Today in Science History -
 This
Science & Math Crossword Puzzle for April 18th has many words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. 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.,
Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
 Radio-controlled flying drones are commonplace
today - so much so that the FAA has enacted legislation to strictly limit who can
fly them, where they can be flown, how big they can be, what type of payloads can
be carried, how far from the pilot they can be flown, etc. - the typical kind of
overreaching and overregulating that governments promulgate (especially in the last
few years). Sport model airplane flying has suffered loss of freedoms because of
it by getting lumped in with multirotor drones. The military, of course, has been
using radio-controlled drones for decades, as highlighted in this 1945 Radio-Craft
magazine article. Author Louis Bruchiss extolls the advantages of being able to
guide an ordinance payload after being released from an aircraft of after being
launched...
 Is this cool or what? Of course I'll never
be able to afford one (maybe an R/C model someday, though). "Electric boats of all
shapes and sizes are beginning to make a splash in the maritime sector. It's estimated
that maritime greenhouse gas emissions account for around 2.5% of the global total,
marginally ahead of the 2% that aviation contributes. If shipping were a country,
it would be the sixth largest emitter of CO2 after China, the USA, India, Russia
and Japan. International shipping - much like long-haul flight - will not be electrified
any time soon, as the energy density of batteries simply cannot facilitate it. And
for an industry that's recently committed to halve its emissions by 2050..."
 Is this the future of engineering, science,
medicine, economics, and all other math-intensive fields? If it is, we're in trouble.
"A
Pathway to Equitable Math Instruction Dismantling Racism in Mathematics Instruction"
is being considered for incorporation into school curriculums across the country.
Its premise is that requiring students to arrive at the correct answer is White
supremacy (p1), and that any wrong answer is the fault of the teacher, who needs
to "Recognize mistakes as miscommunicated knowledge." (p9) Get that? If a student
screws up, it's not her fault. It is worth a few minutes of your time to look through
this. I guarantee you that China demands correct answers of their math students.
They are laughing at idiot school systems in the U.S. We're doing their work for
them in achieving global technical dominance. The training manual was funded by
the Bill and Melinda Gates Foundation. Should we expect future releases of Windows
to adopt the anti-White supremacy, results are interpretive philosophy? A
BSoD is coming
to a computer near you. Apple will need to purge the racist objective measures from
their OS as well.
 This quiz is based on the information presented
in "Introduction
to Infrared and Electro-Optical Systems," by Ronald G. Driggers and Melvin H.
Friedman. 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.
 Here is another exciting episode of the sleuthing
adventures starring Popular Electronics' tech savvy teenagers, Carl and
Jerry. The "Hardy Boys of electronics" are the creation of author John T. Frye,
who created short story adventures for many years - long enough to at one point
require a major modification in the boys' appearances to reflect more modern attire
and eyewear (Carl's "The Far Side"-style glasses had to go). This particular adventure
begins with Carl considering whether his ham radio hobby is more useful from the
standpoint of its technical aspects or of its social aspects. An unrelated electronics-themed
comic is included since it appeared on one of the story pages.
 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...
 Atenlab has been operating in Taiwan for
more than a decade, and has sold and installed hundreds chambers around the world.
Holistic, affordable Over-the-Air
(OTA) measurement systems perform comprehensive measurement and test in a controlled
environment. Compact Antenna Test Range (CATR) with one-touch operation supports
multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA
measurement systems offer reduced time measurements over single-probe systems.
 Windfreak Technologies announces the availability
of the new
SynthHD Mini RF Signal Generator. The SynthHD Mini is the smallest 10 MHz
to 15 GHz RF Signal Generator in the world - a mere 1.60 x 1.60 x 0.48 inches
(4.06 x 4.06 x 1.22 cm). Expect excellent performance despite the ultra-small
size and price of this device. Tune any frequency between 10 MHz and 15 GHz
in 0.01 Hz resolution. Adjust calibrated amplitude in 0.01 dB resolution
up to +20 dBm and across more than 30 dB of range. Perform FM, AM, Pulse,
Sweep, and List Modulations. See the Tabs below to download a full datasheet and
other documents. Windfreak Technologies has set the bar on microwave radio frequency
generators for quality, size, and price. As always, our products are designed and
manufactured in the USA! In Stock.
 "Sensors that can detect magnetic fields
have many potential applications, for instance, in the development of sophisticated
medical devices and transportation systems. Most approaches for
detecting 3D magnetic fields developed so far, however, require several sensors,
which makes them bulky and difficult to implement on a large-scale. With this in
mind, researchers at the Nanoscale Energy-Efficient Device and System (NEEDS) Lab
at Huazhong University of Science and Technology in China set out to develop a single
spin-orbit device that can individually detect 3D magnetic fields. The device they
designed, presented in a paper published in Nature Electronics and inspired by their
previous work, is based on a Ta/CoFeB/MgO (tantalum / cobalt-iron-boron / magnesium
oxide) heterostructure..."
 American physicists Carl Anderson and Seth
Neddermeyer were studying cosmic rays when they discovered the
muon in 1936. The discovery of
this particle was so surprising that Nobel laureate Isidor Isaac Rabi exclaimed:
"Who ordered that?" Dr. Rabi
was an American physicist who won the
Nobel Prize
in Physics in 1944 for his discovery of nuclear magnetic resonance and was a
pioneer in the development of the
cavity magnetron.
 So much time has passed since an average
home garage mechanic could service his car or truck with standard tools - combination
wrenches, screwdrivers, socket sets, timing light, and a multimeter - that asking
"remember when?" is passé. That era pretty much ended in the late 1980s as computerized
cars were becoming the industry norm. A good percentage of people nowadays have
never and will never service their own vehicles. In the mid 1940s, the electronics
world was lamenting a similar situation with diminishing ability to build and modify
electronic components like coils and stacked plate capacitors because of the increasingly
higher frequencies being used in communications (way up into the UHF band!). This
article introduces the
klystron
tube, having been around for less than a decade at the time, as being one of
the culprits that was enabling the disturbing trend...
 I first saw this amazing photograph in the
April 2012 issue of Astronomy magazine. It is an
8-year-long image of the sun's path across the sky as recorded by by Fine Art
student Regina Valkenborgh from August 2012 through September 2020. She lined some
beer cans with photographic paper and punched a tiny hole in the can, mounted them
in locations around an observatory in the UK, then forgot about them. Most perished,
but this one survived and was found by a staffer. Ms. Valkenborgh now has the
honor of being responsible for the longest-ever photographic film time exposure.
Pinhole cameras have no lens, since light rays entering the container follow
a nearly singular path to the film surface. The smaller the hole, the sharper the
focus. Less light enters the camera, so a longer exposure time is required. Pointing
it at the sun provides an intense source of light, but it is still little enough
to not overwhelm the film over a period of 8 years.
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio
Stencils 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). Stencils 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...
 Triad RF Systems designs and manufactures
RF power amplifiers
and systems. Triad RF Systems comprises three partners
(hence 'Triad') with over 40 years of accumulated
knowledge of what is required to design, manufacture, market, sell and service RF/Microwave
amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating
amplifiers are available, in formats including tower mount, benchtop, rack mount,
and chassis mount. "We view Triad more as a technology partner than a vendor for
our line-of-sight communications product line." Please check to see how they can
help your project.
 Here in this 1954 issue of Radio &
Television News magazine is one man's (Commander Paul G. Watson, USNR (ret.)
collection of early vacuum tubes and a bit about them. It reaches back to Dr. Lee
de Forest's farther than even earliest Audion tubes - including the "UltraAudion"
- to include the flame-based detector and amplifiers he worked on. For a very thorough
history of de Forest's work from the vantage point of both the good Dr. and
those who worked with him, including a story by William Howard McCandless (the man
who's glass blowing business built the various tubes for de Forest), check
out the January 1947 issue of Radio-Craft magazine. It celebrated the 40th
anniversary of the de Forest Audio tube. I wonder where this collection of
tubes is today. Many priceless collections of technical history artifacts end up
being mistakenly or ignorantly disposed of...
 "Total
semiconductor
unit shipments, which include integrated circuits as well as optoelectronics,
sensor/actuator, and discrete (O-S-D) devices, are forecast to rise 13% in 2021,
to 1,135.3B (1.1353T) units to set a new all-time annual record, according to IC
Insights' McClean Report - A Complete Analysis and Forecast of the Integrated Circuit
Industry. It would mark the third time that semiconductor units have surpassed one
trillion units in a calendar year - the first time being in 2018. The 13% increase
to 1,135.3B semiconductor units follows a 3% increase in 2020..."
 This quiz is based on the information presented
in
Conquer Radio Frequency, by Francesco Fornetti. See my review for the online
version. This material, which includes a full-color textbook and over 12 hours of
video tutorials (in mp4 format on enclosed DVD-R), provides a comprehensive guide
for the RF and Microwave engineering student or junior professional. It allows the
reader to achieve a good understanding of the foundation theory and concepts behind
high frequency circuits as well illustrating the most common design and simulation
techniques for passive and active RF circuits. A preview of the textbook, a comprehensive
description of the content of the video tutorials and sample video tutorials are
available on the Explore RF website.
 Edel Cashman has a good article on the Electronic
Design website entitled, "The
Engineering Essentials Behind LiDAR." LiDAR works by the same principles as
sonar and radar, but rather than sound and radio frequencies, it uses light. Its
extremely short wavelengths makes it ideal for high precision positioning and navigation
- such as with autonomous vehicles. Mr. Cashman (great name, BTW!) begins,
"LiDAR (light detection and ranging)... applies the principles of reflected light
and accurate timing to measure the distance of an object. LiDAR permits superior
depth sensing due to its high levels of depth and angular resolution. In addition,
it's able to operate in all light conditions due to the active approach that uses
an infrared light transmitter along with a receiver. However, LiDAR is more sophisticated
than just a distance measure. It can also be used in 3D mapping and imaging, making
it very appealing in an engineering context..."
 At least for now, I am going to only scan
and post Radio Service Data Sheets like this one featuring the
Belmont 4-Tube Model 408 (Series A) Battery "Farm" Superhet radio in graphical
format, rather than run OCR on them to separate the textual content. It appeared
in the October 1938 issue of Radio-Craft magazine. There are still many
people who restore and service these vintage radios, and often it can be difficult
or impossible to find schematics and/or tuning information. No example of this radio
could be found on the WWW...
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