, aileron,
and throttle, driven by electrical servomechanisms rather than human hands
and feet, responded to the signals to analog computers fed data from onboard
barometer, accelerometer, level, and compass sensors, and from ground-based
radio directional beams. That was for mostly straight and level flight from
one fixed waypoint to another. An ability to program vectored flight paths
came later. This "Radio
Lands the Plane" article discusses progress being made in the realm of
completely automated landings. As can be seen, the framework for modern instrument
landings systems was being laid...
2.92 mm to SMPM mm Adapter Series are designed based on precision
microwave interconnection technologies. These adapter series are manufactured
to precise microwave specifications and constructed with male and female gender
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F-M interface combinations, passivated stainless steel body. Useful in laboratory
and productions test setups, prototyping, and production interconnections...
"A team at the University of Nottingham
used graphene, a material with high electrical conductivity, in an
ink-jet printing process to build up mesh together electronic structures
that can perform functions such as converting light into electricity. Related:
New 2D Materials Show Promise for Future Electronic Devices The approach demonstrates
a new way to use the material for 3D printing processes as well as provides
insight into the design of next-generation electronic devices, researchers
said. Led by Professor Mark Fromhold, head of the university’s School of Physics
and Astronomy, the team used quantum mechanical modeling to identify how electronics
move through 2D-material layers..."
Barkhausen-Kurz (B-K) oscillator is credited as being the first high power
microwave generator that exploited the electron transit time effect. It was
developed in 1920 by German physicists Heinrich Georg Barkhausen and Karl
Kurz. As this article's author points out, the vacuum tube and supporting
circuits were difficult to produce and were not very well understood theoretically.
Shortly thereafter, the magnetron and klystron tubes came along and dominated
the high power microwave generation realm. Included in Part II of "Microwave
- Generation of Microwaves" is a good, brief explanation of the operation
of both B-K and magnetron circuits...
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...