The
bridged-T filter is a quick-and-dirty construct used to notch out a specific
frequency that is interfering with a desirable frequency or band of frequencies.
It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor
"bridging" a pair of series capacitors having a resistor to ground between them,
or, if preferred, a capacitor bridging one or two inductors. A convenient
nomogram (aka nomograph) is provided by the author in this 1964
Radio-Electronics magazine article for quickly selecting values, which was
a very popular design aid in the pre-calculator era. A slide rule could be used
to calculate a range of values when only a single variable was in play, but
juggling more than one variable (component value) was greatly aided by a
multivariable nomograph. Truth is nomographs can still...
Television, in 1955, was still a relatively
new phenomenon to many - maybe even most - people. According to multiple sources,
the portion of American households with a TV set went from under 20% in 1950 to
nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering
the expense of even a minimal TV. The technology was not even available commercially
when most people were born, so the rush to join in on the craze was akin to the
mass adoption of cellphones in the 1990s. "Carl &
Jerry" creator John Frye used his pair of electronics-savvy teenagers to help
make the "magic" behind recreating a moving picture on a CRT miles away from where
it was created. Water flowing through a garden hose has often been employed as an
analogy for current flowing through a wire to explain electricity to laymen and
beginning students of the craft. Here, it is not water flowing through the hose
but water leaving the hose and flowing through the air that serves to represent
an electron stream travelling from the electron gun to the phosphor-coated glass
front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms
are i
"The
RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its
traditional focus on mobile and infrastructure to drive innovation in the automotive
sector. Each segment within the industry presents unique dynamics and growth opportunities.
After a difficult 2022, the smartphone market is showing signs of recovery, with
expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024.
The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though
it may face stagnation due to market saturation and pricing pressures. This
market is expected to expand, with the 2027 launch of RedCap..."
I'm having a hard time writing this with
my eyes rolled back in my head. The last time I experienced this level of overwhelmedness
was probably the third or fourth week of my feedback and control class at UVM. Even
though
electricity and magnetism shares many complimentary and parallel concepts, for
some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators,
etc., has always caused brain freeze. Maybe it has to do with an ingrained bias
due to my earliest dealings with circuits being from a technician background before
earning an engineering degree. The equations of electric fields and magnetic fields
are very similar so that helps lower...
Temwell is a manufacturer of
5G wireless communications filters for aerospace, satellite communication, AIoT,
5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory,
transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist
since 1994, we have posted >5,000 completed spec sheets online for all kinds
of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass,
bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners,
splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete
coil & inductor solutions.
Here we are with another set of three "What's
Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics
magazine. As usual, those challenges provided by Jack Darr are the purview of television
servicemen of the era. The photo shown of the problematic CRT display looks like
a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently
the artifacts are readily identifiable to an initiated few. The Forbidden Current
Path circuit answer is not what I thought it would be. I maintain that whether my
answer or the designer's answer is correct depends on the physical...
"A new
world record
in wireless transmission, promising faster and more reliable wireless communications,
has been set by researchers from UCL. The team successfully sent data over the air
at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed
is up to 9,380 times faster than the best average 5G download speed in the UK, which
is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more
than five times higher than the previous wireless transmission world record. Typically,
wireless networks transmit information using radio waves over a narrow range of
frequencies..."
Sputnik refers to the first series of satellites
launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The
launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history,
heralding the dawn of the Space Age and sparking a fierce technological competition
known as the Space Race between the United States and the Soviet Union. This satellite,
the world's first artificial one, orbited Earth at an altitude of roughly 215 to
939 kilometers and broadcast a radio signal that astonished the world, particularly
in the United States, where it spurred rapid advancements in aerospace and scientific
research. The successful launch of Sputnik was an achievement that was years in
the making, involving a combination of visionary planning, political motives, and
intensive engineering by some of the Soviet Union's top scientists.
Blog: Air Quality
Measurements with Particle Counters
Transcat | Axiom Test Equipment, an electronic
test equipment rental and sales company has published a new blog post entitled "Provide
Essential Air Quality Measurements with These Particle Counters" that covers
how particle counters can provide essential measurement capabilities that can help
avoid contamination and support high manufacturing yields. These measurement tools
can detect and measure microscopic particles suspended in air that can contaminate
the most carefully planned manufacturing lines. Air particle counters can be designed
for various...
In 1958, most people were not accustomed
to seeing the now-familiar maps plotting
sinusoidal
courses of satellites across the face of the earth. It had only been in October
of the previous year that any object other than the moon was in orbit around our
home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds
enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright
Brothers flew their fragile craft at Kitty Hawk, electronics communications and
scientists worldwide hopped aboard the satellite train. This article from a 1958
issue of Radio & TV News magazine provided insight into the construction
and flight characteristics...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
What were some of the
top issues of the radio and television industry half a century ago? In a lot
of respects, the same things that concern it today. A ready supply of service technicians
was a concern that was taken seriously by the Electronics Industry Association (EIA).
While there are not many local repair shops for electronics products nowadays, there
is still a huge demand to techs who are willing and able to do the hard work of
keeping the world's communication infrastructure operational - climbing towers,
repairing cell equipment. Now, as then, good pay, job security, benefits, and respect
for the job being done were at the top of...
In a parallel to the traditional test setup
of signal generation and signal acquisition, RIGOL Technologies announced today
the latest additions to its portfolio of
performance measurement equipment with the introduction of the DG5000 Pro Series
Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level
performance to RIGOL's respected line of high-resolution oscilloscopes, while the
DG5000 Pro generators do the same for the company's capable Pro Series arbitrary
waveform generators...
When selecting articles for posting here
on RF Cafe, I like to include ones that are directed toward newcomers to the field
of electronics as well as for seasoned veterans. This piece from a 1958 issue of
Radio & TV News magazine entitled "Basic Electronic Counting," is a
prime example in that it introduces the concept of binary numbers. We've all been
there at some point in our careers. A big difference between now and when this article
appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout
[sic] octal and hexadecimal. Only those relatively few people designing and working
with multimillion dollar, vacuum tube-based digital computers installed in universities,
megacorporations, and government research facilities had ever dealt with digital
numbers. The earliest example of powers of two I remember was back in junior high
school. It had to do with a
"Every invention begins with a problem -
and the creative act of seeing a problem where others might just see unchangeable
reality. For one 5-year-old, the problem was simple: She liked to have her tummy
rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell
asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy
bear that would rub her belly for her,' explains Stephanie Couch, executive director
of the Lemelson MIT Program. Its mission is to nurture the
next generation of inventors
and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right
resources and encouragement. 'Invention doesn't come from some innate genius, it's
not something that only really..."
Mechanical filters of the type described
in this 1969 Electronics World magazine article are yet another example
of the genius of some people. They are actually a form of electromechanical device
in that the applied electrical signals are first converted into mechanical signals,
followed by resonant mechanical elements that discriminate according to frequency,
and finally a conversion back to an electrical signal is made. It is fundamentally
the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly
different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents
the basics of mechanical filters in this brief write-up...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
Attempts at making an
electronically printed facsimile (fax) of an original document at a location
distant from the source have been around for quite a while. As mentioned by
Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse
had a crude working device for printing messages on paper even before his eponymously
named code of dots and dashes became famous in 1837. A couple decades earlier, a
fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of
electronically printing images and text on paper using a conductive solution and
a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known
figure in the electronics world, but in his day...
"Researchers have discovered how the 'edge
of chaos' can help electronic chips overcome signal losses, making chips simpler
and more efficient. By using a metallic wire on a semi-stable material, this method
allows for long metal lines to act like superconductors and amplify signals, potentially
transforming chip design by eliminating the need for transistor amplifiers and reducing
power usage. A stubbed toe immediately sends pain signals to the brain through several
meters of axons, which are composed of highly resistive fleshy material. These axons
operate using a principle known as the 'edge of chaos,' or semi-stability, enabling
the swift and precise transmission of information..."
The January 1969 issue of Electronics
World magazine published an extensive list of
Japanese company trade names and their addresses. Many of them went out of business
or were bought by other corporations long ago, as occurs in all countries. "Aiwa"
is listed twice, but that might have been a legitimate duplication due to separate
locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape
deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and
my first "real" stereo receiver was made by Sansui. I remember the line in "Back
to the Future 3" where Doc Brown, having time-travelled from 1955, makes a
disparaging remark about a circuit in the DeLorean failing because of it being labeled
"Made in Japan." Marty counters...
• ARRL Defends
902-928 MHz Amateur Radio Band
• FCC's
Auto Safety Spectrum Rules
• $5M in U.S.
Chips Act Money to Metrology Projects
• U.S. State Department Approves
Surveillance Radar System Sale to Romania
•
5G Americas ITU IMT-2030 Vision for 6G White Paper
John Redman Coxe was a prominent American
physician, scientist, and innovator born on September 20, 1773, in Philadelphia.
Coxe's intellect and curiosity drove him toward an illustrious career in both medicine
and early scientific exploration, which included experimentation in electrochemistry.
He graduated with a degree in medicine in 1794, setting the course for his lifelong
journey into medicine and early scientific innovation. Coxe broadened his approach
to medicine and science, inspiring him to explore the convergence of scientific
methods and practical applications. John Redman Coxe is most remembered not only
for his contributions to medicine but also for his interest in experimental physics,
particularly in the field of electrochemistry...
TotalTemp Technologies has more than 40
years of combined experience providing thermal platforms.
Thermal Platforms are
available to provide temperatures between -100°C and +200°C for cryogenic cooling,
recirculating & circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
When I saw this 1966 Radio-Electronics
magazine article entitled, "Vibration
and Shock - Nature's Wrecking Crew," for some reason the first thing I thought
of was "The Wrecking Crew," that anonymously played the music for a huge number
of popular singers - mostly those without prominent bands of their own during the
1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential
deleterious effects of vibration on electronics was in the 1970s, with airborne
receivers and servos in my radio controlled model airplanes. Even though they were
transistorized, vibration from glow fuel engines could wreak havoc with potentiometers
in servos and solder joints everywhere, including battery packs. I remember seeing
the control surfaces jitter...
You don't see jobs advertisements like this
anymore. Here is an ad that appeared in the the July 1944 edition of QST
(the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon
Manufacturing Company (now just Raytheon Company), looking for
vacuum tube design, test, and processing engineers. Licensed amateur radio operators
were in high demand during the war years because of their knowledge and enthusiasm
for electronics and wireless communications. I hope you didn't come to this page
hoping to really find a tube designer job available. Of course, there are still
vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...
The "carborundum"
signal detector, an innovative device developed by engineer General H. H. C. Dunwoody
in the early 20th century, represents a significant advancement in radio technology,
particularly in the context of crystal detectors used for receiving radio signals.
This device utilized the unique properties of silicon carbide, also known as carborundum,
which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection
between Dunwoody and the material lies in the application of carborundum as a semiconductor
in radio signal detection. The operational theory of the carborundum signal detector
is rooted in its ability to rectify alternating current (AC) signals. When radio
waves, which are essentially electromagnetic waves...
"Researchers have created a cutting-edge
structure by placing a very thin layer of a special insulating material between
two magnetic layers. This new combination acts as a quantum anomalous Hall insulator,
significantly broadening its potential use in developing ultra-efficient electronics
and innovative solar technology. A Monash University-led research team has found
that a structure featuring an ultra-thin topological insulator, sandwiched between
two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous
Hall insulator. This heterostructure opens the door to ultra-low energy electronics
and even topological photovoltaics..."
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Receiving information wirelessly or even
over a wire is taken for granted today, but 80 years ago it was considered a "miracle
of God" - that's what Alexander Graham Bell called it. Some regarded radio as being
of the devil. The same is true of today's omnipresent communications - some consider
it a blessing while others call it a curse. I'm somewhere in the middle. In 1934
when this
Radio
News & Shortwave magazine was published, the telecommunications world
was in its heyday of growth with a reported 17 million listeners of AM radio (no
FM yet). Radio dealers and servicemen were gearing up for customers with unbridled
enthusiasm for the fledgling commercial broadcast industry's offerings. Even in
the midst of the Great Depression, people were joining in on the wireless craze
in large numbers, and amateur radio operators were almost feared for their awesome
ability...
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 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, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
Operators didn't know how good they had it
in 1967. The story talks about the nuisance of having to sift through "hundreds"
of satellites, old rockets, and assorted space junk" in order to search for and
track potentially threatening objects in orbit around the Earth. We're into the
millions of objects in 2019, and the potential threats are infinitely larger. The
article mentions the use of an
AN/FPS-16 radar operating in C-band to detect and measure the
returns and then the results were analyzed in an attempt to determine the character
of the object. Open air test sites and anechoic chambers were used to measure the
radar cross section and characteristic signature of many shapes to populate a database
of recognizable returns that would help to determine whether the space object was
friend or foe...
Here are a couple more
electronics-themed comics from the March 1967 issue of Popular Electronics
magazine for your TGIF enjoyment. The comic on page 100 especially appeals to me since
I am finishing the installation of a Channel Master CM-5020 antenna. It has been a long
time since I installed a traditional style TV antenna - about 40 years ago when I put
a Radio Shack antenna on the roof of my mother's house. The entire 109" long by 100"
wide antenna, including mounting hardware, weighs only 11.5 pounds and presents
a wind resistance of 30 pounds. This is Channel Master's best antenna...
Here is Part 14 of a series entitled
"The
Saga of the Vacuum Tube," by Gerlad Tyne, that appeared in Radio News magazine
in 1944. Part 1 was printed in March 1943, and Part 22, the final chapter,
was published in April 1946. It could have been a stand-alone book. If I manage
to be able to buy issues with some of the other parts, those will be posted as well.
You might be aware of the origins of the amplifying vacuum tubes, beginning with
the accomplishments of Dr. de Forest and his Audion. As with most new technologies,
progress moved very rapidly once other researchers glommed on to the concept. Here,
Mr. Tyne discusses the development of the "Kenotron," "Pliotron," "Dynatron,"
and "Magnetron," by Drs. Langmuir, Dushman and Hull of the General Electric Laboratories,
during the years 1913 to 1921.
Well, at least I know now why my efforts
to sell things usually don't work out too well. A salesman I ain't - neither by
c1947 standards or by contemporary standards. I have a hard time even giving things
away based on the low response rate on notifications for winning free books each
month. My score on this "Biz
Quiz" in Radio-News magazine was around 50% (south of, actually), but
that was probably due to being subconsciously biased to answer what I thought the
creator would expect for a good salesman. It would probably be embarrassing to have
a professional assessment of my true personality, assuming that professional is
not a quack with an agenda...
The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Among other additions, it now has a Butterworth
Bandpass Calculator, and a Highpass 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...
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 225,000 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. If you need your company
news to be seen, RF Cafe is the place to be...
It's Friday and therefore time for a
pop quiz (does that line give you a fearsome flashback to your school
days?). Whenever I have one available, I like to post quizzes from vintage
electronics magazines, like this one on diode circuit functions. Many of them
have vacuum tubes, but this one has the solid state symbols so the under-40
folks won't be uncomfortable. Your job is to look at the diode circuits and
match them with the names of the functions. A couple of them will probably cause
some head scratching, but you should do well. Don't jump to a quick conclusion
with circuit "E" without noticing the two signal generators attached to it...
Even though my fingers stop working when
exposed to temperatures below freezing, I love the northern climate - four full
seasons, snow, iced-over lakes, migrating birds, fiery autumns, cool summers, the
whole experience. Having the option of not participating in the cold outdoor environs
is what makes it good. However, the
U.S. Army Signal Corps guys pulling duty in Alaska during World
War II did not have that luxury. As told by radio engineer Major Colvin in
this story from a 1945 edition of ARRL's QST magazine, winter life in Alaska at
-40° was a real challenge. It was a world where Prestone antifreeze froze, the sun
shone only a few hours a day, vehicles had to be left running 24/7 or risk not being
able to be re-started, and mile-long treks between buildings was common. There were
no snowmobiles. The success of the communications station...
It had been only a little over a decade since
the transistor was invented when this article appeared in the August 1959 edition
of Popular Electronics. Transistors were still a mystery to most people,
including engineers, technicians, and hobbyists. Author James Butterfield takes
a unique approach in presenting the material by writing it as a dialog between an
instructor and a student. If you are also
new to transistors, this will be worth your while to read. The
basics will never change. As an aside (and mentioned in the article), while still
a technician I had a manager one time who actually told an engineer working for
him that a transistor could be made by soldering two diodes together and using the
center node as the base connection...
Here is a timeless subject for anyone routinely
subject to exposed high voltages. Most RF Cafe visitors already know that technically,
it is the amount of electric current through the body that determines severity of
electric shock, not the voltage. However, we also know that voltage
does play a role because a certain voltage, per Ohm's law, is needed to induce
a commensurate current. The body's resistance is determined primarily by perspiration
(salt and water) and the path between contact points (e.g., across adjacent skin
areas or hand-to-hand via the heart). MIL-STD-883 and JEDEC* have decided that the
proper Human Body Model (HBM) for testing semiconductor...
After reading so many articles about vintage
vacuum tube radios and TVs in the older electronics magazines, it makes me appreciate
the relatively trouble-free products we enjoy today thanks to semiconductor technology.
Monthly columns were filled with troubleshooting advice and tips for making modifications
to factory designs that will enhance performance and/or reduce the likelihood of
premature failure. Although many tubes did outlast the lifetime of the chassis in
which they were installed, it was pretty much a given expectation that sooner or
later some
tubes would need to be replaced - that is why they were the only components
that came installed in sockets for easy removal and installation. Fortunately, because
of the huge volumes produced, prices were relatively low, and many stores - not
just electronics shops - had self-serve...
Using
charts and nomographs to solve calculations is not as common in today's world
of portable high-powered computers as it was when computers used vacuum tubes or
even mechanical gears. One exception might be the Smith chart, especially in the
lab or field. You can plug numbers into a programmable calculator or tablet app,
but having the solution presented in the form of a number gives you only that -
a number. That's usually good enough, but if you are doing troubleshooting or tweaking
a design, being able to see how the value got to be what it is by seeing what's
around it can be very helpful. The Smith chart is a particularly good example when
watching the complex impedance point move around...
The December 13, 1965 issue of Electronics
magazine was largely dedicated to assessing
Japan's status in the electronics industry. Japan, with the help of the United
States, made a remarkable recovery from defeat during World War II to have
become an emerging power in electronics. "Made in Japan" labels on products had
transformed from being the butt of jokes because of pre-war low quality products
to representing assurance of low cost, high functionality and high value products.
It still does to this day. The Japanese people have worked hard to acquire the world's
respect as smart innovators and hard workers, and have been sure to maintain manufacturing
bases within their borders. When you read this article, be prepared for a few dated
terms like a "Kita" diode ...
The old-time radio broadcasts available on
the Internet are obviously recorded version of shows made long ago. However, back
in the day those shows were
originally performed live in front of microphones and recorded
in a broadcast studio. With a cast of two or three or even more, the actors would
voice their lines with as much talent and effort as those performing for movies.
The crew usually included a group of people responsible for creating background
sound effects like horses running, car horns tooting, airplanes buzzing by, and
dogs barking. All was done real-time with split-second timing required to pull it
off and sound convincing. Radio audiences were unaware of all the work required
as they sat intently listening to the Adventures of the Lone Ranger and The Shadow.
Behind the scenes were dozens of engineers and technicians tending local radio broadcasting
equipment and all-important telephone landlines used for synchronizing stations
across the country...
This
crossword puzzle from a 1958 issue of Popular Electronics magazine
is a little trickier than some because it uses abbreviations rather than full words.
Not everyone uses the same abbreviation, so some answers are a bit more subjective.
For instance, many people abbreviate the word 'transformer' as 'xfmr,' while others
use 'trans' or 'trr' (I use xfmr). Where you really have to be careful, though,
is with evolutional changes in terminology as is the case for frequency units, where
'cps' was most often used in 1958 rather than today's 'Hz." Enjoy.
Even with the domination of LED, plasma,
and LCD displays, there are still a whole lot of cathode ray tubes (CRTs) on the
job. Hobbyists workbenches are filled with them for sure, but design and manufacturing
facilities still have huge inventories of test equipment with CRTs, and a lot of
computer equipment on the production line with CRTs sitting in racks. LED, LCD,
and plasma displays all have their own claims to genius on the part of their designers,
but cathode ray tube designers - and the designers of the driver circuits - deserve
special recognition. Consider the physics and materials involved: glass, phosphor,
magnetics, thermonics, electrostatics and electrodynamics, relativity (electrons
traveling at relativistic speeds gain mass, requiring stronger deflection
fields)...
If you think electric cars are a new idea,
read on. I saw this article, "The Amazing
Collection in Thomas Edison's Garage," on another website (the equivalent of
Jay Leno's Garage from a century ago) and thought it was a special report,
but then I noticed it was actually a paid promotion. So, I contacted the company,
B.R. Howard & Associates, Inc., asking for permission to re-post it in its entirety
on RF Cafe. They kindly agreed to it. Per their mission statement: "Our company
focuses on the conservation of historic artifacts in accordance with the principles
defined in the American Institute for Conservation of Historic and Artistic Works
Code of Ethics and Guidelines for Practice." Their portfolio of projects include
transportation, industrial, scientific, military, and archeological artifacts. An
opportunity to help support the preservation effort is provided...
This is a great
electronics-themed comic from a February 1972 issue of Popular Electronics.
It encompasses the essence of the stereotypical salesman ruse, especially in that era
when people were sure that electronics repair services were out to rip them off by selling
unneeded services and replacement parts. Aspiring TV technicians who couldn't grasp the
technology moved on to working as mechanics in a garage, poking tiny holes in brake lines
to scare owners into paying for complete braking system rebuilds. I usually like to post
multiple comics on each page, but at the moment only this one is available... |