crossword puzzle for December 11th sports an electronics theme. This being the
eleventh day of the month, many of the words begin and/or end with and/or contain
the letter "K" (denoted by an asterisk). All RF Cafe crossword puzzles are custom
made by me, Kirt Blattenberger, and have only 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, Hedy Lamarr, or
the Tunguska event in Siberia). The technically inclined cruciverbalists amongst
us will appreciate the effort. Enjoy!
This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We
Are the World's Matchmakers" Smith chart design. These would make excellent
gifts for husbands, wives, kids, significant others, and for handing out at company
events or as rewards for excellent service. My graphic has been ripped off by other
people and used on their products, so please be sure to purchase only official RF
Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press.
It's a great way to help support RF Cafe. Thanks...
Long distance radio
communications made significant advances during World War II. It had to. With as
widespread and intense as fighting was, war rooms needed as much and as accurate
information as possible from land, sea, and air forces. Satellite systems were
more than a decade away when this news item on RCA Radiograms appeared in a 1947
issue of Popular Science magazine. While improved transmitters, receivers, and
antennas were extremely important, perhaps the most significant factor in
achieving reliable, predictable long distance communications was a better
understanding of the Earth's upper atmosphere and how it affected the
transmission of electromagnetic waves. No direct measurements of ionospheric
heights and conduction levels had been made at the time, so it was a combination
of theoretical and operational experience that determined parameters necessary
for success. After the war, when some strategic secrets were divulged to the
public, businesses and even private citizens were able to enjoy the newfound
benefits. Many of the companies that helped develop the wartime technology were
able to exploit that effort afterward...
"It would be an overstatement to say that
the modern world runs on
But as overstatements go, that one has more than a grain of truth. Because of their
unique luminescent, electrochemical, and magnetocrystalline properties, rare-earth
elements are essential to some of the most important and fastest-growing tech-based
industries. They're used in the phosphors that make white-light and other LEDs possible,
and they're in compounds used to purify key semiconductor materials such as silicon
carbide and gallium nitride, to indicate just a couple of their scores of applications
in technology. Perhaps most importantly, though, they're essential components of
the permanent magnets used in the motors of most electric vehicles and many appliances,
and also in the generators in most wind turbines. As much as 90 percent of processed
rare-earth elements come from China, a supply-chain dependence that spooks Western
executives and, especially, defense officials. That critical importance of rare-earths
in so many tech industries is of mounting concern in many Western countries. As
much as 90 percent of processed rare-earth elements come from China, a supply-chain
dependence that spooks Western executives and, especially, defense officials. Rare
earths are vital to countless military applications, including night-vision goggles,
As radio equipment builders and
operators, we still battle two fundamental issues that have been around since
the beginning of time (well, from Marconi's time, anyway) -
grounding and power supply fluxuations. Both topics are addressed briefly
here in this editorial column from a 1932 The Wireless World magazine. Back in
the day, grounding was referred to as "earthing," and was/is essential to
optimal wireless and wired performance. Line voltage "fluxuations"
(fluctuations) are generally much less severe today than in the 1930s thanks to
better transformers, automated monitoring and adjusting of line voltages, and
better distribution designs. The worst type of power line fluxuation - a
lightning-induced surge - has been greatly reduced thanks to superior
engineering, primarily by the simple running of a grounded neutral "static" wire
running at the top of all the lines below it on utility poles and transmission
Considering medical-diagnosis and other
safety-critical, sensory-processing applications that require accurate decisions
based on a small amount of noisy input data, the study notes that while Bayesian
neural networks excel at such tasks because they provide predictive uncertainty
assessment, their probabilistic nature requires increased use of energy and computation.
The increase is caused by the fact that implementing the networks in hardware requires
a random number generator to store the probability distributions, i.e. synaptic
weights. "Our paper presents, for the first time, a complete hardware implementation
of a Bayesian neural network utilizing the
intrinsic variability of memristors to store these probability distributions,"
said Elisa Vianello, CEA-Leti chief scientist. "We exploited the intrinsic variability
of memristors to store these probability distributions, instead of using random
number generators." A team comprising CEA-Leti, CEA-List and two CNRS laboratories...
Hughes Aerospace has many openings for qualified
design engineers in Culver City, California. High power airborne transmitters, low
noise receivers using parametric amplifiers, solid state maser component development,
radar processing systems, crystal oscillators, telemetering, and high efficiency
spaceborne power supplies are among the kinds of specialties needed by Hughes to
support military and civilian projects. If you have been looking for just such an
opportunity, then the wait is finally over... provided you happened to see this
advertisement in Electronics magazine back in the fall of 1965. Quiz question:
What is the difference between a geosynchronous orbit and a geostationary orbit?
Beginning in the early days of World War II,
Hitler's navy was laying mines in the water that were
triggered by the magnetic field surrounding the metallic hulls of military and
merchant ships. They usually floated just below the surface or even lay on the sea
floor near shallow ports so as to avoid visual sighting, and then would detonate
when ships passed overhead. It was like laying a spring leg trap on the ground and
covering it with leaves. The ship's crew would never see it coming. The magnetic
mines were as deadly and menacing as any U−Boat. The problem was so dire that by
January 8, 1940, British engineers and flight crews had successfully designed and
implemented a system for detonating the magnetic mines using a Vickers Wellington
bomber fitted with a 51' diameter electromagnetic coil under its belly, powered
by a Ford V−8 engine. The system was called Directional Wireless Installation (DWI).
Because the war in Europe was still in progress, not much detail could be obtained
or printed in 1943 when this news bit appeared in Popular Mechanics magazine...
The Christmas holiday season is here officially
now that Thanksgiving is over. When deciding which articles from vintage electronic
magazines to post, I always try to pick a few that pertain to specific holidays,
like Christmas, Independence Day (aka 4th of July), Halloween, etc. Many companies
ran magazine advertisements - often full-page - in QST, Radio News,
Electronics World, etc. Here is one by the Kenton Transformer Company,
of New York, New York. It alludes to the military buildup that America was conducting
in anticipation of being drawn into the battles which had been going on for two
years already in Europe, North Africa, and the South Pacific. That it appeared in
the very issue of QST that was being delivered just about the time Japanese
attacked Pearl Harbor on December 7th of that very year is the epitome of irony
(or prognostication). Now, I'm not trying to start anything here, but the name Kenyon
is probably pronounced the same as for a person who comes from the country of Kenya
(i.e., Kenyan). I also noted the company's address is 840 Barry Street. Have you
heard of Barry Soetoro? I'm just say'n...
Tim H. will be triggered
by this! "In the latest episode of Brains and Machines, EE Times regular
Dr. Sunny Bains talks to Professor Melika Payvand, who designs neural systems from
the circuit-level up at the Institute of Neuroinformatics in Zurich. You'll find
out the role that memristors are playing in the systems she designs, why neural
circuits need to operate at different timescales, and why copying some features
of biological dendrites could add computational power to silicon brains. Discussion
follows with Dr. Giulia D'Angelo from the Italian Institute of Technology and Professor
Ralph Etienne-Cummings from Johns Hopkins University. Welcome to Brains and Machines,
a deep dive into neuromorphic engineering and biologically inspired technology.
In this episode, EE Times regular Sunny Bains talks to Professor Melika Payvand,
who designs neural systems from the circuit-level up at the Institute of Neuroinformatics
in Zurich. You'll find out the role that memristors are playing in the systems she
Admittedly, the only thing I remember about
Gray Code (aka reflected binary) from college courses is that successive count
values change only one bit per increment, saving power in some digital circuits.
The power savings comes from the fact that, especially for CMOS circuits, current
only flows during the transition of a state change from "0" to "1" or from "1" to
"0." Shaft position encoders were and still are a primary application of Gray Code
switching. If the encoder output digital code is going to be used in a binary computation
system, then there is an advantage in generating a direct binary ("natural") count
that does not require a Gray-Code-to-Binary conversion circuit (or software routine).
When the Wayne-George Corporation introduced its paradigm-changing "Natural Code
Non-Ambiguous Optical Encoder" in 1964, those conversion circuits were probably
not simple, compact, inexpensive semiconductor IC's, but more likely vacuum tube
behemoths. Even if IC's were used, the conversion circuit would have been comprised
of quad packs of AND's, OR's, NAND's, and NOR's, not even a single application...
It was a lot of work, but I finally finished
a version of the "RF & Electronics Schematic & Block Diagram Symbols"" that
works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This
is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector,
waveguide, digital, analog, antenna, and other commonly used symbols for system
block diagrams and schematics created for Visio™. Each of the 1,000 or so symbols
was exported individually from Visio in the EMF file format, then imported into
Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down
without becoming pixelated, so all the shapes can be resized in a document and still
look good. The imported symbols can also be UnGrouped into their original constituent
parts for editing. Check them out!
Although I have never experienced it myself,
I have it on good authority (Mac MacGregor) that the odor which emanates from a
burned up selenium rectifier is very foul. Those were the first form of "tubeless"
rectifiers. Legend has it that TV and radio repairmen could sometimes smell the
burnt up rectifier in a high voltage circuit upon walking into a house on a service
call. My own troubleshooting methodology for anything electrical - circuit board,
motor, even cables and connections - consists of a careful
visual and smell test. Unless very high current is involved, there usually is
not a failure betraying hint of either type on today's low power products. Often
when the ballast of an old commercial fluorescent light fixture fails, it sends
out a nasty hot tar smell. A couple times a year back in elementary, junior high,
and high school (1960s-1970s) that odor would permeate the classroom and hallway.
Although this article from a 1965 issue of Popular Mechanics magazine specifically
refers to TVs, the same principle goes for any malfunctioning electronic device.
I remembered and found the Peanuts comic shown in the thumbnail where Snoopy declares
regarding the suitability of his dinner, "The eye can be deceived, but the nose
knows." That is pretty much universally true...
Continuing its tradition of creating wall
calendars with a test equipment theme, Axiom Test Equipment just announced the availability
of their year
2024 "Test Equipment Museum" calendar. In the past, Axiom's calendars juxtaposed
an unrelated topic with various types of test equipment to result in a clever melding
of the two. The 2022 "Top Hits" calendar used historic rock music bands. "Traveling
Through Time," in 2023, references notable historical eras. This "Test Equipment
Museum" calendar presents both a modern piece of test equipment next to a vintage
version of the same type. For example the month of January has both a circa 1948
Associated Research Hypot Junior 412 instrument and a modern Associated Research
7804 Hypot model. That represents more than half a century technology evolution
by the same company. Both were/are used to test the ability of electronic assemblies
to withstand high voltage potentials without breaking down. Another example of a
company's extensive history with the same product type is the April page with a
1964 era HP 851A Spectrum Analyzer and a modern Keysight N9020B Spectrum Analyzer.
Axiom really reached back for the June exhibit by showing a 1920s-30s B-Battery
Eliminator RT−40 high voltage direct current power supply. "B" batteries had a nominal
output at 45 volts...
If you are typing on your computer or phone
(which is actually more of a computer than a phone) and you need to create a character
other than the standard keyboard set, most programs provide a means to access extended
characters either with a menu selection or an ability to enter ASCII extended character
set codes into the source code. At most, it takes a couple additional keystrokes
(assuming you know how to do it). Back in the days of typewriters, the task was
nowhere near as easy. Some manufacturers of typewriters had the replaceable balls
for allowing a variety of typefaces and fonts, often including one with special
and engineering characters. Those required the typist to reserve space on the
page for the characters, swap out the ball, then go back and fill in the blanks.
It was tedious and error-prone. There is often a noticeable shift in the character
baseline compared to all the rest in the line. The Mechanical Enterprises company
produced an add-on gadget called the TYPIT that needed to be attached to the typewriter
and allowed interchangeable character die to be quickly inserted and removed as
the need required. More than a thousand characters were available...
You have to admire the mechanical and artistic
mastery of these ancient relics. Designing mechanisms around complex physical and
mathematical principles required multiple forms of genius. This one does not present
planet positions, which was difficult prior to Copernicus' heliocentric solar system
model. Replicating retrograde motion of inner planets is quite involved based on
the previous geocentric model. "The
Prague Astronomical Clock is one of the city's most popular landmarks (YouTube). It is well over
600 years old and is one of the oldest functional astronomical clocks in the world.
Like other astronomical clocks, the famous Prague example is effectively a specially
designed mechanism to display astronomical information. Many, like the Orloj, tend
to show the relative positions of the Sun, Moon, Zodiac constellations and, sometimes,
other planets. The astronomical clock in Prague, otherwise known as The Orloj, does
all this, and much more. It tells the time, provides the date, shows astronomical
and zodiacal information, and, best of all, provides some theatre for its viewers
on the hour, every hour."
France's A-1 (aka "Astérix") satellite launch
in November of 1965 made it the sixth country to place a satellite in orbit - behind
Russia, USA, the UK, Canada, and Italy, respectively. Astérix's primary mission
was to test the booster rocket, and verify the ground tracking networks. Onboard
were a radar transponder, a tracking beacon, and a telemetry transmitter. Due to
a presumed damaged antenna, received signals from the beacon were very weak and
only lasted for two days. Although initially France relied on U.S. contractors for
much of its hardware (mechanical and electronic), it endeavored to develop and produce
the majority of the required technology in-country. Note that the commemorative
postage stamp issued by Ecuador uses the same picture of the Diamant-A rocket booster
that is in this December 1965 Electronics magazine article...
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Stencils available for RF, analog, and digital system and schematic drawings!
Every stencil symbol has been built to fit proportionally on the included A-, B-,
and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
Nearly everyone has seen photos and/or videos
of the Operation Crossroads nuclear weapons tests at the Bikini Atoll from shortly
after the end of World War II. Upon the ships were penned various species of
animals - goats, pigs, rats, guinea pigs, etc. - along with radiation and mechanical
measurement equipment. The goal was to determine exposure levels to nuclear and
electromagnetic radiation, as well as to severed physical forces. That was for both
the ship and its "crew." A Fat Man type fission bomb was detonated underwater (90-foot
depth), as opposed to the air drop type. Many sources provide details of the entire
operation, including the findings. Given the extreme complexity and risks involved
in using bombs, laboratory facilities were constructed to simulate exposure from
bombs. This "Death-Ray
Chamber Tests Atom Effects" story from a 1953 issue of Popular Mechanics
magazine describes one method used by the Naval Medical Research Institute...
This is the
electronics market prediction for Belgium, circa 1966. It was part of a comprehensive
assessment by the editors of Electronics magazine of the state of commercial, military,
and consumer electronics at the end of 1965. Military systems for NATO and television
sets were a big part of the picture. Unless you can find a news story on the state
of the industry, detailed reports must be purchased from research companies like
Statista. Their website has a lot of charts on Belgium's current electronics market
showing revenue in the consumer electronics segment amounts of US$2,995M in 2023.
Reports for other countries - Japan, the UK, France, Russia, and more - are also
engineers help implement, deploy, and maintain technology in the field, driving
innovation in areas primarily unseen. The world doesn't fix itself. Doesn't set
itself up. It hardly ever changes - not until a field engineer shows up. Day, night,
cold or hot, these unsung heroes of engineering will answer the call not just because
they get paid, but because they love the job. What's not to love. While most engineers
hardly leave their offices, field engineers rarely spend any time in one. They're
the individuals who bridge the gap between theory and reality, ensuring that technologies
are seamlessly integrated into our daily lives. It's with this that we delve into
the narrative of celebrating field engineers and unravel the pivotal role they play
in the ever-changing world of innovation and progress. Field engineers are the problem
solvers, the troubleshooters, and the architects of the seemingly impossible. They're
the ones outside of the limelight who ensure those technologies keep functioning
behind the scenes..."
The 5-meter band (56-64 MHz) allocated
to U.S. amateur radio operations in the 1930s was reallocated in 1946 to television
broadcasting. However, Hams still are permitted to operate on 6-meter (50-54 MHz)
and 2-meter (144-146 MHz) bands on either side of 5 meters. Therefore, this
1935 Short Wave Craft magazine article on
non-line-of-sight communications within mountainous regions will still be of
interest, even if only from a historical perspective. There is an interesting comment
made about feeding a vertical 1/4-wave antenna from the top rather than from the
bottom (with the entire structure located 50' above the ground). No explanation
is offered as to the reason...
RF Cascade Workbook 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...
A lot of people from the era of rooftop
television antennas were/are familiar with the name Channel Master. Many of their
antennas included an integrated FM radio antenna. Very few were likely aware that
Channel Master also made radios. I don't think they ever made televisions. The fact
is, companies like Channel Master did not design and manufacture their own radios
and televisions; instead, they paid to have custom versions of existing products
branded with their names. Sears, Roebuck's Silvertone line, Montgomery Ward's Airline
products, Western Auto's Truetone line, and others are examples. This
Channel Master Model 6515 "Super Fringe" transistor radio was made by Sanyo.
1960, when this ad appeared in Electronics World magazine, was the transition period
between vacuum tubes and transistors. It was not uncommon to find two or more identical
radios bearing different company logos. Channel Master Model 6515 "Super Fringe"
radios can be found in eBay for around $30...
This 1935 article found in Short Wave
Craft magazine quotes the
Reichs-Rundfunk Gesellschaft (Zeesen) station engineer as saying that they transmitted
with only 5 kW into the farm of directional antenna arrays, and that it was
sufficient to provide what was evidently very high quality reception to many remote
regions of the world. Adolph Hitler had become "Führer und Reichskanzler" the year
before, with plans already in the works to dominate the world. Troops invaded Poland
on September 1, 1939, officially beginning the Second World War. DJC's global reach
was used extensively for propaganda during the war. "On the Shortwaves" website
has a digitized audio file of the 78 rpm greetings record that German shortwave
radio station JDC would send to American listeners upon request...
Axiom Test Equipment, an electronic test
equipment rental and sales company has published a new blog post that covers how
to find the right
AC Power Supply with enough output power for each component, device, and system
during testing. While precisely controlled AC electricity may not be needed when
testing DUTs powered by DC power, an AC supply can help simulate real-world operating
conditions. For certain DUTs, such as electric motors, a well-controlled AC power
supply can mimic the conditions in which the DUT will operate, including power supply
line fluctuations, peaks, and surges. AC power supplies can be compared by electrical
capabilities, such as maximum root-mean-square (RMS) voltage, maximum RMS current,
maximum frequency, and maximum power in volts-amperes (VA) at a given frequency.
They can also be considered by physical attributes, such as the size and weight
needed to fit an application. This is a glimpse of several AC power supplies having
sufficient output power for feeding a wide range of DUTs...
1957 was part of the heyday of the newfound
radio-in-your-car craze, and the public was voraciously consuming all the high
tech equipment it could afford. Rock and Roll music was on every teenager's mind
and many guys for the first time were able to have their own wheels and were outfitting
them with sound systems that could blast the latest works of Buddy Holley, Chuck
Berry, Elvis Presley, and Fats Domino. Those machines were the first babe magnets
used for cruising the strip on Saturday nights. Radio stations were popping up all
over the country, enabling cross-country travel with non-stop music, news, and variety
show entertainment. Ford and Chevrolet were not going to miss an opportunity, so
they delved into the high end mobile radio manufacturing business. As the quality
of broadcasts increased, noise caused by automobile ignition systems bubbled to
the top of issues affecting listening pleasure, including the distance over which
a broadcast could be received. This 1957 Radio & TV News article describes Ford's
efforts to please their customers' demands...
Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 280,000 times per year! 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...
This custom RF Cafe
electronics-themed crossword puzzle for December 3rd contains words and clues
which pertain exclusively to the subjects of electronics, science, physics, mechanics,
engineering, power distribution, astronomy, chemistry, etc. If you do see names
of people or places, they are intimately related to the aforementioned areas of
study. As always, you will find no references to numbnut movie stars or fashion
designers. Need more crossword RF Cafe puzzles? A list at the bottom of the page
links to hundreds of them dating back to the year 2000. Enjoy...
The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Engineering Workbook™. Among other additions, it now has a Butterworth Lowpass
Filter Calculator that does not just gain, but also
phase and group delay! Since 2002, the original Calculator Workbook
has been available as a free download. Continuing the tradition, RF Cafe
Espresso Engineering Workbook™ is also
provided at no cost, compliments of my generous sponsors.
The original calculators are included, but with a vastly expanded and improved user
interface. Error-trapped user input cells help prevent entry of invalid values.
An extensive use of Visual Basic for Applications (VBA) functions now do most of
the heavy lifting with calculations, and facilitates a wide user-selectable choice
of units for voltage, frequency, speed, temperature, power, wavelength, weight,
etc. In fact, a full page of units conversion calculators is included. A particularly
handy feature is the ability to specify the the number of significant digits to
display. Drop-down menus are provided for convenience. Now that a more expandable
basis has been created, I have been adding new calculators on a regular basis...
now America is crying for engineers - 50,000 of them." That is the tag line
from the "Wanted: 50,000 Engineers" article in the January 1953 issue of Popular
Mechanics magazine. The Korean War was winding down (ended in July), inflation
was low (0.7%, compared to 6-7% the last couple years, and 13% in Carter years)
and many technological breakthroughs generated a huge demand for engineers to design
products and systems to exploit and improve upon the knowledge. Here is an apt statement
from the article: "Just what is engineering? It has been called the art that makes
pure science useful." Magazines of the era were chock full of features like this
as well as advertisements attracting men - and sometimes women - to tech schools,
universities, industry, military, and government through promises of great pay and
prestige. Tests in physics, aviation, and geology are included here to help the
reader determine whether he is engineer material. In truth, they are about as useful
as the "Draw Me" type ads for artist schools...
Sam Benzacar of Anatech Electronics, an
RF and microwave filter company, has published his November 2023 newsletter that,
along with timely news items, features his short op−ed entitled "If
Extraterrestrial Life is out There, We're Closer to Finding It." In it, Sam
discusses the current state of the worldwide search for alien intelligent life.
SETI has been around for as long as I remember - established November 11, 1984.
That means SETI and related efforts have been at it for four decades, with no qualifying
signals having ever been identified (which is not to say might have been received
but not recognized). That is just a blip in time on a universal scale, so it is
no reason to demur the effort. Astronomical equipment in all wavelengths - radio,
microwave, mm-wave, infrared, visible, ultraviolet, x-ray - is advancing in sensitivity
and speed at an extreme rate. Keep in mind that prior to the Hubbell Space Telescope,
there was still a debate as to whether the entire sky, if examined closely enough,
would be filled with celestial objects. Now, telescopes operating outside the optical
range with fine resolution are detecting stars and galaxies hiding behind regions
of interstellar gas that blocks light in the red-to-blue visual spectrum. A civilization
would need to have been emitting electromagnetic signals for much longer a time
than the 150 years or so of those originating from the Earth in order for the probability
of something intercepting our position in the universe with enough power to detect...
I remember in one of my circuits classes
in college when the
gyrator was introduced, and I thought it was an ingenious invention. The gyrator
circuit, implemented with an opamp and a couple resistors and capacitors, changed
its measured impedance type from that of a capacitance to that of an inductance.
That is, its impedance represents an R + jX Ω format. Frequency limits
are imposed by a combination of the self-resonant frequencies of the resistors and
capacitors as well as the GBWP of the opamp, and power handling is primarily limited
by the opamp's voltage and current capabilities. You might ask why, with all those
constraints on its use you would even want to use a gyrator circuit? The answer
is that within its limitations, the gyrator often represents a less expensive and
more compact version of a physical inductor. This is particularly true with ICs
where, unless it is a MMIC operating in the tens of gigahertz region, there is no
space available on the die for a printed metallic inductor with enough inductance
to be useful. Any inductors would need to be mounted off-chip on the PCB with I/O
pins interfacing to the IC. Gyrators...
"China announced it has completed the initial
set-up of its first
high-orbit satellite communication network, which is expected to provide a swift
satellite internet service within its borders and in several belt and road nations.
The Chinese project could be an alternative to SpaceX's Starlink, according to a
Beijing-based communications expert. China Aerospace Science and Technology Corporation,
the parent company of the satellite operator, said the network would provide internet
service for industries ranging from aviation and navigation to emergency services
and energy, state news agency Xinhua reported on Monday. The network includes high-throughput
satellites ChinaSat 16, 19 and 26. According to the network operator, the satellites
cover China as well as parts of Russia, Southeast Asia, Mongolia, India, and the
Indian and Pacific Oceans - encompassing much of the area included in the Belt and
Road Initiative, Beijing's strategy to boost infrastructure links and connectivity
across Asia, Africa and Europe..."
National Radio Institute (NRI) was one of the first country-wide organizations
to offer formal electronics training both as classroom and as self-study courses.
Magazines were filled with offers to train men in what was an exciting new career
field. The drums of war were beating in the background in Europe and the South Pacific
by December 1940 when this article appeared in National Radio News, and
the U.S. military was gearing up for what was sure to be an eventuality. Three months
earlier, the Tripartite Pact united Japan, Italy and Germany to formalize the Axis
Powers, and Hitler's forces had invaded Western Europe. The push was on to train
a large number of engineers and technicians to handle communications and control
systems for Army and Navy forces. It is always interesting to read pieces penned
at the time events were unfolding, rather than after having been filtered through
the worldview of subsequent authors...
With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
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...
Ask anyone who has ever asked me to fix
something electrical or electronic and they will tell you my motto on such things,
born of extensive experience, is that the vast majority of the problems are caused
by poor electrical contacts of one form or another. The culprit can be a dirty or
broken connector, a cold or broken solder joint, a dirty potentiometer (contact
between wiper and resistor), etc. I have repaired everything from ceiling lights,
to car starters, to kitchen appliances, to large screen TVs simply by finding and
repairing connections. When possible, I always do a final cleaning with isopropyl
alcohol and then spray with a silicon contact protector. This
Contact Shield product from Channel Master would be a good choice. I can honestly
say I cannot think of a single instance where the restored connection failed again.
Of course sometimes it is not that simple, but enough that my initial approach to
troubleshooting - unless a broken or burnt component is immediately apparent - is
to unplug and inspect connectors (then plug-unplug-plug to wipe contacts clean),
flip switches on-off a few times while applying various directional forces (left-right,
up-down, twisting), tugging on wires, etc. People's eyes light up in amazement when
a sophisticated piece of equipment starts working after doing so. Then, I me